JP2019535498A - Nanocapsules containing liquid crystal media - Google Patents

Abstract

The present invention relates to nanocapsules comprising a mesogenic medium, a polymer shell and one or more additives, their use in electro-optical devices, and a method for producing the nanocapsules.

Description

  The present invention relates to a nanocapsule comprising a mesogenic medium, a polymer shell and one or more additives described below, its use in an electro-optical device, and a method for producing the nanocapsule.

  Liquid crystal (LC) media are widely used in liquid crystal displays (LCD), particularly electro-optic displays with active matrix or passive matrix addressing, for displaying information. In the case of active matrix displays, individual pixels are usually addressed by integrated non-linear active elements such as transistors, eg thin film transistors (TFTs), whereas in the case of passive matrix displays, individual pixels are Usually, it is addressed by a multiplexing method as is known from the prior art.

  TN (“twisted nematic”) type LCDs are still commonly used, but this has the disadvantage that the viewing angle dependence of contrast is strong. In addition, so-called VA (“vertically aligned”) displays with a wider viewing angle are known. Furthermore, OCB (“optically compensated bend”) displays are known which have LC layers based on the birefringence effect and which have a so-called “bend” alignment. Also known are so-called IPS (“in-plane switching”) displays, which include an LC layer between two substrates, with the two electrodes being disposed on only one of the two substrates. And preferably have an interdigitated comb structure. In addition, a so-called FFS (“fringe-field switching”) display is provided, the display comprising two electrodes on the same substrate, one electrode being structured in a comb-like manner and the other electrode being Not structured. This produces a strong, so-called “fringe field”, ie a strong electric field near the electrode edges and an electric field having both a strong vertical and a strong horizontal component throughout the cell.

  A further development is the so-called PS (“polymer suspended”) or PSA (“polymer suspended alignment”) type display, for which the term “polymer stabilized” is sometimes also used. In the same display, after adding a small amount, eg 0.3% by weight, typically less than 1% by weight of one or more polymerizable compounds, preferably a polymerizable monomer compound, to the LC medium and filling the display with the LC medium. The polymerizable compound is polymerized or cross-linked in situ, usually by UV photopolymerization, optionally applying a voltage to the electrodes of the display. The polymerization is performed at a temperature at which the LC medium exhibits a liquid crystal phase, usually at room temperature. It has been found that it is particularly suitable to add polymerizable mesogenic compounds or liquid crystal compounds, also known as reactive mesogens or “RMs”, to the LC mixture.

  In addition, displays based on polymer dispersed liquid crystal (PDLC) films have been described. See for example US Pat. No. 4,688,900 (US 4,688,900). In such a PDLC film, usually, micrometer-sized droplets (microdroplets) of the LC medium are randomly distributed in the polymer matrix. The LC domains in these phase separation systems have a size that can result in strong light scattering. PDLC membranes are usually manufactured using polymerization induced phase separation (PIPS) methods, and phase separation is induced by the reaction. Alternatively, PDLC membranes can be made based on temperature induced phase separation (TIPS) or solvent induced phase separation (SIPS). In addition to PDLC films, so-called polymer network liquid crystal (PNLC) systems are known, in which polymer networks are formed in a continuous LC phase.

  In addition, micrometer-sized encapsulated LC materials (microcapsules) for use in displays are described, wherein the microcapsules are LC materials using an immiscible binder, such as polyvinyl alcohol (PVA), that functions as an encapsulating medium. It is manufactured by forming an aqueous emulsion. See, for example, US Pat. No. 4,435,047 (US 4,435,047).

  A method for microencapsulation of electro-optic fluids using polymerization and crosslinking of at least partially solubilized polymer precursors is described in WO 2013/110564 (WO 2013/110564 A1).

  In addition to the display type described above, an LCD including a layer containing nanocapsules has recently been proposed in which the nanocapsules include liquid crystal molecules. For example, the construction of an LCD device arranged with a layer comprising such nanocapsules in a so-called buffer material is described in US 2014/0184984 A1 (US 2014/0184984 A1).

  Another LCD device with nanocapsules disposed therein is described in US 2012/0113363 A1.

  Kang and Kim in Optics Express, 2013, Vol. 21, pp. 15719-15727 describes an optically isotropic nanoencapsulated LC for use in displays based on the Kerr effect and in-plane switching. Add nematic LC to a mixture of shell-forming polymer dissolved in aqueous solution and nonionic polymer surfactant that functions as water-soluble emulsifier and PVA to form nanoemulsion, heat nanoemulsion to cloud point and stir Thus, nanocapsules having an average diameter of about 110 nm are produced by phase-separating the PVA around the LC nanodroplets and cross-linking the polymer shell with a cross-linking agent such as dialdehyde. Furthermore, a coating solution containing the manufactured LC nanocapsules, hydrophilic PVA as a binder and ethylene glycol as a plasticizer is described.

  International Publication No. 2009/085082 (WO 2009/085082 A1) describes porous nanoparticles composed of cross-linked polymers, which nanoparticles act like a sponge that absorbs LC substances. It can be used as a phase retardation film in LCDs.

  There is a need in the art for nanocapsules with improved and appropriately tunable electro-optic and physical properties, particularly for use in electro-optic devices. Furthermore, there is a need for an improved and easy method that provides ease of manufacture of such nanocapsules. In addition, there is a need for compositions useful in this method.

  The object of the present invention is therefore to provide improved nanocapsules comprising mesogenic media and having favorable properties. A further object is to provide an improved method for producing nanocapsules containing mesogenic media, where the compositions and materials used in this production allow for favorable performance during encapsulation. And further with it, benefits are provided in the resulting nanocapsules. It is an object to provide nanocapsules that allow a reduction in operating voltage, especially in electro-optic applications, and to provide methods and improved compositions that contribute to obtaining the nanocapsules, further comprising Beneficial properties such as excellent dark state, conveniently low hysteresis and suitability for deposition can be obtained simultaneously. The mesogenic medium contained in the nanocapsules has a suitably high Δε and high electrical resistance and favorable values for a suitably high Δn and electro-optic parameters, and more particularly provides a relatively low rotational viscosity and favorable reliability. It is a further object to provide such nanocapsules. Furthermore, it is an object that the mesogenic medium contained in the nanocapsules exhibits a broad and stable LC, in particular a nematic phase range, a low melting point and a relatively high clearing point and a suitably high voltage holding ratio. In particular, the threshold voltage is suitably low, the response time is advantageously short, the low temperature behavior is improved, the operating characteristics at low temperature are improved, and the temperature dependence of electro-optic parameters such as threshold voltage is minimal, It is a further object to provide stable and reliable nanocapsules useful for light modulation elements and electro-optic devices having high contrast and composite systems comprising the nanocapsules and a binder. It is a further object to provide nanocapsules and composite systems in light modulation elements and electro-optic devices that have a advantageously wide viewing angle range and are substantially insensitive to external forces such as touching. Further objects of the present invention will be readily apparent to those skilled in the art from the following detailed description.

  These objects are solved by the subject matter defined in the independent claims, while preferred embodiments are described in the respective dependent claims and are further described below.

  The present invention provides the following items, including in particular the main aspects, preferred embodiments and specific features, which each alone and in combination contribute to the solution of the above object and ultimately provide further advantages: To do.

A first aspect of the present invention is a method for producing nanocapsules, the method comprising:
(A)
(I) Formula I
R-A-Y-A'-R 'I
[Where:
R and R ′ are, independently of each other, F, CF ₃ , OCF ₃ , CN and straight or branched alkyl or alkoxy having 1 to 15 carbon atoms or straight chain having 2 to 15 carbon atoms. It represents a group selected from linear or branched alkenyl, wherein the alkyl, alkoxy or alkenyl is unsubstituted or substituted, and optionally mono- or polysubstituted by or halogen is monosubstituted by CN or CF _3, One or more CH ₂ groups are, in each case, independently of one another, in a manner such that the oxygen atoms are not directly bonded to one another, —O—, —S—, —CO—, —COO—, —OCO—, May be replaced by -OCOO- or -C≡C-
A and A ′ are independently of each other -Cyc-, -Phe-, -Cyc-Cyc-, -Cyc-Phe-, -Phe-Phe-, -Cyc-Cyc-Cyc-, -Cyc-Cyc- A group selected from Phe-, -Cyc-Phe-Cyc-, -Cyc-Phe-Phe-, -Phe-Cyc-Phe-, -Phe-Phe-Phe- and their respective mirror images, wherein Cyc is trans-1,4-cyclohexylene, in which one or two non-adjacent CH ₂ groups may be replaced by O, Phe is 1,4-phenylene, Phe In which one or two non-adjacent CH groups may be replaced by N and Phe may be replaced by one or two F;
Y is a single bond, —COO—, —CH ₂ CH ₂ —, —CF ₂ CF ₂ —, —CH ₂ O—, —CF ₂ O—, —CH═CH—, —CF═CF— or —C Shows ≡C-]
A mesogenic medium comprising one or more compounds of (ii) and (ii) a composition comprising one or more polymerizable compounds;
(B) using one surfactant to disperse the composition as nanodroplets in the aqueous phase;
(C) polymerizing the one or more polymerizable compounds to obtain nanocapsules each including a polymer shell and a core containing the mesogenic medium,
Here, in addition, one or more additives,
-Before the polymerization, in addition to the composition or the nanodroplets;
And / or a method of adding to the resulting nanocapsules is provided.

  Surprisingly, the method of the invention comprising a combination of steps (a) to (c) as described above, wherein one or more additional additives are further added to the nanodroplets before polymerization or nano By providing a method for inclusion in droplets and / or addition to the resulting nanocapsules, it may be possible to produce nanocapsules containing mesogenic media in an improved and surprisingly easy way It was found. The nanocapsules that can be obtained from this method exhibit advantageous properties with regard to their physical and chemical attributes, in particular with regard to their electro-optical properties and their compatibility in light modulation elements and electro-optical devices.

  The additive can be added to the composition or nanodroplet before the polymerization step is performed. Alternatively or in addition, it is also possible to add additives after polymerisation has been performed to form nanocapsules.

  According to one embodiment, one or more additives are added to the resulting nanocapsules in step (d) after the polymerization according to step (c).

  In one embodiment, two or more surfactants are used in step (b). This is the case when the additive added is a surfactant. For example, it may be preferred to use two surfactants to adjust the droplet size and the interfacial properties of the droplets and the capsules formed. It is also possible to add one or more further additives, ie in addition to the surfactant, before, during or after the formation of the nanodroplet dispersion according to step (b). For example, agents that affect wettability, solubility, viscosity or osmotic pressure may be used. In particular, a hydrophobic agent or a hydrophobizing agent can be further added, preferably before, during or after the step (b).

  In a preferred embodiment, the one or more additives added in step (d) are one or more surfactants. The added additives, preferably the surfactants, may be selected such that they match or are compatible with the surfactants used in step (b), and furthermore they may be the same . However, in step (d), an additive, preferably a surfactant, is more freely selected and used, that is, selected and used generally independently from the surfactant utilized in step (b). Is also possible and is preferred in many cases.

  Surprisingly, the use of the additive from step (b) is added either before the polymerization or by step (d), and optionally before or after the polymerization It has been found that when used in combination, nanocapsules can be provided that allow favorable electro-optic performance with reduced operating voltage. The combined use of the additives and surfactants described above can provide additional benefits at the same time, especially for achieving excellent darkness, high contrast ratio, conveniently low hysteresis and film suitability. Can contribute.

  The amount of additive added before polymerization or added in step (d) to the composition provided in step (a) is preferably not more than 5% by weight, more preferably 2.5% by weight. Hereinafter, it is more preferably 1% by weight or less. In one embodiment, the amount of additive relative to the composition provided in step (a) is particularly preferably in the range 0.05% to 1% by weight, even more preferably 0.1% to 1% by weight. Is set in the range.

  Another aspect of the present invention is a nanocapsule, each comprising a polymer shell, a core containing a mesogenic medium comprising one or more compounds of formula I as described above and below, and one or more additives About.

  Advantageously, nanocapsules that are improved in terms of lowering the operating voltage, in particular in electro-optic applications with the additional beneficial properties described above and below, are obtained or can be obtained by carrying out the method according to the invention It was recognized that. In this respect, a decrease in operating voltage can in turn advantageously lead to a decrease in temperature dependence of electro-optic switching.

  In one embodiment, one or more additives are included in the polymer shell. In addition or alternatively, one or more additives may be included in the core containing the mesogenic medium. Particularly preferably, the additive or at least a part thereof is present at or near the interface between the shell and the core. It is preferred that the additive can function as a surfactant.

  Preferably, the nanocapsules contain additives in an amount of 5 wt% or less, more preferably 2.5 wt% or less, even more preferably 1 wt% or less, based on the entire capsule composition. In one embodiment, the amount of additive based on the whole capsule composition is particularly preferably set in the range of 0.05% to 1% by weight, even more preferably in the range of 0.1% to 1% by weight. Is done.

  In a further aspect, the present invention provides a method for producing a nanocapsule according to the present invention comprising (i) a core containing a polymer shell and a mesogenic medium comprising one or more compounds of formula I as described above and below. Provided is a method comprising providing nanocapsules each comprising: (ii) adding one or more additives to the provided nanocapsules.

In another aspect of the present invention, a composite manufacturing method comprising:
-Polymer shell,
Providing a core containing a mesogenic medium as described above and below and optionally nanocapsules each comprising one or more additives;
-Adding one or more binders to the nanocapsule;
-Adding a one or more additives with or following the addition of said one or more binders.

  The combination of nanocapsules and binder materials can suitably affect and improve the processability and applicability of light modulating materials, especially in terms of coating, dripping or printing and film formation on substrates. It was found. One or more binders can act as both a dispersant and an adhesive or binder, and can provide adequate physical and mechanical stability while still maintaining or promoting flexibility. Furthermore, the density or concentration of the capsule can be advantageously adjusted by varying the amount of binder or buffer material provided.

  By concentrating the produced nanoparticles or capsules, e.g. by centrifugation, filtration or drying, and having the possibility to redisperse them, the density or ratio of the particles in the membrane or layer is obtained from the original production process. It is possible to set or adjust independently of the set concentration.

  Furthermore, surprisingly, when one or more additives, preferably one or more surfactants, are added during the production of the composite system, the characteristics of the nanocapsules in the composite system and the characteristics of the entire composite system are improved. It has been found that significant improvements can be made. In particular, this makes it possible to obtain a system which exhibits a reduced operating voltage while still providing suitable or favorable properties such as excellent dark conditions, conveniently low hysteresis and improved performance during deposition. Become.

  Such an improvement can be achieved when the provided nanocapsules already contain one or more additives, preferably surfactants. In this case, the nanocapsules can be produced, for example, by the method described above, and one or more additives are further added during the production of the composite system. The additive to be added may be the same as that previously contained in the provided nanocapsules or may be different.

  However, it is also possible to obtain a convenient composite system when the initially provided nanocapsules do not contain additives. Such nanocapsules can be obtained, for example, by performing steps (a) to (c) of the method for producing nanocapsules described above, but without adding an additive before polymerization and in step (d). One or more additives, preferably surfactants, are then added only in the production of the composite system. This is an alternative to adding additives to the nanocapsules themselves.

  In either case, the additive, preferably a surfactant, can be added simultaneously with a binder, such as PVA. This can be done, for example, by mixing the additive with a binder and then adding the nanocapsules to the mixture. Alternatively, or in addition, it is possible to add one or more additives at a stage after the binder has been added to or mixed with the nanocapsules.

  Advantageously, the additive may be the same as described in step (d) for the case of capsule production.

  Preferably, the amount of additive added by the method is 5 wt% or less, more preferably 2.5 wt% or less, even more preferably 1 wt% or less, based on the total system composition produced. . The amount of additive added by this method is particularly preferably in the range from 0.05% to 1% by weight, even more preferably from 0.1% to 1% by weight, based on the total system composition to be produced. Is set in the range.

For this reason, in another aspect,
-A nanocapsule each comprising a polymer shell and a core containing a mesogenic medium as described above and below;
-One or more binders;
-A composite system comprising one or more additives is provided.

  A composite system comprising the nanocapsules according to the invention, one or more binders and one or more additives, preferably one or more surfactants, is conveniently obtained by carrying out the above method or Can be obtained.

  In one embodiment, the one or more additives are included and specifically incorporated in the nanocapsule. In addition or alternatively, one or more additives may be included in the binder. Particularly preferably, the additive is contained in capsules and binders. It is preferred that the additive can function as a surfactant.

  Preferably the composite system comprises additives in an amount of 5 wt% or less, more preferably 2.5 wt% or less, even more preferably 1 wt% or less, based on the total composition. In one embodiment, the amount of additive based on the total composition is particularly preferably set in the range of 0.05% to 1% by weight, even more preferably in the range of 0.1% to 1% by weight. Is done.

  Nanocapsules and composite systems according to the present invention are particularly useful for light modulation elements or electro-optic devices.

  Particularly surprisingly, by the use of one or more additives according to the invention in a nanocapsule comprising a polymer shell and a core containing a mesogenic medium or in a composite comprising said nanocapsule and one or more binders, It has been found that the operating voltage can be advantageously reduced. At the same time, more appropriate product properties can be obtained.

  A further aspect of the invention provides an electro-optical device comprising a nanocapsule according to the invention or a composite system according to the invention.

  In a further aspect, a method for reducing switching voltage in an electro-optic device, comprising: a nanocapsule comprising a polymer shell and a core containing a mesogenic medium as described above and below, or one or more of said nanocapsules and There is provided a method of incorporating one or more additives into a composite comprising a binder and incorporating the resulting nanocapsule or composite into the device.

  The device comprises a nanocapsule according to the invention or a composite system according to the invention.

  By providing the nanoencapsulated LC media according to the present invention, optionally in combination with a binder material, several important advantages can be obtained in electro-optic devices. These include, for example, good mechanical stability, flexibility and externally applied forces or pressures, such as insensitivity to touch and further advantageous properties regarding switching speed, transmission, dark state, viewing angle behavior and threshold voltage, In particular, it includes reduced operating voltage and reduced hysteresis. A further advantage is that a flexible substrate can be used, the film thickness or layer thickness can be changed, and further a deviation or variation in film thickness is acceptable. In this regard, the light modulating material can be applied to the substrate using simple dripping, coating, laminating or printing methods.

  Furthermore, the installation of an alignment layer on the substrate, for example a conventionally used polyimide (PI) alignment layer, and / or rubbing of the substrate surface is not necessary.

  When two electrodes in a device are provided on the same substrate, as in IPS or FFS, a single substrate is sufficient to provide or support functionality and stability. In some cases, the provision of an opposing substrate is merely optional. However, such opposing substrates may still be beneficial, for example in terms of providing additional optical elements or physical or chemical protection. Given the possibility of encapsulation and inclusion in the binder material, it would no longer be necessary to seal the layer containing the LC material to ensure sufficient material encapsulation and prevent material leakage from the layer. .

  Accordingly, without limiting the invention, the invention will now be illustrated by a detailed description of aspects, embodiments and specific features, and specific embodiments will be described in more detail.

  The term “liquid crystal” (LC) relates to a material or medium having a liquid crystal mesophase in some temperature range (thermotropic LC) or some concentration range in solution (lyotropic LC). They contain mesogenic compounds.

  The terms “mesogenic compound” and “liquid crystal compound” have the ability to induce one or more calamitic (rod or board / lass shape) or discotic (disc shape) mesogenic groups, ie liquid crystal phase or mesophase behavior It means a compound containing a group.

