阅读说明：本技术 一种变色颗粒及其制备方法 (Color-changing particle and preparation method thereof ) 是由 刘继广 张启 于 2019-11-22 设计创作，主要内容包括：本发明公开了一种变色颗粒及其制备方法。该颗粒包括基底聚合物颗粒和无机组分两部份,该颗粒对紫外光、可见光和温度具有响应性。该颗粒的制备方法包括：将响应性聚合物颗粒加入溶剂中,将无机前驱体加入,然后加入催化剂使无机物沉积在颗粒中。本发明提供的颗粒可用于智能变色表面、变色纤维或服装以及柔性显示等,在艺术、防伪、军事伪装以及传感等多种领域具有广泛应用前景,其制备方法简便,易控制,具有普适性,适于大批量生产和应用。(The invention discloses a color-changing particle and a preparation method thereof. The particles include two parts, a base polymer particle and an inorganic component, the particles being responsive to ultraviolet light, visible light and temperature. The preparation method of the particle comprises the following steps: responsive polymer particles are added to a solvent, an inorganic precursor is added, and then a catalyst is added to deposit the inorganic in the particles. The particles provided by the invention can be used for intelligent color-changing surfaces, color-changing fibers or clothes, flexible display and the like, have wide application prospects in various fields of art, anti-counterfeiting, military camouflage, sensing and the like, have simple and convenient preparation methods, are easy to control, have universality and are suitable for mass production and application.)

1. An intelligent color-changing particle comprises two parts of a responsive polymer and an inorganic substance,

the responsive polymer is: polymers of N-ethylacrylamide, N-ethyl-2-methylacrylamide, N-diethylacrylamide, N-dimethylacrylamide, N-isopropylacrylamide, N-isopropylmethacrylamide, acrylic acid, methacrylic acid, ethacrylic acid, propylacrylic acid, N-dimethylaminoethyl methacrylate, cyclopropylmethacrylamide, N-dimethylaminoethyl ester, N-vinylcaprolactam monomers or copolymers thereof with a crosslinking agent, or copolymers thereof in any combination with other monomers;

the responsive polymer is preferably a polymer of N-isopropylacrylamide or a copolymer thereof with a crosslinking agent or a copolymer thereof with other monomers;

the other monomers in the copolymer with other monomers are: a carboxyl group-containing olefin monomer, acrylate, N-methylolacrylamide, N-hydroxyethylacrylamide, N- (2-hydroxypropyl) methacrylamide, diacetone acrylamide, glycidyl methacrylate, hydroxyethyl methacrylate, ethyl acetoacetate methacrylate, acrylamide, N' -methylenebisacrylamide, styrene, or vinylpyridine;

when the responsive polymer is a copolymer of N-isopropylacrylamide and other monomers, the molar ratio of N-isopropylacrylamide to the other monomers is preferably 50% or more;

the inorganic matter is at least one of metal oxide, metal hydroxide, metal oxyacid or metal salt thereof, metal carbonate and metal oxalate;

wherein the metal at least comprises a metal with valence variation characteristics, and the metal with valence variation characteristics is as follows: at least one metal selected from tungsten, molybdenum, scandium, and rhodium.

2. The smart color-changing particle of claim 1, wherein: the cross-linking agent is ethylene glycol dimethacrylate, divinyl benzene, N N' -methylene bisacrylamide and the like; at least one of 1, 6-hexanediol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, diacetone acrylamide, diethylene glycol diacrylate, tetraethylene glycol-diacrylate;

when a crosslinking agent is contained, the amount of the crosslinking agent added is 0.5% to 50% of the total amount of monomers forming the polymer or copolymer.

3. The smart color changing particle of claim 1 or 2, wherein: the inorganic substances are: tungsten oxide, molybdenum oxide, rhodium hydroxide, sodium molybdate, sodium tungstate, potassium tungstate or tungstic acid, molybdic acid, scandium hydroxide, scandium oxide, scandium oxalate, rhodium oxalate, tungsten carbonate, tungsten oxalate, scandium carbonate;

other inorganic components may also be included;

the other inorganic components are: iron oxide, ferroferric oxide, titanium dioxide, silicon dioxide, zinc oxide, vanadium oxide, cobalt oxide, sodium oxide, potassium oxide, magnesium oxide, antimony trioxide and barium sulfate.

