CN101033299A - Polymer colloid photon crystal film with photon band-gap position at near infrared region and its preparing method and use - Google Patents

Abstract

The invention belongs to the technical field of colloidal photonic crystal film preparation, and in particular relates to a polymer colloidal photonic crystal film with a large photonic bandgap in the near-infrared region, a preparation method and application thereof. Evenly cover the monodisperse large particle size polymer latex particle emulsion on the flat substrate, and after the dispersion solvent water volatilizes, a periodic arrangement of monodisperse large particle size polymer latex particles stacked in face-centered cubic order is obtained. The three-dimensional photonic crystal film of monodisperse large particle size polymer latex particles is formed by agglomeration of several hard core-soft shell latex particles in the polymerization process; the particle size range of monodisperse large particle size polymer latex particles It is 400-1200nm, and the polydispersity index is less than or equal to 0.005. According to the difference in the particle size of the monodisperse polymer latex with large particle size, the photonic bandgap of the latex photonic crystal film obtained in the present invention can be distributed in different wave bands of 800-3000nm in the near infrared region. Latex photonic crystal film can be used as radiation protection and thermal insulation coating.

Description

Polymer colloidal photonic crystal film with photonic bandgap position in near-infrared region, preparation method and application thereof

technical field

The invention belongs to the technical field of preparation of colloidal photonic crystal films, in particular to a polymer colloidal photonic crystal film with a large photonic bandgap in the near-infrared region and a preparation method thereof, as well as its application in anti-radiation coatings; One-step polymerization method to prepare monodisperse polymer latex particles with large particle size.

Background technique

Colloidal photonic crystal materials refract or diffract light with a periodic structure formed by the regular arrangement of monodisperse latex particles to achieve special regulation of light. Depending on the size of the periodic arrangement, the wavelength of the modulated light is different. Correspondingly prepared colloidal crystals have different application fields. In the usual patent literature, colloidal photonic crystal films are mainly used in filters (such as CN: 01105105.1, CN: 98110990.X), photoelectric switching (CN: 0310004.4, CN: 02160207.7), optical waveguides (CN: 02804125.9, CN: 99810798, CN: 01132293.4, CN: 02811132.X), optical fiber (CN: 00803964.X, CN: 00803960.7, CN: 03127694.6), etc., but few reports apply photonic crystal film to the coating field, especially the application of radiation protection Insulation coating.

The present invention is based on the inventor's previous patent application (patent application number: CN: 200510011219.2, CN: 200510012021.6, CN: 200510012047.0, CN: 200510012021.6) for the simple preparation of monodisperse latex particles, and the rapid preparation of large-area colloids in visible and ultraviolet regions Photonic crystal film, and its application in decorative coatings, UV-preventing coatings, cosmetics and enhanced photoluminescent devices, prepared a photonic crystal with a photonic band gap in the near-infrared region, and tried to apply it in radiation-proof insulation Coating aspect. The usual thermal insulation coating is mainly aimed at avoiding conduction, convection, and radiation in the way of heat loss. In order to reduce the heat conduction function, hollow materials with small thermal conductivity (CN: 02145516.3, CN: 02132991.5, CN: 02133287.8, CN: 90105780) are generally introduced into the thermal insulation coating, such as foamed polymers, natural inorganic porous materials, such as, Expanded perlite, mica powder, fine ceramic particles, etc. The disadvantages of this method are mainly the long process cycle, poor adhesion between the material and the wall, weak impact resistance, and large drying shrinkage. There are also reflective heat-insulating coatings, which are coated on the aluminum-based surface, or suitable resins and metals are selected to obtain high-emissivity coatings to achieve heat insulation effects. But this method is costly. There are also radiation heat-insulating coatings (CN: 03145447.1), which scatter the absorbed light and heat through radiation. The key is to prepare coating components with high thermal emissivity. Various metal oxides, such as MnO ₂ , CO ₂ O ₃ , CuO, Fe ₂ O ₃ and other doped materials with inverse spinel structure have the characteristics of high thermal emissivity. The common feature of the above three methods is that specific specific materials must be used to realize the so-called heat insulation function.

Contents of the invention

One of the objectives of the present invention is to provide a polymer colloidal photonic crystal film with a large photonic bandgap in the near-infrared region, and the cost of the colloidal photonic crystal film is low.

The second object of the present invention is to provide a method for preparing a polymer colloidal photonic crystal film whose photonic band gap is in the near-infrared region.