  The LC compound or material and the mesogenic compound or material containing a mesogenic group are not necessarily required to exhibit a liquid crystal phase. It is also possible that they exhibit liquid crystal phase behavior only in mixtures with other compounds. This includes low molecular weight non-reactive liquid crystal compounds, reactive or polymerizable liquid crystal compounds and liquid crystal polymers.

  Calamitic mesogenic compounds usually comprise a mesogenic core consisting of one or more aromatic or non-aromatic cyclic groups bonded to each other directly or via a linking group, optionally with end groups attached to the ends of the mesogenic core. Including and optionally including one or more side groups attached to the long side of the mesogenic core, these end groups and side groups usually being for example carbyl or hydrocarbyl groups, polar groups such as halogen, nitro, hydroxy Or selected from polymerizable groups.

  For brevity, the term “liquid crystal” material or medium is used for both liquid crystal material or medium and mesogenic material or medium, and vice versa, and the term “mesogen” refers to the mesogenic group of the material. used.

  The term “non-mesogenic compound or material” means a compound or material that does not have a mesogenic group as defined above.

  As used herein, the term “polymer” encompasses the backbone of one or more distinct types of repeating units (the smallest building block of a molecule) and is generally known as an “oligomer”, “copolymer”, “ It will be understood to mean a molecule encompassing a term such as “homopolymer”. In addition, the term polymer will be understood to encompass residues from initiators, catalysts and other elements associated with the synthesis of such polymers, in addition to the polymer itself, where It is understood that the residues are not covalently incorporated into them. In addition, such residues and other elements are usually removed during the post-polymerization purification process, but are typically mixed or mixed with the polymer so that they can be placed between containers or in a solvent or dispersion. When transferred between the media, it generally remains with the polymer.

  As used herein, the term “(meth) acrylic polymer” includes polymers obtained from acrylic monomers, polymers obtained from methacrylic monomers, and corresponding copolymers obtained from mixtures of such monomers.

  The term “polymerization” means a chemical process in which a polymer is formed by bonding together a plurality of polymerizable groups or a polymer precursor (polymerizable compound) having such polymerizable groups.

  A polymerizable compound having one polymerizable group is also referred to as a “monoreactive” compound, and a compound having two polymerizable groups is also referred to as a “bireactive” compound, and has three or more polymerizable groups. Compounds having are also referred to as “multi-reactive” compounds. Compounds that do not contain a polymerizable group are also referred to as “non-reactive” or “non-polymerizable” compounds.

  The terms “membrane” and “layer” include a rigid or flexible, self-supporting or independent membrane or layer with some significant mechanical stability and on a support substrate or between two substrates. Of coatings or layers.

  Visible light is electromagnetic radiation having a wavelength in the range of about 400 nm to about 745 nm. Ultraviolet (UV) light is electromagnetic radiation having a wavelength in the range of about 200 nm to about 400 nm.

  Surprisingly, the use of additives and surfactants in the manufacture of nanocapsules and membranes containing nanocapsules and the inclusion of these additives in the product also reduces the operating voltage of the product in electro-optic applications. It has been found that it can be done. At the same time it is possible to maintain or further improve other product properties such as proper dark state, deposition capability, low hysteresis, good VHR, proper refractive index matching and sufficient transparency and transmission. .

  Advantageously, the addition of the additives added in addition to the one surfactant described above in (b) may be carried out at different stages of the production process, differently or in addition thereto. In particular, it can be carried out before and during capsule formation and processing, capsule post-treatment and concentration, and also during or after film formation using a binder material. In addition, the addition of the present methods and additives, even in the presence of an aqueous system or an aqueous environment, provides adequate performance and appropriate results.

  In a first aspect, the present invention provides a method for producing nanoparticles comprising a composition comprising a mesogenic medium as described above and below and one or more polymerizable compounds, and then one interface. It relates to a method of dispersing the composition as nanodroplets in an aqueous phase using an active agent. Following the generation of nanodroplets, one or more polymerizable compounds are polymerized to obtain nanocapsules. Here, each nanocapsule includes a polymer shell and a core containing a mesogenic medium. The method further includes the addition of one or more additives. In one embodiment, in addition to the surfactant, further additives may be included in the nanodroplet dispersion, i.e. before the polymerization takes place. One or more additives can be added to the formed nanocapsules, ie after the polymerization step, which is preferred in some cases. In yet another embodiment, the additive is added before and after the nanocapsules are formed.

  Surprisingly, according to the present invention, an efficient and controlled process is ultimately performed on the nanoscale, thereby creating a typically spherical or elliptical nano-sized container enclosing the LC material. It has been found that it can be produced. In this method, a dispersion, in particular a nanoemulsion, also called a miniemulsion, is used, and a nanosize phase comprising the LC material and a reactive polymerizable compound is dispersed in a suitable dispersion medium. Furthermore, it has been found that the addition and addition of one or more additives added to the nanodroplets or formed nanocapsules can further improve or tune the properties and performance of the nanocapsules.

  Initially, a composition comprising a mesogenic medium and one or more polymerizable compounds is provided. In order to set and affect the solubility, solubilization and / or mixing, an organic solvent may optionally and preferably be added to the composition, which advantageously affects, for example, phase separation during polymerization. Can affect. Accordingly, in a preferred embodiment, the composition provided in step (a) further comprises one or more organic solvents.

  The composition is then dispersed in the aqueous phase as nanodroplets. By supplying a surfactant prior to polymerization, formation of discrete nanodroplets in a dispersion medium, particularly an aqueous dispersion medium, where the nanodroplets comprise an LC medium and a polymerizable compound, and thereafter It has been found that it is possible to expediently promote the stabilization, particularly ionic stabilization and / or steric stabilization.

  Agitation, preferably mechanical agitation, especially high shear mixing, can suitably produce or further achieve dispersions, particularly emulsions and homogenization, as well as promote nanodroplet formation. it can. As an alternative, for example, membrane emulsification may be used.

  For this reason, both mechanical agitation and surfactant supply play an advantageous role in obtaining nanodroplets and nanosized capsules, especially nanocapsules with a substantially uniform size distribution or low polydispersity. Can fulfill.

  The dispersed phase exhibits insufficient solubility in the dispersion medium, which means that it exhibits low solubility or is virtually even insoluble in the dispersion medium forming a continuous phase. Conveniently, a continuous or external phase is formed using water, aqueous or aqueous solutions or mixtures.

  By dispersion, the individual nanodroplets are separated from each other in such a way that each droplet constitutes a separate nano-sized reaction volume for subsequent polymerization.

  Aqueous mixtures can be produced or provided in various ways. In one embodiment, a surfactant solution or mixture, preferably in water, is prepared and can be added to the composition comprising the mesogenic medium and the polymerizable compound. The provided aqueous mixture is then stirred, in particular mechanically stirred, to obtain nanodroplets comprising a polymerizable compound dispersed in the aqueous phase and the LC medium according to the invention. Agitation or mixing can be done using high shear mixing. For example, a high-performance dispersion device using the rotor-stator principle, such as a commercially available Turrax (IKA), can be used. In some cases, such high shear mixing may be replaced by sonication, particularly high power ultrasound. It is also possible to combine sonication and high shear mixing, preferably sonication is preferred over high shear mixing.

  The combination of agitation and surfactant supply described above can advantageously result in proper formation and stabilization of the dispersion, particularly the emulsion. In addition to the mixing described above, the use of a high-pressure homogenizer that is optionally and preferably used is to set or adjust the droplet size, respectively, to make it smaller, and to narrow the droplet size distribution, i.e. By improving the uniformity of the particle size, the production of nanodispersions, in particular nanoemulsions, can be influenced more advantageously. It is particularly preferred to repeat the high-pressure homogenization, in particular several times, for example 3, 4 or 5 times. For example, a commercially available microfluidizer can be used.

  Therefore, in a preferred embodiment, a high-pressure homogenizer is used in step (b) of the production method according to the invention.

  Subsequent to the formation of the nanodroplets, one or more polymerizable compounds are polymerized to obtain nanocapsules comprising a polymer shell and a core containing a mesogenic medium.

  The production of nanocapsules according to the present invention is not limited thereto, and may be produced by other methods such as encapsulation with preformed polymer, coacervation, solvent evaporation or solute co-diffusion, It has been advantageously recognized that nanocapsules containing LC media can be conveniently manufactured by methods using in situ polymerization.

  Furthermore, it was recognized that instead of providing a ready-made polymer to encapsulate the LC media, encapsulation of the nanoscale mesogenic media can be conveniently initiated in situ from the polymer precursor. For this reason, the use of preformed polymers and the emulsifiers specially provided therewith can be advantageously avoided. In this regard, the use of a given preformed polymer may make it difficult to form and stabilize the nanoemulsion and may limit the overall process tunability.

  The in situ polymerization method is not particularly limited, and for example, interfacial polymerization can be used. On the other hand, preferably in situ polymerization according to the invention is based in particular on polymerization-induced phase separation.

  In this method based on polymerization-induced phase separation, according to the invention, the polymerizable compound is at least partially soluble or at least partially solubilized in the phase comprising the mesogenic medium, preferably One or more polymerizable compounds and the mesogenic medium are intimately mixed, particularly homogeneously mixed, where the mixture separates the nanophases by polymerization, ie polymerization induced phase separation (PIPS). The temperature can be set and adjusted to favorably affect solubility.

  The provided LC media described above and below are adequately stable to the encapsulation process, in particular to polymerization and associated conditions such as exposure to UV light from heat or UV lamps in the wavelength range of 300 nm to 380 nm. Is advantageously observed. Considering the fact that no polymerization between glass substrates need to take place, the choice of wavelength is not conveniently limited to the UV cut-off of the glass, for example in terms of the material properties and stability of the composition Can do.

  The method advantageously utilizes in situ polymerization and is conveniently and preferably based on polymerization combined with phase separation, in particular a combination of nanodispersion and PIPS. The method offers significant advantages in that it provides a controlled and adaptable manufacturing method. The nanocapsules obtained or thereby obtainable by the present method exhibit a suitable and tunable particle size while at the same time advantageously having a high particle size uniformity, i.e. advantageously a low polydispersity, and in turn advantageous Give uniform product properties. Surprisingly, it has been found that lower polydispersities observed and achieved while setting the appropriate capsule nanosize can have a favorable effect on the operating voltage. In view of the controllability and adaptability of the method, the electro-optical parameters of the resulting nanocapsules and in particular the LC medium contained therein can be conveniently set and adjusted.

  The size provided by the nanodroplets sets the length scale or volume of conversion or separation, resulting in polymerization-induced nanophase separation. Furthermore, the droplet interface can serve as a template for the encapsulating polymer shell. Polymer chains or networks that form or begin to form nanodroplets can separate at the interface with the aqueous phase or be driven to the water phase or accumulate at the interface with the aqueous phase. Where polymerization proceeds and can be terminated to form a closed encapsulating layer. In this regard, each polymer shell being formed or formed is substantially immiscible with both the aqueous phase and the LC medium.

  Thus, in embodiments of the present invention, polymerization can occur, be accelerated and / or continue at the interface between the aqueous phase and the phase comprising the LC medium. In this respect, the interface can act as a diffusion barrier and as a reaction site.

  In addition, the properties of the capsule during and of the formed interface, in particular the structure and building blocks of the polymer, can be determined via material behavior, in particular LC alignment, for example via switching behavior in response to homeotropic anchoring, anchoring energy and electric field. Can affect. In one embodiment, anchoring energy or anchoring intensity is reduced to favorably affect electro-optic switching, where, for example, the polymer surface morphology and polarity can be set and adjusted appropriately.

  In one embodiment, the surfactant used according to step (b) can be incorporated into the polymer capsule shell at least partially, especially at the interface with the LC inside the capsule. Surfactant molecules thus incorporated into the interface can advantageously affect electro-optic performance and lower the operating voltage, especially by setting or adjusting the interface properties and interactions. In one example, the surfactant favorably affects the alignment of LC molecules, for example, facilitating homeotropic alignment, resulting in a radial configuration. In addition or alternatively, surfactant molecules can affect the morphology and physicochemical attributes of the inner polymer surface such that anchoring strength is reduced. For this reason, the surfactant provided by step (b) not only contributes to the advantageous method according to the invention, but can also bring benefits to the resulting nanocapsules.

  In a preferred embodiment, two surfactants or one surfactant and another additive are used in step (b). In this way, it may be possible to adjust or adjust some properties, such as size and interface properties or alignment, even more effectively and efficiently. For example, it may be useful to combine agents that can each or together contribute to affecting wettability, solubility, viscosity, polarity, or hydrophobicity. Such optional additives further provided in step (b) are also preferably present or can accumulate at the interface.

  The combined components of the method can advantageously result in the production of a large number of individual dispersed or dispersible nanocapsules, each having a core comprising a polymer shell and LC material, and the interface used The active agent can advantageously contribute to a low tendency to agglomerate.

  In the PIPS process, the properties of the phase separation and the formed polymer shell, in particular the stability and immiscibility with the LC component, are advantageously influenced by cross-linking of the forming or formed polymer chains optionally and preferably. Can receive. However, the properties of the capsule can already be sufficiently good without such crosslinking.

  The miscibility, solubility and compatibility of each of the various components, or in particular the LC material, the one or more polymerizable compounds and the dispersion medium and the possible lack of the forming and formed polymer, in particular the mixed interaction energy and It has been recognized that it plays an important role of mixing free energy with mixed entropy.

  Furthermore, it was noted that the encapsulation process is based on a polymerization reaction, that is, the capsule formation is based on a specific dynamic process. It is now generally observed that polymerizable compounds, particularly those used for encapsulation, have adequate miscibility with the LC medium, while the formed capsule shell polymer exhibits a suitably low solubility with the LC material. ing.

  In the process according to the invention, the polymerization conversion or completion rate can be surprisingly high and the amount of residual unreacted polymerizable compound can be advantageously low. This can ensure that the properties and performance of the LC medium in the capsules formed are not affected or only minimally affected by the remaining reactive monomer.

  In step (c), the dispersed nanodroplets are subjected to polymerization. In particular, a polymerizable compound contained in or mixed with the nanodroplet is polymerized. Preferably and conveniently, this polymerization results in PIPS. By this polymerization, nanocapsules having the core-shell structure described above and below are formed. Nanocapsules obtained or obtainable are typically spherical, substantially spherical or elliptical. In this regard, some form of asymmetry or small deformation may be beneficial, for example, in terms of operating voltage.

  Polymerization in the emulsion droplets and at each droplet interface can be performed using conventional methods. The polymerization can be performed in one or more steps. In particular, the polymerization of the polymerizable compounds in the nanodroplets is preferably achieved by exposure to heat or actinic radiation, which means exposure to light, for example UV light, visible light or IR, X-rays Alternatively, it means irradiation with gamma rays or irradiation with high energy particles such as ions or electrons. In a preferred embodiment, free radical polymerization is performed.

  If the polymerization is carried out in two or more steps, a shell with two or more layers can be produced, for example a shell structure with two layers, with further reactivity for further polymerization steps. Monomers are provided. Depending on the polymer precursor and / or the polymerization conditions in the process, the shell layer may have different compositions and different properties, respectively. For example, the shell can be formed by a more lipophilic inner layer facing the core and a more hydrophilic outer layer facing the external environment, such as a binder in the composite membrane.

  The polymerization may be performed at a suitable temperature. In one embodiment, the polymerization is performed at a temperature below the clearing point of the mesogen mixture. However, in other embodiments, it is possible to carry out the polymerization at or above the clear point.

  In one embodiment, the polymerization is carried out by heating the emulsion, ie by thermal polymerization, for example by thermal polymerization of acrylate and / or methacrylate compounds. Particularly preferred is a thermally initiated free radical polymerization of a reactive polymerizable precursor that results in nanoencapsulation of the LC material.

  In another embodiment, the polymerization is carried out by light irradiation, ie light, preferably UV light. As a source for actinic radiation, for example, a single UV lamp or a set of UV lamps can be used. When using high lamp power, the curing time can be shortened. Another possible source of light irradiation is a laser, for example a UV laser, a visible laser or an IR laser.

  In order to accelerate the reaction, suitable and customary thermal initiators or photoinitiators, such as azo compounds or organic peroxides, such as Luperox type initiators, may be added to the composition. Furthermore, suitable conditions for the polymerization as well as suitable types and amounts of initiators are known in the art and described in the literature.

  For example, when polymerizing with UV light, a photoinitiator can be used that generates free radicals or ions that decompose under UV irradiation to initiate the polymerization reaction. For polymerizing acrylate or methacrylate groups, preferably a radical photoinitiator is used. Cationic photoinitiators are preferably used for polymerizing vinyl, epoxide or oxetane groups. It is also possible to use a thermal polymerization initiator that decomposes when heated to produce free radicals or ions that initiate polymerization. Typical radical photoinitiators are, for example, commercially available Irgacure (R) or Darocur (R) (Ciba Geigy AG, Basel, Switzerland). A typical cationic photoinitiator is, for example, UVI 6974 (Union Carbide).

  In one embodiment, an initiator is used that is sufficiently soluble in the nanodroplet but is water insoluble or at least substantially water insoluble. For example, azobisisobutyronitrile (AIBN) can be used in a method for producing nanocapsules, which in certain embodiments is further included in a composition according to the present invention.

  Alternatively or in addition, a water soluble initiator, such as 2,2'-azobis (2-methylpropionamido) dihydrochloride (AIBA) or the like may be provided.

  Additional additives may be added. In particular, the polymerizable material may further comprise one or more additives such as, for example, catalysts, sensitizers, stabilizers, inhibitors and chain transfer agents.

  For example, the polymerizable material may also include one or more stabilizers or inhibitors to prevent unwanted spontaneous polymerization, such as commercially available Irganox® (Ciba Geigy AG, Basel, Switzerland).

  By adding one or more chain transfer agents to the polymerizable material, the properties of the resulting or obtainable polymer may be modified. By using a chain transfer agent, the length of the free polymer chain and / or the length of the polymer chain between two crosslinks in the polymer can be adjusted, typically increasing the amount of chain transfer agent Then, the polymer chain length in the polymer is shortened.

  The polymerization is preferably carried out under an inert gas atmosphere, for example under nitrogen or argon, more preferably in a heated nitrogen atmosphere. However, polymerization in air is also possible.

  The polymerization is carried out in the presence of an organic solvent, preferably the organic solvent is more preferably provided in the composition comprising the LC medium. The use of organic solvents, such as hexadecane or 1,4-pentanediol, can be advantageous in adjusting the solubility of the reactive compound with the LC material and stabilizing the nanodroplets, affecting the phase separation. It can also be beneficial in terms of effects. However, the amount of organic solvent, if used at all, should typically be limited to less than 25 wt%, more preferably less than 20 wt%, especially less than 15 wt%, based on the total composition. Is preferred.

  The formed polymer shell suitably exhibits low solubility in both the LC material and water, ie is substantially insoluble. Furthermore, in the present method, the solidification or aggregation of the produced nanocapsules can be appropriately and conveniently limited or even avoided.

  It is also preferred that the forming polymer in the shell or the formed polymer be crosslinked. Such cross-linking may provide benefits for the formation of a stable polymer shell and proper inclusion and imparting a barrier function while maintaining sufficient mechanical flexibility.

