EP1660415A2

EP1660415A2 - Use of core-shell particles

Info

Publication number: EP1660415A2
Application number: EP04763795A
Authority: EP
Inventors: Holger Winkler; Rene Schneider; Goetz Peter Hellmann; Tilmann Eberhard Ruhl; Peter Spahn
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2003-09-04
Filing date: 2004-08-04
Publication date: 2006-05-31
Also published as: TW200523089A; WO2005028396A2; JP2007504307A; WO2005028396A3; US20060292344A1

Abstract

The invention relates to the use of core-shell particles whose shell forms a matrix and whose core is essentially solid, and which comprises an essentially monodisperse size distribution. The shell is joined to the core via an intermediate layer, and the shell has thermoplastic properties. The core-shell particles are used for producing shaped bodies having homogeneous, evenly arranged cavities. The invention also relates to a method for producing shaped bodies having homogeneous, evenly arranged cavities, and to the corresponding shaped bodies themselves.

Description

Use of core-shell particles

The invention relates to the use of core-shell particles for the production of moldings with homogeneous, regularly arranged cavities, a process for the production of moldings with homogeneous, regularly arranged cavities and the corresponding moldings.

Shaped bodies with homogeneous, regularly arranged cavities in the sense of the present invention are materials which have three-dimensional photonic structures. Under three-dimensional photonic structures i. a. Systems understood that have a regular, three-dimensional modulation of the dielectric constant (and therefore also the refractive index). If the periodic modulation length corresponds approximately to the wavelength of the (visible) light, the structure interacts with the light in the manner of a three-dimensional diffraction grating, which manifests itself in angle-dependent color phenomena. An example of this is the naturally occurring gemstone opal, which consists of a densely packed ball packing made of silicon dioxide balls and cavities in between, which are filled with air or water. The inverse structure to this arises from the fact that regular spherical hollow volumes are arranged in the densest packing in a solid material. An advantage of such inverse structures over the normal structures is the formation of photonic band gaps with already much lower dielectric constant contrasts (K. Busch et al. Phys. Rev. Letters E, 198, 50, 3896).

Three-dimensional inverse structures can be created by template synthesis:

• As a structure-giving template, monodisperse spheres are arranged in the densest spherical packing.

• The hollow volumes between the balls are determined by using

Capillary effects are filled with a gaseous or liquid precursor or a solution of a precursor.

• The precursor is (thermally) converted into the desired material. • The templates are removed, leaving the inverse structure.

Many such methods are known in the literature. For example, SiO ₂ spheres can be arranged in the densest packing, the hollow volumes are filled with solutions containing tetraethyl orthotitanate. After several tempering steps, are in an etching process

HF removes the balls, leaving the inverse structure of titanium dioxide (V. Colvin et al. Adv. Mater. 2001, 13, 180).

De La Rue et al. (De La Rue et al. Synth. Metals, 2001, 116, 469) describe the production of inverse, consisting of TiO opals according to the following method: A dispersion of 400 nm in size

Polystyrene balls are dried on a filter paper under an IR lamp. The filter cake is suctioned off with ethanol, transferred to a glove box and infiltrated with tetraethyl orthotitanate using a water jet pump. Carefully remove the filter paper from the latex-ethoxide composite and transfer the composite to a tube furnace. The calcination takes place in the tube furnace at 575 ° C. for 8 hours in an air stream, whereby titanium dioxide is formed from the ethoxide and the latex particles are burned out. An inverse TiO ₂ opal structure remains.

Martinelli et al. (M. Martinelli et al. Optical Mater. 2001, 17, 11) describe the production of inverse TiO ₂ opals using 780 nm and 3190 nm large polystyrene balls. A regular arrangement in the densest spherical packing is achieved by centrifuging the aqueous spherical dispersion at 700-1000 rpm for 24-48 hours and then decanting, followed by air drying. The regularly arranged balls are moistened with ethanol on a filter on a Buchner funnel and then dropwise provided with an ethanolic solution of tetraethyl orthotitanate. After the titanate solution has soaked in, the sample is dried in a vacuum desiccator for 4 to 12 hours. This filling procedure is repeated 4 to 5 times. The polystyrene balls are then burned out at 600 ° C - 800 ° C for 8 - 10 hours. Stein et al. (A. Stein et al. Science, 1998, 281, 538) describe the synthesis of inverse TiO ₂ opals from polystyrene spheres with a diameter of 470 nm as a template. These are made in a 28 hour process, subjected to centrifugation and air dried. Then the latices template are applied to a filter paper. Ethanol is sucked into the latex template via a Büchner funnel, which is connected to a vacuum pump. Then tetraethyl orthotitanate is added dropwise with suction. After drying in a vacuum desiccator for 24 h, the latices are burned out at 575 ° C for 12 h in an air stream.

Vos et al. (WL Vos et al. Science, 1998, 281, 802) produce inverse TiO ₂ opals by using polystyrene spheres with diameters of 180-1460 nm as templates. A sedimentation technique is used to set the densest spherical packing of the spheres, which is supported by centrifugation for up to 48 h. After slowly evacuating to dry the template structure, an ethanolic solution of tetra-n-propoxy orthotitanate is added to it in a glove box. After approx. 1 h, the infiltrated material is brought into the air to allow the precursor to react to form TiO ₂ . This procedure is repeated eight times to ensure complete filling with TiO ₂ . The material is then calcined at 450 ° C.

The production of photonic structures from inverse opals is very complex and time-consuming according to the processes described in the literature: • lengthy / complex production of the template, or the arrangement of the balls forming the templating structure in a densest packing

• lengthy / complex, because the filling of the

Cavities of the template structure with precursors

• lengthy / complex procedure for removing the template

• only limited or no possibility of producing larger photonic structures with inverse opal structure and transfer from laboratory synthesis to technical production. The disadvantages make it difficult to produce the desired photonic materials with an inverse opal structure. There is therefore a need for an easy-to-implement manufacturing process that is also transferable to the technical scale.

Core-shell particles, the shell of which forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution, are described in German patent application DE-A-10145450. The use of such core-shell particles, the shell of which forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution as a template for the production of inverse opal structures and a method for the production of inverse opal-like structures using such core-shell particles is described in the older German patent application DE 10245848.0. The moldings described with homogeneous, regularly arranged cavities (i.e. inverse opal structure) preferably have walls made of metal oxides or elastomers. Consequently, the moldings described are either hard and brittle or have an elastomeric character with low mechanical strength.

Surprisingly, it has now been found that the use of core-shell particles whose shell has thermoplastic properties leads to moldings with homogeneous, regularly arranged cavities whose mechanical properties are particularly advantageous.

A first object of the present invention is therefore the use of core-shell particles whose shell forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution and whose shell is connected to the core via an intermediate layer and whose shell is thermoplastic Has properties for the production of moldings with homogeneous, regularly arranged cavities.