The third object of the present invention is to provide a method for preparing monodisperse large-diameter polymer latex particles through a one-step process. The method adopts the batch method of soap-free emulsion polymerization. By properly adjusting the emulsion polymerization process, the monodisperse polymer latex particles with large particle size prepared by the one-step method can achieve a monodispersity index of less than or equal to 0.005 without any purification. The diameter ranges from 400 to 1200nm.

The fourth object of the present invention is to provide the application of the polymer colloidal photonic crystal film whose photonic bandgap position is in the near-infrared region, and use the polymeric colloidal photonic crystal film with the photonic bandgap in the near-infrared region for industrial production, especially in the defense Radiant insulation coating aspects.

The invention adopts a batch method of soap-free emulsion polymerization, and by properly adjusting the emulsion polymerization process, the monodisperse polymer latex particles with large particle size prepared by the one-step method can achieve a monodispersity index less than or equal to 0.005 without any purification.

The polymer colloidal photonic crystal film whose photonic bandgap position is in the near-infrared region of the present invention is a three-dimensional photonic crystal film that is periodically arranged and ordered by stacking monodisperse large-diameter polymer latex particles in a face-centered cubic manner. Monodisperse large particle size polymer latex particles are formed by agglomeration of several hard core-soft shell latex particles during the polymerization process; the number of agglomeration depends on the amount of electrolyte added during the polymerization process; monodisperse The particle diameter range of the large-diameter polymer latex particles is 400-1200nm, and the polydispersity index is less than or equal to 0.005.

The photonic bandgap of described colloidal photonic crystal film relates to each wave band of near-infrared region; Along with the particle diameter of monodisperse large particle diameter polymer latex particle changes from small to large (from 400 to 1200nm increases), the obtained The peak position of the reflection spectrum of the colloidal photonic crystal film is red-shifted (the photonic band gap is red-shifted).

The monodisperse polymer latex particles with large particle size prepared by the method of the present invention are formed by the aggregation of several hard core-soft shell latex particles in the polymerization process; the number of the aggregation depends on the number of polymerization The amount of electrolyte added in the process; the particle size range of the monodisperse large-diameter polymer latex particles is 400-1200nm, and the polydispersity index is less than or equal to 0.005. The photonic bandgap of the prepared colloidal photonic crystal film is distributed in the near-infrared region of 800-3000nm, and colloidal photonic crystals with different bandgaps can be obtained by adjusting the particle size of monodisperse large-diameter polymer latex particles as required. As the particle size of the monodisperse large-diameter polymer latex particles changes from small to large, the peak position of the reflectance spectrum of the obtained film is red-shifted.

The preparation of the monodisperse large particle size polymer latex particles of the present invention is realized in one step by batch method soap-free emulsion polymerization, and the typical process adopted is: monomer 1, monomer 2, monomer 2 which increase hydrophilicity successively Body 3 is mixed and dispersed in an aqueous electrolyte solution containing a pH buffering agent and used to adjust the particle size of the monodisperse large-diameter polymer latex; the resulting emulsion polymerization system is stirred at a speed of 200 to 500 rpm, preferably 350 rpm Mix and heat to 65-85°C (preferred temperature is 70°C), add 3/5 of the total amount of initiator to start the reaction, and then add 1/5 of the total amount of initiator to initiate the reaction after 2-4.5 hours The remaining initiators are added after continuing to react for 2 to 4.5 hours. The total amount of the initiators is equivalent to 0.5wt% to 2wt% of the total weight of the monomers, preferably 1wt%. The reaction is then continued for 1-3 hours to end, and monodisperse large-diameter polymer latex particles with a monodispersity index less than or equal to 0.005 and a particle diameter range of 400-1200 nm are obtained. With the introduction of the electrolyte solution to adjust the particle size of the monodisperse large particle size polymer latex particles in the polymerization system, the latex particles with a hard core-soft shell structure formed by homogeneous nucleation at the initial stage of polymerization will coalesce, and with With the increase of the amount of electrolyte solution introduced, the degree of agglomeration of latex particles increases, and finally a monodisperse large-diameter polymer latex particle formed by agglomeration of several hard-core-soft-shell latex particles in the polymerization process is obtained.

Wherein, the amount of monomer 1 is 90-95wt% of the total weight of monomers in the emulsion polymerization system, monomer 2 is 3-6wt%, monomer 3 is 0-6wt%, the concentration of pH buffering agent in the emulsion polymerization system The concentration of the electrolyte in the emulsion polymerization system is 0-0.7 wt%.