  For this reason, the method according to the invention provides encapsulation and confinement of mesogenic media while maintaining the electro-optic performance of the LC material, in particular electrical responsiveness. In particular, compositions and process conditions are provided so that the stability of the LC material is maintained. Thus, LC may exhibit favorable properties in the formed nanocapsules, such as a suitably high Δε, a suitably high Δn, a convenient high clearing point and a low melting point. In particular, provided LC materials may exhibit suitable and favorable stability in polymerization, for example with respect to exposure to heat or UV light.

  Optionally and optionally, preferably in step (d) of the method, one or more additives are added to the nanocapsules obtained by carrying out step (c). Surprisingly, it has been found that even after the nanoparticles have been formed, the addition of suitable additives can still affect and tune the properties of the nanoparticles. Nanoparticles obtained by polymerization generally already have suitable and useful properties, and the properties of the product are mainly due to the structure and configuration of the LC material contained in the core and the preformed polymer shell. It is determined. However, unexpectedly, after producing the encapsulated nanoparticles themselves, some attributes of the nanoparticles can still be further improved or changed by an additional step of adding one or more additives to the nanocapsules. Such improvements or adjustments of the nanocapsules can be particularly beneficial under certain conditions or from a particular application point of view.

  The additive according to the present invention may be selected in view of achieving or adapting specific product properties. For example, agents that advantageously affect wettability and solubility, chemical resistance such as water resistance, film formation and defoaming may be used. In one embodiment, an organic solvent or a hydrophobic or hydrophobizing agent may be added. However, in a preferred embodiment of the present invention, the one or more additives are specifically selected to be one or more surfactants. These surfactants that may be used as additives by step (d) may provide additional benefits, such as contributing to proper film formation, favorable darkness or reasonably low hysteresis, It has been recognized that this additive may be useful in reducing the operating voltage when nanocapsules are used in electro-optic devices.

  According to the present invention, one or more additives are used in combination with one surfactant provided in step (b). In this regard, the surfactant provided by step (b) is also used during the formation of nanodroplets and in subsequent polymerizations. As noted above, the surfactants therein are useful during the process, for example, by promoting and stabilizing the miniemulsion and by preventing or minimizing particle aggregation during and after capsule formation. It is. In addition, surfactants can additionally affect product properties, such as capsule size, but can also affect the electro-optical properties described above, for example by adjusting the interfacial interaction between the shell and the core. Can affect. Thus, they should perform several functions and provide adequate performance during the manufacture of capsules from the precursor material.

  The additive used in step (d), preferably a surfactant, is added only after the capsule is formed. Thus, they can be selected generally independently of the requirements of the emulsion and polymerization process. However, in some cases, the additive, preferably the surfactant, also takes into account the surfactant provided by step (b) and optionally the additive, i.e. adapted or adjusted to them. The same surfactant may be used. Thus, in one embodiment, the additive from step (d) is selected to be the same as the surfactant provided in step (b).

  In other cases, the surfactant according to step (d) may be selected independently and more freely, for example taking into account other criteria. In a particularly preferred embodiment, the additive of step (d) is provided from the viewpoint of reducing the operating voltage. Thus, in another embodiment, the additive from step (d) is different from the surfactant provided in step (b).

  In this method, stable nanocapsules are produced and dispersed appropriately. After obtaining the nanocapsules, the aqueous phase can optionally and preferably be removed, the amount of water can be reduced or depleted, or the aqueous phase can be exchanged for another dispersion medium.

  In one embodiment, the dispersed or dispersible nanocapsules are substantially or completely separated from the aqueous phase, for example by filtration or centrifugation. Conventional filtration, such as membrane filtration, dialysis, crossflow filtration and especially crossflow filtration and / or centrifugation techniques combined with dialysis may be used. Additional benefits can be provided by filtration and / or centrifugation, for example, by removing excess or undesirable or even residual surfactant provided in step (b). Thus, it is possible not only to concentrate the nanocapsules but also to provide purification, for example by removing contaminants, impurities or unwanted ions.

  Preferably and conveniently, the amount of capsule surface charge is minimized. Based on mechanical stability, nanocapsules can be subjected to separation techniques relatively easily, for example using evaporation or extraction methods. It is also possible to dry the nanocapsules, where drying means removing the dispersion medium but leaving the included LC material in the capsule. Conventional techniques such as drying in air, critical point drying and lyophilization, in particular lyophilization, can be used. Other conventional means of solvent removal, separation, purification, concentration and work-up, such as chromatography or size fractionation can also be performed.

  In the method according to the invention, one or more additives, preferably one or more surfactants, can be added to the nanocapsules before any further steps of depleting, removing or replacing the aqueous phase. Alternatively, one or more additives, preferably one or more surfactants, can be added to the nanocapsule after any further step of depleting, removing or replacing the aqueous phase. It is also possible to add additives, preferably surfactants, both before and after depletion, removal or exchange of the aqueous phase.

  Depending on the material properties and the respective circumstances, the additives, preferably surfactants, may be added as is or as a solution using a suitable solvent, such as water or an aqueous solvent, isopropanol or acetone. May be. The nanocapsules and additives are then mixed appropriately, for example using agitation, sonication and / or heating.

  The additives used in accordance with step (b) and optional step (d), in particular surfactants, either alone or in combination, respectively, at least through interaction at the internal interface of the capsule wall and By affecting even the LC material, the nanocapsule properties can be favorably affected. Surfactants can adsorb, permeate, dissolve or permeate or even pass through the polymer composition forming the capsule shell, in certain cases or under certain conditions, for example It is believed that the shell characteristics can be adjusted with respect to charging, conductivity or dielectric constant. Surfactant molecules also play a role at the interface between the polymer shell and the LC material, for example affecting or reducing the anchoring energy of the LC material with the polymer shell surface or affecting the alignment of the LC molecules. May affect. When some of the surfactants or additives are mixed with the LC material, the elastic constant or viscosity of the material and then its electro-optic properties can also change. In addition, when the surfactant or additive molecule is located on the outer surface of the nanocapsule, the interaction with the environment, e.g. solubility and wettability, is altered and conveniently adjusted, e.g. in terms of compatibility with the binder. May be.

  In the present method, water or an aqueous solution is conveniently used as a dispersion medium. However, it is further observed in this respect that the provided compositions and the resulting nanocapsules show adequate stability and chemical resistance to the presence of water, for example with respect to hydrolysis. In one embodiment, the amount of water may be reduced or substantially minimized by providing or adding a polar medium, preferably a non-aqueous polar medium, for example containing formamide or ethylene glycol or a hydrofluorocarbon. .

  Advantageously, the method according to the invention provides a large number of individual nanocapsules that are dispersible and even redispersible. Thus, they can be further used and applied to various environments easily and flexibly. Due to its stability, a particularly suitably long shelf life also makes it possible to store the capsules before use in various applications. However, rapid further processing is also a convenient option. In this respect, the capsule is adequately stable during the procedure, especially for coating applications.

  The above method provides a convenient way to produce nanocapsules in a controlled and adaptable manner. In particular, the size of the capsule particle size can be appropriately adjusted while keeping the polydispersity low, for example, by adjusting the amount of the surfactant in the composition. Surprisingly, it has been found that a properly set uniform capsule size can be particularly advantageous in terms of reducing the operating voltage in electro-optic applications. In addition, additives added to the nanodroplets prior to polymerization or added in step (d) can advantageously further contribute to lowering the operating voltage.

  It has further been found that the composition provided by step (a) of the method exhibits adequate behavior and performance both in the manufacturing process and in the resulting product. This means on the one hand that the composition is well-suited for nanoencapsulation, i.e. the formation of nanocapsules, where the capsule shell formed of each capsule contains LC media in a nano-sized volume . On the other hand, they are also useful to obtain favorable product performance, for example in electro-optic applications.

  In particular, the composition provided by the present invention makes it possible to produce advantageous nanocapsules containing mesogenic media in a convenient process, in particular a process using in situ polymerization, in particular a process based on PIPS. Here, the composition has favorable performance in these processes. Furthermore, these compositions make it possible to obtain nanocapsules that offer significant benefits with regard to their physical and chemical attributes, in particular with regard to their electro-optical properties and their compatibility in electro-optical devices. Become. For this reason, the composition of this invention is useful for manufacture of a nanocapsule.

  The composition can be provided by appropriately mixing or blending the components.

  In a preferred embodiment, the composition according to the invention is in an amount of 5% to 95% by weight, more preferably 15% to 75% by weight, in particular 25% to 65% by weight, based on the total composition. Includes LC media.

  In a preferred embodiment, the composition according to the invention further comprises one or more organic solvents. It has been found that the provision of an organic solvent can provide additional benefits in the method of producing the nanocapsules of the present invention. In particular, one or more organic solvents can contribute to setting or adapting the solubility or miscibility of the components. The solvent may act as a suitable co-solvent, where the solvent power of other organic components may be enhanced or affected. Furthermore, the organic solvent can have a favorable effect during phase separation induced by the polymerization of polymerizable compounds.

  In this respect as organic solvents, standard organic solvents can be used. The solvent is, for example, an aliphatic hydrocarbon, a halogenated aliphatic hydrocarbon, an aromatic hydrocarbon, a halogenated aromatic hydrocarbon, an alcohol, a glycol or an ester, ether, ester, lactone, ketone, etc., more preferably a diol. , N-alkanes and fatty alcohols. It is also possible to use a mixture of two, three or more of the above solvents.

  In one embodiment, 1,5-dimethyltetralin, 3-phenoxytoluene, cyclohexane or 5-hydroxy-2-pentanone may be added.

  In preferred embodiments, the solvent is cyclohexane, tetradecanafluorohexane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, heptadecane, hexadecan-1-ol, 2-isopropoxyethanol, octyldodecanol, 1,2-ethanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, pentanediol, especially 1,4-pentanediol, hexanediol, especially 1,6-hexanediol, heptanediol, octanediol, It is selected from one or more of ethanolamine, ethyl acetate, ethyl hexanoate and butyl acetate. The organic solvent used particularly preferably contains hexadecane or 1,4-pentanediol, in particular hexadecane or 1,4-pentanediol. In a further embodiment, a combination comprising hexadecane and 1,4-pentanediol is used.

  The organic solvent, in particular hexadecane, is preferably added in an amount of 0.1% to 35% by weight, more preferably 1% to 25% by weight, in particular 3% to 17% by weight, based on the total composition. .

  In one embodiment, hexadecane used in the manufacture of nanocapsules is considered not to constitute a further additive according to the present invention.

  The organic solvent can enhance solubility or solubilization, or can dilute other organic components and can contribute to viscosity adjustment.

  In one embodiment, the organic solvent acts as a hydrophobic agent. The addition of a nanoemulsion or miniemulsion to the dispersed phase can affect the osmotic pressure in the nanodroplets, in particular the osmotic pressure can be increased. This can contribute to stabilization of the “oil-in-water” emulsion by inhibiting Ostwald ripening. Preferred organic solvents that function as hydrophobic agents have a solubility in water that is lower than the solubility of liquid crystals in water, but are soluble in liquid crystals. Organic solvents, preferably hydrophobic agents, can act as stabilizers or co-stabilizers.

  In the composition according to the invention, one or more polymerizable compounds are provided as precursors of a polymer shell or wall that includes or surrounds the LC medium.

［式中、
Ｗ^１は、Ｈ、Ｃｌ、ＣＮ、フェニルまたは１〜５個のＣ原子を有するアルキル、特にＨ、ＣｌまたはＣＨ_３であり、Ｗ^２およびＷ^３は、互いに独立して、Ｈまたは１〜５個のＣ原子を有するアルキル、特にＨ、メチル、エチルまたはｎ−プロピルであり、Ｐｈｅは、１，４−フェニレンであり、ｋ_１およびｋ_２は、互いに独立して、０または１である］から選択される。 The polymerizable compound has at least one polymerizable group. The polymerizable group is preferably

[Where:
W ¹ is H, Cl, CN, phenyl or alkyl having 1 to 5 C atoms, in particular H, Cl or CH ₃ , W ² and W ³ are independently of each other H or 1 to 5 Alkyl having 1 C atom, in particular H, methyl, ethyl or n-propyl, Phe is 1,4-phenylene and k ₁ and k ₂ are independently of each other 0 or 1] Selected from.

  The one or more polymerizable compounds are selected so that they have appropriate and sufficient solubility in the LC component or phase. Furthermore, they need to be sensitive to polymerization conditions and the environment. In particular, the polymerizable compound can undergo appropriate polymerization at a high conversion and advantageously results in a small amount of residual unreacted polymerizable compound after the reaction. This may provide benefits in terms of LC media stability and performance. Further, the polymerizable component is selected such that the polymer formed therefrom suitably phase separates or the polymer formed therefrom phase separates to form a polymer capsule shell. In particular, solubility of the LC component in the shell polymer and swelling or gelation of the formed polymer shell is advantageously avoided or minimized, and the amount and composition of the LC medium is also substantially reduced in the formed capsule. Remains constant. This advantageously minimizes or avoids any preferential solubility of any LC compound of the LC material at the wall.

  Swelling or rupturing of the nanocapsules and undesirable leakage of the LC material from the capsules are advantageously minimized or even avoided by providing a suitably tough polymer shell.

  The time of polymerization or curing includes, inter alia, the reactivity and amount of the polymerizable material, the thickness of the capsule shell formed, and the type and amount of the polymerization initiator, if present, and the reaction temperature and / or radiation, such as UV Determined by the lamp output. Polymerization or curing times and conditions can be obtained, for example, so that a fast process for the polymerization is obtained or, for example, a slower process (in which the polymer conversion and separation integrity can be advantageously affected). As may be selected. Thus, it may be preferable to have a short polymerization and curing time, for example less than 5 minutes, but in other embodiments, longer polymerization times, such as 1 hour or more or even at least 3 hours may be preferred.

  In one embodiment, non-mesogenic polymerizable compounds are used, ie compounds that do not have mesogenic groups. However, they exhibit sufficient and appropriate solubility or miscibility with the LC component. In a preferred embodiment, an organic solvent is further provided.

  In another embodiment, polymerizable mesogenic or liquid crystal compounds, also known as reactive mesogens (RM), are used. These compounds have a mesogenic group and one or more polymerizable groups, i.e. functional groups suitable for polymerization.

  Optionally, in one embodiment, the polymerizable compound according to the invention comprises only reactive mesogens, i.e. all reactive monomers are mesogens. Alternatively, RM can be provided in combination with one or more non-mesogenic polymerizable compounds. The RM can be mono-reactive or bi-reactive or multi-reactive. The RM may exhibit favorable solubility or miscibility with the LC medium. However, it is further devised that the polymer being formed or formed therefrom exhibits a suitable phase separation behavior. Preferred polymerizable mesogenic compounds contain at least one polymerizable group as a terminal group, a mesogenic group as a core group, and more preferably a spacer and / or a linking group between the polymerizable group and the mesogenic group. In one embodiment, 2-methyl-1,4-phenylene-bis [4 [3 (acryloyloxy) propyloxy] benzoate (RM257, Merck KGaA) is used. Alternatively or in addition, one or more side groups of the mesogenic group may be a polymerizable group.

  In yet another embodiment, the use of mesogenic polymerizable compounds is avoided.

In a preferred embodiment, the one or more polymerizable compounds are vinyl chloride, vinylidene chloride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, methyl-, ethyl-, n- or tert-butyl-, cyclohexyl-, 2- Ethylhexyl-, phenyloxyethyl-, hydroxyethyl-, hydroxypropyl-, _C2-5 -alkoxyethyl-, tetrahydrofurfuryl acrylate or methacrylate, vinyl acetate, -propionate, -acrylate, -succinate, N-vinylpyrrolidone, N -Vinylcarbazole, styrene, divinylbenzene, ethylene diacrylate, 1,6-hexane diacrylate, bisphenol-A-diacrylate and -dimethacrylate, trimethylyl Lopandiacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, tripropylene glycol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylpropane tetraacrylate or dipenta It is selected from erythritol penta- or hexaacrylate. Also preferred are thiol-enes such as, for example, commercially available Norland 65 (Norland Products).

  The polymerizable or reactive group is preferably selected from vinyl groups, acrylate groups, methacrylate groups, fluoroacrylate groups, oxetane groups or epoxy groups, particularly preferably acrylate groups or methacrylate groups.

  Preferably the one or more polymerizable compounds are selected from acrylates, methacrylates, fluoroacrylates and vinyl acetate, wherein the composition is more preferably selected from diacrylates, dimethacrylates, triacrylates and trimethacrylates. It further comprises one or more direactive and / or trireactive polymerizable compounds.

  In one embodiment, the one or more polymerizable compounds (ii) described above comprise one, two or more polymerizable groups selected from acrylate groups, methacrylate groups and vinyl acetate groups; Here, this compound is preferably a non-mesogenic compound.

  In a preferred embodiment, the composition according to the invention comprises one or more monoacrylates, preferably 0.1% to 75% by weight, more preferably 0.5% to 50%, based on the total composition. It is added in an amount of% by weight, especially 2.5% to 25% by weight. Particularly preferred monoreactive compounds are methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, t-butyl acrylate, pentyl acrylate, hexyl acrylate, nonyl acrylate, 2-ethyl-hexyl acrylate, 2-hydroxy-ethyl acrylate , 2-hydroxy-butyl acrylate, 2,3-dihydroxypropyl acrylate and glycidyl acrylate.

  In addition or alternatively, vinyl acetate may be added.

  In another preferred embodiment, the composition according to the invention optionally comprises, in addition to the monoacrylate, one or more monomethacrylates, preferably 0.1% to 75% by weight, based on the total composition. %, More preferably 0.5% to 50% by weight, in particular 2.5% to 25% by weight. Particularly preferred monoreactive compounds are methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, t-butyl methacrylate, pentyl methacrylate, hexyl methacrylate, nonyl methacrylate, 2-ethyl-hexyl methacrylate, 2-hydroxyethyl methacrylate, It is selected from 2-hydroxybutyl methacrylate, 2,3-dihydroxypropyl methacrylate, glycidyl methacrylate, stearyl methacrylate, adamantyl methacrylate and isobornyl methacrylate.

  It is particularly preferred that at least one crosslinking agent, ie a polymerizable compound having two or more polymerizable groups, is added to the composition. Crosslinking of the polymer shell in the produced particles can provide further benefits, particularly with respect to further improving stability and inclusion, and adjusting or reducing susceptibility to swelling, particularly swelling with solvents. In this respect, the bireactive and polyreactive compounds help to form their own polymer network and / or to crosslink the polymer chains that are substantially formed from the monoreactive compound during polymerization. obtain.

  Conventional crosslinking agents known in the art can be used. It is particularly preferred to further provide direactive or polyreactive acrylates and / or methacrylates, preferably 0.1% to 75% by weight, more preferably 0.5% to 50%, based on the total composition. It is added in an amount of% by weight, especially 2.5% to 25% by weight. Particularly preferred compounds are ethylene diacrylate, propylene diacrylate, butylene diacrylate, pentylene diacrylate, hexylene diacrylate, glycol diacrylate, glycerol diacrylate, pentaerythritol tetraacrylate, ethylene dimethacrylate, also known as ethylene glycol dimethacrylate , Propylene dimethacrylate, butylene dimethacrylate, pentylene dimethacrylate, hexylene dimethacrylate, tripropylene glycol diacrylate, glycol dimethacrylate, glycerol dimethacrylate, trimethylpropane trimethacrylate and pentaerythritol triacrylate.

  The ratio of monoreactive monomer to direactive or polyreactive monomer can be conveniently set and adjusted to affect the polymer composition of the shell and its properties.

