KR20180113418A - Dispersion of phonic crystalic particles and preparing method of the same, and photonic crystal display device including the same - Google Patents

Abstract

The present invention relates to: a dispersion of photonic crystal particles which includes a core-shell particle having an organic core and an organic shell dispersed in a hydrophobic dispersion solvent containing a charge control agent; a preparing method of the dispersion of the photonic crystal particles; and a photonic crystal display device including the dispersion of the photonic crystal particles. The dispersion of photonic crystal particles according to the present invention can be simply produced by dispersing the core-shell particle including the organic core and organic shell in the hydrophobic dispersion solvent containing the charge control agent.

Description

TECHNICAL FIELD [0001] The present invention relates to a photonic crystal particle dispersion, a photonic crystal particle dispersion, and a photonic crystal display device including the photonic crystal particle dispersion,

The present invention relates to photocrystalline particle dispersions comprising core-shell particles comprising an organic core and an organic shell dispersed in a hydrophobic dispersion solvent containing a charge control agent, a process for producing the photocrystalline particle dispersion, And a photonic crystal display device including the photonic crystal particle dispersion.

Recently, various display devices that can be electrically driven have been developed. Of these, electronic ink is one of the next generation display devices. The electronic ink is a technique in which black and white particles having different electric charges are dispersed in a liquid dispersion solvent and then encapsulated, and white and black are displayed by application of an electric field to change the content displayed over time. The electronic ink can be driven at a low power, and is capable of producing a flexible display device. However, the electronic ink has a disadvantage in that it can display only black and white, and the switching of display contents is slow. In order to overcome the disadvantage of the electronic ink, a full-color reflective display device using a photonic crystal principle, which is arranged in a face-centered cubic structure to reflect light of a specific wavelength when particles are dispersed in a liquid dispersion solvent, has been studied .

Conventionally, the nanoparticles used in the method of controlling color using a liquid photonic crystal have a structure in which a core-shell, a multi-core, or a cluster is formed of different materials and the charge layer is wrapped around these particles After the formation, the reflection color was adjusted using electric polarization [Korean Patent Registration No. 10-1199601]. The above method has a disadvantage that the particle manufacturing process is complicated and the unit cost is high. In addition, as a simple polymer particle production process, there is a method of controlling the color reaction using electrophoresis (Korean Patent No. 10-0922892). This method is disadvantageous in that water is electrolyzed by dispersing the particles in water having a high dielectric constant and an additional manufacturing process for sealing the glass electrode plate is required in order to prevent electrolysis of the water. In order to improve the electrolysis and volatility of water, Korean Patent Laid-Open Publication No. 2015-0009719 discloses that photocrystalline is formed by dispersing photonic crystal particles in two or more complex dispersion solvents, so that there is no side reaction and stability is low due to low volatility, The spacing of the photonic crystal particles was precisely controlled by adjusting the concentration of the dispersion solvent. However, since the basic dispersion solvent should be water and the polar solvent to be mixed with water should be used in the above method, there is a limit to the fundamental problem-solving method.

Therefore, the liquid crystal photonic crystal display responds quickly to an electric field, realizes full color, and can be applied to a flexible display. However, it has not been solved, and a relatively simple photonic crystal particle manufacturing method A stable dispersion solvent is also required in the electric field.

The present invention relates to photocrystalline particle dispersions comprising core-shell particles comprising an organic core and an organic shell dispersed in a hydrophobic dispersion solvent containing a charge control agent, a process for producing the photocrystalline particle dispersion, And a photonic crystal display device (device) including the photonic crystal particle dispersion.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

According to a first aspect of the present invention, there is provided a method for producing a core-shell particle comprising the steps of: synthesizing core-shell particles comprising an organic core and an organic shell; And dispersing the core-shell particles in a hydrophobic dispersion solvent containing a charge control agent.

A second aspect of the present invention provides a photonic crystal particle dispersion comprising core-shell particles comprising an organic core and an organic shell dispersed in a hydrophobic dispersion solvent containing a charge control agent.

A third aspect of the present application provides a light emitting device comprising: at least two light-transmitting electrodes disposed in a chamber; And a photocrystalline particle dispersion solution according to the second aspect of the present invention formed between the two or more light-transmitting electrodes.

In embodiments of the present application, by dispersing core-shell particles comprising an organic core and an organic shell as photonic crystal particles in a hydrophobic dispersion solvent containing a charge control agent, A photonic crystal particle dispersion can be prepared.

In embodiments of the present invention, the core-shell particles are formed into an organic core-organic shell structure using an organic core and an organic shell. The synthesis process of conventional inorganic core-organic shell or organic core-inorganic shell particles requires two or more steps and is more difficult to synthesize than organic core-organic shell particles in the case of inorganic core-inorganic shell particles, The organic core-organic shell structure according to the present invention can be synthesized through a batch process in one reactor, which is characterized in that the synthesis process is simple. In addition, since it is possible to synthesize core-shell particles having a uniform size, the sharpness of reflected light can be improved.

In the conventional display, photonic crystal particles are prepared by using an oil and a mineral core as a dispersion medium (dispersion solvent), or polymer particles having a small difference in refractive index from the dispersion solvent. However, The color strength is not good (blue is hardly visible). On the other hand, photocrystalline particles according to embodiments of the present invention are prepared by using photocatalytic particles having an organic core-organic shell by using an organic core having a difference in refractive index with a dispersion solvent, thereby further increasing color strength . In particular, the color strength of the organic core-organic shell structure can be determined by controlling the difference in refractive index between the organic core shell and the organic solvent shell depending on the constituent material of the core, and the refractive index of the particles may be different depending on the composition ratio of the core and the shell. And the color intensity can be controlled and increased by using such core-shell type photonic crystal particles.

In embodiments of the present invention, it is possible to precisely control the core-shell particle spacing and electrical color variability contained in the photonic crystal particle dispersion by controlling the amount of the charge control agent in the production of the photonic crystal particle dispersion. Thus, the desired reflection color peak can be precisely controlled regardless of the concentration of the particles determined by the synthesis of the core-shell particles.