The reaction time of the system is 5-12 hours, preferably 8-10 hours.

The reactive monomer is a compound containing at least one ethylenic bond in the molecule, and its hydrophilicity increases sequentially. Monomer 1 is a reactive monomer with poor hydrophilicity, such as styrene, methylstyrene or a mixture thereof and monomer 2 is relatively good hydrophilic monomer, such as acrylates, vinyl acetate or their mixtures, etc., the acrylates are methyl methacrylate, ethyl methacrylate, methyl methacrylate butyl acrylate, isobutyl acrylate or any mixture thereof; monomer 3 is a highly hydrophilic water-soluble reactive monomer, such as acrylic acid, methacrylic acid, acrylamide, acrylonitrile or any mixture thereof. The introduction of a small amount of water-soluble reactive monomer 3 is to increase the stability of the system.

The initiator is alkali metal persulfate, ammonium persulfate or their mixture. The initiator is introduced into the polymerization system in the form of aqueous solution, and the concentration of the solution is 2-5 wt%.

The alkali metal is potassium or sodium.

The electrolyte for adjusting the particle size of the final latex particles is selected from one or more mixtures of sodium chloride, potassium chloride, calcium chloride and the like.

The pH buffering agent is selected from one or more mixtures of ammonium bicarbonate, sodium bicarbonate, sodium hydrogen phosphate and the like.

In order to ensure the effective realization of the monodispersity of latex particles, the stirring rate, feeding and heating procedures are strictly controlled during the polymerization process to avoid the occurrence of secondary nucleation.

The amount of electrolyte used in the polymerization system of the present invention is different, and the particle diameters of the obtained monodisperse large-diameter polymer latex particles are different, resulting in different photonic band gaps of the final colloidal photonic crystal film. For example, when the weight ratio of the amount of electrolyte to the total amount of monomers in the polymerization system is 0%, 0.238%, 0.476.%, 0.952%, 1.43%, and 1.90%, the prepared monodisperse large-diameter polymer latex particles The particle sizes are 400, 450, 480, 510, 550, and 600 in sequence, and the photonic bandgap positions of the corresponding colloidal photonic crystal films are 914, 1045, 1128, 1208, 1272, and 1388 nm, respectively.

The preparation method of the photonic bandgap position of the present invention is in the polymer colloidal photonic crystal film of near-infrared region, comprises the following steps:

(1) Disperse the monodisperse large particle size polymer latex particles in water at room temperature, and then uniformly cover the obtained monodisperse large particle size polymer latex particle emulsion on the flat substrate, wherein the monodisperse large particle size polymer latex particles The concentration of the latex particle emulsion is 5-30wt%.

(2) Under normal temperature and pressure, the solvent water of step (1) dispersing the monodisperse large particle size polymer latex particles is volatilized, and the monodisperse large particle size polymer latex particles are piled up on the substrate with face-centered cubic, and form periodic The ordered three-dimensional photonic crystal film is peeled off from the base material after the coating film is dried, and a polymer colloidal photonic crystal film with a photonic bandgap in the near-infrared region can be obtained.

The monodispersity index of the monodisperse large-diameter polymer latex particles is less than or equal to 0.005, and the particle diameter ranges from 400 to 1200 nm. The photonic bandgap of the obtained photonic crystal film is red-shifted as the particle size of the monodisperse large-particle-diameter polymer latex increases from 400 to 1200 nm.

The substrate includes glass, silicon chip, paper or stainless steel plate and the like.

The polymer colloidal photonic crystal film with photonic bandgap in the near-infrared region of the present invention mainly has a radiation-proof function for the band in the near-infrared region, including part of the radiation emitted by sunlight and most of the radiation emitted by incandescent lamps; it can be used as Anti-radiation coating.

According to different colloidal photonic crystal film-forming substrates, the obtained polymer colloidal photonic crystal film can be used on different substrates.

The photonic bandgap position of the present invention mixes the application process of the polymer colloid photonic crystal film in the near-infrared region with other transparent coatings and can be carried out as follows:

The colloidal photonic crystal film of the present invention is peeled off from the base material, crushed to a micron particle size, mixed with a transparent paint and a solvent, and the colloidal photonic crystal film can exhibit a thermal insulation effect, wherein the colloidal photonic crystal film in the mixed solution is 1- 10wt%, the transparent paint is 50-70wt%, and the solvent is 20-40wt%.

The transparent paint is selected from one or more mixtures of acrylic varnish, polyurethane varnish, 582-2 melamine resin and nitro varnish.