4. A smart color changing particle according to any one of claims 1-3 wherein: the mass ratio of the inorganic substance to the responsive polymer is 10:1-1:10000, preferably: 1:1-1:100.

5. A method of making the smart color-changing particles of any of claims 1-4, comprising:

dispersing the particles of the responsive polymer in a solvent, adding the metal salt or the soluble compound, and separating the particles after full contact to obtain intelligently-changed particles; or

Dispersing the particles of the responsive polymer in a solvent, adding the salt or soluble compound of the metal, adding a precipitator, reacting, and separating out the particles to obtain the intelligently-changed particles.

6. The method of claim 5, wherein: the salts or soluble compounds of the metals are: tungstate, molybdate, rhodium oxide, scandium trichloride, rhodium trichloride and hydrates thereof, zincate, vanadate, cobaltate, zinc salt, K [ Rh (H)₂O)Cl₃]、K₂[Rh(H₂O)Cl₅]And rhodium oxide.

7. The method according to claim 5 or 6, characterized in that: the precipitating agent is: at least one of hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

8. Use of the smart color-changing particles of any one of claims 1-4 in the preparation of a color-changing material.

9. Use according to claim 8, characterized in that: the color change refers to a change in color of the particles with ultraviolet light, visible light, temperature, and/or current.

10. Use of the smart color changing particles of any one of claims 1-4 for anti-counterfeiting, apparel, camouflage, flexible displays.

Technical Field

The invention relates to a color-changing particle and a preparation method thereof, in particular to a hybrid color-changing particle containing a responsive polymer and an inorganic component and a preparation method thereof.

Background

In the field of material chemistry, the development of intelligent materials has attracted people's extensive interest, and the extensive application of color-changing materials in the fields of art design, military camouflage, anti-counterfeiting, sensing, display and the like becomes one of the hot spots of research. At present, the color-changing materials are mainly divided into two categories of inorganic color-changing materials and organic color-changing materials, wherein the inorganic color-changing materials are silver chloride, tungsten oxide, molybdenum oxide, titanium dioxide and the like, but the color-changing efficiency is low; organic color-changing materials such as spiropyrans and fulgides have high color-changing efficiency but poor stability.

There has been a great interest in environmentally responsive chemicals that can change their morphology, structure or properties in response to certain environmental factors, such as poly (N-isopropylacrylamide), which in aqueous solution is in an extended chain configuration at temperatures below a critical value (about 32 ℃) and exhibits hydrophilicity, and in aqueous solutions at temperatures above a critical value, the chains undergo shrinkage aggregation and exhibit lipophilicity (Y.Hirokawa et al Chemical Physics1984,81(12), 6379-6380). In recent years, there have been reports of particles having photoresponse simultaneously, such as N-isopropylacrylamide containing organic color-changing groups, and copolymers (B) of acrylic acid and color-changing monomers.Et al Soft Matter, 2013, 9, 8754-8760). Their use is often limited due to the single nature of inorganic or organic. The combination of the two can not only integrate the advantages of the two, but also bring about the expansion of the application field.

If the environment responsive substance is compounded with an inorganic component, it will be possible to obtain various kinds of intelligence such as volume-changing hybrid particles (e.g., 201711275548.7). By combining specific inorganic components with these responsive polymers it will be possible to create new properties, such as particles with color-changing properties. Most of the current organic-inorganic hybrid materials are inorganic color-changing substances dispersed in polymers (such as Mengchun Wu and the like, ACS appl. Mater. interfaces 2018,10,39819-39827), and such materials have the general color-changing capability, but due to the compatibility problem with the polymers, the strength of the materials is often influenced; and in the present day that the materials are developed to microcosmic, the material with macroscopic color change is difficult to realize in the aspect of controlling the microcosmic color change distribution of the materials, and the color change particles with regular shapes have wider application. The introduction of metal particles (e.g., gold, silver, etc.) into these smart particles may also exhibit color changes in light (Shotaro Imao et al, Journal of Photochemistry and Photobiology A: Chemistry 2013, 252, 37-45) or in heat (Ayong Choe et al, NPG Asia Materials, 2018,10, 912-. Inorganic color-changing materials (such as tungsten oxide, molybdenum oxide and the like) which are important materials with multiple photochromic characteristics are applied to a plurality of materials, but are mostly prepared into various forms (such as films) in a dispersed form for use, and the color-changing particles with regular shapes are not reported, so that the application range of the inorganic color-changing materials is severely limited.