In the present invention, thermoplastic properties are understood to mean that the corresponding materials have one Have flow transition area above room temperature. In particular, those materials are meant here which are referred to as thermoplastics in accordance with DIN 7724, TI.2, the materials which have an energy-elastic behavior at room temperature - that is to say the thermoplastics in the narrower sense - being among the preferred materials.

Another object of the present invention is a method for producing moldings with homogeneous, regularly arranged cavities, characterized in that core-shell particles, the shell of which forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution and is connected to the core via an intermediate layer and the jacket of which has thermoplastic properties, is processed into shaped bodies, preferably films, using a mechanical force and elevated temperature, and the cores are subsequently removed.

The use of core-shell particles according to the invention leads in particular to the following advantages:

when drying dispersions from core-shell particles, the crack formation in the template (= arrangement of the balls) can be reduced or even completely prevented when drying,

large areas of high order can be obtained in the template,

- Tensions occurring during the drying process can be compensated for by the elastic nature of the jacket, - If polymers form the jacket, they can intertwine and thus mechanically stabilize the regular arrangement of balls in the template, - Since the jacket - preferably by grafting - is firmly connected to the core via an intermediate layer, the templates can be processed via melting processes.

The products obtainable with the use according to the invention are a further subject of the present invention. Claimed are therefore molded articles with homogeneous, regularly arranged cavities, characterized in that the regularly arranged cavities are embedded in a matrix of thermoplastic or thermosetting _n properties.

Because it is easier to process, it is particularly preferred if the regularly arranged cavities are embedded in a matrix with thermoplastic properties, the matrix m. preferably made of poly (styrene), thermoplastic poly (acrylate) derivatives, preferably poly (methyl methacrylate) or poly (cyciohexyl methacrylate), or thermoplastic copolymers of these polymers with other acrylates, such as preferably styrene-acrylonitrile copolymers, styrene-ethyl acrylate copolymers or Methyl methacrylate-ethyl acrylate) - _n copolymers is built up.

"Built up" in the sense of the present invention means that the materials are contained in such a large amount that the material properties of the shaped bodies are dominated by these polymers. However, the shaped bodies can also contain other constituents, in particular processing aids, in amounts of up to contain 50 wt .-%.

In order to achieve the optical or photonic effect according to the invention, it is desirable for the core-shell particles to have an average particle diameter in the range from about 5 nm to about 2000 nm. It can be particularly preferred if the core-shell particles have an average particle diameter in the range from about 5 to 20 nm, preferably 5 to 10 nm. In this case the nuclei can be called "quantum dots"; they show the corresponding effects known from the literature. To achieve color effects in the visible light range, it is particularly advantageous if the core-shell particles have an average particle diameter in the range of approximately 50-800 nm. Particles in the range from 100 to 600 nm and very particularly preferably in the range from 200 to 450 nm are particularly preferably used, since with particles in this order of magnitude (depending on the refractive index contrast which can be achieved in the photonic structure) the reflections of different wavelengths of visible light become clear distinguish from each other and so the opalescence, which is particularly important for optical effects in the visible range, occurs particularly distinctly in a wide variety of colors. In a variant of the present invention, however, it is also preferred to use multiples of this preferred particle size, which then lead to reflections corresponding to the higher orders and thus to a broad play of colors.

The cavities of the shaped bodies according to the invention then each have corresponding average diameters, which are approximately identical to the diameter of the cores. With preferred core-shell ratios of the particles, the cavity diameter thus corresponds to approximately 2/3 of the core-shell particle diameter. It is particularly preferred according to the invention if the mean diameter of the cavities is in the range from about 50 to 500 nm, preferably in the range from 100 to 500 nm and very particularly preferably in the range from 200 to 280 nm.

In a preferred embodiment of the invention, the intermediate layer is a layer of crosslinked or at least partially crosslinked polymers. The interlayer can be crosslinked via free radicals, for example induced by UV radiation, or preferably via di- or oligofunctional monomers. Preferred intermediate layers of this embodiment contain 0.01 to 100% by weight, particularly preferably 0.25 to 10 % By weight, di- or oligo-functional monomers. Preferred di- or oligo-functional monomers are in particular isoprene and allyl methacrylate (ALMA). Such an intermediate layer of crosslinked or at least partially crosslinked polymers preferably has a thickness in the range of

10 to 20 nm. If the intermediate layer turns out thicker, the

Refractive index of the layer chosen so that it corresponds either to the refractive index of the core or the refractive index of the cladding.

If copolymers are used as the intermediate layer which, as described above, contain a crosslinkable monomer, the person skilled in the art will have no problem in selecting suitable copolymerizable monomers in a suitable manner. For example, corresponding copolymerizable monomers can be selected from a so-called Q-e scheme (cf. textbooks of macromolecular chemistry). Monomers such as methyl methacrylate and methyl acrylate can preferably be polymerized with ALMA.

In another, likewise preferred embodiment of the present invention, shell polymers are grafted directly onto the core via a corresponding functionalization of the core. The surface functionalization of the core forms the intermediate layer according to the invention.

The type of surface functionalization depends mainly on the material of the core. Silicon dioxide surfaces can, for example, advantageously be suitably modified with silanes which carry correspondingly reactive end groups, such as epoxy functions or free double bonds. , The monodisperse cores are dispersed in alcohols and modified with common organoalkoxysilanes. The silanization of spherical oxide particles is also described in DE 43 16 814. Such silanization improves the dispersibility of inorganic

Cores and thus facilitates in particular the polymerisation of the

Interlayer polymers by emulsion polymerization. About these

Functionalization can also directly achieve the growth of the shell polymers, i.e. the silane modification then serves as an intermediate layer.

In a preferred embodiment, the shell of these core-shell particles consists of essentially uncrosslinked organic polymers which are preferably grafted onto the core via an at least partially crosslinked intermediate layer. The core can consist of various materials. It is only essential in the sense of the present invention that the cores can be removed under conditions in which the wall material is stable. The selection of suitable core / cladding / interlayer wall material combinations does not pose any difficulties for the person skilled in the art.

It is further preferred according to the invention if the core of the core-shell particles consists of a material which either does not flow or becomes flowable at a temperature above the flow temperature of the shell material. This can be achieved by using polymeric materials with a correspondingly high glass transition temperature (T _g ), preferably crosslinked polymers, or by using inorganic core materials. The suitable materials are described in detail below.