The solvent is one or a mixture of ethanol, ethyl acetate or butyl acetate.

In the present invention, monodisperse large particle size polymer latex particles are prepared by a one-step method of soap-free emulsion polymerization, and the latex particles are formed by aggregating several hard core-soft shell latex particles in the polymerization process; The amount depends on the amount of electrolyte added in the polymerization process; this special shape determines its unique performance. The preparation process is simple, and the size and shape of the monodisperse large-diameter polymer latex particles are easy to control. The prepared monodisperse large-particle-diameter polymer latex particles can achieve a monodispersity index of less than or equal to 0.005 without any purification. The self-assembly preparation of the colloidal photonic crystal film of the present invention is realized by a simple method: uniformly cover a certain concentration of monodisperse large-particle-diameter polymer latex particles on a flat substrate, and wait for the dispersion in it to evaporate and dry. A periodically arranged three-dimensional photonic crystal film is formed, and the order degree of the photonic crystal is excellent. The method of the invention is simple and easy, and the required equipment is simple, which is beneficial to realize the large-scale preparation of the photonic crystal film. According to the difference of the monodisperse large-diameter polymer latex particles used, the photonic band gap of the colloidal photonic crystal film obtained in the present invention changes in the near-infrared region.

The monodisperse latex particles with a hard core-soft shell structure prepared by one-step emulsion polymerization have deformation in the shell during the self-assembly process to form a dense structure, which is conducive to improving the mechanical stability of the film.

The invention realizes the thermal insulation effect by using the photonic crystal with the photonic band gap in the near infrared region to control the light, and the method has low cost and is easy to realize.

Since the milk crystal film prepared by the method of the invention is a polymer film, it is non-toxic to the human body during use and can be widely used in radiation protection coatings.

Since the material used for the polymer colloidal photonic crystal film with a photonic band gap in the near-infrared region is a functionally adjustable polymer, this makes the colloidal crystal film have good adhesion to various substrates.

The thermal insulation coating obtained by the polymer photonic crystal film adopted in the present invention has the following advantages:

1) There is no specific selectivity for materials, and general paint substrates are used, such as styrene-acrylic emulsion;

2) It can effectively realize the heat preservation function. The photonic crystal film utilizes the regulation effect of the photonic band gap on light, and can effectively prevent the indoor temperature from falling when used indoors, and can effectively prevent outdoor energy from entering the room when used outdoors. At the same time, the nano-scale pore structure of the membrane itself is used to effectively prevent heat conduction;

3) Since the photonic crystal film adopts a traditional paint substrate, there are no series of problems such as painting, drying, and bonding with the substrate;

4) The method is simple, low in cost and easy to implement.

The present invention will be further described below in conjunction with the accompanying drawings and examples.

Description of drawings:

Fig. 1. The SEM photo of the three-dimensional periodic arrangement long-range ordered latex photonic crystal film of Example 4 of the present invention (particle size is 470nm).

Fig. 2. The reflectance spectrogram of the colloidal photonic crystal film of embodiment 4 of the present invention, according to latex particles change from small to large, the photonic bandgap positions are respectively: 914, 1045, 1128, 1208, 1272, 1388nm.

Detailed ways

Embodiment 1: Preparation of monodisperse large particle size polymer latex particles

The monomer mixture methyl methacrylate (1 g), styrene (19 g), and methacrylic acid (1 g), pH buffer ammonium bicarbonate (0.2 g) and sodium chloride (0.2 g) were dispersed in In water (95 mL), the resulting mixed system was stirred and mixed at 350 rpm, and heated to 70°C. Add 15 milliliters of ammonium persulfate (0.2 gram is dissolved in 25 milliliters of water) aqueous solution and start to react, react and add 5 milliliters of ammonium persulfate aqueous solution again after 2 hours, all the other ammonium persulfate aqueous solutions add after continuing reaction 2 hours, After the reaction continued for 2 hours, the temperature was raised to 80° C. and the reaction was completed for another 2 hours. Finally, monodisperse large-diameter polymer latex particles with a monodispersity index less than or equal to 0.005 and a particle diameter range of 480 nm are obtained.

When the consumption of sodium chloride is changed to 0, 0.1, 0.3, 0.4, 0.5, 0.75 or 1g respectively, the particle size range of the final monodisperse large particle size polymer latex particles obtained is respectively 400, 450, 510, 550 , 600, 750, 1020nm. The monodispersity index of latex particles is less than or equal to 0.005.