In addition, a RGB full color can be realized by using a hydrophobic dispersion solvent having a low dielectric constant as a dispersion solvent for dispersing the photonic crystal particles (organic core-organic shell particles). Since the hydrophobic dispersion solvent is low in volatility, deterioration of stability over a long period of time due to solvent volatilization can be avoided. By using a hydrophobic dispersion solvent as the dispersion solvent, it is possible to eliminate side reactions such as water electrolysis which has occurred when water is conventionally used as a dispersion solvent, and to solve the coloring phenomenon of the cathode.

That is, according to embodiments of the present invention, by dispersing the photonic crystal particles (organic core-organic shell particles) in the hydrophobic dispersion solvent, electrochemical reactions by the dispersion solvent can be blocked, and stability of the display can be increased. Further, by lowering the electric current flowing in the dispersion solvent by the voltage, it is possible to provide a polymer colloid-containing photonic crystal display device capable of realizing a clear color even in a hydrophobic dispersion solvent.

FIG. 1 is a schematic diagram illustrating a method for producing an organic core-organic shell photocrystalline particle dispersion containing charge control agent according to an embodiment of the present invention.
2 is a schematic diagram showing an organic core-organic shell particle dispersed in a photonic crystal particle dispersion according to an embodiment of the present invention.
3A and 3B are schematic diagrams of a photonic crystal display device according to an embodiment of the present invention.
FIGS. 4A and 4B are a photograph (FIG. 4A) and a reflectance spectrum (FIG. 4B) of a digital camera showing a change in reflected light color of the photonic crystal display device according to one embodiment of the present invention.
5 is a graph showing the reflectivity peak wavelength of a photonic crystal display device according to an embodiment of the present invention.
6 is a graph showing an angle-dependent peak wavelength of the UV-vis spectrum in one embodiment of the present invention.
FIG. 7A is a graph showing a current according to a voltage of a conventional photonic crystal display device using water as a dispersion solvent according to one comparative example of the present invention. FIG. In which a voltage is measured according to a voltage of a power supply.
8 is a photograph of a digital camera showing a change in the color of light reflected by the photonic crystal display device according to the comparative example of the present application.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as " including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The terms " about ", " substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure. The word " step (or step) " or " step " used to the extent that it is used throughout the specification does not mean " step for.

Throughout this specification, the term " combination (s) thereof " included in the expression of the machine form means a mixture or combination of one or more elements selected from the group consisting of the constituents described in the expression of the form of a marker, Quot; means at least one selected from the group consisting of the above-mentioned elements.

Throughout this specification, the description of "A and / or B" means "A or B, or A and B".

Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments and examples and drawings.

According to a first aspect of the present invention, there is provided a method for producing a core-shell particle comprising the steps of: synthesizing core-shell particles comprising an organic core and an organic shell; And dispersing the core-shell particles in a hydrophobic dispersion solvent containing a charge control agent. The present invention also provides a method for producing a photonic crystal particle dispersion solution (dispersion liquid).

In one embodiment of the present invention, the photonic crystal particle dispersion can be simply produced by dispersing the organic core-organic shell particles as the photocrystalline particles in the hydrophobic dispersion solvent containing the charge control agent.

In one embodiment of the present invention, the core-shell particles are formed into an organic core-organic shell structure using an organic core and an organic shell. The synthesis process of conventional inorganic core-organic shell or organic core-inorganic shell particles requires two or more steps, and in the case of inorganic core-inorganic shell particles, it is necessary to use a multistage process that is more complex than the organic core- On the other hand, the organic material core-organic material shell structure according to the embodiments of the present invention is characterized in that both the core and the shell are organic materials such as polymers, and thus can be synthesized through a batch process in one reactor, thereby simplifying the synthesis process. In addition, since it is possible to synthesize core-shell particles having a uniform size, the sharpness of reflected light can be improved.

In the conventional display, photonic crystal particles are prepared by using an oil and a mineral core as a dispersion medium (dispersion solvent), or polymer particles having a small difference in refractive index from the dispersion solvent. However, The color strength is not good (blue is hardly visible). On the other hand, photocrystalline particles according to embodiments of the present invention are prepared by using photocatalytic particles having an organic core-organic shell by using an organic core having a difference in refractive index with a dispersion solvent, thereby further increasing color strength . In particular, the color strength of the organic core-organic shell structure can be determined by controlling the difference in refractive index between the organic core shell and the organic solvent shell depending on the constituent material of the core, and the refractive index of the particles may be different depending on the composition ratio of the core and the shell. And the color intensity can be controlled and increased by using such core-shell type photonic crystal particles.

In one embodiment of the invention, the organic core-organic shell particles comprise a polymeric colloid having a surface charge, wherein the core-shell particles have a surface charge of the same sign in the photonic crystal, Can be arranged.

In one embodiment of the present invention, the synthesis of the organic core-organic shell particles may be performed by reacting a polymer monomer, a cross-linking agent, and an initiator by an oil-free neutralization method, but the present invention is not limited thereto.

In one embodiment of the present invention, the organic core and the organic shell may be formed of the same or different polymers. For example, the polymer may be poly (t-butylmethacrylate), poly (PMMA), poly (n-butylmethacrylate), polymethylacrylate, polystyrene, and combinations thereof. But are not limited thereto. For example, the core-shell particles can be selected from the group consisting of poly tert-butyl methacrylate / polymethyl methacrylate, polymethyl methacrylate / poly tert-butyl methacrylate, polystyrene / poly tert-butyl methacrylate, polystyrene / Poly-n-butyl methacrylate / poly-tert-butyl methacrylate, poly-n-butyl methacrylate / polymethyl methacrylate, poly But are not limited to, acrylate / poly tert-butyl methacrylate, polyacrylate / polymethyl methacrylate, polystyrene / polyacrylate, and the like. For example, it is possible to use polytert-butyl methacrylate having a high specific gravity as an organic core or an organic shell of the core-shell particle, or a polymer having a large difference in refractive index from the dispersion solvent of the photonic crystal particles (Such as, but not limited to, polymethyl methacrylate). For example, when the poly-tert-butyl methacrylate is used as an organic shell to synthesize the core-shell particles, the surface of the core-shell particle can be formed into an anion-introduced state using an anionic initiator Alternatively, the surface of the core-shell particle can be formed with a cation introduced using a cationic initiator, but the present invention is not limited thereto.