  According to step (b) of the method, the composition is dispersed as nanodroplets in the aqueous phase using one surfactant. In one embodiment, the surfactant may be mixed and included in the composition provided in step (a). Alternatively, the surfactant is preferably added as an aqueous mixture after step (a). In this case, the surfactant is provided in the aqueous phase and then mixed with the composition provided in (a).

  Thus, according to a preferred embodiment, the surfactant can be prepared or provided separately in the first step and then added to the other ingredients. In particular, surfactants can be prepared or provided as aqueous mixtures or compositions, which are then added to other components including mesogenic media and polymerizable compounds described above and below. Particularly preferably, one surfactant is provided as an aqueous surfactant.

  Surfactants can be useful in reducing surface tension or interfacial tension and promoting emulsification and dispersion.

  Anionic surfactants such as sulfates such as sodium lauryl sulfate, sulfonate, phosphate and carboxylate surfactants, cationic surfactants such as secondary or tertiary amines and quaternary ammonium Includes salt surfactants, zwitterionic surfactants such as betaines, sultaines and phospholipid surfactants and nonionic surfactants such as long chain alcohols and phenols, ethers, esters or amides nonionic surfactants Conventional surfactants known in the art can be used.

  In a preferred embodiment according to the present invention, a nonionic surfactant is used. The use of nonionic surfactants can provide benefits during the process of manufacturing nanocapsules, particularly in the formation and stabilization of dispersions and PIPS. It has further been recognized that it may be advantageous to avoid charged surfactants when the formed nanocapsules contain a surfactant, such as a residual surfactant. For this reason, the use of nonionic surfactants and avoidance of ionic surfactants can also be beneficial in composite systems and electro-optic devices in terms of nanocapsule stability, reliability, and electro-optic properties and performance.

  Particular preference is given to polyethoxylated nonionic surfactants. Preferred compounds include polyoxyethylene glycol alkyl ether surfactants, polyoxypropylene glycol alkyl ether surfactants, glucoside alkyl ether surfactants, polyoxyethylene glycol octylphenol ether surfactants such as Triton ™ X-100, Polyoxyethylene glycol alkylphenol ether surfactants, glycerol alkyl ester surfactants, polyoxyethylene glycol sorbitan alkyl ester surfactants such as polysorbates, sorbitan alkyl ester surfactants, cocamide monoethanolamine, cocamide diethanolamine and dodecyldimethyl Selected from the group of amine oxides.

  In a particularly preferred embodiment, the surfactant used is selected from polyoxyethylene glycol alkyl ether surfactants including commercially available Brij® agents (manufactured by Sigma-Aldrich). Particular preference is given to surfactants comprising tricosaethylene glycol dodecyl ether, more preferably consisting of tricosaethylene glycol dodecyl ether. In a very particularly preferred embodiment, the commercially available Brij® L23 (Sigma-Aldrich), also called Brij35 or polyoxyethylene (23) lauryl ether, is used. In a further specific embodiment, the commercially available Brij® 58, also known as polyethylene glycol hexadecyl ether or polyoxyethylene (20) cetyl ether, also known as polyethylene glycol dodecyl ether or polyoxyethylene (4) lauryl ether. Commercially available Brij® L4 is preferred.

In another embodiment, an alkylaryl polyether alcohol, preferably commercially available Triton ™ X-100 and especially 4- (1,1,3,3-tetramethylbutyl) phenyl-polyethylene glycol and the formula C ₁₄ H ₂₂ It is preferred to use a compound of O (C ₂ H ₄ O) _n H where n is 9 and 10. Alternatively or in addition, an octylphenol ethoxylate surfactant, such as ECOSURF ™ surfactant (commercially available from Dow), eg ESOSURF ™ EH-9 (90%) or TERGITL® interface An activator (commercially available from Dow), such as TERGITOL® 15-S-9, can be preferably used.

In another embodiment, organosilicones such as polyether siloxanes and polyether siloxane copolymers, such as the commercially available TEGO® additive (Evonik), preferably TEGO® Wet 270 and especially 3- [methyl-bis Preferably, a surfactant comprising, preferably consisting of (trimethylsilyloxy) silyl] propyl-polyethylene glycol or preferably TEGO® Wet280 is used. In addition, silicone surfactants described in TEGO® WET260 and TEGO® Wet KL245 and US Pat. No. 7,618,777 (US 7,618,777), such as H ₃ CSi ( CH ₃ ) ₂ OSiO (CH ₃ ) (CH ₂ CH ₂ CH ₂ O (CH ₂ CH ₂ O) ₇ CH ₃ ) Si (CH ₃ ) ₃ may be preferably used.

  In yet another embodiment, a fluorosurfactant, preferably FluorN322 and especially 2-[[2-methyl-5- (3,3,4,4,5,5,6,6,7,7,8, It is preferred to use a surfactant comprising, more preferably consisting of 8,8-tridecafluoro-octoxycarbonylamino) phenyl] carbamoyloxy] ethyl-polypropylene glycol. Other fluorosurfactants such as commercially available FluorN 561 and FluorN 562 (Cytonix) can also be preferably used.

  In yet another embodiment, a poloxamer copolymer, preferably a copolymer comprising units of polyethylene oxide and polypropylene oxide, more preferably a triblock consisting of a central hydrophobic block of polypropylene glycol adjacent to two hydrophilic blocks of polyethylene glycol. Preference is given to using copolymers and in particular the commercially available poloxamer 407 or Pluronic® F-127 (BASF) or Synperonic PE / F127 (Croda). Alternatively or in addition, other Pluronic® additives such as Pluronic® 10R5 may preferably be used.

  The surfactant is preferably in an amount of less than 30% by weight, more preferably less than 25% by weight, even more preferably less than 20% by weight, in particular less than 15% by weight, based on the composition provided in step (a). Provided in.

  According to a preferred embodiment, when the surfactant is provided as an aqueous mixture produced, the amount of water is not considered to contribute to the entire composition with respect to weight, ie water is excluded in this respect.

  Polymer surfactants or surface active polymers or block copolymers can also be used in the method for producing nanocapsules according to the present invention.

  However, in certain embodiments, the use of such polymeric surfactants or surfactant polymers is avoided.

  According to an aspect of the present invention, a polymerizable surfactant, i.e. a surfactant comprising one or more polymerizable groups, can be used.

  Such polymerizable surfactants can be used alone, ie as the only surfactant provided or in combination with non-polymerizable surfactants. In one embodiment, the polymerizable surfactant is provided in addition to and in combination with a non-polymerizable surfactant. This optional supply of polymerizable surfactant can provide the combined benefit of contributing to proper droplet formation and stabilization as well as the formation of a stable polymer capsule shell. Therefore, these compounds act simultaneously as a surfactant and a polymerizable compound. Particular preference is given to polymerizable nonionic surfactants, in particular nonionic surfactants additionally having one or more acrylate and / or methacrylate groups. This embodiment involving the use of polymerizable surfactants can have the advantage that the template properties at the amphiphilic interface can be preserved particularly well during polymerization. Furthermore, the polymerizable surfactant may not only participate in the polymerization reaction, but may also be conveniently incorporated as a building block in the polymer shell, more preferably on the shell surface, thereby favoring interfacial interactions. May have an impact. In a particularly preferred embodiment, a silicone polyether acrylate, more preferably a crosslinkable silicone polyether acrylate, is used as the polymerizable surfactant. In another embodiment, PEG methyl ether methacrylate is used.

  In the present method, the composition is added to an aqueous mixture, where the composition is dispersed in the aqueous phase. In this regard, the provided surfactants can advantageously contribute to forming dispersions, particularly emulsions, to stabilize and promote homogenization.

  If an aqueous mixture is provided, the amount of water is not considered to contribute to the entire composition in terms of weight, ie water is excluded at this point.

  Preferably the water is provided as purified water, especially deionized water.

  According to the present invention, the composition provided in step (a) is then dispersed in the aqueous phase as nanodroplets.

  The composition may contain further compounds, for example one or more pleochroic dyes, in particular dichroic dyes, one or more chiral compounds and / or other customary and suitable additives.

  The pleochroic dye is preferably a dichroic dye and can be selected, for example, from azo dyes and thiadiazole dyes.

  Suitable chiral compounds are for example standard chiral dopants such as R- or S-811, R- or S-1011, R- or S-2011, R- or S-3011, R- or S-4011, R Or sorbitol as described in S-5011 or CB15 (all available from Merck KGaA, Darmstadt, Germany), WO 98/00428 (WO 98/00428), British Patent Application No. 2,328,207 Hydrobenzoin described in the specification (GB 2,328,207), chiral binaphthol described in WO 02/94805 (WO 02/94805), WO 02/34739 (WO 02/34739) ) Chiral binaphthol acetal , Described in WO 02/06265 (WO 02/06265) or described in WO 02/06196 (WO 02/06196) or WO 02/06195 (WO 02/06195). It is a chiral compound having a fluorinated linking group.

  In addition, substances can be added to change the dielectric anisotropy, optical anisotropy, viscosity and / or temperature dependence of the electro-optic parameters of the LC material.

  The mesogenic medium according to the present invention comprises one or more compounds of formula I described above.

  In a preferred embodiment, the liquid crystal medium consists of 2 to 25, preferably 3 to 20, compounds, at least one of which is a compound of formula I. The medium preferably comprises one or more compounds of formula I according to the invention, more preferably two or more, most preferably three or more. The medium is preferably selected from nematic or nematogenic substances such as the known classes of azoxybenzene, benzylidene-aniline, biphenyl, terphenyl, phenyl or cyclohexylbenzoate, phenyl or cyclohexyl ester of cyclohexanecarboxylic acid, phenyl of cyclohexylbenzoic acid. Or cyclohexyl ester, cyclohexyl cyclohexane carboxylic acid phenyl or cyclohexyl ester, benzoic acid, cyclohexane carboxylic acid and cyclohexyl cyclohexane carboxylic acid cyclohexyl phenyl ester, phenyl cyclohexane, cyclohexyl biphenyl, phenyl cyclohexyl cyclohexane, cyclohexyl cyclohexane, cyclohexyl Cyclohexene, cyclo Xylcyclohexylcyclohexene, 1,4-bis-cyclohexylbenzene, 4,4'-bis-cyclohexylbiphenyl, phenyl- or cyclohexylpyrimidine, phenyl- or cyclohexylpyridine, phenyl- or cyclohexylpyridazine, phenyl- or cyclohexyldioxane, phenyl -Or cyclohexyl-1,3-dithiane, 1,2-diphenyl-ethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane, 1-cyclohexyl-2- (4-phenylcyclohexyl) -ethane, 1 -Cyclohexyl-2-biphenyl-ethane, 1-phenyl-2-cyclohexyl-phenylethane, optionally halogenated stilbene, benzylphenyl ether, Is selected from nematic or nematogenic substances cinnamic acid and further classes are substituted include low molecular weight liquid crystal compounds. Also, the 1,4-phenylene group in these compounds may be mono- or difluorinated laterally. The liquid crystal mixture is preferably based on this kind of achiral compound.

  In a preferred embodiment, the LC host mixture is preferably a nematic LC mixture without a chiral LC phase.

  A suitable LC mixture may have a positive dielectric anisotropy. Such a mixture is disclosed in, for example, JP-A-07-181439 (JP 07-181439 A), European Patent Application Publication No. 0667555 (EP 0667555), European Patent Application Publication No. 0673986 (EP 0673986), German Patent Application Publication No. 19509410 (DE 19509410), German Patent Application Publication No. 19528106 (DE 19528106), German Patent Application Publication No. 19528107 (DE 19528107), International Publication No. 96 / 23851 (WO 96/23851), WO 96/28521 (WO 96/28521) and WO 2012/079676 (WO 2012/079676).

  In another embodiment, the LC medium has a negative dielectric anisotropy. Such a medium is described, for example, in EP 1378557 (EP 1378557 A1).

In a particularly preferred embodiment, the one or more compounds of formula I are of formula Ia, Ib, Ic and Id

［式中、
Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５およびＲ^６は、互いに独立して、１〜１５個の炭素原子、好ましくは１〜７個の炭素原子を有する直鎖もしくは分枝鎖アルキルもしくはアルコキシまたは２〜１５個の炭素原子を有する直鎖もしくは分枝鎖アルケニルを示し、前記アルキル、アルコキシまたはアルケニルは、置換されていないか、ＣＮもしくはＣＦ_３により一置換されているかまたはハロゲンにより一置換もしくは多置換されており、１つ以上のＣＨ_２基は、各場合において、互いに独立して、酸素原子が互いに直接結合しないような様式で、−Ｏ−、−Ｓ−、−ＣＯ−、−ＣＯＯ−、−ＯＣＯ−、−ＯＣＯＯ−または−Ｃ≡Ｃ−により置き換えられていてもよく、
Ｘ^１およびＸ^２は、互いに独立して、Ｆ、ＣＦ_３、ＯＣＦ_３またはＣＮを示し、
Ｌ^１、Ｌ^２、Ｌ^３、Ｌ^４およびＬ^５は、互いに独立して、ＨまたはＦであり、
ｉは、１または２であり、
ｊおよびｋは、互いに独立して、０または１である］
の化合物から選択される。

[Where:
R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are independently of each other a linear or branched alkyl having 1 to 15 carbon atoms, preferably 1 to 7 carbon atoms. Or alkoxy or straight-chain or branched alkenyl having 2 to 15 carbon atoms, said alkyl, alkoxy or alkenyl being unsubstituted, monosubstituted by CN or CF ₃ or monohalogenated One or more CH ₂ groups, which are substituted or polysubstituted, in each case, independently of one another, in such a way that the oxygen atoms are not directly bonded to one another, —O—, —S—, —CO—, May be replaced by -COO-, -OCO-, -OCOO- or -C≡C-;
X ¹ and X ² independently of one another represent F, CF ₃ , OCF ₃ or CN;
L ¹ , L ² , L ³ , L ⁴ and L ⁵ are independently of each other H or F;
i is 1 or 2,
j and k are independently 0 or 1]
Selected from the following compounds:

  The one or more additives according to the invention can serve a convenient or suitable function during manufacture, in particular the action that can impart or at least contribute to one or more advantageous or useful properties in the resulting product. It is an agent. Additives can be useful, for example, to adjust material properties, solubility or miscibility, or provide benefits related to film-forming capabilities.

  The additive may be provided before the polymerization step or may be provided by step (d).

  In particular, the additive according to the invention provided in step (d) is preferably a surfactant. The surfactant is a surface active agent. This agent can reduce the surface or interfacial tension between liquids or between liquids and solids. The surfactants herein may include or act as detergents, wetting agents, emulsifiers, foaming agents and dispersing agents.

  In the method for producing nanocapsules according to the present invention in step (b), one or more surfactants are used. The surfactants herein can promote or contribute to nanodroplet formation and nanoemulsion stabilization. It may also be useful for setting or adjusting the size and size distribution of the droplets and the size and size distribution of the manufactured nanocapsules.

  The surfactant added in step (d) may in some cases be the same as that used in step (b). However, this additive from step (d) is added directly after the capsule is formed. At this stage, other factors may be specifically handled or taken into account, which are different from droplet stabilization and particle size setting. Thus, additives that serve different or additional functions or affect other or further properties may be used. Thus, in other cases, the surfactant added by step (d) may be different from the surfactant used in step (b), i.e., another or second surfactant. . In addition, combinations of additives such as surfactants and film-forming agents may be utilized.

  According to a preferred embodiment, the additive in step (d) means a surfactant. In this embodiment, in step (d), an anionic surfactant, such as a sulfate, such as sodium lauryl sulfate, sulfonate, phosphate and carboxylate surfactant, a cationic surfactant, such as a second Quaternary or tertiary amine and quaternary ammonium salt surfactants, zwitterionic surfactants such as betaines, sultaines and phospholipid surfactants and nonionic surfactants such as long chain alcohols and phenols, ethers, esters or Conventional surfactants known in the art can be used, including amide nonionic surfactants, particularly alkyl polyethers and polyethoxy alcohols.

  In a preferred embodiment according to the present invention, a nonionic surfactant is used. The use of non-ionic surfactants and the avoidance of ionic surfactants can also be beneficial in composite systems and electro-optic devices in terms of nanocapsule stability, reliability and electro-optic properties and performance.

  Particular preference is given to polyethoxylated nonionic surfactants. Preferred compounds include polyoxyethylene glycol alkyl ether surfactants, polyoxypropylene glycol alkyl ether surfactants, glucoside alkyl ether surfactants, polyoxyethylene glycol octylphenol ether surfactants such as Triton X-100, polyoxyethylene Glycol alkylphenol ether surfactants, glycerol alkyl ester surfactants, polyoxyethylene glycol sorbitan alkyl ester surfactants such as polysorbates, sorbitan alkyl ester surfactants, cocamide monoethanolamine, cocamide diethanolamine and dodecyldimethylamine oxide Selected from the group.

  In a particularly preferred embodiment, the surfactant used is selected from polyoxyethylene glycol alkyl ether surfactants, including commercially available Brij® agents (Sigma-Aldrich). Particular preference is given to surfactants comprising tricosaethylene glycol dodecyl ether, more preferably consisting of tricosaethylene glycol dodecyl ether. In a very particularly preferred embodiment, the commercially available Brij® L23 (Sigma-Aldrich), also called Brij35 or polyoxyethylene (23) lauryl ether, is used. In a further specific embodiment, the commercially available Brij® 58, also known as polyethylene glycol hexadecyl ether or polyoxyethylene (20) cetyl ether, also known as polyethylene glycol dodecyl ether or polyoxyethylene (4) lauryl ether. Commercially available Brij® L4 is preferred.

In another embodiment, alkylaryl polyether alcohols, preferably commercially available Triton X-100 and especially 4- (1,1,3,3-tetramethylbutyl) phenyl-polyethylene glycol and the formula C ₁₄ H ₂₂ O (C _It is preferred to use a compound of ₂ H ₄ O) _n H, where n is 9 and 10. Alternatively or in addition, octylphenol ethoxylate surfactants such as ECOSURF ™ surfactant (commercially available from Dow) such as ESOSURF ™ EH-9 (90%) or TERGITOL® A surfactant (commercially available from Dow), such as TERGITOL® 15-S-9, can be preferably used.

In another embodiment, organosilicones such as polyether siloxanes and polyether siloxane copolymers, such as the commercially available TEGO® additive (Evonik), preferably TEGO® Wet 270 and especially 3- [methyl-bis Preferably, a surfactant comprising, preferably consisting of (trimethylsilyloxy) silyl] propyl-polyethylene glycol or preferably TEGO® Wet280 is used. In addition, silicone surfactants described in TEGO® WET260 and TEGO® Wet KL245 and US Pat. No. 7,618,777 (US 7,618,777), such as H ₃ CSi ( CH ₃ ) ₂ OSiO (CH ₃ ) (CH ₂ CH ₂ CH ₂ O (CH ₂ CH ₂ O) ₇ CH ₃ ) Si (CH ₃ ) ₃ may be preferably used.

  In yet another embodiment, a fluorosurfactant, preferably FluorN322 and especially 2-[[2-methyl-5- (3,3,4,4,5,5,6,6,7,7,8, It is preferred to use a surfactant comprising, more preferably consisting of 8,8-tridecafluoro-octoxycarbonylamino) phenyl] carbamoyloxy] ethyl-polypropylene glycol. Other fluorosurfactants such as commercially available FluorN 561 and FluorN 562 (Cytonix) can also be preferably used.