Embodiment 2: Preparation of monodisperse large particle size polymer latex particles

The monomer mixture vinyl acetate (0.5 g), butyl acrylate (0.5 g), methyl styrene (19 g), and acrylic acid (1 g), pH buffer sodium bicarbonate (0.1 g) and ammonium bicarbonate (0.1 g) and sodium chloride (0.2 g) were dispersed in water (95 mL), and the resulting mixed system was stirred and mixed at 300 rpm, and heated to 70°C. Add 15 milliliters of initiator (obtained by dissolving 0.2 gram of ammonium persulfate and 0.1 gram of sodium persulfate in 25 milliliters of water) aqueous solution to start the reaction, add 5 milliliters of ammonium persulfate aqueous solution after reacting for 2 hours, and the remaining persulfate The ammonium aqueous solution was added after the reaction was continued for 2 hours, and after the reaction was continued for 2 hours, the temperature was raised to 80° C. and the reaction was completed for another 2 hours. Finally, monodisperse large-diameter polymer latex particles with a monodispersity index less than or equal to 0.005 and a particle diameter range of 480 nm are obtained.

When the amount of acrylic acid was changed to 0, 0.1, 0.2, 0.3, 0.4, 0.5g respectively, the particle size ranges of the final monodisperse large particle size polymer latex particles were 920, 700, 670, 640, 620, 580nm. The monodispersity index of latex particles is less than or equal to 0.005.

Embodiment 3: Preparation of monodisperse large particle size polymer latex particles

The monomer mixture isobutyl methacrylate (1 g), styrene (19 g), acrylic acid (0.5 g) and acrylamide (0.5 g), pH buffer sodium bicarbonate (0.1 g) and ammonium hydrogen phosphate (0.1 g) and sodium chloride (0.2 g) were dispersed in water (95 mL), and the resulting mixed system was stirred and mixed at 400 rpm, and heated to 70°C. Add 15 milliliters of ammonium persulfate (0.2 gram is dissolved in 25 milliliters of water) aqueous solution and start to react, react and add 5 milliliters of ammonium persulfate aqueous solution again after 2 hours, all the other ammonium persulfate aqueous solutions add after continuing reaction 2 hours, After the reaction continued for 2 hours, the temperature was raised to 80° C. and the reaction was completed for another 2 hours. Finally, monodisperse polymer latex particles with a monodispersity index less than or equal to 0.005 and a particle size range of 480 nm are obtained.

When the amount of the initiator is changed to 0, 0.1, 0.3, 0.4, 0.5 respectively, the particle size ranges of the obtained final monodisperse large particle size polymer latex particles are 540, 500, 460, 440, 420, respectively. The monodispersity index of latex particles is less than or equal to 0.005.

Example 4: Preparation of a polymer colloidal photonic crystal film with a photonic bandgap position in the near-infrared region

At room temperature, uniformly cover the monodisperse large-diameter polymer latex particles prepared in Example 1 with a concentration of 5wt% on clean glass, silicon wafers or stainless steel plate substrates, and wait until the water in the dispersion evaporates to dryness. Finally, the monodisperse large-diameter polymer latex particles are stacked on the substrate in a face-centered cubic manner, and form a periodically arranged three-dimensional photonic crystal film. The particle diameters of the monodisperse large-particle-diameter polymer latex particles obtained in Example 1 are 400, 450, 480, 510, 550, and 600, respectively, and the corresponding photonic bandgap positions of the colloidal photonic crystal film prepared are 914, 1045, respectively. , 1128, 1208, 1272, 1388nm.

Embodiment 5: used as anti-radiation thermal insulation coating

The monodisperse polymer latex particles with a latex particle size of 400 nm prepared by the method in Example 1 were used to prepare a colloidal photonic crystal film with a photonic bandgap position of 914 nm by using the method in Example 4. This film can be applied to the anti-radiation and thermal insulation coating in the 914nm wave band.

Embodiment 6: Used as anti-radiation thermal insulation coating

The monodisperse large particle size polymer latex particles with particle diameters prepared by the method of Example 1 were respectively 400, 450, 480, 510, 550, and 600, and the colloidal photonic crystal films prepared by the method of Example 4 were obtained from glass The substrate is peeled off (amount of 10wt%), crushed to a micron size, and mixed with acrylic varnish (60wt%) and a certain amount of ethanol (30wt%) respectively to obtain a radiation-proof thermal insulation coating.