Furthermore, in a variant of the invention, it is particularly preferred if the cores are composed of an inorganic material, preferably a metal or semimetal or a metal chalcogenide or metal pnictide. For the purposes of the present invention, chalcogenides are compounds in which an element of the 16th group of the periodic table is the electronegative binding partner; as Pnictide those in which an element of the 15th group of the

Periodic table is the electronegative binding partner. preferred

Cores consist of metal chalcogenides, preferably metal oxides, or metal pnictides, preferably nitrides or phosphides. Metal in

The meaning of these terms are all elements that are compared to the

Counterions can occur as electropositive partners, such as the classic metals of the subgroups or the main group metals of the first and second main groups, but also all elements of the third main group, as well as silicon, germanium, tin, lead, phosphorus, arsenic, antimony and bismuth. The preferred metal chalcogenides and metal pnictides include in particular silicon dioxide, aluminum oxide, gallium nitride, boron and aluminum nitride as well as silicon and phosphorus nitride.

In a variant of the present invention, monodisperse silicon dioxide cores are preferably used as the starting material for the production of the core-shell particles to be used according to the invention, which can be obtained, for example, by the process described in US Pat. No. 4,911,903. The cores are produced by hydrolytic polycondensation of tetraalkoxysilanes in an aqueous-ammoniacal medium, whereby a sol of primary particles is first produced and then the SiO ₂ particles obtained are brought to the desired particle size by continuous, controlled metering in of tetraalkoxysilane. This method can be used to produce monodisperse SiO ₂ cores with average particle diameters between 0.05 and 10 μm with a standard deviation of 5%.

Monodisperse cores made of non-absorbent metal oxides such as TiO ₂ , ZrO ₂ , ZnO ₂ , SnO ₂ or Al ₂ O ₃ or metal oxide mixtures can also be used as the starting material. Their manufacture is described for example in EP 0 644 914. Furthermore, the method according to EP 0 216 278 for producing monodisperse SiO ₂ cores is straightforward and easy same result transferable to other oxides. To a mixture of

Alcohol, water and ammonia, the temperature of which with a

Thermostats are set exactly to 30 to 40 ° C, with intensive mixing tetraethoxysilane, tetrabutoxytitanium, tetrapropoxy-zirconium or mixtures thereof are added in one pour and the mixture obtained is stirred intensively for a further 20 seconds, with a suspension of monodisperse cores in the Forms nanometer range. After a post-reaction time of 1 to 2 hours, the cores are removed in the usual way, e.g. by centrifugation, separated, washed and dried.

In another preferred embodiment of the present invention, the core in the core-shell particles consists essentially of a material which can be degraded with UV radiation, preferably a UV-degradable organic polymer and particularly preferably poly (tert-butyl methacrylate), poly ( methyl methacrylate), poly (n-butyl methacrylate) or copolymers containing one of these polymers. 0

The wall of the molded body with homogeneous, regularly arranged cavities is formed from the polymers of the shell of the core-shell particles. 5

In the inventive method for producing a molded article having homogeneous, regularly arranged cavities a mechanical strength of the core-shell particles _Q is formed a "positive" opal structure as a template in a first step by application.

The mechanical action of force can, according to the invention, be such a force action that occurs in the usual processing steps of polymers. In preferred variants 5 of the present invention, the mechanical force is applied either: by uniaxial pressing or

Force application during an injection molding process or during a transfer press process, during a (co-) extrusion or during a calendering process or - during a blowing process.

If the force is exerted by uniaxial pressing, the shaped bodies according to the invention are preferably films. Films according to the invention can preferably also be produced by calendering, film blowing or flat film extrusion. The various possibilities of processing polymers under the influence of mechanical forces are well known to the person skilled in the art and can be found, for example, in the standard textbook Adolf Franck, "Plastic Compendium"; Vogel-Verlag; 1996 are taken. The processing of core-shell particles by the action of mechanical force, as is preferred here, is also described in detail in the international patent application WO 2003025035.

In a preferred variant of the production according to the invention

Shaped body, the temperature during production is at least 40 ° C, preferably at least 60 ° C above the glass point of the shell of the core-shell particles. It has been shown empirically that the

Flowability of the jacket in this temperature range

Requirements for an economic production of the moldings corresponds to a particular extent.

In a likewise preferred process variant, which leads to moldings according to the invention, the flowable core-shell particles are cooled under the action of the mechanical force to a temperature at which the shell is no longer flowable.

If moldings are produced by injection molding, it is particularly preferred if the demolding takes place only after the mold with the molding contained therein has cooled. In the technical implementation it is advantageous if molds with a large cooling channel cross section are used, since the cooling can then take place in a shorter time. It has been shown that the color effects according to the invention become significantly more intense as a result of the cooling in the mold. It is assumed that this uniform cooling process leads to a better arrangement of the core-shell particles with the lattice. It is particularly advantageous if the mold was heated before the injection process.

The moldings according to the invention can, if it is technically advantageous, contain auxiliaries and additives. They can be used to optimally set the application data or properties desired or required for application and processing. Examples of such auxiliaries and / or additives are antioxidants, UV stabilizers, biocides, plasticizers, film-forming aids, leveling agents, fillers, melting aids, adhesives, release agents, application aids, mold release agents, agents for viscosity modification, for. B. thickener.

Additions of film-forming aids and film-modifying agents based on compounds of the general formula HO-C _n H ₂ nO- (CnH ₂ nO) mH, in which n is a number from 2 to 4, preferably 2 or 3, and m is a number of Is 0 to 500. The number n can vary within the chain and the various chain links can be built in in a statistical or block-wise distribution. Examples of such auxiliaries are ethylene glycol, propylene glycol, di-, tri- and tetraethylene glycol, di-, tri- and tetrapropylene glycol, polyethylene oxides, polypropylene oxide and ethylene oxide / propylene oxide mixed polymers with molecular weights of up to approx. 15000 and statistical or block-like distribution of the ethylene oxide and propylene oxide assemblies.

If appropriate, organic or inorganic solvents, dispersants or diluents are also available, for example the open time of the formulation, ie the time for their application to substrates standing time, extend waxes or hot melt adhesive as additives possible.

If desired, stabilizers against UV radiation and weather influences can also be added to the moldings. For this purpose, z. B. derivatives of 2,4-dihydroxybenzophenone, derivatives of 2-cyan-3,3'-dephenyl acrylate, derivatives of 2,2 ', 4,4 ^, -tetrahydroxybenzophenone, derivatives of o-hydroxyphenyl-benzotriazole, salicylic acid esters, o-hydroxyphenyl -s-triazines or sterically hindered amines. These substances can also be used individually or as mixtures.

The total amount of auxiliaries and / or additives is up to 40% by weight, preferably up to 20% by weight, particularly preferably up to 5% by weight, of the weight of the moldings.

The cores can be removed in various ways. If the cores are made of suitable inorganic materials, they can be removed by etching. For example, silicon dioxide cores can preferably be removed with HF, in particular dilute HF solution. With this procedure, it can again be preferred if, before or after the removal of the cores, the jacket is crosslinked, as described above. In this case, the jacket and thus the matrix of the molded body are given thermosetting properties.