  In yet another embodiment, a poloxamer copolymer, preferably a copolymer comprising units of polyethylene oxide and polypropylene oxide, more preferably a triblock consisting of a central hydrophobic block of polypropylene glycol adjacent to two hydrophilic blocks of polyethylene glycol. Preference is given to using copolymers and in particular the commercially available poloxamer 407 or Pluronic® F-127 (BASF) or Synperonic PE / F127 (Croda).

  In some cases, it may be preferable to provide a nonionic, partially water soluble surfactant that has a low molecular weight or is an oligomer.

  Surprisingly, relatively small amounts of additives may already be sufficient to favorably affect product properties. Preferably the additives comprise less than 10% by weight of the finally obtained capsule, more preferably less than 5% by weight, in particular less than 2.5% by weight. It is further preferred that the capsule contains the additive in an amount of at least 0.01% by weight, more preferably at least 0.05% by weight, based on the weight of the whole capsule.

  In a preferred embodiment, the amount of additive added prior to or in step (d) of the polymerization step (c) is not more than 10% by weight relative to the composition provided in step (a), preferably Is limited to 5 wt% or less, more preferably 2.5 wt% or less, and even more preferably 1 wt% or less. In one embodiment, the amount of additive relative to the composition provided in step (a) is particularly preferably in the range 0.05% to 1% by weight, even more preferably 0.1% to 1% by weight. Is set in the range.

  Another aspect of the present invention is a nanocapsule, each comprising a polymer shell, a core containing a mesogenic medium comprising one or more compounds of formula I as described above and below, and one or more additives About. Preferably and expediently the nanocapsules are obtained or can be obtained by carrying out the method according to the invention.

  Advantageously, nanocapsules that are improved in terms of lowering the operating voltage, in particular in electro-optic applications with the additional beneficial properties described above and below, are obtained or can be obtained by carrying out the method according to the invention It was recognized that.

  Furthermore, surprisingly, it is possible to provide stable and reliable nanocapsules including mesogenic media with favorable electro-optical properties and adequate reliability, while further providing the same and / or additional benefits, such as It has been found that one or more additives, preferably one or more surfactants, can be incorporated that can provide or contribute to a reduction in operating voltage.

  It has further been recognized that the nanocapsules according to the invention can be obtained or obtained from a method based on in situ polymerization and in particular PIPS in nanoemulsions. Thus, unexpectedly, it is possible to provide a light modulating material comprising LC nano-sized droplets (nanodroplets) as a core encapsulated by a polymer shell, where the entire nanocapsules, and even The mesogenic medium included therein also has suitable and further improved properties.

  As mentioned above, the properties of the nanocapsules can be further influenced and adjusted by adding, preferably incorporating, an additive, preferably a surfactant. Surprisingly, even after the nanocapsules have been manufactured or provided, the subsequent introduction of the additive still contributes to the properties and performance of the nanocapsules, and under certain conditions these can be further increased. It has also been found that it may improve.

  By providing the nanocapsules according to the present invention, it is possible to confine discrete amounts of LC material in the nanovolume, which can be stably included and handled individually, and incorporated into various environments. Or dispersion becomes possible. The LC material nanoencapsulated by the polymer shell can be easily applied to and supported by a single substrate. The substrate may be flexible and the layer thickness or film thickness may be variable or variable. The LC media surrounded by, or encapsulated by, the polymer wall can operate in at least two states.

  However, each nanodroplet provides only a relatively small amount of LC. Thus, LC components that now have a suitably large Δn and also exhibit good transmission and good reliability, such as particularly suitable voltage holding ratio (VHR) and thermal and UV stability, and relatively low rotational viscosity Has been realized to be preferred and expedient. Furthermore, a relatively low threshold voltage can be obtained in an electro-optical device application by conveniently providing the LC component with an appropriate and reasonably high value of the dielectric anisotropy Δε. In this respect, the operating voltage can be further appropriately reduced by using the above surfactant.

  In addition, in nanocapsules, the interfacial region between the LC core and the polymer shell is relatively large compared to the provided nanovolume, so that the respective properties of the polymer shell component and the LC core component and their interrelationship are It was recognized that particular considerations need to be taken into account. In the nanocapsules according to the invention, the interaction between the polymer and the LC component can be conveniently and appropriately set and tuned, which was mainly provided for nanoencapsulation according to the invention It can be obtained by the composition and the control and adaptability of the provided manufacturing method. Furthermore, additives, preferably surfactants, can further influence or change these interactions.

  For example, interfacial interactions may support or prevent the formation of any alignment or orientation in the LC nanodroplets.

  Considering the small size of the nanocapsules, which is a subwavelength of visible light and can be even smaller than λ / 4 of visible light, it is advantageous if the capsule is only a very weak scatterer of visible light There is.

  Furthermore, in the absence of an electric field, depending on the interfacial interaction, LC media may in some cases form a disordered phase, in particular an isotropic phase, that has little or no orientation in the nanosize volume. For example, excellent viewing angle behavior can be provided. Furthermore, having an isotropic phase that is in a non-powered or non-addressed state is advantageous in device applications in that a very good dark state can be achieved, especially when using a polarizer. obtain.

  For example, in contrast to the occurrence of radial or bipolar orientation, it is believed that in some cases such orientation may not occur or at least be restricted due to the small volume provided in the nanocapsules.

  Alternatively, and also as preferred in certain embodiments, interfacial interactions to induce or affect alignment and orientation in the LC media, for example, by setting or adjusting the anchoring strength with the capsule wall The structure that can be used may arise. In such cases, uniform planar, radial or bipolar alignment can occur. If such nanocapsules, each and individually with LC orientation or alignment, are randomly dispersed, overall optical isotropy can be observed.

  Spherical or elliptical geometries along the curve set constraints or boundary conditions on the nematic configuration as well as the alignment of liquid crystal molecules, which is the anchoring of LC at the capsule surface, the elastic properties and the bulk and It can be further determined by the surface energy as well as the capsule size. The electro-optic response is then determined by the LC order and orientation in the nanocapsules.

  Further, the presence or absence of possible alignment and orientation of the encapsulated LC media is independent of the substrate. Therefore, it is not necessary to provide an alignment layer on the substrate.

  In particular, when the LC in the capsule has a radial configuration and the particle size is below the wavelength of light, the nanocapsule is substantially optically isotropic or exhibits pseudo-isotropic optical properties. Thereby, an excellent dark state can be realized when two crossed polarizers are used. An axial configuration that is optical anisotropy can be obtained during field switching, particularly in-plane switching, and the induced birefringence transmits light. Thus, in a preferred embodiment, the LC material contained in the nanocapsule has a radial configuration.

  For switching, in particular for switching based on birefringence induced in IPS configurations, dielectrically positive or dielectrically negative LC media may be used.

  The present invention provides convenient nanocapsules, ie capsules constituting a nanocontainer with a polymer shell, which is optionally and preferably cross-linked and filled with LC material. The nanocapsule further comprises one or more additives as described above. Capsules are individual and discrete, ie discrete and dispersive particles, having a core-shell structure. The capsules can act individually, but can also act collectively as a light modulating material. They can be applied to various environments and can be redispersed in various media depending on the dispersion medium. For example, they may be dispersed in water or an aqueous phase, dried and dispersed in a binder, preferably a polymer binder.

  Nanocapsules can also be referred to as nanoparticles. In particular, the nanoparticles comprise a nanoscale LC material surrounded by a polymer shell. These nano-encapsulated liquid crystals may optionally be further embedded in a polymer binder.

  On the other hand, if the phase separation is less pronounced or less complete, the polymer network may be able to form inside the droplet, so that the LC material fills the voids. Capsules exhibiting a uniform or porous interior are obtained. In this case, the LC material fills the pores of the sponge-like structure or network, while the shell surrounds the LC material.

  In a further different case, the separation between the LC material and the polymer may be at an intermediate level, where the interface or boundary between the LC interior and the wall is less noticeable and the gradient Shows behavior.

  However, it is preferred that an efficient and complete separation of the shell polymer and the LC material is obtained, and a shell having a particularly smooth inner surface is obtained.

  Optionally, the included mesogenic medium may further contain one or more chiral dopants and / or one or more pleochroic dyes and / or other conventional additives.

  Advantageously, the nanocapsules according to the invention can be obtained or obtained from the polymerization of the composition described above, in particular from the efficient and controlled method described herein. it can. Surprisingly, in the nanocapsules, the shell polymer can be provided by polymerizing the above precursor compounds that are particularly well suited for LC components and compatible with LC performance. It is preferred that the electrical impedance of the capsule polymer is at least equal to the electrical impedance of the LC material, more preferably greater than the electrical impedance of the LC material. Additives can be useful in appropriately adjusting properties and performance in this regard.

  In addition, the shell polymer may be advantageous in terms of dispersibility and avoiding unwanted aggregation. Furthermore, the shell polymer can function well in combination with a binder, for example in film-forming composite systems, especially in electro-optic applications. Additives can also advantageously affect capsule properties in this regard, for example from the viewpoint of avoiding agglomeration or improving film formability.

  The capsules according to the invention in which the liquid crystals are encapsulated by shell material components are characterized in that they are nano-sized. Preference is given to nanocapsules having an average size of 400 nm or less.

  Preferably, the nanocapsules have an average size of 400 nm or less, more preferably 300 nm or less, even more preferably 250 nm or less, as measured by dynamic light scattering analysis. Dynamic light scattering (DLS) is a generally known technique useful for measuring the size and size distribution of particles in the submicron region. For example, a commercially available Zetasizer (Malvern) may be used for DLS analysis.

  Even more preferably, the average size of the nanocapsules is preferably below 200 nm, in particular 150 nm or less, as measured by DLS. In a particularly preferred embodiment, the average nanocapsule size is below the wavelength of visible light, in particular smaller than λ / 4 of visible light. Advantageously, the nanocapsules according to the invention can be very weak scatterers of visible light in at least one state, in particular with an appropriate LC alignment or configuration, i.e. they do not scatter or substantially display visible light. Was found not to scatter. In this case, the capsule may be useful for modulating the phase shift between the two polarization components of light, i.e. the phase delay, but does not exhibit or substantially exhibits undesired scattering of light in either state. Absent.

  In one embodiment, the phase delay is set to approximately λ / 2, particularly λ / 2 for a wavelength of 550 nm. This can be accomplished, for example, by providing the appropriate type and amount of nanocapsules in the membrane and setting the appropriate thickness.

  For electro-optic applications, the polymer encapsulated mesogenic medium preferably exhibits a confinement size of 15 nm to 400 nm, more preferably 50 nm to 250 nm, especially 75 nm to 150 nm.

  Considering that the size of the capsule becomes very small, especially when approaching the molecular size of the LC molecule, the amount of encapsulated LC material is reduced and the mobility of the LC molecule is more limited, so the functionality of the capsule is May become less efficient.

  The thickness of the polymer shell or wall forming the discrete individual structure is relatively flexible and the LC material's thickness while the contained LC medium is effectively contained and stably confined. It is selected such that excellent electrical responsiveness is still possible. From the standpoint of capacitance and electro-optic performance, the shell should preferably be as thin as possible and still provide strength suitable for inclusion. Thus, the typical capsule shell or wall thickness is below 100 nm. Preferably the polymer shell has a thickness of less than 50 nm, more preferably less than 25 nm, in particular less than 15 nm. In a preferred embodiment, the polymer shell has a thickness of 1 nm to 15 nm, more preferably 3 nm to 10 nm, especially 5 nm to 8 nm.

  Microscopic techniques, particularly SEM and TEM, can be used to observe the size, structure and morphology of the nanocapsules. The wall thickness can be determined, for example, by TEM of a frozen and crushed sample. A neutron scattering technique may also be used. Furthermore, for example, AFM, NMR, ellipsometry techniques, and sum frequency generation techniques may be useful for studying nanocapsule structures. The nanocapsules according to the invention typically have a spherical or elliptical shape, in which a hollow spherical or elliptical shell is filled with the LC medium according to the invention, or a hollow spherical or elliptical shape. Shaped shells include LC media according to the present invention.

  For this reason, the present invention provides a plurality of discrete spherical or elliptical LCs, each nano-encapsulated by a polymer shell, each capable of operating individually or collectively in at least two states in an electro-optic device. Provide an object or particle.

  The LC component provides the beneficial chemical, physical and electro-optical properties described above, such as good reliability and stability and low rotational viscosity. In a preferred embodiment, the LC medium according to the invention has a birefringence of Δn ≧ 0.15, more preferably ≧ 0.20, most preferably ≧ 0.25. Even more preferably, the LC medium according to the invention further has a dielectric anisotropy of Δε ≧ 10.

  Surprisingly, by properly providing and setting the birefringence and dielectric anisotropy according to the present invention, it is sufficient to modulate light effectively and efficiently, even for small nanovolumes of LC. In that case, only a moderate electric field or a moderate driving voltage need be used to cause or change the alignment of the LC molecules in the nanocapsules.

  Furthermore, another advantage of the present invention is the possibility of obtaining a substantially uniform capsule size, i.e. achieving a low polydispersity. This uniformity may advantageously provide uniform electro-optic performance of the capsule in device applications.

  Furthermore, the capsules obtained or obtainable from the controlled and adaptable method according to the invention can be adjusted and adjusted with respect to the capsule size, so that in particular the Kerr effect in particular. The electro-optical performance can be adjusted as desired based on the above.

  The small and uniform size of the nanocapsules can be beneficial in terms of obtaining fast and uniform switching in response to an applied electric field, preferably a low millisecond or even sub-millisecond response time.

  It has been found that the combination of nanocapsules and binder materials can suitably affect and improve the processability and applicability of light modulating materials, particularly in terms of coating, dripping or printing and film formation on a substrate. It was issued. Accordingly, in another aspect, the present invention provides a method for producing a composite system comprising nanocapsules and a binder. In addition, the method is devised such that the resulting system further comprises one or more additives, preferably one or more surfactants as described above. Products further improved or tuned with this system, preferably with additives incorporated into the nanocapsules, preferably at least to some extent, especially with respect to operating voltage, but also with respect to, for example, excellent dark conditions, advantageously low hysteresis and film formation Properties can be given. Advantageously, the composite manufacturing method provides useful flexibility as to when and how additives can be added.

  In this method, nanocapsules that already contain one or more additives may also be provided. However, in a different embodiment, the initially provided nanocapsules do not contain one or more additives. The nanocapsules are suitably mixed with one or more binders, in addition to the one or more additives described above. In particular, the additives used in step (d) of capsule production can also be used advantageously for the production of the composite system according to the invention. The addition of an additive, preferably a surfactant, can be performed simultaneously with and / or after the addition of the binder. However, it is preferable that an additive is added with a binder so that the component containing a nanocapsule can be mixed more easily and in a wider range.

  The one or more binders can act as both a dispersant and an adhesive or binder, and can provide adequate physical and mechanical stability while maintaining or further promoting flexibility. Furthermore, the density or concentration of the capsule can be advantageously adjusted by changing the amount of binder or buffer material provided.

  Thus, the present invention provides a composite system comprising nanocapsules according to the present invention, one or more binders and one or more additives, wherein the system is preferably and conveniently described above. And can be obtained by performing the method described below.

  Discrete nanocapsules can be mixed with the binder material, where the mixed nanocapsules substantially maintain, preferably completely maintain, their integrity in the composite, while the binder It has been found to be bound, retained or immobilized. In this regard, the binder material may be the same material as the polymer shell material or a different material. Thus, according to the present invention, the nanocapsules can be dispersed in a binder composed of the same material as the material of the nanocapsule shell or a different material. Preferably the binder is a different material or at least a modified material. In addition, according to the present invention, one or more additives, preferably surfactants, that appropriately affect the properties of the resulting system are incorporated.

  Binders can be useful in that the nanocapsules can be dispersed and the amount or concentration of capsules can be set and adjusted. Surprisingly, providing the capsules and a suitable binder independently not only adjusts the amount of capsules in the combined composite, but also if required, especially at a very high content, or Even very low contents can be adjusted. Typically, the nanocapsules are included in the composite in a proportion of about 2% to about 95% by weight. Preferably the composite contains nanocapsules in the range of 10 wt% to 85 wt%, more preferably 30 wt% to 70 wt%. In a preferred embodiment, the amount of binder and nanocapsules used is approximately the same. The amount of additive in the composite system is typically significantly less than the amount of nanocapsules or binder. Preferably, the amount of additive in the resulting system is 5 wt% or less, more preferably 2.5 wt% or less, and even more preferably 1 wt% or less, based on the total system composition. The amount of additive in the composite system is particularly preferably set in the range of 0.05% to 1% by weight, even more preferably in the range of 0.1% to 1% by weight, based on the total system composition. Is done.

  The binder material and preferably also the additives or a combination of both can improve or affect the coatability or printability of the capsules and the ability and performance of the film formation. Preferably, the binder can provide mechanical support and function as a matrix while maintaining a suitable degree of flexibility. Furthermore, the binder exhibits adequate and sufficient transparency.

  In one embodiment, the binder may be selected from inorganic glass monoliths or other inorganic materials as described, for example, in US Pat. No. 4,814,211 (US 4,814,211).

  However, the binder is preferably a polymer material. Suitable materials may be synthetic resins such as thermosetting epoxy resins and polyurethanes. In addition, vinyl compounds and acrylates, in particular polyvinyl acrylate and polyvinyl acetate, may be used. In addition, polymethyl methacrylate, polyurea, polyurethane, urea formaldehyde, melamine formaldehyde, melamine urea formaldehyde may be used or added. In some embodiments, acrylates and methacrylates are used as binders.

  Particularly preferred are water-soluble polymers such as polyvinyl alcohol (PVA), starch, carboxymethylcellulose, methylcellulose, ethylcellulose, polyvinylpyrrolidine, gelatin, alginate, casein, gum arabic or latex-like emulsion. The binder may be selected in consideration of setting hydrophobicity or hydrophilicity, for example.

  In one embodiment, the binder, especially the dry binder, absorbs little or no water.

  In a particularly preferred embodiment, the one or more binders comprise polyvinyl alcohol comprising partially and fully hydrolyzed PVA. Advantageously, water solubility and hydrophilicity can be adjusted by changing the degree of hydrolysis. Thus, water uptake may be controlled or reduced. Properties of PVA, such as mechanical strength or viscosity, may be conveniently set, for example, by adjusting molecular weight, degree of hydrolysis, or by chemical modification of PVA.

  Binder properties can also be influenced advantageously by binder crosslinking. Thus, particularly where PVA is provided as a binder, in one embodiment, the binder is preferably cross-linked by a cross-linking agent such as a dialdehyde such as glutaraldehyde, formaldehyde and glyoxal. Such cross-linking may advantageously reduce, for example, the tendency for undesirable crack formation.

  In addition to the one or more additives described above, preferably surfactants, the composite may further comprise conventional additives such as stabilizers, antioxidants, free radical scavengers and / or plasticizers. Good.

  For binders, especially PVA, ethylene glycol can be used as a preferred plasticizer. It is also possible to use 1-octanol glycerol, or alternatively or in addition thereto.

  In one embodiment, the nanocapsules are mixed with PVA and glycerol, more preferably with PVA, glycerol and 1-octanol, even more preferably with PVA, glycerol, TEGO® Wet 270 and optionally 1-octanol. The

  In addition, film forming agents such as polyacrylic acid and antifoaming agents may be added to favorably affect the film forming properties.

  Such agents may be used to improve film formability and substrate wettability. Optionally, the coating composition can be degassed and / or filtered to further improve the membrane properties. Similarly, setting and adjusting the binder viscosity can favorably affect the film being formed or formed.