Disclosure of Invention

The invention aims to provide a smart color-changing particle.

By smart color change is meant that the color of the particles changes with ultraviolet light, visible light, temperature and/or current, and thus the properties.

The intelligent color-changing particles provided by the invention comprise two parts, namely responsive polymers and inorganic matters.

The mass ratio of the inorganic substance to the responsive polymer can be 10:1-1:10000, and is preferably: 1:1 to 1:100, more preferably 0.5:1 to 1: 50.

The responsive polymer may be: a polymer of a monomer such as N-ethylacrylamide, N-ethyl-2-methylacrylamide, N-diethylacrylamide, N-dimethylacrylamide, N-isopropylacrylamide, N-isopropylmethacrylamide, acrylic acid, methacrylic acid, ethacrylic acid, propylacrylic acid, N-dimethylaminoethyl methacrylate, cyclopropylmethacrylamide, N-dimethylaminoethyl methacrylate, N-vinylcaprolactam, or a copolymer thereof with a crosslinking agent, or a copolymer thereof in any combination with another monomer, or a copolymer thereof with another monomer;

the crosslinking agent is an olefin monomer having at least two double bonds, such as 1, 5-hexadiene, triallyl isocyanurate, ethylene glycol dimethacrylate, divinylbenzene, N N' -methylenebisacrylamide, 1, 6-hexanediol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, diacetone acrylamide, diethylene glycol diacrylate, tetraethylene glycol-diacrylate, etc.

The other monomers in the copolymer with other monomers may be: olefin monomers containing carboxyl groups (such as acrylic acid, methacrylic acid, ethacrylic acid), acrylic esters (such as methyl methacrylate, ethyl methacrylate, butyl methacrylate), N-methylolacrylamide (NMA), N-hydroxyethyl acrylamide, N- (2-hydroxypropyl) methacrylamide, diacetone acrylamide (DAAM), Glycidyl Methacrylate (GMA), hydroxyethyl methacrylate (HEMA), ethyl acetoacetate methacrylate, acrylamide, N' -methylenebisacrylamide, styrene or vinylpyridine;

the polymer also includes derivative polymers obtained by further reaction on the polymer, such as sulfonation products of poly (N-isopropylacrylamide-styrene) and hydrolysis products of poly (N-isopropylacrylamide-methyl methacrylate).

The responsive polymer may specifically be: polymers of N-isopropylacrylamide or copolymers thereof with crosslinkers or copolymers thereof with other monomers, such as poly (N-isopropylacrylamide), poly (N-isopropylacrylamide-acrylic acid), poly (N-isopropylacrylamide-styrene), poly (N-isopropylacrylamide-methacrylic acid); or poly (N, N-diethylacrylamide-divinylbenzene), polyethylene glycol, and the like.

When the responsive polymer is a copolymer of N-isopropylacrylamide and other monomers, the molar ratio of the N-isopropylacrylamide to the other monomers is not less than 50%.

When a crosslinking agent is contained, the addition amount of the crosslinking agent is 0.5 to 50 percent of the total amount of monomers for forming the polymer or the copolymer; preferably 2 to 20 percent.

Preferably, the responsive polymer is an N-isopropylacrylamide polymer containing a crosslinking agent, wherein the crosslinking agent specifically can be: ethylene glycol dimethacrylate, divinylbenzene, N N' -methylenebisacrylamide and the like; 1, 6-hexanediol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, diacetone acrylamide, diethylene glycol diacrylate, tetraethylene glycol diacrylate.

The inorganic substance may be at least one of metal oxide, metal hydroxide, metal oxyacid or metal salt thereof (such as sodium molybdate, potassium molybdate, sodium tungstate, potassium tungstate or tungstic acid, molybdic acid, etc.), metal carbonate and metal oxalate.