In one embodiment herein, the polymeric core-shell polymer particles are prepared by copolymerizing a cross-linking agent selected from the group consisting of ethylene glycol dimethacrylate (EGDMA), divinylbenzene (DVB), and combinations thereof And may include, but is not limited to, cross-linked polymer forms.

In one embodiment of the invention, the size of the core-shell particles may be from about 100 nm to about 300 nm, but is not limited thereto. For example, the size of the core-shell particle can be from about 100 nm to about 300 nm, from about 100 nm to about 250 nm, from about 100 nm to about 200 nm, from about 100 nm to about 150 nm, from about 150 nm to about 300 nm, from about 200 nm to about 300 nm, or from about 250 nm to about 300 nm, but the present invention is not limited thereto. In one embodiment of the present invention, when using core-shell particles having a particle size of about 100 nm to about 300 nm as described above, a color of the visible light region can be obtained. For example, the size of the core-shell particle is controlled by controlling the content of monomers for producing the core and the polymer forming each shell, and the size and / or thickness of each of the core and the shell Can be controlled by adjusting the monomer content ratio of the polymer. For example, the size of the core-shell particles can be increased by increasing the content of monomers for making the core and the shell, and the size and / or thickness of each of the core and shell Can be controlled by adjusting the monomer content ratio of each polymer.

In one embodiment of the present invention, the core-shell particles may include, but are not limited to, about 10 parts by weight to about 60 parts by weight per 100 parts by weight of the photonic crystal particle dispersion. For example, the core-shell particles may be present in an amount of from about 10 parts by weight to about 60 parts by weight, from about 20 parts by weight to about 60 parts by weight, from about 30 parts by weight to about 60 parts by weight based on about 100 parts by weight of the photonic crystal particle dispersion, About 10 parts by weight to about 40 parts by weight, about 10 parts by weight to about 30 parts by weight, about 10 parts by weight to about 30 parts by weight, about 40 parts by weight to about 60 parts by weight, about 50 parts by weight to about 60 parts by weight, , Or from about 10 parts by weight to about 20 parts by weight. For example, if the core-shell particle is less than about 10 parts by weight based on the total weight of the photonic crystal particle dispersion, diffraction may not occur for sufficient color development, and if greater than about 60 parts by weight, As the viscosity of the particle dispersion becomes high and the speed of the photonic crystal particle dispersion becomes slow, it is not easy to adjust the interval of the particles, so that color implementation may not be easy.

In one embodiment of the present invention, dispersing the core-shell particles in the hydrophobic dispersion solvent is performed after dispersing the synthesized core-shell particles in an intermediate dispersion solvent and then precipitating using a centrifugal separator But may not be limited thereto. Specifically, dispersing the core-shell particles in the hydrophobic dispersion solvent first disperses the core-shell particles in an intermediate dispersion solvent. Then, the core-shell particles are settled in the intermediate dispersion solvent by a centrifugal separator. Finally, the precipitated core-shell particles are dispersed in the hydrophobic dispersion solvent containing the charge control agent.

In one embodiment of the present invention, it is possible to precisely control the core-shell particle spacing and electrical color variability contained in the photonic crystal particle dispersion by controlling the amount of the charge control agent in the preparation of the core-shell particle dispersion. Thus, the desired reflection color peak can be precisely controlled regardless of the concentration of the particles determined by the synthesis of the core-shell particles.

In addition, a RGB full color can be realized by using a hydrophobic dispersion solvent having a low dielectric constant as a dispersion solvent for dispersing the core-shell particles. Since the hydrophobic dispersion solvent is low in volatility, deterioration of stability over a long period of time due to solvent volatilization can be avoided. By using a hydrophobic dispersion solvent as the dispersion solvent, it is possible to eliminate side reactions such as water electrolysis which has occurred when water is conventionally used as a dispersion solvent, and to solve the coloring phenomenon of the cathode.

In this regard, FIG. 1 is a schematic diagram showing a method of manufacturing a photonic crystal particle dispersion according to an embodiment of the present invention. Shell particles 300 are dispersed in a hydrophobic dispersion solvent 200 containing a reversed micelle of the charge control agent 100 so that the polarity of the charge control agent 100 and the core- The surface charge of the particle 300 may be coupled, but may not be limited thereto.

In one embodiment of the present invention, by using the polymer core-polymer shell particles having a high specific gravity, the core-shell particles are precipitated by centrifugation instead of the conventional freeze-drying method, - Shell particles can be dispersed.

In one embodiment of the present invention, the intermediate dispersion solvent may include, but is not limited to, is selected from the group consisting of isopropanol, 1-propanol, ethanol, and combinations thereof.

In one embodiment of the present invention, the hydrophobic dispersion solvent may include, but not limited to, a polarized solution having a low dielectric constant and a low polarity. In one embodiment of the invention, the hydrophobic dispersion solvent is selected from the group consisting of isoparaffinic hydrocarbon solvent (ISOPAR) G, isopara C, isopara D, isopara E, isopara F, isopara H, isopara I, Methyl acetate, butyl acetate, 2-butanol, acetonitrile, acetic acid, propylene carbonate, and combinations thereof, in the presence of a base such as triethylamine, triethylamine, But are not limited to, those selected from the group consisting of < RTI ID = 0.0 > For example, as the hydrophobic dispersion solvent, isopara G, which is a low molecular weight branched alkane represented by the following formula 1, may be used, but it may not be limited thereto:

[Chemical Formula 1]

In the above formula (1), n is 1 to 8.