  It is also possible to add wetting or drying agents to the binder.

  The binder can be provided as a liquid or paste, and the carrier medium or solvent, such as water, aqueous solvent or organic solvent, is removed from the composite mixture, for example by evaporation at high temperature, during or after film formation. be able to.

  The binder is preferably well mixed and united with the nanocapsules. In this case, the additive contributes appropriately depending on the case. Furthermore, capsule agglomeration is adequately avoided or minimized, for example so that light leakage can be avoided or minimized, which in turn can enable a very good dark state. Furthermore, the binder can be selected such that a high density of nanocapsules can be provided in the composite, for example in a film formed from the composite. Furthermore, in the composite, the structural and mechanical advantages of the binder can be combined with the favorable electro-optical properties of the LC capsule. Additives can be useful to further improve these properties.

  A top coating or overcoat may be applied to the produced membrane comprising nanocapsules and binder using, for example, cellulose or cellulose derivatives, polysiloxane or thiolene as such coatings.

  The nanocapsules according to the invention can be applied to a wide variety of different environments, in particular by (re) dispersing them. They may conveniently be dispersed as a plurality of capsules in the binder or mixed with the binder. The binder can not only improve the film forming behavior but also the film properties, and in particular, the binder can hold the capsule against the substrate. Typically, the capsules are randomly distributed or randomly oriented in the binder. Due to the alignment of the LC in the capsule, in particular in the case of radial alignment and / or due to a random distribution throughout the capsule, it is optically isotropic on a macroscopic scale or at least substantially optically isotropic. A certain material can be obtained.

  The composite containing the binder material, but also the nanocapsules alone may be suitably applied or laminated to the substrate. For example, only composites or nanocapsules can be applied onto a substrate by conventional coating techniques such as spin coating, blade coating or drop coating. Alternatively, they can be applied to the substrate by a known printing method such as inkjet printing. It is also possible to dissolve the capsule or composite in a suitable solvent. This solution is then coated or printed onto the substrate, for example by spin coating or printing or other known techniques, and the solvent is allowed to evaporate. In many cases, it is appropriate to heat the mixture to facilitate evaporation of the solvent. As solvent, for example, water, aqueous mixtures or standard organic solvents can be used.

  It is also preferred that the material applied to the substrate is a composite, i.e. it also contains a binder. Typically, a film is formed having a thickness of less than 25 μm, preferably less than 15 μm. In a preferred embodiment, the membrane composed of the composite has a thickness of 0.5 μm to 10 μm, very preferably 1 μm to 7 μm, in particular 2 μm to 5 μm. In particularly preferred embodiments, the layer thickness is in the range of 2 μm to 4 μm, more preferably 3 μm to 4 μm, even more preferably 3.5 μm to 4.0 μm.

  As the substrate, for example, glass, silicon, quartz sheet or plastic film can be used. It is also possible to place the second substrate on the applied, preferably coated or printed material. Isotropic or birefringent substrates can be used. It is also possible to apply the optical coating, in particular with an optical adhesive.

  In a preferred embodiment, the substrate can be a flexible material. Given the flexibility provided by the composite, an overall flexible system or device is obtained.

  Suitable and preferred plastic substrates are for example films of polyester, such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyvinyl alcohol (PVA), polycarbonate (PC) or triacetyl cellulose (TAC), more preferably PET or It is a TAC film. As the birefringent substrate, for example, a uniaxially stretched plastic film can be used. PET films are commercially available, for example, from DuPont Teijin Films under the trade name Melinex®.

  The substrate may be transparent and may be transmissive or reflective. For electro-optical addressability, the substrate can exhibit electrodes. In an exemplary embodiment, a glass substrate having an ITO electrode is provided.

  The electrical and optical properties of the LC material, polymer capsule shell and binder are conveniently and preferably adapted or arranged in terms of compatibility and the respective application. The composite according to the invention may provide suitable and advantageous electro-optical behavior and performance. In this respect, the additive can adequately affect behavior and performance.

  Furthermore, excellent physical and chemical stability can be obtained, for example, preferably and conveniently by reducing water uptake. In particular, good stability and durability against thermal or mechanical stress can be achieved, while at the same time providing adequate mechanical flexibility.

  In view of the LC electrical responsiveness and the appropriate dielectric constant close to the dielectric constant of the LC material to limit the charge at the interface, the binder and preferably the polymer shell also preferably have a relatively large impedance. It is observed that the dielectric constant of the binder is high enough to ensure that the electric field is applied efficiently across the LC medium in the capsule. Any charge or ionic content in these materials is preferably minimized to keep the conductivity very low. In this respect, it has been found that the properties of the provided binder, preferably PVA, can be improved by purification, in particular by removing impurities or charged contaminants. For example, binders, particularly PVA, may be dissolved in deionized water or alcohol, washed and processed by dialysis or Soxhlet purification.

Furthermore, the refractive indices of the LC material, polymer capsule shell and binder are conveniently and preferably adapted or arranged in view of optimal performance in the respective application. In particular, the LC material and the binder have the same refractive index. In particular the refractive index and the case of the binder, the refractive index of the capsule polymer is also extraordinary refractive index of the LC _(n e), taking into account normal refractive index of the LC _{(n o)} or the average refractive index of the LC and _{(n avg)} Configuration Or can be adjusted. In particular, the refractive index of the binder and shell polymer can also be closely matched to the n _e , n _o or n _avg of the LC material.

In one embodiment, the nanocapsules are dispersed in a binder, and the capsules in the binder exhibit random orientation with respect to each other. This mutual random orientation of the capsules, regardless of the possible presence or absence of alignment or orientation of the LC material within each individual capsule, results in an LC material that yields an overall observed average refractive index (n _avg ). Can be done. Considering the nano size of the capsule and its favorable possibility of acting only as a very weak scatterer of light, in this embodiment the application of an electric field (where the electric field forces (re) alignment of the LC material) Can modulate the phase shift or phase delay of transmitted or reflected light, but does not change the apparent scattering, even if there is an apparent scattering. In such a case, especially when the capsule size is clearly smaller than the wavelength of light, the refractive index of the binder and preferably the polymer capsule shell can also be adjusted and adapted appropriately and advantageously to eg n _{avg of the} liquid crystal material. . Thus, nanocapsules can behave as efficient nanoscale phase modulators.

  If the capsule is nano-sized and there is no electric field, light scattering can be substantially suppressed, preferably completely suppressed, especially for sizes smaller than 400 nm. Further, scattering and refraction can be controlled by adapting or adjusting the refractive index of the LC material and the polymer material.

  If the capsules and the respective LC directors are randomly oriented in the binder, in one embodiment, the phase shift may be independent of polarization for normal incident light.

  In another embodiment, the capsules are aligned or oriented in the binder.

  The composite system according to the invention advantageously makes it possible to set and adjust a high degree of flexibility and in particular a multi-degree of freedom in terms of adjusting electro-optical properties and functionality. For example, the thickness of a layer or film can be set, adapted or changed while independently changing the density of the nano-sized LC material in the film, and the nanocapsule size, i.e. the LC in each individual capsule. The amount of material can also be preset and adjusted accordingly. In addition, the LC medium can be selected to have certain characteristics, such as reasonably high values of Δε and Δn.

  In a preferred embodiment, the amount of LC in the compositions, nanocapsules and composites is suitably maximized to conveniently achieve high electro-optic performance.

  According to the present invention, a relatively easy-to-manufacture and highly workable composite that can enable good transmission, low operating voltage, improved VHR and good darkness can be advantageously provided. Surprisingly, it can be applied to a single substrate that does not have an alignment layer or that does not rub the surface, and it is suitable for deviations in layer thickness or for external forces such as touching and light. A robust, effective and efficient system can be obtained which can be relatively insensitive to leakage. Furthermore, a wide viewing angle can be obtained without providing an alignment layer or an additional phase retardation layer.

  Preferably and conveniently, the provided nanocapsule and composite systems exhibit sufficient processability so that the capsule is concentrated and filtered, mixed with a binder, filmed, and optionally the film is dried. Aggregation is minimized.

  The nanocapsules and composite systems according to the invention are useful in optical and electro-optical applications, in particular light modulation elements or electro-optical devices, in particular displays. In display applications, fast response and switching times, and thus, for example, fast video and / or sequential color capabilities can be obtained.

  In particular, nanocapsules containing LC media, preferably mixed with a binder, are suitable for efficient control and modulation of light. They can be used, for example, in optical filters, variable polarizers and lenses and phase plates. As phase modulators, they can be useful for optical devices, optical communications and information processing and three-dimensional displays. A further application is a switchable smart window or privacy window.

  For this reason, the present invention advantageously provides a light modulation element and an electro-optic modulator. These elements and modulators comprise nanocapsules according to the invention, preferably the capsules are mixed and dispersed in a binder. The use of one or more additives according to the invention in nanocapsule and / or composite systems can advantageously reduce the operating voltage. At the same time, in addition to the favorable effect on the threshold voltage and the switching voltage, further suitable product properties can be obtained.

  Further provided are electro-optic devices, in particular electro-optic displays, which advantageously use the nanocapsules and / or composite systems described above and below. The device is provided with a plurality of nanocapsules.

  Many of the mesogenic compounds described above and below or mixtures thereof are commercially available. All these compounds are known or described in the literature (for example in the authoritative work, eg Houben-Weyl, Method der Organicis Chemie [Methods of Organic Chemistry], Georg-Thiet, Sir. Which is known per se, but can precisely be prepared by processes known and appropriate for the reaction conditions. Here, variants which are known per se but are not mentioned in detail here may be used.

  The medium according to the invention is itself produced in a customary manner. Overall, the components are dissolved with each other, preferably at high temperatures. By suitable additives, the liquid crystal phase of the present invention can be modified so that it can be used in a liquid crystal display device. Such additives are known to those skilled in the art and are described in detail in the literature (H. Kelker / R. Hatz, Handbook of Liquid Crystals, Verlag Chemie, Weinheim, 1980). For example, pleochroic dyes can be added for the production of colored guest-host systems, and materials can be added to alter the dielectric anisotropy, viscosity and / or alignment of the nematic phase.

  The term “alkyl” according to the invention preferably includes straight-chain and branched alkyl groups having 1 to 7 carbon atoms, in particular the straight-chain groups methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl. To do. Groups having 2 to 5 carbon atoms are generally preferred.

  Alkoxy may be straight-chain or branched, preferably straight-chain, having 1, 2, 3, 4, 5, 6 or 7 carbon atoms and therefore preferably methoxy, ethoxy, propoxy , Butoxy, pentoxy, hexoxy or heptoxy.

The term “alkenyl” according to the invention includes straight-chain and branched alkenyl groups, preferably straight-chain groups, preferably having 2 to 7 carbon atoms. Particularly preferred alkenyl _groups, C _{2 ~C} 7 -1E- _alkenyl, C _{4 ~C} 7 -3E- _alkenyl, C _{5 ~C} 7 -4E- _alkenyl, C _{6 ~C} 7 -5E- alkenyl and _C 7 -6E - alkenyl, in particular _C 2 _{-C 7-1E-alkenyl,} C ₄ -C 7 -3E-alkenyl and _C 5 _~C 7 -4E- alkenyl. Examples of preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z -Hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl and 6-heptenyl. Groups having up to 5 carbon atoms are generally preferred.

Alkyl fluoride or alkoxy is CF ₃ , OCF ₃ , CFH ₂ , OCFH ₂ , CF ₂ H, OCF ₂ H, C ₂ F ₅ , OC ₂ F ₅ , CFHCF ₃ , CFHCF ₂ H, CFHCHFH ₂ , CH ₂ CF ₃ , CH ₂ CF ₂ H, CH ₂ CFH ₂ , CF ₂ CF ₂ H, CF ₂ CFH ₂ , OCHFHCF ₃ , OCHFHCF ₂ H, OCHFHCHF ₂ , OCH ₂ CF ₃ , OCH ₂ CF ₂ H, OCH ₂ CFH ₂ , _{OCF 2 CF 2 H, OCF 2} CFH 2, C 3 F 7 or _OC 3 _{F 7,} in particular _{CF 3, OCF 3, CF 2} H, OCF 2 H, C 2 F 5, OC 2 F 5, CFHCF 3, CFHCF _{2 H, CFHCFH 2, CF 2} CF 2 H, CF 2 CFH 2, OCFHCF 3, OCFHCF 2 H, OC _{HCFH 2, OCF 2 CF 2 H} , OCF 2 CFH 2, C 3 F 7 or _OC 3 _{F 7,} particularly preferably from OCF ₃ or OCF ₂ H. In a preferred embodiment, the fluoroalkyl is a linear group containing a terminal fluorine, i.e. fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. Is included. However, fluorine at other positions is not excluded.

Oxaalkyl, preferably of the formula _{C n H 2n + 1 -O- (} CH 2) m [ wherein, n and m are, independently of one another, are 1 to 6 includes straight chain groups. Preferably n = 1 and m is 1-6.

  Oxaalkyl is preferably linear 2-oxapropyl (= methoxymethyl), 2-(= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2 -, 3-, 4- or 5-oxahexyl, 2-, 3-, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

  Halogen is preferably F or Cl, in particular F.

If one of the groups mentioned above is an alkyl group in which one CH ₂ group is replaced by —CH═CH—, this can be straight-chained or branched. The group is preferably straight-chain and has 2 to 10 carbon atoms. Thus, this group is in particular vinyl, prop-1- or prop-2-enyl, but-1-, -2- or but-3-enyl, penta-1-, -2-, -3- or penta- 4-enyl, hexa-1-, -2-, -3-, -4- or hexa-5-enyl, hepta-1-, -2-, -3-, -4-, -5, or hepta- 6-enyl, octa-1-, -2-, -3-, -4-, -5, -6, or octa-7-enyl, nona-1-, -2-, -3-, -4 -, -5, -6, -7- or non-8-enyl, deca-1-, -2-, -3-, -4-, -5, -6, -7-,- 8- or Dec-9-enyl.

If one of the groups mentioned above is an alkyl group in which one CH ₂ group is replaced by —O— and one is replaced by —CO—, these are preferably adjacent. ing. For this reason, they contain an acyloxy group —CO—O— or an oxycarbonyl group —O—CO—. These are preferably straight-chain and have 2 to 6 carbon atoms.

  Thus, these are in particular acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxy Ethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl , Propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarboxy) ethyl, 2- (ethoxycarbonyl) ethyl, 2- ( Ropo carboxymethyl carboxyethyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl or 4- (methoxycarbonyl) butyl.

One of the groups mentioned above is replaced by —CH═CH—, in which one CH ₂ group is unsubstituted or substituted, and the adjacent CH ₂ group is CO, CO—O Or when it is an alkyl group replaced by O-CO, this may be straight-chain or branched. The group is preferably straight-chain and has 4 to 13 carbon atoms. Accordingly, the same group is particularly acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl, 8-acryloyl. Oxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl, methacryloyloxymethyl, 2-methacryloyloxyethyl, 3-methacryloyloxypropyl, 4-methacryloyloxybutyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7 -Methacryloyloxyheptyl, 8-methacryloyloxyoctyl or 9-methacryloyloxynonyl.

If one of the groups mentioned above is an alkyl or alkenyl group that is monosubstituted by CN or CF ₃ , this group is preferably straight-chain. Substitution with CN or CF ₃ is in any position.

  When one of the groups mentioned above is an alkyl or alkenyl group that is at least monosubstituted by halogen, this group is preferably straight-chain and the halogen is preferably F or Cl, more preferably Is F. In the case of polysubstitution, the halogen is preferably F. The resulting group also includes a perfluorinated group. In the case of monosubstitution, the fluoro or chloro substituent may be in any desired position, but is preferably in the ω position.

  Compounds containing branching groups can be important in some cases in order to improve solubility in some conventional liquid crystal base materials. However, if they are optically active, they are particularly suitable as chiral dopants.

  Such branching groups generally contain no more than one chain branch. Preferred branching groups are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethylhexoxy, 1-methylhexoxy or 1-methylheptoxy It is.

Where one of the groups mentioned above is an alkyl group in which two or more CH ₂ groups are replaced by —O— and / or —CO—O—, this is a straight-chain or branched It can be a chain. The group is preferably branched and has 3 to 12 carbon atoms. Therefore, this group is notably biscarboxymethyl, 2,2-biscarboxyethyl, 3,3-biscarboxypropyl, 4,4-biscarboxybutyl, 5,5-biscarboxypentyl, 6,6-biscarboxyhexyl. 7,7-biscarboxyheptyl, 8,8-biscarboxyoctyl, 9,9-biscarboxynonyl, 10,10-biscarboxydecyl, bis (methoxycarbonyl) methyl, 2,2-bis (methoxycarbonyl) ethyl 3,3-bis (methoxycarbonyl) propyl, 4,4-bis (methoxycarbonyl) butyl, 5,5-bis (methoxycarbonyl) pentyl, 6,6-bis (methoxycarbonyl) hexyl, 7,7-bis (Methoxycarbonyl) heptyl, 8,8-bis (methoxycarbonyl) octyl Bis (ethoxycarbonyl) methyl, 2,2-bis (ethoxycarbonyl) ethyl, 3,3-bis (ethoxycarbonyl) propyl, 4,4-bis (ethoxycarbonyl) butyl or 5,5-bis (ethoxycarbonyl) pentyl It is.

  The LC medium according to the invention preferably has a nematic phase range of −10 ° C. to + 70 ° C. The LC medium may even more suitably have a nematic phase range of −20 ° C. to + 80 ° C. It is even more advantageous when the LC medium according to the invention has a nematic phase range of −20 ° C. to + 90 ° C.

  The LC medium according to the invention preferably has a birefringence of Δn ≧ 0.15, more preferably Δn ≧ 0.20, most preferably Δn ≧ 0.25.

  The LC medium according to the present invention preferably has a dielectric anisotropy of Δε ≧ + 10, more preferably Δε ≧ + 15, most preferably Δε ≧ + 20.

The LC media according to the present invention preferably and conveniently exhibit high reliability and high electrical resistance (also known as specific resistance (SR)). The SR value of the LC medium according to the invention is preferably ≧ 1 × 10 ¹³ Wcm, very preferably ≧ 1 × 10 ¹⁴ Wcm. Unless otherwise stated, the SR measurement is based on G. Weber et al. , Liquid Crystals 5, 1381 (1989).

  Also, the LC media according to the invention preferably and conveniently exhibit a high voltage holding ratio (VHR). S. Matsumoto et al. , Liquid Crystals 5, 1320 (1989); Niwa et al. , Proc. SID Conference, San Francisco, June 1984, p. 304 (1984); Jacob and U.S. See “Merck Liquid Crystals—Physical Properties of Liquid Crystals”, 1997 by Finkenzeller. The VHR of the LC medium according to the invention is preferably ≧ 85%, more preferably ≧ 90%, even more preferably ≧ 95%. Unless otherwise noted, VHR measurements are determined by T.W. Jacob, U .; It is carried out as described in “Merck Liquid Crystals—Physical Properties of Liquid Crystals” by Finkenzeller, 1997.

  In this specification, unless stated otherwise, all concentrations are given in weight percent and relate to the respective complete mixture, except for the aqueous solvent or aqueous phase indicated above.

  All temperatures are in degrees Celsius (° C) and all temperature differences are in degrees Celsius (° C). All physical properties and physicochemical or electro-optical parameters are generally obtained by known methods, in particular “Merck Liquid Crystals, Physical Properties of Liquid Crystals”, Status Nov. 1997, Merck KGaA, Germany, and given at a temperature of 20 ° C. unless otherwise specified.