If the cores in the core-shell particles are made of a UV-degradable material, preferably a UV-degradable organic polymer, the cores are removed by UV radiation. In this procedure, too, it can in turn be preferred if, before or after the removal of the cores, the jacket is crosslinked, as described above.

However, if the cavities of the shaped bodies are to be impregnated again with liquid or gaseous materials, it may also be preferred if the matrix is not or only very slightly crosslinked. The Impregnation can consist, for example, of storing liquid crystals, as described, for example, in Ozaki et al., Adv. Mater. 2002, 14, 514 and Sato et al., J. Am. Chem. Soc. 2002, 124, 10950.

The impregnation with such or other materials allows the optical, electrical, acoustic and mechanical properties to be influenced by external energy fields. In particular, it is possible to make these properties switchable with an external energy field, by removing the field, the system showing different properties than when the field is present.

By means of a locally addressable control using the external field, it is possible to manufacture electro-optical devices in this way. The use of the shaped bodies according to the invention with homogeneous, regularly arranged cavities for the production of electro-optical devices and electro-optical devices containing the shaped bodies according to the invention are therefore further objects of the present invention.

Electro-optical devices based on liquid crystals are well known to the person skilled in the art and can be based on various effects. Such devices are, for example, cells with dynamic scattering, DAP cells (deformation of aligned phases), guest host cells, TN cells with twisted nematic ("twisted nematic")

Structure, STN cells ("super-twisted nematic"), SBE cells

("superbirefringence effect") and OMI cells ("optical mode interference").

The most common display devices are based on the

Helfrich effect and have a twisted nematic structure.

The corresponding liquid crystal materials must have good chemical and thermal stability and good stability against electric fields and electromagnetic radiation. Furthermore, the liquid crystal materials should have low viscosity and in give the cells short response times, low threshold voltages and a high contrast.

Furthermore, they should be used at normal operating temperatures, i.e. possess a suitable mesophase in the broadest possible range below and above room temperature, for example for the above-mentioned ones

Cells a nematic or cholesteric mesophase. Since liquid crystals are usually used as mixtures of several components, it is important that the components are good with each other

'are miscible. Other properties, such as electrical conductivity, dielectric anisotropy and optical anisotropy, must meet different requirements depending on the cell type and field of application. For example, materials for cells with a twisted nematic structure should have positive dielectric anisotropy and low electrical conductivity.

For example, for matrix liquid crystal displays with integrated non-linear elements for switching individual pixels (MLC displays), 0 media with large positive dielectric anisotropy, relatively low birefringence, wide nematic phases, very high specific resistance, good UV and temperature stability and low vapor pressure are desired. 5

Such matrix liquid crystal displays are known. For example, active elements (i.e. transistors) can be used as non-linear elements for the individual switching of the individual pixels. 0 One speaks then of an "active matrix", whereby one can distinguish two types:

1. MOS (Metal Oxide Semiconductor) or other diodes on silicon wafers as a substrate.

2. Thin film transistors (TFT) on a glass plate as a substrate. The use of monocrystalline silicon as the substrate material limits the display size, since the module-like composition of various partial displays also leads to problems at the joints.

In the more promising type 2, which is preferred, the TN effect is usually used as the electro-optical effect. There are two technologies: TFTs made from compound semiconductors such as CdSe or

TFTs based on polycrystalline or amorphous silicon. The latter technology is being worked on with great intensity worldwide.

The TFT matrix is applied to the inside of one glass plate of the display, while the other glass plate carries the transparent counter electrode on the inside. Compared to the size of the pixel electrode, the TFT is very small and practically does not disturb the image. This technology can also be expanded for fully color-compatible image representations, with a mosaic of red, green and blue filters being arranged in such a way that one filter element each is opposite a switchable image element.

The TFT displays usually work as TN cells with crossed polarizers in transmission and are illuminated from behind.

The term MLC displays here includes any matrix display with integrated non-linear elements, i.e. In addition to the active matrix, displays with passive elements such as varistors or diodes (MIM = metal-insulator-metal).

MLC displays of this type are particularly suitable for TV applications (for example pocket TVs) or for high-information displays for computer applications (laptops) and in automobile or aircraft construction. With decreasing resistance, the contrast of an MLC display deteriorates and the problem of "after image elimination" can occur. Since the resistivity of the liquid crystal mixture generally decreases over the lifetime of an MLC display due to interaction with the inner surfaces of the display, a high (initial) resistance is very important in order to obtain acceptable service lives.

In the case of higher twisted cells (STN), media are desirable that have a higher one

Allow multiplexability and / or smaller threshold voltages and / or wider nematic phase ranges (especially at low temperatures). _, For this purpose, a further expansion of the available parameter space (clearing point, smectic-nematic transition or melting point, viscosity, dielectric parameters, elastic parameters) is urgently desired.

The moldings according to the invention can in principle be used in combination with suitable liquid crystal mixtures which are known to the person skilled in the art in electro-optical displays based on all the principles described, in particular for MFK, IPS, TN or STN displays.

The shaped bodies obtainable according to the invention with homogeneous, regularly arranged cavities are suitable on the one hand for the use described above as photonic material, preferably with the impregnation mentioned, but on the other hand also for the production of porous surfaces, membranes, separators, filters and porous supports. These materials can also be used, for example, as fluidized beds in fluidized bed reactors.

On the basis of the considerations set out here, it is expedient if the shell of the core-shell particles according to the invention contains one or more polymers and / or copolymers or polymer precursors and, if appropriate, auxiliaries and additives, the composition of the shell being able to be selected such that it in non-swelling environment at room temperature is essentially dimensionally stable and tack-free.

With the use of polymer substances as a sheath material and possibly core material, the person skilled in the art gains the freedom of their relevant properties, such as. B. their composition, particle size, the mechanical data, the glass transition temperature, melting point, and the weight ratio of core: shell set and hence the performance properties of the core / shell _particles. which ultimately also have an effect on the properties of the moldings produced therefrom.

In principle, all polymers of the classes already mentioned above are suitable for the jacket material, provided that they are selected or constructed in such a way that they correspond to the specification given above for the jacket polymers.

Polymers that meet the specifications for a sheath material can also be found in the groups of polymers and copolymers of polymerizable unsaturated monomers, as well as the polycondensates and copolycondensates of monomers with at least two reactive groups, such as, for. B. the high molecular weight aliphatic, aliphatic / aromatic or fully aromatic polyesters and polyamides.

Taking into account the above conditions for the properties of the shell polymers (= matrix polymers), selected building blocks from all groups of organic film formers are in principle suitable for their production.

Some other examples may illustrate the wide range of polymers suitable for making the sheath.