In one embodiment of the invention, the charge control agent may be an ionic amphoteric molecule or a nonionic amphoteric molecule. The ampholytic molecule consists of a hydrophilic head portion and a hydrophobic tail portion. For example, the charge control agent may be sodium bis (2-ethylhexyl) sulfosuccinate (AOT), sodium A surfactant such as sodium dodecylsulfonate (SDS), cetyltrimethylammonium bromide (CTAB), a span surfactant, a pluronic surfactant, a tween surfactant, and combinations thereof But are not limited to, those selected from the group consisting of < RTI ID = 0.0 > The span surfactant, pluronic surfactant, and twin surfactant are nonionic surfactants. For example, the span-based surfactant can include, but is not limited to, sorbitan fatty acid esters, sorbitan monolaurate (span-20), or sorbitan monopalmitate (span-40) have. For example, the pluronic surfactant may be (PEO) ₂₀ (PPO) ₇₀ (PEO) ₂₀ , prepared by adding ethylene oxide to polypropylene glycol, but may not be limited thereto. For example, the twin surfactant may be a polyoxyethylene sorbitan fatty acid ester such as polyoxyethylene sorbitan monolaurate (Tween-20), polyoxyethylene sorbitan monostearate (Tween-60), or poly Oxyethylene sorbitan monooleate (Tween-80), but the present invention is not limited thereto.

In one embodiment of the present invention, the charge control agent may include, but is not limited to, about 0.1 part by weight to about 10 parts by weight per 100 parts by weight of the photocatalytic dispersion. For example, for about 100 parts by weight of the photonic crystal particle dispersion, the charge control agent may be present in an amount of from about 0.1 parts by weight to about 10 parts by weight, from about 0.1 parts by weight to about 9 parts by weight, from about 0.1 parts by weight to about 8 parts by weight, About 0.1 part by weight to about 3 parts by weight, about 0.1 part by weight to about 7 parts by weight, about 0.1 part by weight to about 6 parts by weight, about 0.1 to about 5 parts by weight, about 0.1 part by weight to about 4 parts by weight, From about 1 part to about 10 parts, from about 2 parts to about 10 parts, from about 3 parts to about 10 parts, from about 0.1 parts to about 2 parts, from about 0.1 parts to about 1 part, from about 1 part to about 10 parts, 4 parts by weight to about 10 parts by weight, about 5 parts by weight to about 10 parts by weight, about 6 to about 10 parts by weight, about 7 to about 10 parts by weight, about 8 to about 10 parts by weight, About 9 parts by weight to about 10 parts by weight may be included, but the present invention is not limited thereto.

In one embodiment of the present invention, the spacing of the core-shell particles dispersed in the photonic crystal particle dispersion may be controlled according to the amount of the charge control agent, but the present invention is not limited thereto.

In one embodiment of the present invention, the charge control agent may further include, but is not limited to, acting as a surfactant. In one embodiment of the present invention, in the hydrophobic dispersion solvent, since the core-shell particle can not be charged, by adding the charge control agent serving as the emulsifier, even in the hydrophobic dispersion solvent, the core- May be charged, but may not be limited thereto.

The second aspect of the present invention provides a photonic crystal particle dispersion comprising as a photonic crystal particle core-shell particles comprising an organic core and an organic shell dispersed in a hydrophobic dispersion solvent containing a charge control agent do.

The second aspect of the present invention relates to a polymer colloid produced according to the method of manufacturing a photonic crystal particle dispersion according to the first aspect of the present invention, and a detailed description thereof is omitted for the parts overlapping with the first aspect of the present invention. Although the description of the first aspect is omitted from the second aspect of the present application, the same can be applied.

In this regard, FIG. 2 is a schematic diagram showing core-shell particles dispersed in a hydrophobic dispersion solvent, including a charge control agent 100 formed on the surface of an organic core-organic shell particle 300 according to an embodiment of the present invention.

In one embodiment of the present invention, the organic core-organic shell particles dispersed in the hydrophobic dispersion solvent may be formed by coupling the polar group of the charge control agent 100 and the surface charge of the core-shell particle, .

In one embodiment herein, the organic core and the organic shell may comprise the same or different polymers, for example, poly (t-butylmethacrylate), polymethylmethacrylate But may be selected from the group consisting of polymethylmethacrylate, poly (n-butylmethacrylate), polymethylacrylate, polystyrene, and combinations thereof. But is not limited to. For example, the core-shell particles can be selected from the group consisting of poly tert-butyl methacrylate / polymethyl methacrylate, polymethyl methacrylate / poly tert-butyl methacrylate, polystyrene / poly tert-butyl methacrylate, polystyrene / Poly-n-butyl methacrylate / poly-tert-butyl methacrylate, poly-n-butyl methacrylate / polymethyl methacrylate, poly Acrylate / poly tert-butyl methacrylate, polyacrylate / polymethyl methacrylate, polystyrene / polyacrylate, and the like. For example, it is possible to use polytert-butyl methacrylate having a high specific gravity as an organic core or an organic shell of the core-shell particle, or a polymer having a large difference in refractive index from the dispersion solvent of the photonic crystal particles (Such as, but not limited to, polymethyl methacrylate). For example, when the poly-tert-butyl methacrylate is used as an organic shell to synthesize the core-shell particles, the surface of the core-shell particle can be formed into an anion-introduced state using an anionic initiator Alternatively, the surface of the core-shell particle can be formed with a cation introduced using a cationic initiator, but the present invention is not limited thereto.

In the conventional display, photonic crystal particles are prepared by using an oil and a mineral core as a dispersion medium (dispersion solvent), or polymer particles having a small difference in refractive index from the dispersion solvent. However, The color strength is not good (blue is hardly visible). On the other hand, photocrystalline particles according to embodiments of the present invention are prepared by using photocatalytic particles having an organic core-organic shell by using an organic core having a difference in refractive index with a dispersion solvent, thereby further increasing color strength . In particular, the color strength of the organic core-organic shell structure can be determined by controlling the difference in refractive index between the organic core shell and the organic solvent shell depending on the constituent material of the core, and the refractive index of the particles may be different depending on the composition ratio of the core and the shell. And the color intensity can be controlled and increased by using such core-shell type photonic crystal particles.

In one embodiment of the invention, the size of the core-shell particles may be from about 100 nm to about 300 nm, but is not limited thereto. For example, the size of the core-shell particle can be from about 100 nm to about 300 nm, from about 100 nm to about 250 nm, from about 100 nm to about 200 nm, from about 100 nm to about 150 nm, from about 150 nm to about 300 nm, from about 200 nm to about 300 nm, or from about 250 nm to about 300 nm, but the present invention is not limited thereto. In one embodiment of the present invention, when using core-shell particles having a particle size of about 100 nm to about 300 nm as described above, a color of the visible light region can be obtained.