である。誘電率異方性Δεは、２０℃および１ｋＨｚで決定される。光学異方性Δｎは、２０℃および５８９．３ｎｍの波長で決定される。 Above and below, [Delta] n denotes the optical anisotropy is Δn ₌ n e -n _o, Δε represents a dielectric anisotropy,

It is. The dielectric anisotropy Δε is determined at 20 ° C. and 1 kHz. The optical anisotropy Δn is determined at 20 ° C. and a wavelength of 589.3 nm.

The Δε and Δn values and the rotational viscosity (γ ₁ ) of the compounds according to the invention are 5% to 10% of the respective compounds according to the invention and 90% to 95% of the commercially available liquid crystal mixtures ZLI-2857 or ZLI-4792 ( Both mixtures are obtained by linear extrapolation from a liquid crystal mixture consisting of Merck KGaA).

  In addition to the usual well-known abbreviations, the following abbreviations are used. C: crystalline phase; N: nematic phase; Sm: smectic phase; I: isotropic phase. The number between these symbols indicates the transition temperature of the material concerned.

In the present invention and particularly in the following examples, the structure of mesogenic compounds is indicated by abbreviations, also called acronyms. In these acronyms, chemical formulas are abbreviated as follows, using Tables A to C below. All the groups C _n H _{2n + 1} , C _m H _{2m + 1} and C _l H _{2l + 1} or C _n H _2n−1 , C _m H _2m−1 and C _l H ₂₁₋₁ are respectively n, m and l C atoms. Represents straight-chain alkyl or alkenyl, preferably 1-E-alkenyl. Table A lists the symbols used for the ring elements of the core structure of the compound, while Table B shows the linking groups. Table C shows the meaning of the symbols for the left-hand or right-hand end groups. The acronym consists of a symbol for a ring element with an optional linking group, followed by a symbol for the first hyphen and the left hand end group and a symbol for the second hyphen and right hand end group. Table D shows exemplary structures of the compounds along with their respective abbreviations.

  Here, n and m each represent an integer, and the three points “...” Are synonyms for other abbreviations in this table.

  The following table shows exemplary structures along with their respective abbreviations. These are shown to explain the meaning of the abbreviation rules. These further represent compounds which can preferably be used.

ここで、ｎ、ｍ、ｌおよびｚは、好ましくは互いに独立して、１〜７を表す。

Here, n, m, l and z preferably represent 1 to 7 independently of each other.

  The following table shows exemplary compounds that can be used as additional stabilizers in the mesogenic medium according to the invention.

Table E
Table E shows possible stabilizers that can be added to the LC medium according to the invention, where n is 1 to 12, preferably 1, 2, 3, 4, 5, 6, 7 or 8. The terminal methyl group is not shown.

  The LC medium preferably comprises 0 to 10% by weight of stabilizer, in particular 1 ppm to 5% by weight, particularly preferably 1 ppm to 1% by weight.

  Table F below shows exemplary compounds that can be preferably used as chiral dopants in mesogenic media according to the present invention.

  In a preferred embodiment of the invention, the mesogenic medium comprises one or more compounds selected from the compounds shown in Table F.

  The mesogenic medium according to the present invention preferably contains 2 or more, preferably 4 or more compounds selected from the compounds shown in Tables D to F above.

  The LC medium according to the present invention preferably contains 3 or more compounds, more preferably 5 or more compounds shown in Table D.

  The following examples are merely illustrative of the invention and should not be considered as limiting the scope of the invention in any way. In light of the present disclosure, embodiments and variations or other equivalents thereof will be apparent to those skilled in the art.

は、２０℃、１ｋＨｚでのダイレクタに平行な誘電率を表し、

は、２０℃、１ｋＨｚでのダイレクタに垂直な誘電率を表し、
Δεは、２０℃、１ｋＨｚでの誘電率異方性を表し、
ｃｌ．ｐ．， Ｔ（Ｎ，Ｉ）は、澄明点［℃］を表し、
γ_１は、磁場で回転法により求められた、２０℃で測定された回転粘度［ｍＰａ・ｓ］を表し、
Ｋ_１は、２０℃での「スプレイ」変形の弾性定数［ｐＮ］を表し、
Ｋ_２は、２０℃での「ツイスト」変形の弾性定数［ｐＮ］を表し、
Ｋ_３は、２０℃での「ベンド」変形の弾性定数［ｐＮ］を表す。 In the example example,
V _o represents the capacitive threshold voltage [V] at 20 ° C.,
n _e is, 20 ° C., represents the extraordinary refractive index at 589 nm,
n _o represents the ordinary refractive index at 20 ° C. and 589 nm,
Δn represents optical anisotropy at 20 ° C. and 589 nm,

Represents the dielectric constant parallel to the director at 20 ° C. and 1 kHz,

Represents the dielectric constant perpendicular to the director at 20 ° C. and 1 kHz,
Δε represents the dielectric anisotropy at 20 ° C. and 1 kHz,
cl. p. , T (N, I) represents the clearing point [° C.]
γ ₁ represents the rotational viscosity [mPa · s] measured at 20 ° C. determined by the rotational method in a magnetic field,
K ₁ represents the elastic constant [pN] of the “spray” deformation at 20 ° C.
K ₂ represents the elastic constant [pN] of the “twist” deformation at 20 ° C.
K ₃ represents the elastic constant [pN] of the “bend” deformation at 20 ° C.

The term “threshold voltage” in the context of the present invention relates to the capacitive threshold (V _o ) unless stated otherwise. In the example, the optical threshold may be shown for a relative contrast (V ₁₀ ) of 10%, as is generally normal.

Reference example 1
A liquid crystal mixture B-1 having the composition and properties shown in the following table is prepared and characterized with respect to its general physical properties.

Reference example 2
A liquid crystal mixture B-2 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Reference example 3
A liquid crystal mixture B-3 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Reference example 4
A liquid crystal mixture B-4 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Reference example 5
A liquid crystal mixture B-5 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Reference example 6
A liquid crystal mixture B-6 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Reference example 7
A liquid crystal mixture B-7 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Reference example 8
A liquid crystal mixture B-8 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Reference example 9
A liquid crystal mixture B-9 having the composition and properties shown in the table below is prepared and characterized with respect to its general physical properties.

Example 1
Preparation of nanocapsules LC mixture B-1 (1.00 g), hexadecane (175 mg), methyl methacrylate (100 mg), hydroxyethyl methacrylate (40 mg) and ethylene glycol dimethacrylate (300 mg) are weighed into a 250 ml tall beaker.

  Brij® L23 (50 mg) (from Sigma-Aldrich) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated in an ultrasonic bath for 5-10 minutes.

  This Brij® L23 surfactant aqueous solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  This mixture is charged to a flask with condenser and AIBN (35 mg) is added and heated to 70 ° C. for 3 hours. The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 213 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

Addition of additives From the resulting nanocapsule sample, two portions, each containing 0.21 g of nanocapsules in 20 ml of solution, are each added to a centrifuge tube.

  Add 0.01 g Brij® L23 and Triton X-100 (Sigma-Aldrich) to 0.1 ml water in a centrifuge tube, respectively. 0.01 g Brij® L4 (Sigma-Aldrich) and TEGO® Wet 270 (Evonik) are each added to 0.1 ml isopropanol (IPA) in a centrifuge tube. To these four centrifuge tubes, each containing additives, add a 20 ml portion of the resulting nanocapsule sample (0.21 g).

  Six centrifuge tubes are placed on rollers for 48 hours.

  Thereafter, each of these particle suspensions is concentrated by centrifugation, in which case the centrifuge tube is placed in a centrifuge (ThermoFisher Biofuge Stratos) and centrifuged at 6,500 rpm for 10 minutes and then at 15,000 rpm for 20 minutes. Centrifuge for minutes. The pellets obtained are redispersed in 1 ml of supernatant each.

Production of 30% solids PVA binder PVA (PVA molecular weight _Mw : 31 k; 88% hydrolyzed) is first washed in a Soxhlet apparatus for 3 days to remove ions.

  46.66 g of deionized water is added to a 150 ml bottle, a large magnetic stirrer bar is added, and the bottle is placed on a 50 ° C. stirrer hotplate to this temperature. Weigh 20.00 g of washed solid 31k PVA into a beaker. A vortex is created at the bottom and this 31k PVA is gradually added over about 5 minutes and stopped to disperse the suspended PVA in the mixture. The hot plate is raised to 90 ° C. and stirring is continued for 2-3 hours. The jar is placed in an oven at 80 ° C. for 20 hours. While still warm, the mixture is filtered through a 50 μm fabric filter under an air pressure of 0.5 bar. This filter is replaced with a Millipore 5 μm SVPP filter and filtration is repeated.

  The filtered solid content of the binder is measured three times, an empty DSC pan is weighed using a DSC microbalance, about 40 mg of binder mixture is added to the DSC pan, the weight is recorded and the pan is Placed on a hot plate for 1 hour, then brought the hot plate to 110 ° C. for 10 minutes, removed the pan from the hot plate, allowed to cool, recorded the weight of the dried pan, and calculated the average by calculating the solids content. calculate.

Fabrication of the composite system The resulting 6 nanocapsule samples are first checked under a microscope for unwanted agglomeration or agglomeration and this is also done after deposition. The solid content of each concentrated nanocapsule suspension is measured. At that time, the solid content of each sample is measured three times to calculate the average. These samples are weighed into an empty DSC pan using a DSC microbalance, where each sample is added to the DSC pan and the weight is recorded. The pan is placed on a 60 ° C. hot plate for 1 hour and then the hot plate is brought to 110 ° C. for 10 minutes. Remove bread from hot plate and allow to cool. Record the weight of the dried bread and calculate the solids.

  The manufactured PVA is added to individual concentrated nanocapsule samples, with about 30% of the washed 31k PVA mixture added to 2.5 ml vials, and then each nanocapsule is added to these vials. The weight ratio of PVA to capsule is 50:50. Deionized water is added to bring the total solids to 20%. The mixture is stirred using a vortex stirrer and the mixture is left on a roller overnight to disperse the PVA.

Production of the film on the substrate The substrate used is IPS (in-plane switching) glass with comb-shaped electrodes coated with ITO and having an electrode width of 4 μm and a gap of 8 μm. The substrate is placed in a cleaning rack and a plastic box. Deionized water is added and the sample is placed in the sonicator for 10 minutes. Remove the substrate from the water and blot with a paper towel to remove excess water. For ion chromatography, washing is repeated with acetone, 2-propanol (IPA) and finally with water. The substrate is then dried using a compressed air gun. The substrate is treated with UV-ozone for 10 minutes.

  Next, six composite systems containing each nanocapsule and binder are each coated on the substrate. 40 μL of the mixture is coated as a film using a coating machine (K Control Coater, RK PrintCoat Instruments, bar coating with k-bar 1, coating speed 7). The sample is dried for 10 minutes at 60 ° C. on a hot plate under the lid to prevent drafting and stop contaminants from falling onto the membrane. Record the appearance of the membrane. The produced membrane is stored in a dry box between measurements.

  The film thickness is measured by removing the film from above the electrical contacts with a razor blade. The film thickness is measured in the region of the intermediate electrode using a profilometer (Dektak XT surface profiler, Bruker) at a needle pressure of 5 mg and a scan length of 3000 nm for 30 seconds.

Measurement of electro-optical properties The appearance of each film is visually checked for uniformity and defects. Solder the two electrodes to the glass. The voltage-transmittance curve is measured using dynamic scattering mode (DSM).

  Dark and bright images are also recorded using a microscope at the voltage required for 0% or 10% and 90% transmission respectively.

  The switching speed is measured at 40 ° C. and 25 ° C. with a modulation frequency of 150 Hz and optionally 10 Hz.

The electro-optic parameters measured for the manufactured films containing nanocapsules and binder are shown in the table below. In this example and in the following examples, determine the hysteresis in V _50.

  The electro-optical characteristics shown in the following table are measured by Display Measurement System (Autotronic-Merchers). At this time, the backlight intensity is set to transmittance T100%, and the dark state between crossed polarizers is determined to be transmittance. In this case, switching is performed at 24 ° C. at 1 kHz.

  In particular, it has been found that the improvement of the dark state and the reduction of hysteresis are advantageous, and the additive can appropriately contribute to the reduction of the operating voltage.

Example 2
LC mixture B-1 (1.00 g), hexadecane (175 mg), methyl methacrylate (100 mg), hydroxyethyl methacrylate (40 mg) and ethylene glycol dimethacrylate (300 mg) are weighed into a 250 ml tall beaker.

  Brij® 58 (50 mg) (Sigma-Aldrich) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij® 58 surfactant solution is poured directly into a beaker containing organic material. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  The mixture is then further processed and tested as described above in Example 1.

Example 3
LC mixture B-1 (2.01 g), hexadecane (358 mg), ethylene dimethacrylate (597 mg), 2-hydroxyethyl methacrylate (80 mg) and methyl methacrylate (190 mg) are weighed into a 400 ml tall beaker.

  Brij® 58 (100 mg) is weighed into a 400 ml Erlenmeyer flask and water (250 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij surfactant aqueous solution is poured directly into a beaker containing an organic substance. This mixture is mixed on a turrax at 10,000 rpm for 10 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  This mixture is charged to a flask with condenser and heated to 73 ° C. for 4 hours after adding AAPH (20 mg). The reaction mixture is cooled, filtered, and then subjected to material size analysis with a Zetasizer instrument.

  The resulting capsules have an average size of 230 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer) and a polydispersity of 0.051.

  Samples are concentrated before further use. This is done by passing the sample through a cross-flow filtration device (Sartorius Vivaflow 200, membrane with a molecular weight cut off of 100,000 Da) at a flow rate of 100 ml per minute until the volume is reduced by half. The sample is then transferred to a vacuum suitable lid and washed with a solution composed of 450 ml water and Brij® 58 (200 mg) using the same apparatus.

  After washing the sample, the instrument is operated in a concentrated mode and continued at 100 ml per minute until the minimum volume is reached. Remove the sample from the filter. This sample is suitable for further use.

  The solid content of this sample was measured and found to be 19%.

  Thereafter, a composite system containing a binder and a coating are prepared as described in Example 1, except that the weight ratio of capsule to PVA is 60:40.

For this coated sample, V ₉₀ is 41 V and the dark transmittance is 1.25%.

Example 4
Preparation of nanocapsules LC mixture B-8 (2.00 g), methyl methacrylate (165 mg), hydroxyethyl methacrylate (75 mg) and ethylene glycol dimethacrylate (660 mg) are weighed into a 250 ml tall beaker.

  Brij® L23 (150 mg) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij® L23 surfactant aqueous solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  This mixture is charged to a flask with condenser and AIBN (35 mg) is added and heated to 70 ° C. for 3 hours. The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 167 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

Addition of additive From the resulting nanocapsule sample, a portion of 0.40 g nanocapsule in 20 ml solution is added to a centrifuge tube.

  Add 0.019 g Triton X-100 to 0.1 ml water in a centrifuge tube. 0.019 g Brij® L4, 0.019 g FluorN 561 (Cytonix) and 0.019 g TEGO® Wet 270 are each added to 0.1 ml isopropanol (IPA) in a centrifuge tube. To these four centrifuge tubes, each containing additives, add a 20 ml portion of the resulting nanocapsule sample (0.40 g).

  Five centrifuge tubes are placed on rollers for 48 hours.

  Thereafter, each of these particle suspensions is concentrated by centrifugation, where the centrifuge tube is placed in a centrifuge (ThermoFisher Biofuge Stratos), centrifuged at 6,500 rpm for 10 minutes, and 15,000 rpm for 20 minutes. Centrifuge for minutes. The pellets obtained are redispersed in each 0.7 ml supernatant.

Production of PVA Binder and Composite System and Production of Membrane on Substrate PVA binder, composite system and membrane are produced as described for Example 1.

Measurement of electro-optical properties The appearance of each film is visually checked for uniformity and defects. Solder the two electrodes to the glass. The voltage-transmittance curve is measured using dynamic scattering mode (DSM).

  Dark and bright images are also recorded using a microscope at the voltage required for 0% or 10% and 90% transmission respectively.

  The switching speed is measured at 40 ° C. and 25 ° C. with a modulation frequency of 150 Hz and optionally 10 Hz.

  The electro-optic parameters measured for the manufactured films containing nanocapsules and binder are shown in the table below.

  The electro-optical characteristics shown in the following table are measured by Display Measurement System (Autotronic-Merchers). At this time, the backlight intensity is set to transmittance T100%, and the dark state between crossed polarizers is determined to be transmittance. In this case, switching is performed at 24 ° C. at 1 kHz.

  In particular, it has been found that the improvement of the dark state and the reduction of hysteresis are advantageous, and the additive can appropriately contribute to the reduction of the operating voltage.

Example 5
Preparation of nanocapsules LC mixture B-1 (6.00 g), hexadecane (300 mg), methyl methacrylate (225 mg), hydroxyethyl methacrylate (510 mg) and ethylene glycol dimethacrylate (2000 mg) are weighed into a 250 ml tall beaker.

  Brij® L23 (450 mg) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij® L23 surfactant aqueous solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  This mixture is charged to a flask with condenser and AIBN (75 mg) is added and heated to 70 ° C. for 3 hours. The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 173 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

  The resulting nanoparticle suspension is concentrated by centrifugation, where the centrifuge tube is placed in a centrifuge (ThermoFisher Biofuge Stratos) and centrifuged at 6,500 rpm for 10 minutes and then at 15,000 rpm for 20 minutes. Centrifuge.

Addition of additives The resulting 0.32 g pellet is redispersed in 1 ml supernatant and placed in a 2.5 ml glass bottle.

  Add 0.01 g Brij® L23, Triton X-100, TEGO® Wet 270 and FluorN 322 to each 0.99 g acetone in a 2.5 ml glass bottle. The acetone is then evaporated on a hot plate at 40 ° C. for 10 minutes. Add 1 ml portions of the resulting nanocapsules (0.32 g) to four 2.5 ml glass bottles, each containing additives.

  Five glass tubes are placed on a roller for 48 hours.

Production of PVA Binder and Composite System and Production of Membrane on Substrate PVA binder, composite system and membrane are produced as described for Example 1.

Measurement of electro-optical properties The appearance of each film is visually checked for uniformity and defects. Solder the two electrodes to the glass. The voltage-transmittance curve is measured using dynamic scattering mode (DSM).

  Dark and bright images are also recorded using a microscope at the voltage required for 0% or 10% and 90% transmission respectively.

  The switching speed is measured at 40 ° C. and 25 ° C. with a modulation frequency of 150 Hz and optionally 10 Hz.

  The electro-optic parameters measured for the manufactured films containing nanocapsules and binder are shown in the table below.

  The electro-optical characteristics shown in the following table are measured by Display Measurement System (Autotronic-Merchers). At this time, the backlight intensity is set to T100%, and the dark state between the crossed polarizers is set to the transmittance. In this case, switching is performed at 24 ° C. at 1 kHz.

  In particular, it has been found that the improvement of the dark state and the reduction of hysteresis are advantageous, and the additive can appropriately contribute to the reduction of the operating voltage.

Example 6
Preparation of nanocapsules LC mixture B-1 (1.00 g), hexadecane (179 mg), methyl methacrylate (102 mg), hydroxyethyl methacrylate (40 mg) and ethylene glycol dimethacrylate (303 mg) are weighed into a 250 ml tall beaker.