If the sheath is to have a comparatively low refractive index, polymers such as polyacrylates, polymethacrylates, polybutadiene, polymethyl methacrylate, polyesters, polyamides and polyacrylonitrile are suitable, for example. If the sheath is to be comparatively high-index, then, for example, polymers with a preferably aromatic basic structure such as polystyrene, polystyrene copolymers such as. B. SAN, aromatic-aliphatic polyesters and polyamides, aromatic polysulfones and polyketones, and with a suitable choice of a high-index core material also polyacrylonitrile.

With regard to the processability of the core-shell particles to inverse opal structures, it is preferred if the weight ratio of core to shell is in the range from 5: 1 to 1:10, in particular in the range from 2: 1 to 1: 5 and particularly preferred is in the range 1, 5: 1 to 1: 2.

The core-shell particles which can be used according to the invention can be produced by various processes.

A preferred way of obtaining the particles is a process for the production of core-shell particles, by a) surface treatment of monodisperse cores, and b) application of the shell from organic polymers to the treated cores.

In a preferred process variant, a crosslinked polymeric intermediate layer is applied to the cores, preferably by emulsion polymerization or by ATR polymerization, which preferably has reactive centers to which the jacket can be covalently attached. ATR-Polymerization stands here for Atomic Transfer Radicalic Polymerization, as for example in K. Matyjaszewski, Practical Atom Transfer Radical Polymerization, Polym. Mater. Be. Closely. 2001, 84. Encapsulation of inorganic materials using ATRP is described, for example, in T. Werne, TE Patten, Atom Transfer Radical Polymerization from Nanoparticles: A Tool for the Preparation of Well-Defined Hybrid Nanostructures and for Understanding the Chemistry of Controlled / "Living" Radical Polymerization from Surfaces, J. Am. Chem.

Soc. 2001, 123, 7497-7505 and WO 00/11043. The

Implementation of both this method and the implementation of

Emulsion polymerizations are familiar to the person skilled in the art of polymer production and are described, for example, in the abovementioned. References described.

The liquid reaction medium in which the polymerizations or copolymerizations can be carried out consists of those used in polymerizations, in particular in processes of the emulsion

^{, υ} polymerization, commonly used solvents, dispersants or diluents. The selection is made in such a way that the emulsifiers used to homogenize the core particles and shell precursors can develop sufficient effectiveness. Aqueous media, in particular water, are favorable as a liquid reaction medium for carrying out the process according to the invention.

For initiating the polymerization, for example, polymerization initiators are suitable which either decompose thermally or photochemically, form radicals, and thus initiate the polymerization. Among the thermally activatable polymerization initiators, preference is given to those which decompose between 20 and 180 ° C., in particular between 20 and 80 ° C. Particularly preferred polymerization initiators are ⁵ peroxides, such as dibenzoyl peroxide, di-tert-butyl peroxide, peresters, percarbonates, perketals, hydroperoxides, but also inorganic peroxides, such as H ₂ O ₂ , salts of peroxosulfuric acid and peroxodisulfuric acid, azo compounds, boron compounds and 0 homolytically decomposing hydrocarbons , The initiators and / or photoinitiators, which, depending on the requirements for the polymerized material, are used in amounts between 0.01 and 15% by weight, based on the polymerizable components, can be used individually or, in order to take advantage of advantageous synergistic effects, in combination 5 applied with each other. Redox systems are also used Application, such as salts of peroxodisulfuric acid and peroxosulfuric acid in combination with low-valent sulfur compounds, in particular ammonium peroxodisulfate in combination with sodium dithionite.

Appropriate processes have also been described for the production of polycondensation products. So it is possible that

To disperse starting materials for the production of polycondensation products in inert .Liquids and, preferably with low molecular weight reaction products such as water or - z. B. when using dicarboxylic acid di-lower alkyl esters for the production of

Condensate polyester or polyamides - lower alkanols.

Polyaddition products are obtained analogously by reaction with compounds which have at least two, preferably three reactive groups, such as, for. B. epoxy, cyanate, isocyanate, or isothiocyanate groups, with compounds that carry complementary reactive groups. For example, isocyanates react with alcohols to form urethanes, with amines to form urea derivatives, while epoxides react with these complementaries to form hydroxyethers or hydroxyamines. Like the polycondensation reactions, polyaddition reactions can advantageously also be carried out in an inert solvent or dispersant.

Dispersing aids are generally used to prepare the stable dispersions required for these polymerization-polycondensation or polyaddition processes.

Dispersing aids are preferably water-soluble, high molecular weight organic compounds with polar groups, such as polyvinyl pyrrolidone, copolymers of vinyl propionate or acetate and vinyl pyrrolidone, partially saponified copolymer list of an acrylic ester and acrylonitrile, polyvinyl alcohols with different residual acetate content, cellulose ethers, Gelatin, block copolymers, modified starch, low molecular weight, carbon and / or sulfonic acid group-containing polymers or mixtures of these substances are used.

Particularly preferred protective colloids are polyvinyl alcohols with a residual acetate content of less than 35, in particular 5 to 39 mol% and / or vinylpyrrolidone-oleyl propionate copolymers with a vinyl ester content of less than 35, in particular 5 to 30% by weight.

Nonionic or ionic emulsifiers, optionally also as a mixture, can be used. Preferred emulsifiers are, where appropriate, ethoxylated or propoxylated, longer-chain alkanols or alkylphenols with different degrees of ethoxylation or propoxylation (eg adducts with 0 to 50 mol of alkylene oxide) or their neutralized, sulfated, sulfonated or phosphated derivatives. Neutralized dialkylsulfosuccinic acid esters or alkyldiphenyloxide disulfonates are also particularly suitable.

Combinations of these emulsifiers with the protective colloids mentioned above are particularly advantageous since they are particularly fine-particle

Dispersions can be obtained.

By setting the reaction conditions, such as temperature, pressure, reaction time and the use of suitable catalyst systems, which influence the degree of polymerization in a known manner, and the selection of the monomers used for their preparation - in terms of type and proportion - the desired combinations of properties of the required polymers can be set in a targeted manner , The particle size can be set, for example, via the selection and amount of the initiators and other parameters, such as the reaction temperature. The appropriate setting of these parameters does not pose any difficulties for the person skilled in the field of polymerization. Monomers which lead to polymers with a high refractive index are generally those which either have aromatic partial structures or those which have heteroatoms with a high atomic number, such as, for example, B. halogen atoms, especially bromine or iodine atoms, sulfur or metal ions, that is, atoms or groupings of atoms which increase the polarizability of the polymers.

Polymers with a low refractive index are accordingly obtained from monomers or monomer mixtures which do not contain the mentioned partial structures and / or atoms with a high atomic number or only in a small proportion.

An overview of the refractive indices of various common homopolymers can be found e.g. B. in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, volume A21, page 169. Examples of free-radically polymerizable monomers that lead to polymers with a high refractive index are:

Group a): styrene, alkyl-substituted styrenes in the phenyl nucleus, α-methylstyrene, mono- and dichlorostyrene, vinylnaphthalene, isopropenylnaphthalene, isopropenylbiphenyl, vinylpyridine, isopropenylpyridine, vinylcarbazole, vinylanthracene, N-benzyl-methacrylamide, p-hydroxymethane-acrylamide.