In one embodiment of the present invention, the core-shell particles may include, but are not limited to, about 10 parts by weight to about 60 parts by weight per 100 parts by weight of the photonic crystal particle dispersion. For example, the core-shell particles may be present in an amount of from about 10 parts by weight to about 60 parts by weight, from about 20 parts by weight to about 60 parts by weight, from about 30 parts by weight to about 60 parts by weight based on about 100 parts by weight of the photonic crystal particle dispersion, About 10 parts by weight to about 40 parts by weight, about 10 parts by weight to about 30 parts by weight, about 10 parts by weight to about 30 parts by weight, about 40 parts by weight to about 60 parts by weight, about 50 parts by weight to about 60 parts by weight, , Or from about 10 parts by weight to about 20 parts by weight. For example, if the core-shell particle is less than about 10 parts by weight based on the total weight of the photonic crystal particle dispersion, diffraction may not occur for sufficient color development, and if greater than about 60 parts by weight, As the viscosity of the particle dispersion becomes high and the speed of the photonic crystal particle dispersion becomes slow, it is not easy to adjust the interval of the particles, so that color implementation may not be easy.

For example, the size of the core-shell particle is controlled by controlling the content of monomers for producing the core and the polymer forming each shell, and the size and / or thickness of each of the core and the shell Can be controlled by adjusting the monomer content ratio of the polymer. For example, the size of the core-shell particles can be increased by increasing the content of monomers for making the core and the shell, and the size and / or thickness of each of the core and shell Can be controlled by adjusting the monomer content ratio of each polymer.

In one embodiment of the present invention, the hydrophobic dispersion solvent may include, but not limited to, a polarized solution having a low dielectric constant and a low polarity. In one embodiment of the invention, the hydrophobic dispersion solvent is selected from the group consisting of isoparaffinic hydrocarbon solvent (ISOPAR) G, isopara C, isopara D, isopara E, isopara F, isopara H, isopara I, Methyl acetate, butyl acetate, 2-butanol, acetonitrile, acetic acid, propylene carbonate, and combinations thereof, in the presence of a base such as triethylamine, triethylamine, But are not limited to, those selected from the group consisting of < RTI ID = 0.0 > For example, as the hydrophobic dispersion solvent, isopara G, which is a low molecular weight branched alkane represented by the following formula 1, may be used, but it may not be limited thereto:

[Chemical Formula 1]

In the above formula (1), n is 1 to 8.

In one embodiment, the charge control agent 100 may be an ionic amphoteric molecule or a nonionic amphoteric molecule. The ampholytic molecule consists of a hydrophilic head portion and a hydrophobic tail portion. For example, the charge control agent may be sodium bis (2-ethylhexyl) sulfosuccinate (AOT), sodium A surfactant such as sodium dodecylsulfonate (SDS), cetyltrimethylammonium bromide (CTAB), a span surfactant, a pluronic surfactant, a tween surfactant, and combinations thereof But are not limited to, those selected from the group consisting of < RTI ID = 0.0 >

In one embodiment of the present invention, the hydrophobic dispersion solvent may include, but not limited to, a polarized solution having a low dielectric constant and a low polarity. In one embodiment herein, the hydrophobic dispersing solvent is selected from the group consisting of isopara G, halocarbons, decane, undecane, dodecane, diethyl ether, methyl-t-butyl ether, ethyl acetate, butyl acetate, But are not limited to, those selected from the group consisting of nitrile, acetic acid, propylene carbonate, and combinations thereof.

In one embodiment of the invention, the charge control agent may be an ionic amphoteric molecule or a nonionic amphoteric molecule. The ampholytic molecule consists of a hydrophilic head portion and a hydrophobic tail portion. For example, the charge control agent may be sodium bis (2-ethylhexyl) sulfosuccinate (AOT), sodium A surfactant such as sodium dodecylsulfonate (SDS), cetyltrimethylammonium bromide (CTAB), a span surfactant, a pluronic surfactant, a tween surfactant, and combinations thereof But are not limited to, those selected from the group consisting of < RTI ID = 0.0 > The span surfactant, pluronic surfactant, and twin surfactant are nonionic surfactants. For example, the span-based surfactant can include, but is not limited to, sorbitan fatty acid esters, sorbitan monolaurate (span-20), or sorbitan monopalmitate (span-40) have. For example, the pluronic surfactant may be (PEO) ₂₀ (PPO) ₇₀ (PEO) ₂₀ , prepared by adding ethylene oxide to polypropylene glycol, but may not be limited thereto. For example, the twin surfactant may be a polyoxyethylene sorbitan fatty acid ester such as polyoxyethylene sorbitan monolaurate (Tween-20), polyoxyethylene sorbitan monostearate (Tween-60), or poly Oxyethylene sorbitan monooleate (Tween-80), but the present invention is not limited thereto.

In one embodiment of the present invention, the charge control agent may be included in an amount of about 0.1 part by weight to about 10 parts by weight based on about 100 parts by weight of the photonic crystal particle dispersion, but may not be limited thereto. For example, for about 100 parts by weight of the photonic crystal particle dispersion, the charge control agent may be present in an amount of from about 0.1 parts by weight to about 10 parts by weight, from about 0.1 parts by weight to about 9 parts by weight, from about 0.1 parts by weight to about 8 parts by weight, About 0.1 part by weight to about 3 parts by weight, about 0.1 part by weight to about 7 parts by weight, about 0.1 part by weight to about 6 parts by weight, about 0.1 to about 5 parts by weight, about 0.1 part by weight to about 4 parts by weight, From about 1 part to about 10 parts, from about 2 parts to about 10 parts, from about 3 parts to about 10 parts, from about 0.1 parts to about 2 parts, from about 0.1 parts to about 1 part, from about 1 part to about 10 parts, 4 parts by weight to about 10 parts by weight, about 5 parts by weight to about 10 parts by weight, about 6 to about 10 parts by weight, about 7 to about 10 parts by weight, about 8 to about 10 parts by weight, About 9 parts by weight to about 10 parts by weight may be included, but the present invention is not limited thereto.