Claims (9)

1. a photon band gap position is at the photon crystal membrane of polymer colloid of near-infrared region, it is characterized in that: described photon crystal membrane of polymer colloid is to pile up the orderly three-D photon crystal film of periodic arrangement that forms by the monodispersed large grain-size polyalcohol emulsion particle with face-centered cubic, and this monodispersed large grain-size polyalcohol emulsion particle is formed by emulsion particle coalescence in polymerization process of several hard core-soft core structures; The particle size range of monodispersed large grain-size polyalcohol emulsion particle is 400～1200nm, and polydispersity index is less than or equal to 0.005.

2. photon crystal membrane of polymer colloid according to claim 1 is characterized in that: the photon band gap of described colloid photonic crystal film relates to each wave band of near-infrared region; Along with the particle diameter of monodispersed large grain-size polyalcohol emulsion particle increases the peak generation red shift of the reflection spectrum of resulting colloid photonic crystal film by 400 to 1200nm.

3. photon crystal membrane of polymer colloid according to claim 1 and 2 is characterized in that: described monodispersed large grain-size polyalcohol emulsion particle is prepared by following method:

With the monomer 1 that wetting ability increases successively, monomer 2, monomer 3 blending dispersion are containing pH buffer reagent and the aqueous electrolyte liquid that is used for regulating monodispersed large grain-size polyalcohol emulsion particle particle diameter; Be to mix under the rotating speed of 200～500rpm resulting emulsion polymerization systems at rotating speed, and be heated to 65～85 ℃, the initiator that adds initiator total amount 3/5 makes reaction begin to carry out, react the initiator that adds initiator total amount 1/5 after 2～4.5 hours again, remaining initiator is continuing reaction adding after 2～4.5 hours, 0.5wt%～the 2wt% of the suitable total monomer weight of the total consumption of described initiator, obtain single dispersion index after reaction finishes and be less than or equal to 0.005, particle size range is the monodispersed large grain-size polyalcohol emulsion particle of 400～1200nm;

Wherein, the consumption of monomer 1 is 90～95wt% of total monomer weight in the emulsion polymerization systems, and monomer 2 is 3～6wt%, and monomer 3 is 0～6wt%, the concentration of pH buffer reagent in emulsion polymerization systems is 0～0.99wt%, and the concentration of ionogen in emulsion polymerization systems is 0～0.7wt%;

Described monomer 1 is vinylbenzene, vinyl toluene or their mixture;

Described monomer 2 is acrylate, vinyl acetate or their mixture

Described monomer 3 is vinylformic acid, methacrylic acid, acrylamide, propylene cyanogen or their any mixture.

4. photon crystal membrane of polymer colloid according to claim 3 is characterized in that: described acrylate is methyl methacrylate, Jia Jibingxisuanyizhi, butyl methacrylate, isobutyl acrylate or their any mixture.

5. photon crystal membrane of polymer colloid according to claim 3 is characterized in that: described initiator is that the form with the aqueous solution is incorporated in the polymerization system, and its strength of solution is 2～5wt%; Initiator is alkali metal sulfates, ammonium persulphate or their mixture.

6. photon crystal membrane of polymer colloid according to claim 3 is characterized in that: described ionogen is selected from one or more the mixture in sodium-chlor, Repone K, the calcium chloride.

7. photon crystal membrane of polymer colloid according to claim 3 is characterized in that: described pH buffer reagent is selected from one or more the mixture in bicarbonate of ammonia, sodium bicarbonate, the sodium hydrogen phosphate.

8. the preparation method according to each described photon crystal membrane of polymer colloid of claim 1～7 is characterized in that, described preparation method may further comprise the steps:

(1) earlier the monodispersed large grain-size polyalcohol emulsion particle is dispersed in the water under the room temperature, then resulting monodispersed large grain-size polyalcohol emulsion particle emulsion is evenly covered on the flat substrates, wherein the concentration of monodispersed large grain-size polyalcohol emulsion particle emulsion is 5～30wt%;

(2) make step (1) disperse the aqueous solvent volatilization of monodispersed large grain-size polyalcohol emulsion particle under the normal temperature and pressure, the monodispersed large grain-size polyalcohol emulsion particle is piled up with face-centered cubic on base material, and form the orderly three-D photon crystal film of periodic arrangement, behind dried coating film, peel off from base material, obtain the photon crystal membrane of polymer colloid of photon band gap position in the near-infrared region.

9. purposes according to each described photon crystal membrane of polymer colloid of claim 1～7, it is characterized in that: described photon crystal membrane of polymer colloid is as the radioprotective heat insulation coating.

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