Group b): Acrylates, the aromatic

Have side chains, such as. B. phenyl (meth) acrylate (= abbreviation for the two compounds phenyl acrylate and

Phenyl methacrylate) and benzyl (meth) acrylate.

Group c): The refractive index of polymers can also be increased by polymerizing mono- containing carboxylic acid groups erer and transfer of the "acidic" polymers thus obtained into the corresponding salts with metals of higher atomic weight, such as. B. preferably with K, Ca, Sr, Ba, Zn, Pb, Fe, Ni, Co, Cr, Cu, Mn, Sn or Cd.

The above monomers, which make a high contribution to

Refractive index of the polymers produced therefrom can be homopolymerized or copolymerized with one another. They can also be copolymerized with a certain proportion of monomers that make a lower contribution to the refractive index. Such copolymerizable monomers with a lower refractive index contribution are, for example, acrylates, methacrylates, vinyl ethers or vinyl esters with purely aliphatic radicals.

In addition, all bifunctional or polyfunctional compounds which can be copolymerized with the monomers mentioned above or which can subsequently react with the polymers with crosslinking can also be used as crosslinking agents for producing crosslinked matrix materials.

In the following, examples of suitable crosslinkers are presented, which are divided into groups for systematization:

Group 1: bisacrylates, bismethacrylates and bisvinyl ethers of aromatic or aliphatic di- or polyhydroxy compounds, in particular of butanediol (butanediol-di (meth) acrylate, butanediol-bis-vinyl ether), hexanediol (hexanediol-di (meth) acrylate, hexanediol-bis- vinyl ether), pentaerythritol, hydroquinone, bis-hydroxyphenylmethane, bis-hydroxyphenyl ether, bis-hydroxymethyl-benzene, bisphenol A or with ethylene oxide spacers, propylene oxide spacers, or mixed ethylene oxide-propylene oxide spacers. Other crosslinkers in this group are e.g. B. di- or polyvinyl compounds, such as divinybenzene, or also methylene-bisacrylamide, triallyl cyanurate, divinylethylene urea, trimethylolpropane tri- (meth) acrylate, trimethylolpropane tricinyl ether, pentaerythritol tetra (meth) acrylate, pentaerythritol tetra vinyl ethers, and crosslinkers with two or more different reactive ends, such as. B. (Meth) aliyl (meth) acrylates of the formulas:

(where R is hydrogen or methyl).

Group 2: reactive crosslinking agents which have a crosslinking action, but mostly have a postcrosslinking action, e.g. B. with heating or drying, and which are copolymerized into the core or shell polymers as copolymers.

Examples include: N-methylol- (meth) acrylamide, acrylamidoglycolic acid, and their ethers and / or esters with C ₁ to C ₆ alcohols, diacetone acrylamide (DAAM), glycidyl methacrylate (GMA), methacryloyloxypropyltrimethoxysilane (MEMO), vinyl trimethoxysilane, m-isopropenyl benzyl isocyanate (TMI).

Group 3: Carboxylic acid groups which have been incorporated into the polymer by copolymerization of unsaturated carboxylic acids are crosslinked like polyvalent metal ions. Acrylic acid, methacrylic acid, maleic anhydride, itaconic acid and fumaric acid are preferably used as unsaturated carboxylic acids for this purpose. Mg, Ca, Sr, Ba, Zn, Pb, Fe, Ni, Co, Cr, Cu, Mn, Sn, Cd are suitable as metal ions. Ca, Mg and Zn, Ti and Zr are particularly preferred. Monovalent metal ions, such as Na or K, are also suitable. Group 4: Post-crosslinked additives. This is understood to mean additives which are functionalized to a degree or higher and which react irreversibly with the polymer (by addition or preferably condensation reactions) to form a network. Examples of this are compounds that are per

Molecule have at least two of the following reactive groups: epoxy, aziridine, isocyanate acid chloride, carbodiimide or carbonyl groups, further z. B. 3,4-dihydroxy-imidazolinone and its derivatives.

As already explained above, post-crosslinkers with reactive groups, such as, for. B. epoxy and isocyanate groups, complementary, reactive groups in the polymer to be crosslinked. For example, isocyanates react with alcohols to form urethanes, with amines to form urea derivatives, while epoxides react with these complementary groups to form hydroxyethers or hydroxyamines.

Post-crosslinking is also understood to mean photochemical curing, an oxidative, or an air- or moisture-induced curing of the systems.

The monomers and crosslinking agents mentioned above can be combined with one another in a targeted manner and (co) polymerized, so that an optionally crosslinked (co) polymer is obtained with the desired refractive index and the required stability criteria and mechanical properties.

It is also possible to use other common monomers, e.g. B. acrylates,

In addition, copolymerize methacrylates, vinyl esters, butadiene, ethylene or styrene in order, for example, to adjust the glass transition temperature or the mechanical properties of the shell polymers as required. According to the invention, it is also preferred if the coating of organic polymers is applied by grafting, preferably by emulsion polymerization or ATR polymerization. The methods and monomers described above can be used accordingly.

The following examples are intended to explain the invention in more detail without limiting it.

Examples

Abbreviations:

ALMA allyl methacrylate

CHMA cyclohexyl methacrylate

KOH potassium hydroxide

SDS sodium dodecyl sulfate

MMA methyl methacrylate

MPS methacryloxypropyltrimethoxysilane

PCHMA poly (cyclohexyl methacrylate)

PMMA poly (methyl methacrylate)

PS polystyrene

PTBMA poly (tert-butyl methacrylate)

SPS sodium peroxodisulfate

TEOS tetraethyl orthosilicate

TBMA tert-butyl methacrylate

Monomers and chemicals:

KOH, SPS, SDS, TEOS, sodium bisulfite, sodium peroxodisulfate, ammonia solution 25% (all VWR), Triton X405 (Fluka) and MPS (Dynasilan ™ MEMO, Degussa) are used as received. ALMA (Degussa) is destabilized with Dehibit ™ 100 (Polyscience). Styrene (BASF) and CHMA (Degussa) are distilled in vacuo. MMA (BASF) was shaken out with 1 N sodium hydroxide solution, washed neutral with water and dried over sodium sulfate. The water content of technical absolute ethanol (Mundo) is determined by Karl Fischer titration to be 0.14% by weight. Example 1: Production of SiO ₂ cores:

The SiO ₂ cores are produced by hydrolysis and condensation of TEOS in a solution of water, ammonia and ethanol using a modified Stöber process. First seed particles are produced, which are then enlarged in a step process. For the synthesis of the seed particles, 500 ml of ethanol and 25 ml of ammonia solution (25% by weight) are placed in a 2 round-bottom flask with a water bath, magnetic stirrer and pressure compensation. After the reaction temperature of 35 ° C has been reached, 19 ml of TEOS are quickly injected. After stirring for 2.5 h, the particles are enlarged by adding 4 ml of ammonia solution and injecting 15 mH TEOS. The reaction is stirred for a further 4 h. The suspension formed contains 0.69 M NH ₃ , 2 MH ₂ O and 2.5% by weight SiO ₂ .