In one embodiment of the present invention, the spacing of the core-shell particles dispersed in the photonic crystal particle dispersion may be controlled according to the amount of the charge control agent, but the present invention is not limited thereto.

In one embodiment of the present invention, the charge control agent may further include, but is not limited to, acting as a surfactant. In one embodiment of the present invention, in the hydrophobic dispersion solvent, since the core-shell particle can not be charged, by adding the charge control agent serving as the emulsifier, even in the hydrophobic dispersion solvent, the core- May be charged, but may not be limited thereto.

A third aspect of the present application provides a light emitting device comprising: at least two light-transmitting electrodes disposed in a chamber; And a photonic crystal particle dispersion according to the second aspect of the present invention formed between the two or more light-transmitting electrodes.

The third aspect of the present invention relates to a photonic crystal display device comprising the photocrystalline particle dispersion of the second aspect according to the method for producing the polymer colloid of the first aspect of the present application and is characterized in that the first and / Although a detailed description of the overlapping portions has been omitted, the description of the first and / or second aspects of the present invention can be equally applied to the third aspect of the present invention.

In this regard, FIGS. 3A and 3B are schematic diagrams of a photonic crystal display device according to an embodiment of the present invention. In one embodiment of the present invention, the photonic crystal display device includes at least two light-permeable electrodes disposed in a chamber, and a core-and-sheath layer formed on the surface of the charge control agent dispersed in the hydrophobic dispersion solvent 200 formed between the light- Shell particles 300. The photocatalytic particle dispersion includes a shell particle.

In one embodiment of the present invention, by dispersing photocrystalline particles (core-shell particles) in the hydrophobic dispersion solvent, electrochemical reactions by the dispersion solvent can be blocked, so that the stability of the display can be increased. Further, by lowering the electric current flowing in the dispersion solvent by the voltage, it is possible to provide a polymer colloid-containing photonic crystal display device capable of realizing a clear color even in a hydrophobic dispersion solvent.

In one embodiment of the invention, the chamber comprising the photonic crystal particle dispersion formed between the two or more light-transmitting electrodes may be enclosed, but may not be limited thereto. For example, after injecting the photonic crystal particle dispersion according to the second aspect of the present invention between the two or more electrodes, the chamber may be sealed.

In one embodiment of the present invention, the light-transmitting electrode is not particularly limited as long as it is a transparent electrode used in a photonic crystal display device. For example, an ITO electrode may be used as the light-transmitting electrode, but the present invention is not limited thereto.

In an embodiment of the present invention, the spacing of the core-shell particles 300 included in the photonic crystal particle dispersion solution may be controlled by applying an electric field to the light-transmitting electrode. However, the present invention is not limited thereto.

In one embodiment of the invention, the electric field applied between the light-transmitting electrodes may be from about 0.1 V to about 20 V, but may not be limited thereto. For example, the electric field may be in the range of about 0.1 V to about 20 V, about 0.1 V to about 15 V, about 0.1 V to about 10 V, about 0.1 V to about 5 V, about 0.1 V to about 1 V, To about 20 V, from about 5 V to about 20 V, from about 10 V to about 20 V, or from about 15 V to about 20 V, for example.

In one embodiment of the present invention, the light-transmitting electrode may include, but is not limited to, dividing the region to which the electric field is applied into two or more partial regions and applying an electric field to each region, respectively .

In one embodiment of the present invention, the wavelength of the color of the photonic crystal display device may be controlled by controlling the interval of the core-shell particles 300 included in the photonic crystal composite dispersion, .

In one embodiment of the present invention, by dispersing the organic core-organic shell photocrystalline particles in the hydrophobic dispersion solvent, the stability of the display can be increased by blocking electrochemical reactions by the dispersion solvent. Further, by lowering the electric current flowing in the dispersion solvent by the voltage, it is possible to provide a polymer colloid-containing photonic crystal display device capable of realizing a clear color even in a hydrophobic dispersion solvent. In addition, in one embodiment of the present invention, by dispersing the organic core-organic shell photocrystalline particles in the hydrophobic dispersion solvent, it is possible to increase the reflection intensity with respect to the color of a specific wavelength band. For example, .

In the conventional display, photonic crystal particles are prepared by using an oil and a mineral core as a dispersion medium (dispersion solvent), or polymer particles having a small difference in refractive index from the dispersion solvent. However, The color strength is not good (blue is hardly visible). On the other hand, photocrystalline particles according to embodiments of the present invention are prepared by using photocatalytic particles having an organic core-organic shell by using an organic core having a difference in refractive index with a dispersion solvent, thereby further increasing color strength . In particular, the color strength of the organic core-organic shell structure can be determined by controlling the difference in refractive index between the organic core shell and the organic solvent shell depending on the constituent material of the core, and the refractive index of the particles may be different depending on the composition ratio of the core and the shell. And the color intensity can be controlled and increased by using such core-shell type photonic crystal particles.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited thereto.

Example  1: PMMA / PMMA dispersed in a hydrophobic dispersion solvent PtBMA - Photonic crystal  Photonic crystal display device comprising core-shell particles

1. Synthesis of PMMA / PtBMA-photonic crystal core-shell particles

Methyl methacrylate as a core polymer monomer, t-butyl methacrylate as a shell polymer monomer, ethylene glycol dimethacrylate as a shell polymer crosslinking agent, and potassium persulfate, an anionic initiator, as an initiator were used. The following syntheses were carried out through an emulsion polymerization under nitrogen. 0.02 g to 0.03 g of potassium persulfate was added to 240 mL of distilled water and 2 g to 3 g of methyl methacrylate was added thereto to synthesize spherical polymethylmethacrylate particles (hereinafter referred to as PMMA particles) g to 0.02 g of potassium persulfate, 0.8 g to 1 g of t-butyl methacrylate, and 0.2 g to 0.4 g of ethylene glycol dimethacrylate to obtain a crosslinked polyt-butyl methacrylate spherical Particles (hereinafter, PMMA / PtBMA photonic crystal particles) were synthesized. The PMMA / PtBMA photonic crystal particles having a size of 100 nm to 250 nm were prepared by controlling the size of the PMMA / PtBMA photonic crystal particles, Were synthesized. The PMMA / PtBMA photonic crystal particles having a size of 100 nm to 250 nm were prepared by controlling the size of the PMMA / PtBMA photonic crystal particles, Were synthesized.