  Brij® L23 (50 mg) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij® L23 surfactant aqueous solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with turrax is complete, the crude emulsion is passed through a high pressure homogenizer 4 times at 30,000 psi.

  This mixture is charged to a flask with condenser and AIBN (35 mg) is added and heated to 70 ° C. for 3 hours. The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 167 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

  The resulting nanoparticle suspension is concentrated by centrifugation, where the centrifuge tube is placed in a centrifuge (ThermoFisher Biofuge Stratos) and centrifuged at 6,500 rpm for 10 minutes and at 15,000 rpm for 20 minutes. Centrifuge.

Preparation of PVA Binder A PVA binder is prepared as described for Example 1.

Preparation of composite system The prepared 0.22 g nanocapsules in 1.5 ml solution and 0.33 g PVA prepared in 1.2 ml aqueous solution were mixed to give a PVA to capsule weight ratio of 60:40. Get.

  The mixture is stirred using a vortex stirrer and the mixture is left on a roller overnight to disperse the PVA.

  Three separate parts are produced from this mixture. One of these parts is used for film formation without the addition of further additives and the other two are added as follows.

Additive Addition 0.2 μL TEGO® Wet 270 in 0.02 g acetone and 0.2 μL TEGO® Wet 280 in 0.02 g isopropanol (IPA), each in separate bottles Add to. The solvent is evaporated over the next 24 hours. To each bottle, add a 0.20 g portion of the prepared PVA and nanocapsule mixture.

  Mixtures containing TEGO® Wet 270 or TEGO® Wet 280 are further mixed for 24 hours.

Production of the membrane on the substrate The membrane is produced as described for Example 1.

Measurement of electro-optical properties The appearance of each film is visually checked for uniformity and defects. Solder the two electrodes to the glass. The voltage-transmittance curve is measured using dynamic scattering mode (DSM).

  Dark and bright images are also recorded using a microscope at the voltage required for 0% or 10% and 90% transmission respectively.

  The switching speed is measured at 40 ° C. and 25 ° C. with a modulation frequency of 150 Hz and optionally 10 Hz.

  The electro-optic parameters measured for the manufactured films containing nanocapsules and binder are shown in the table below.

  The electro-optical characteristics shown in the following table are measured by Display Measurement System (Autotronic-Merchers). At this time, the backlight intensity is set to T100%, and the dark state between the crossed polarizers is set to the transmittance. In this case, switching is performed at 24 ° C. at 1 kHz.

  In particular, it has been found that the improvement of the dark state and the reduction of hysteresis are advantageous, and the additive can appropriately contribute to the reduction of the operating voltage.

Examples 7-14
Instead of B-1, the LC mixtures B-2, B-3, B-4, B-5, B-6, B-7, B-8 and B-9 were each treated as described above in Example 1. Thus, a nanocapsule, a composite system containing a binder, and a coating film are manufactured.

Example 15
LC mixture B-1 is processed as described above in Example 1 to produce nanocapsules, a composite system comprising a binder, and a coating film, wherein 1,4-pentane is substituted for hexadecane, respectively. The diol (Example 15.1), dodecane (Example 15.2) or tetradecane (Example 15.3) are used.

Example 16
LC mixture B-3 (1.0 g), ethylene dimethacrylate (0.34 g), 2-hydroxyethyl methacrylate (0.07 g) and hexadecane (0.25 g) are weighed into a 250 ml tall beaker.

  This mixture is processed and tested as described above in Example 1.

Example 17
LC mixture B-1 (2.66 g), hexadecane (0.66 g) and methyl methacrylate (3.30 g) are weighed into a 250 ml tall beaker.

  This mixture is processed and tested as described above in Example 4.

Example 18
Manufacture of nanocapsules
Comparative Example 18.1
LC mixture B-1 (1.00 g), hexadecane (175 mg), methyl methacrylate (100 mg), hydroxyethyl methacrylate (40 mg) and ethylene glycol dimethacrylate (300 mg) are weighed into a 250 ml tall beaker.

  Brij® L23 (50 mg) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated for 5-10 minutes.

  This aqueous surfactant solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  This mixture is charged to a flask with condenser and AIBN (35 mg) is added and heated to 70 ° C. for 3 hours. The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 167 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

  The resulting nanoparticle suspension is concentrated by centrifugation, where the centrifuge tube is placed in a centrifuge (ThermoFisher Biofuge Stratos) and centrifuged at 6,500 rpm for 10 minutes and at 15,000 rpm for 20 minutes. Centrifuge. Measure solids three times in a DSC pan holding about 40 μL of concentrated nanocapsules on a hot plate at 40 ° C. for 10 minutes.

Examples 18.2, 18.3 and 18.4
The nanocapsule production is repeated as described for Comparative Example 18.1, except that in addition to Brij® L23 (50 mg), 50 mg each of TEGO® Wet 270 (Example 18.2), Weigh 50 mg Triton X-100 (Example 18.3) or 50 mg Brij® L4 (Example 18.4) into a 250 ml Erlenmeyer flask.

Preparation of PVA Binder A PVA binder is prepared as described for Example 1.

Preparation of composite system Centrifugation of 0.5 g suspension containing 15 wt% nanocapsules, each produced, is mixed with PVA to obtain a PVA to capsule weight ratio of 60:40.

  The four mixtures are stirred using a vortex stirrer and these mixtures are left on a roller overnight.

Production of the membrane on the substrate The membrane is produced as described for Example 1.

Measurement of electro-optical properties The appearance of each film is visually checked for uniformity and defects. Solder the two electrodes to the glass. The voltage-transmittance curve is measured using dynamic scattering mode (DSM).

  Dark and bright images are also recorded using a microscope at the voltage required for 0% or 10% and 90% transmission respectively.

  The switching speed is measured at 40 ° C. and 25 ° C. with a modulation frequency of 150 Hz and optionally 10 Hz.

  The electro-optic parameters measured for the manufactured films containing nanocapsules and binder are shown in the table below.

  The electro-optical characteristics shown in the following table are measured by Display Measurement System (Autotronic-Merchers). At this time, the backlight intensity is set to T100%, and the dark state between the crossed polarizers is set to the transmittance. In this case, switching is performed at 24 ° C. at 1 kHz.

  In particular, it has been found that the improvement of the dark state and the reduction of hysteresis are advantageous, and the additive can appropriately contribute to the reduction of the operating voltage.

Example 19
LC mixture B1 (2.00 g), 1,4-pentanediol (102 mg), ethylene dimethacrylate (658 mg), 2-hydroxyethyl methacrylate (77 mg) and methyl methacrylate (162 mg) are weighed into a 250 ml tall beaker.

  Brij® L23 (100 mg) is weighed into a 250 ml Erlenmeyer flask and water (100 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij surfactant aqueous solution is poured directly into a beaker containing an organic substance. This mixture is mixed on a turrax at 10,000 rpm for 10 minutes. When mixing with the turrax is complete, the crude emulsion is circulated through a high pressure homogenizer at 30,000 psi for 8 minutes.

  The mixture is charged to a flask with condenser and heated to 70 ° C. for 4 hours after adding AAPH (20 mg). The reaction mixture is cooled, filtered, and then subjected to material size analysis with a Zetasizer instrument.

  The resulting capsules have an average size of 180 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

  The resulting sample is further processed as described in Example 1.

Example 20
LC mixture B-9 (2.00 g), hexadecane (100 mg), methyl methacrylate (100 mg), hydroxyethyl methacrylate (130 mg) and ethylene glycol dimethacrylate (198 mg) are weighed into a 250 ml tall beaker.

  Brij® L23 (300 mg) is weighed into a 250 ml Erlenmeyer flask and water (100 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij® L23 surfactant aqueous solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  The mixture is charged to a flask with a condenser and heated to 70 ° C. for 3 hours after adding AIBA (20 mg). The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 129 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

Addition of additive From the resulting nanocapsule sample, a portion of 0.28 g nanocapsule in 20 ml solution is added to a centrifuge tube.

  Add 0.01 g Triton X-100 to 0.1 ml water in a centrifuge tube. 0.01 g Brij® L4, 0.01 g FluorN 322 and 0.01 g TEGO® Wet 270 are each added to 0.1 ml isopropanol (IPA) in a centrifuge tube. To these four centrifuge tubes, each containing additives, add a 20 ml portion of the resulting nanocapsule sample (0.28 g).

  Five centrifuge tubes are placed on rollers for 48 hours.

  Thereafter, each particle suspension is concentrated by centrifugation, where the centrifuge tube is placed in a centrifuge (ThermoFisher Biofuge Stratos) and centrifuged at 6,500 rpm for 10 minutes and at 15,000 rpm for 20 minutes. Centrifuge. The pellets obtained are redispersed in each 0.7 ml supernatant.

Production of PVA Binder and Composite System and Production of Membrane on Substrate PVA binder, composite system and membrane are produced as described for Example 1.

Measurement of electro-optical properties The appearance of each film is visually checked for uniformity and defects. Solder the two electrodes to the glass. The voltage-transmittance curve is measured using dynamic scattering mode (DSM).

  Dark and bright images are also recorded using a microscope at the voltage required for 0% or 10% and 90% transmission respectively.

  The switching speed is measured at 40 ° C. and 25 ° C. with a modulation frequency of 150 Hz and optionally 10 Hz.

  The electro-optic parameters measured for the manufactured films containing nanocapsules and binder are shown in the table below.

  The electro-optical characteristics shown in the following table are measured by Display Measurement System (Autotronic-Merchers). At this time, the backlight intensity is set to transmittance T100%, and the dark state between crossed polarizers is determined to be transmittance. In this case, switching is performed at 24 ° C. at 1 kHz.

  In particular, it has been found that the improvement of the dark state is advantageous, and the additive can appropriately contribute to the reduction of the operating voltage.

Example 21
Weigh each LC mixture B-1 (1.00 g), hexadecane (175 mg), methyl methacrylate (100 mg), hydroxyethyl methacrylate (40 mg) and ethylene glycol dimethacrylate (300 mg) into four 250 ml tall beakers.

  Brij® L23 (50 mg) is first weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. In addition, three 250 ml Erlenmeyer flasks were charged with Brij® L23 (50 mg), water (150 g) and Brij® L4 (50 mg), TEGO® Wet 270 (50 mg) or Triton X-100, respectively. (50 mg) is added. These mixtures are then sonicated for 5-10 minutes.

  These four aqueous solutions are poured directly into four beakers containing organic substances. These mixtures are mixed for 5 minutes at 10,000 rpm on a turrax. When mixing with turrax is complete, the crude emulsion is passed through a high pressure homogenizer four times at 30,000 psi each.

  The four mixtures are charged to a flask with condenser and heated to 70 ° C. for 3 hours after adding AIBA (20 mg). The reaction mixture is cooled, filtered, and then size analysis of each resulting material is performed with a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules of Comparative Example 21.1 (Brij® L23 only) have an average size of 129 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer). The resulting capsules of Example 21.2 (added Brij® L4) have an average size of 192 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer). The resulting capsules of Example 21.3 (added TEGO® Wet 270) have an average size of 200 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer). The resulting capsule of Example 21.4 (with Triton X-100 added) has an average size of 180 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

  A composite system and membrane comprising 4 nanocapsule samples is then produced as described in Comparative Example 1.1.

  The electro-optical properties are measured as described in Example 1. The electro-optic parameters measured for the manufactured films containing nanocapsules and binder are shown in the table below.

  In particular, it has been found that the improvement of the dark state and the reduction of hysteresis are advantageous, and the additive can appropriately contribute to the reduction of the operating voltage.

Example 22
LC mixture B-1 is processed as described above in Example 1 to produce nanocapsules, a composite system comprising a binder, and a coating film, where 100 mg each of hexadecane instead of 175 mg of hexadecane. And 75 mg 1,5-dimethyltetralin (Example 22.1), 100 mg hexadecane and 75 mg 3-phenoxytoluene (Example 22.2), 100 mg hexadecane and 75 mg cyclohexane (Example 22.3), or 100 mg Hexadecane and 75 mg of 5-hydroxy-2-pentanone (Example 22.4) are used.

Example 23
LC mixture B-1 (1.00 g), hexadecane (125 mg), methyl methacrylate (100 mg), hydroxyethyl methacrylate (40 mg) and ethylene glycol dimethacrylate (300 mg) are weighed into a 250 ml tall beaker. In addition, 50 mg of PEG methyl ether methacrylate is added.

  Brij® L23 (50 mg) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij® L23 surfactant aqueous solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  The mixture is charged to a flask with a condenser and heated to 70 ° C. for 3 hours after adding AIBA (20 mg). The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 211 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

  A composite system and membrane containing nanocapsule samples are then produced as described in Comparative Example 1.1.

The electro-optical properties are measured as described in Example 1. The electro-optical parameters measured for the produced film (3.42 μm) are as follows: V ₉₀ = 51.5 V; T = 13.8% at V ₉₀ ; T = 1.07 at V ₀ %; Hysteresis = 1.1V.

Example 24
LC mixture B-1 (1.00 g), hexadecane (100 mg), methyl methacrylate (16 mg), hydroxyethyl methacrylate (89 mg) and ethylene glycol dimethacrylate (250 mg) are weighed into a 250 ml tall beaker. In addition, 100 mg of stearyl methacrylate is added.

  Brij® L23 (75 mg) is weighed into a 250 ml Erlenmeyer flask and water (150 g) is added. The mixture is then sonicated for 5-10 minutes.

  This Brij® L23 surfactant aqueous solution is poured directly into a beaker containing organic substances. This mixture is mixed on a turrax at 10,000 rpm for 5 minutes. When mixing with the turrax is complete, the crude emulsion is passed through the high pressure homogenizer four times at 30,000 psi.

  The mixture is charged to a flask with a condenser and heated to 70 ° C. for 3 hours after adding AIBA (20 mg). The reaction mixture is cooled, filtered, and then subjected to material size analysis on a Zetasizer (Malvern Zetasizer Nano ZS) instrument.

  The resulting capsules have an average size of 178 nm as measured by dynamic light scattering (DLS) analysis (Zetasizer).

  A composite system and membrane containing nanocapsule samples are then produced as described in Comparative Example 1.1.

The electro-optical properties are measured as described in Example 1. The electro-optical parameters measured for the produced film (4.70 μm) are as follows: V ₉₀ = 64.5 V; T = 14.3% at V ₉₀ ; T = 0.59 at V ₀ %; Hysteresis = 4.8V.

Claims (16)

A method for producing nanocapsules, the method comprising:
(A)
(I) Formula I
R-A-Y-A'-R 'I
[Where:
R and R ′ are, independently of each other, F, CF ₃ , OCF ₃ , CN and straight or branched alkyl or alkoxy having 1 to 15 carbon atoms or straight chain having 2 to 15 carbon atoms. It represents a group selected from linear or branched alkenyl, wherein the alkyl, alkoxy or alkenyl is unsubstituted or substituted, and optionally mono- or polysubstituted by or halogen is monosubstituted by CN or CF _3, One or more CH ₂ groups are, in each case, independently of one another, in a manner such that the oxygen atoms are not directly bonded to one another, —O—, —S—, —CO—, —COO—, —OCO—, May be replaced by -OCOO- or -C≡C-
A and A ′ are independently of each other -Cyc-, -Phe-, -Cyc-Cyc-, -Cyc-Phe-, -Phe-Phe-, -Cyc-Cyc-Cyc-, -Cyc-Cyc- A group selected from Phe-, -Cyc-Phe-Cyc-, -Cyc-Phe-Phe-, -Phe-Cyc-Phe-, -Phe-Phe-Phe- and their respective mirror images, wherein Cyc is trans-1,4-cyclohexylene, in which one or two non-adjacent CH ₂ groups may be replaced by O, Phe is 1,4-phenylene, Phe In which one or two non-adjacent CH groups may be replaced by N and Phe may be replaced by one or two F;
Y is a single bond, —COO—, —CH ₂ CH ₂ —, —CF ₂ CF ₂ —, —CH ₂ O—, —CF ₂ O—, —CH═CH—, —CF═CF— or —C Shows ≡C-]
A mesogenic medium comprising one or more compounds of (ii) and (ii) a composition comprising one or more polymerizable compounds;
(B) using one surfactant to disperse the composition as nanodroplets in the aqueous phase;
(C) polymerizing the one or more polymerizable compounds to obtain nanocapsules each including a polymer shell and a core containing the mesogenic medium,
Here, in addition, one or more additives,
-Before the polymerization, in addition to the composition or the nanodroplets;
And / or-adding to the obtained nanocapsules.   The method according to claim 1, wherein the one or more additives are added to the obtained nanocapsules in the step (d) after the polymerization according to the step (c).   After obtaining the nanocapsules, the aqueous phase is depleted, removed or exchanged in a further step, before and / or after the further step of depleting, removing or replacing the aqueous phase. The method of claim 2, wherein the one or more additives are added according to step (d).   The method according to any one of claims 1 to 3, wherein the further added one or more additives, preferably the one or more additives added to the obtained nanocapsules are surfactants. .   The method according to any one of claims 1 to 4, wherein the composition provided in (a) further comprises one or more organic solvents.   6. The one or more polymerizable compounds according to claim 1, comprising one, two or more polymerizable groups selected from acrylate groups, methacrylate groups and vinyl acetate groups. The method of any one of these. The one or more compounds of formula I contained in the mesogenic medium of claim 1 are of formulas Ia, Ib, Ic and Id

[Where:
R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are, independently of one another, linear or branched alkyl or alkoxy having 1 to 15 carbon atoms or 2 to 15 carbon atoms A straight or branched alkenyl having the above alkyl, alkoxy or alkenyl, which is unsubstituted, monosubstituted by CN or CF ₃ or monosubstituted or polysubstituted by halogen; The above CH ₂ groups are, in each case, independently of one another, in a manner such that oxygen atoms are not directly bonded to one another, —O—, —S—, —CO—, —COO—, —OCO—, —OCOO. -Or -C≡C- may be substituted,
X ¹ and X ² independently of one another represent F, CF ₃ , OCF ₃ or CN;
L ¹ , L ² , L ³ , L ⁴ and L ⁵ are independently of each other H or F;
i is 1 or 2,
j and k are independently 0 or 1]
7. A method according to any one of claims 1 to 6 selected from   Nanocapsules obtained or obtainable by carrying out the method according to any one of claims 1-7. A polymer shell;
A core containing the mesogenic medium according to claim 1 or 7,
Nanocapsules each including one or more additives. A composite manufacturing method,
-Polymer shell,
Providing a core containing the mesogenic medium of claim 1 or 7 and optionally nanocapsules each comprising one or more additives;
-Adding one or more binders to the nanocapsule;
Adding one or more additives with or following the addition of said one or more binders.   The method of claim 10, wherein the one or more binders comprise polyvinyl alcohol.   A composite system obtained or obtainable by carrying out the method according to claim 10 or 11. Nanocapsules each comprising a polymer shell and a core containing a mesogenic medium according to claim 1 or 7;
-One or more binders;
A composite system comprising one or more additives.   Use of a nanocapsule according to claim 8 or 9 or a composite system according to claim 12 or 13 in a light modulation element or electro-optical device.   An electro-optical device comprising the nanocapsule according to claim 8 or 9, or the composite system according to claim 12 or 13.   One or more in a nanocapsule comprising a polymer shell and a core containing a mesogenic medium according to claim 1 or 7 or in a composite comprising said nanocapsule and one or more binders for reducing the switching voltage Use of additives.