The seed particles are gradually enlarged. For this purpose, the suspension is diluted with ethanol and ammonia solution such that the concentration of SiO _{2 was} 0.5% by weight before each reaction step and 2.5% by weight after the reaction step. The concentrations of ammonia and water are kept constant at 0.69 M NH ₃ and 2 MH ₂ O. For example, 265 ml of SiO ₂ suspension are placed in a 2 l round-bottom flask with water bath, magnetic stirrer and pressure equalization and diluted with 165.5 ml of ethanol and 9.5 ml of ammonia solution (25% by weight). After the reaction temperature of 35 ° C has been reached, 13 ml of TEOS are quickly injected. The reaction is stirred for at least 4 h. The next reaction step can be carried out directly afterwards or after cooling and storing the suspension for several days.

The analysis of the particle diameters by TEM gives the following

correlations:

Drying paint medium diameter standard deviation pale violet 143 nm 5.6% violet 184 nm 4.9% blue-green 218 nm 4.2% yellow-green 270 nm 4%

Example 2: Functionalization of the SiO ₂ cores

To 1.3 l of ethanolic suspension with 2.5% by weight of SiO ₂ (SiO ₂ suspension in ι ^υ with violet drying paint (wavelength maximum 1111 = 400 nm, average particle diameter according to TEM 201 nm; according to Example 1), 0.69

M NH ₃ and 2 MH ₂ O 3 ml of MPS dissolved in ethanol are added with stirring at room temperature. The mixture is on a rotary evaporator

15 first slowly heated to 65 ° C under normal pressure. After 1.5 hours, the distillation of an azeotropic mixture of ethanol and water is started by reducing the pressure. The distilled liquid is replaced by absolute ethanol. A total of 1.2 l of ethanol-water

Mixture removed. After 2 hours the reaction solution is concentrated to 300 ml and transferred to a 1 liter round bottom flask. 0.06 g of SDS, dissolved in 120 g of water, are added and ethanol is distilled off again at 65.degree. The distilled liquid is replaced by water.

The other samples from Example 1 are implemented analogously.

Example 3: Emulsion Polymerization

30

The emulsion polymerization is carried out in a double-walled, 250 ml glass reactor thermostatted to 75 ° C. with an inert gas feed, propeller stirrer and reflux condenser. 110 g (contain 17 g SiO ₂ ) SiO ₂ suspension according to Example 2 are argon for 20 min

35 bubbled. Then 0.1 g SDS are added and the mixture in

Submitted reactor. Then 0.05 g PLC, dissolved in 3 g

Water, added. After 15 min, a monomer emulsion of 5.4 g

MMA, 0.6 g ALMA, 0.02 g SDS (0.33% by weight on monomer), 0.04 g KOH and 30 g water were metered in continuously over a period of 90 min.

The reactor contents are stirred for 20 minutes without further addition. Then 0.02 g of APS was added, dissolved in 3 g of water. After 10 minutes, a second monomer emulsion of 20 g of CHMA, 0.08 g SDS (0.4 wt .-% on monomer) and 40 g of water over a period of 200 min ^ι 0 ^u kontinuieriich added. For almost complete reaction of the monomers, the mixture is then stirred for a further 120 min. The core-shell particles are then precipitated in 500 ml of ethanol, the precipitation is completed by adding 15 g of concentrated aqueous saline solution 5, the suspension with 500 ml of dist. Water is added, suction filtered and the polymer is dried at 50 ° C. in vacuo.

Example 4 Production of template film 0

The dried, powdery polymers from Example 3 are granulated in an extruder (microextruder from DSM Research) at 200 ° C. The granules are heated ⁵ in a hydraulic press (Collin 300 P) and pressed at a predetermined hydraulic pressure. Flat metal sheets covered with PET film are used as the mold. A typical press program for the production of films with a diameter of approximately 10 cm and a thickness of approximately 0.15 mm is: 0 weight 2 - 3 g polymer;

Preheat for 5 min at 180 ° C, pressureless;

3 min pressing with 1 bar hydraulic pressure at 180 ° C;

3 min pressing with 150 bar hydraulic pressure at 180 ° C; 5 10 min slow cooling at 150 bar hydraulic pressure, reached about 90 ° C; rapid cooling to room temperature, without pressure.

Example 5 Etching of the films with hydrofluoric acid

The films are covered with hydrofluoric acid (10% by weight) in open vessels and exposed to RT for one week. Evaporating hydrofluoric acid is replaced by fresh one. After rinsing with water and drying, the etched film pieces show clearly recognizable reflection colors. The examination of ultrathin sections (100 nm) of the films after the etching proves that the SiO ₂ cores are detached from the films and that ordered porous films are formed while maintaining the order (FIGS. 1, 2). In the entire cross section of the film, pores are formed by dissolving SiO ₂ cores, with almost all SiO ₂ cores being removed in a region from the surface of the film to a depth of about 5 μm.

Example 6: Preparation of a latex PTBMAcsPS

50 mg of sodium bisulfite, dissolved in 5 g of water, are mixed into an emulsion which is at 4 ° C. and consists of 217 g of water, 0.4 g of ALMA, 3.6 g of TBMA and 30 mg of SDS, and the emulsion is mixed at 75 ° C. preheated

Transferred reactor. Immediately after filling, the reaction is carried out by adding 220 mg of sodium peroxodisulfate and another 50 mg

Sodium bisulfite, each dissolved in 5 g of water, started. After 20 min

Monomer emulsion I from 9.6 g ALMA, 96 g TBMA, 0.45 g SDS, 0.1 g KOH and 130 g water was metered in continuously over a period of 180 min. The reactor contents are stirred for 30 minutes without further addition. Then 150 mg of sodium peroxodisulfate, dissolved in 5 g of water, are added. After stirring for 15 min, monomer emulsion II from 120 g of styrene, 0.4 g of SDS and 120 g of water is metered in continuously over a period of 200 min. For almost complete reaction of the monomers, the mixture is then stirred for a further 60 min. Dried samples of the latex show a green color. Electron microscopic examination of latex deposits shows that the polymer particles have an irregular shape and an average particle size of approximately 210 nm. The core-shell particles are then precipitated in 1 liter of ethanol, the precipitation is completed by adding 25 g of concentrated aqueous saline, the suspension with 1 liter of distilled water. Water is added, suction filtered and the polymer is dried at 50 ° C. in vacuo.