The PMMA / PtBMA core-shell The particle size is shown in Table 1 below.

[Table 1]

2. PMMA / PtBMA-photonic crystal core-shell particles dispersed in a hydrophobic dispersion solvent

The PMMA / PtBMA photocrystalline particles synthesized in the distilled water were precipitated by using a centrifugal separator, and the PMMA / PtBMA photocrystalline particles were dispersed in isopropanol as an intermediate dispersion solvent. Subsequently, the PMMA / PtBMA photocrystalline particles were precipitated using a centrifugal separator and then immersed in a mixed solution of isopara G and halocarbon (isopara G: halocarbon = 1.7: 1), which is a hydrophobic dispersion solvent, in an amount of 40 to 50% The PMMA / PtBMA photocrystalline particles were dispersed in weight%. At this time, the hydrophobic dispersion solvent contains reversed-micelles of sodium bis (2-ethylhexyl) sulfosuccinate (AOT) as a charge control agent.

The charge control agent was included in the hydrophobic dispersion solvent to increase the charge of the photonic crystal particle. In the polar dispersing solvent, the Bjerrum length of the PMMA / PtBMA photocrystalline particles having a charge on the surface is about 0.7 nm, but the ratio of the PMMA / PtBMA photocrystalline particles having charge on the surface in the hydrophobic dispersion solvent as described above The erorum length is about 28 nm. That is, the electrostatic attraction of the hydrophobic dispersion solvent is about 40 times larger than that of the polar dispersion solvent.

In addition, the ionization energy of the PMMA / PtBMA photonic crystal particle charge is low in the polar dispersing solvent but high in the hydrophobic dispersing solvent, so that the charge can not be easily seen. Therefore, by adding the charge control agent to the hydrophobic dispersion solvent, the charge control agent can act as a surfactant, and a high charge can be obtained even in the hydrophobic dispersion solvent.

The measurement of the zeta potential according to the content of the charge control agent is shown in Table 2 below.

[Table 2]

3. The PMMA / PtBMA Photonic crystal  Fabrication of photonic crystal display device containing core-shell particles and electrochromic experiment

45% by weight of PMMA / PtBMA-1 photonic crystal particles (185 nm in size) formed according to Example 1 was immersed in a mixed solution of isopara G and halocarbons containing 5% AOT (isopara G: halocarbon = 1.7: 1) to form a polymer colloid. Then, a polymeric colloid was formed between the two ITO electrodes to a thickness of about 60 mu m, and the resultant structure was sealed to manufacture a photonic crystal display device. As shown in FIG. 1, a plurality of PMMA / PtBMA-1 photonic crystal complexes dispersed are electrically stabilized by a repulsive force due to the surface negative potential formed by the charge control agent surrounding the particles, thereby forming a face-centered cubic photonic crystal alignment structure. As shown in FIG. 3B, when white light such as sunlight is incident, it operates as a display device that reflects only light of a special wavelength by Bragg diffraction phenomenon. When a DC electric field of 0.1 V or more is applied between the ITO electrodes in which the photonic crystal particle dispersion liquid is sealed, the negatively charged particles migrate toward the positive electrode (+) due to the electrical attraction, And the wavelength of the Bragg reflected light is shortened, so that the color of the display device changes to blue. FIG. 4 is a photograph of a digital camera showing a change in reflected light color of the photonic crystal display device according to the first embodiment, wherein a voltage of 0 V to 5.0 V is applied to the photonic crystal display device at intervals of 1.0 V, there was.

4. Charge control agent  Depending on concentration Photonic crystal  Electrochromatography of display devices Reflection color  Experiment of changing wavelength range

40% by weight of the PMMA / PtBMA-2 particles (190 nm in size) was added to a mixed solution of isopara G and halocarbon (isopara G: halocarbon = 1.7: 1) containing 5% and 7% To form a polymer colloid, and thereafter, a thickness of about 60 mu m was formed between the two ITO electrodes, followed by sealing. Reflectance measurements were performed using a UV-vis spectrometer, with a voltage between 0 V and 6 V being applied. 5 is a graph showing changes in the peak position of the reflectance spectrum (FIG. 5) according to the application of a voltage to the photonic crystal display device including the AOT concentration of 5% and 7%, respectively, in Example 1, It was confirmed that the distance between the photonic crystal particles was decreased with the increase of the surface charge of the particles, and the wider reflectance wavelength range was exhibited.

5. Observation of color change according to viewing angle of photonic crystal display

The reflection wavelength according to the angle of the photonic crystal display device manufactured in Example 1 was observed as shown in FIG. It was confirmed that there was almost no change in the wavelength until the viewing angle was inclined at 20 ° from the vertical (0 °).

≪ Comparative Example 1: Photonic crystal display device comprising PS photonic crystal particles dispersed in water >

15% by weight of polystyrene spherical particles (size: 170 nm) was dispersed in water to form a photonic crystal particle dispersion, and then injected at a thickness of about 60 탆 between two ITO electrodes, followed by sealing to prepare a photonic crystal display device .

The electrochromic stability test of the photonic crystal display device according to Example 1 and Comparative Example 1

When the DC voltage was repeatedly applied to the photonic crystal display device manufactured in Comparative Example 1 at intervals of 2.5 seconds in the order of 2.6 V, 3.1 V, 3.6 V, and 3.1 V for 750 seconds in the order of 750 seconds, And FIG. 7B. As in Comparative Example 1, when water was used as the dispersion solvent, it was confirmed that a current of 1.5 mA flowed when a voltage of 3.6 V was applied, and the current was continuously decreased to 0.4 mA after repeating 100 cycles ( 7A).