By changing the type and concentration of emulsifier, further latices with a larger particle diameter and a more uniform particle shape are produced:

Example 7: Pressing the films

To produce films, the polymer powders from the examples

6a-6d in a hydraulic press (Collin 300 P) and heated

Melt pressed at a specified hydraulic pressure Flat metal plates covered with PET film are used as the mold. A typical press program for making films with one

Diameter of about 10 cm and a thickness of about 0.2 mm is:

Weight 1 - 2 g polymer;

Preheat for 5 min at 180 ° C, pressureless;

3 min pressing with 1 bar hydraulic pressure at 180 ° C;

3 min pressing with 150 bar hydraulic pressure at 180 ° C;

10 min slow cooling at 150 bar hydraulic pressure, reached about 90 ° C; rapid cooling to room temperature, without pressure. Example 8: Production of molded articles with homogeneous, regularly arranged cavities

The films from Example 7 are placed under a UV lamp (high-pressure HG steam lamp, power 300 watts, distance lamp - film: 20 cm) over a period of 24 hours. After UV exposure, the films show brilliant, iridescent color effects. The cavities of the shaped body obtained according to Example 6a, 7 and 8 can be seen in FIG.

List of figures

Figures 1a and 1b:

Transmission electron microscope image (TEM image) of ultra-thin sections (100 nm) of the cross section of etched films from example 5. A film cross section is shown. In the lower right part of the pictures you can see the epoxy resin used to embed the films. The arrangement of the pores (light) in the polymer matrix (dark) can be seen starting from the film surface.

FIG. 2: Scanning electron micrograph (SEM image) of the surface of a film from example 5 etched with HF. Regularly arranged pores can be seen at a damaged area, which have arisen from the loosening of the SiO ₂ cores.

Figure 3:

Scanning electron micrograph (SEM) of the

Surface of a film from Example 8 treated with UV light.

Claims

claims

1. Use of core-shell particles whose shell forms a matrix and whose core is essentially solid and one in

_ has essential monodisperse size distribution and their

5

Jacket is connected to the core via an intermediate layer and the jacket has thermoplastic properties for

Production of moldings with homogeneous, regularly arranged cavities. 10

2. Use according to claim 1, characterized in that the core consists of a material that is either not or at a temperature above the flow temperature of the jacket material

15 becomes flowable.

3. Use according to at least one of the preceding claims, characterized in that in the core-shell particles the weight ratio of core to shell in the range from 5: 1 to 1:10, 0 in particular in the range from 2: 1 to 1: 5 and particularly preferably in the range 1.5: 1 to 1: 2.

4. Use according to at least one of the preceding claims, 5 characterized in that in the core-shell particles

Jacket consists of essentially uncrosslinked organic polymers which are grafted onto the core via an at least partially crosslinked intermediate layer, the jacket preferably comprising 0 poly (styrene), thermoplastic poly (acrylate) derivatives, in particular with reference to poly (methyl methacrylate) or poly (cyclohexyl methacrylate) ), or thermoplastic copolymers of these polymers with others

Acrylates, such as preferably styrene-acrylonitrile copolymers, styrene

Ethyl acrylate copolymers or methyl methacrylate-ethyl acrylate) - 5 Contains copolymers and the intermediate layer is preferably composed of methyl methacrylate-allyl methacrylate copolymers.

5. Use according to at least one of the preceding claims, characterized in that in the core-shell particles, the core consists essentially of an inorganic material, preferably a metal or semimetal or a metal chalcogenide or

Metallic picide, particularly preferably silicon dioxide.

6. Use according to at least one of claims 1 to 4, characterized in that in the core-shell particles, the core consists essentially of a UV-degradable material, preferably a UV-degradable organic polymer and 5 particularly preferably of poly (tert-butyl methacrylate),

Poly (methyl methacrylate), poly (n-butyl methacrylate) or copolymers containing one of these polymers.

7. Use according to at least one of the preceding claims, 0 characterized in that the core-shell particles have an average particle diameter in the range from about 50 to 800 nm, preferably in the range from 100 to 600 nm and particularly preferably in the range from 200 to 450 nm. 5

8. Use according to at least one of the preceding claims, characterized in that the cores

Surface modification, preferably with silanes bearing reactive end groups, such as epoxy functions or free ones

Double bonds have.

9. Use according to at least one of the preceding claims, characterized in that the shaped bodies are 5 films.

10. A process for the production of moldings with homogeneous, regularly arranged cavities, characterized in that core-shell particles, the shell of which forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution and with the core via an intermediate layer is connected and the jacket of which has thermoplastic properties, are processed into shaped articles, preferably films, using a mechanical force and elevated temperature, and the cores are subsequently removed.

11. The method according to claim 10, characterized in that the application of a mechanical force by uniaxial pressing or during an injection molding process or during a

Transfer pressing process or during a (co) extrusion or during a calendering process or during a blowing process.

12. The method according to claim 10 and / or 11, characterized in that the core-shell particles are cooled under the action of the mechanical force to a temperature at which the shell is no longer flowable.

13. The method according to at least one of claims 10 to 12, characterized in that the removal of the cores is carried out by etching, preferably by etching with HF.

14. The method according to at least one of claims 10 to 12, characterized in that the removal of the cores is carried out by UV radiation.

15. The method according to at least one of claims 10 to 14, characterized in that the sheath is crosslinked before or after the removal of the cores

16. Shaped body with homogeneous, regularly arranged cavities, characterized in that the regularly arranged cavities are embedded in a matrix with thermoplastic or thermosetting properties.

17. Shaped body according to claim 16, characterized in that the regularly arranged cavities are embedded in a matrix with thermoplastic properties. 5 18. Shaped body according to at least one of claims 16 or 17, characterized in that the matrix of poly (styrene), thermoplastic poly (acrylate) derivatives, preferably

Poly (methyl methacrylate) or poly (cyclohexyl methacrylate), or thermoplastic copolymers of these polymers with other acrylates, such as preferably styrene-acrylonitrile copolymers, styrene-ethyl acrylate copolymers or methyl methacrylate-ethyl acrylate) copolymers. 5 ig. Shaped body according to at least one of claims 16 to 18, characterized in that the cavities have an average diameter in the range from about 50 - 500 nm, preferably in the range from 100 - 500 nm and very particularly preferably in the range 0 from 200 to 280 nm.

20. Use of moldings according to at least one of claims 16 to 19 and / or of moldings produced according to at least one of claims 10 to 15 as a photonic material.

21. Use of moldings according to at least one of claims 16 to 19 and / or of moldings produced according to at least one of claims 10 to 15 for the production of electro-optical devices.

22. Electro-optical device containing shaped bodies according to at least one of claims 16 to 19 and / or shaped bodies produced according to at least one of claims 10 to 15.