However, the photonic crystal particles dispersed in the low-dielectric-constant liquid according to the first embodiment and the photonic crystal display device including the photonic crystal particles according to the first embodiment have a very small initial current of 0.001 mA as compared with the voltage application of 3.6 V, It was confirmed that the degree of the decrease of the current was very small after 100 cycles of repetition (FIG. 7B).

In the electrochromic experiment, the difference in electric current can be compared even with the discoloration degree of the ITO when the display device is disassembled and the surface of the cathode ITO is compared after 100 cycles of the experiment. In the case where water was used as a dispersion solvent as in the above Comparative Example, the ITO surface was discolored to be black (as shown in Fig. 7A), whereas when the hydrophobic dispersion solvent according to Example 1 was used, there was almost no change in transparency of the ITO surface (Fig. 7B).

< Comparative Example  2: hydrophobic In dispersion media  Distributed PtBMA Photonic crystal  Particle-containing Photonic crystal  Display device>

40% by weight to 50% by weight of poly (tert-butyl methacrylate) spherical particles (171 nm) were dispersed in a hydrophobic dispersion medium containing 5% of AOT to form a photonic crystal particle dispersion. Mu] m, and then sealed to manufacture a photonic crystal display device.

Example  1 and Comparative Example  According to 2 Photonic crystal  Electrochromatography of display devices Reflection color  Strength comparison experiment

A photocell was photographed with a digital camera while applying a DC voltage of 0 V to 6.8 V to the photonic crystal display device manufactured in Comparative Example 2. 9, when the polymer was used only as the poly (tert-butyl methacrylate) as in Comparative Example 2, the reflection color of the photonic crystal display device was weaker as the voltage was applied, and blue was not observed.

However, when the core polymer is used as polymethylmethacrylate according to Example 1, the difference in refractive index between the hydrophobic dispersion medium and the polymethylmethacrylate is greater than the refractive index difference between the hydrophobic dispersion medium and the polarized butyl methacrylate Because of its size, it may be showing a stronger reflection color.

As the voltage was applied to the photonic crystal display device fabricated according to Example 1, a strong blue color was observed while maintaining the reflection color intensity of the photonic crystal display device (FIG. 4). As a result, the full color of the display is more clearly realized in the photonic crystal display device according to the first embodiment. In this regard, the color strength can be further improved by forming a core using a PMMA polymer having a refractive index higher than that of the dispersion solvent.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention.

100: Charge control agent
200: hydrophobic dispersion solvent
300: core-shell particle
400: organic core
500: Organic shell

Claims (17)

Synthesizing core-shell particles comprising an organic core and an organic shell; And
Dispersing the core-shell particles in a hydrophobic dispersion solvent containing a charge control agent
Wherein the photocatalytic dispersion liquid contains at least one of the following.
The method according to claim 1,
The hydrophobic dispersing solvent may be selected from the group consisting of isopara G, isopara C, isopara D, isopara E, isopara F, isopara H, isopara I, isopara J, isopara K, halocarbon, decane, undecane, Wherein the photoacid generator is selected from the group consisting of methanol, ethanol, ethanol, methanol, ethanol, methanol, ethanol, &Lt; / RTI &gt;
The method according to claim 1,
Wherein the organic core and the organic shell are each independently selected from the group consisting of poly tert-butyl methacrylate, polymethyl methacrylate, poly n-butyl methacrylate, polymethyl acrylate, polystyrene, and combinations thereof Wherein the photocatalytic dispersion contains a polymer.
The method according to claim 1,
Wherein the core-shell particles are contained in an amount of 10 parts by weight to 60 parts by weight per 100 parts by weight of the photonic crystal particle dispersion.
The method according to claim 1,
The charge control agent may be selected from the group consisting of sodium bis (2-ethylhexyl) sulfosuccinate, sodium dodecylsulfonate, cetyltrimethylammonium bromide, a span surfactant, a pluronic surfactant, a tween surfactant, Wherein the photocatalytic dispersion is selected from the group consisting of:
The method according to claim 1,
Wherein the charge control agent is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the photonic crystal particle dispersion.
A photocrystalline particle dispersion comprising core-shell particles comprising an organic core and an organic shell dispersed in a hydrophobic dispersion solvent containing a charge control agent.
8. The method of claim 7,
Wherein the organic core and the organic shell are each independently selected from the group consisting of poly tert-butyl methacrylate, polymethyl methacrylate, poly n-butyl methacrylate, polymethyl acrylate, polystyrene, and combinations thereof Wherein the photocatalytic dispersion comprises a polymer which is a photocatalyst.
8. The method of claim 7,
Wherein the core-shell particle size is from 100 nm to 300 nm.
8. The method of claim 7,
Wherein the core-shell particles are contained in an amount of 10 parts by weight to 60 parts by weight per 100 parts by weight of the photonic crystal particle dispersion.
8. The method of claim 7,
The hydrophobic dispersing solvent is selected from the group consisting of isopara G, isopara C, isopara D, isopara E, isopara F, isopara H, isopara I, isopara J, isopara K, halocarbon, decane, undecane, Wherein the photoacid generator is selected from the group consisting of methanol, ethanol, ethanol, methanol, ethanol, methanol, ethanol, Particle dispersion.
8. The method of claim 7,
The charge control agent may be selected from the group consisting of sodium bis (2-ethylhexyl) sulfosuccinate, sodium dodecylsulfonate, cetyltrimethylammonium bromide, a span surfactant, a pluronic surfactant, a tween surfactant, &Lt; / RTI &gt; wherein the photocatalytic dispersion is selected from the group consisting of:
8. The method of claim 7,
Wherein the charge control agent is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the dispersion solvent.
8. The method of claim 7,
Wherein the spacing of the core-shell particles is controlled according to the amount of the charge control agent.
At least two light-transmitting electrodes disposed in the chamber; And
A photonic crystal particle dispersion according to any one of claims 7 to 14, formed between the two or more light-
The photonic crystal display device.
16. The method of claim 15,
Wherein an interval between the core-shell particles contained in the photonic crystal particle dispersion is controlled by applying an electric field to the light-transmitting electrode.
17. The method of claim 16,
Wherein the wavelength of the color of the photonic crystal display device is adjusted by adjusting the interval of the core-shell particles.

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