Wherein the metal at least comprises a metal with valence variation characteristics, and the metal with valence variation characteristics can be: at least one metal selected from tungsten, molybdenum, scandium, and rhodium.

The inorganic substance may specifically be: tungsten oxide (e.g., tungsten trioxide, tungsten dioxide), molybdenum oxide (e.g., molybdenum trioxide, molybdenum dioxide), rhodium oxide, rhodium hydroxide, sodium molybdate, sodium tungstate, potassium tungstate or tungstic acid, molybdic acid, scandium hydroxide, scandium oxide, etc., and may also be an oxalate or carbonate, such as scandium oxalate, rhodium oxalate, tungsten carbonate, tungsten oxalate, scandium carbonate, etc.; other inorganic components such as iron oxide, ferroferric oxide, titanium dioxide, zinc oxide, vanadium oxide, cobalt oxide, silicon dioxide, sodium oxide, potassium oxide, magnesium oxide, antimony trioxide, barium sulfate, etc. may also be included.

The intelligent color-changing particles can be specifically: tungsten oxide/poly (N-isopropylacrylamide) smart color-changing particles, tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) smart color-changing particles, molybdenum oxide/poly (N-isopropylacrylamide) smart color-changing particles, molybdenum oxide-titanium oxide/poly (N-isopropylacrylamide-acrylic acid) smart color-changing particles, rhodium hydroxide/poly (N-isopropylacrylamide-styrene) smart color-changing particles, scandium oxide/poly (N-methylethylacrylamide-methacrylic acid-styrene) smart color-changing particles, molybdenum oxide/poly (N, N-dimethylaminoethyl methacrylate-styrene) smart color-changing particles, tungstic oxide-vanadium oxide/poly (N-isopropylacrylamide-methacrylic acid) electrochromic particles, tungsten oxide-titanium oxide, Any one of tungsten oxide/poly (N, N-diethylacrylamide-divinylbenzene) smart color-changing particles.

The intelligent color-changing particles are prepared by the method comprising the following steps:

dispersing the responsive polymer particles in a solvent, adding the metal salt or soluble compound, and separating the particles after full contact to obtain intelligent color-changing particles; or

Dispersing the particles of the responsive polymer in a solvent, adding the salt or soluble compound of the metal, adding a precipitator, reacting, and separating out the particles to obtain the intelligently-changed particles.

In the above method, the solvent may be: water, ethanol, propanol, butanol, isopropanol, tetrahydrofuran, N-dimethylformamide, or a mixed solution thereof, preferably water or a mixed solution of water and alcohol.

The salt or soluble compound of the metal may be: tungstate, molybdate, rhodium oxide, scandium trichloride, rhodium trichloride, hydrates thereof, and K [ Rh (H)₂O)Cl₃]、K₂[Rh(H₂O)Cl₅]And rhodium oxide, or a zinc salt (such as zinc chloride, zinc sulfate, zinc nitrate) or at least one of a zincate, vanadate, cobalt salt or cobaltate

The mass ratio of the salt or soluble compound of the metal to the particles of the responsive polymer may be 0.01 to 100, and specifically may be 0.1 to 10.

The precipitating agent may be: at least one of hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

The inventors have in previous studies noticed occasionally that the particles thus structured have a tendency to become slightly darker in colour under the sun's illumination; through careful and intensive study, the following results are further found: hybrid particles prepared by incorporating certain oxides or metal salts into polymers can exhibit significant color change under ultraviolet or visible light illumination.

The application of the intelligent color-changing particles in preparing color-changing materials also belongs to the protection scope of the invention.

The color change refers to a change in color of the particles with ultraviolet light, visible light, temperature, and/or current.

Furthermore, the application of the intelligent color-changing particles in the aspects of anti-counterfeiting, clothing, camouflage, flexible display and the like also belongs to the protection scope of the invention.

For example: the tungsten oxide/poly (N-isopropyl acrylamide) particles turn blue under the irradiation of ultraviolet light, and the absorption wavelength is changed from 320nm to about 620 nm; the color of the granules faded to white or yellow upon temperature increase or under visible light.

These color-changing properties make them useful in a wide range of applications in the field of smart materials; and the preparation method is suitable for mass production.

The invention has the advantages that:

the intelligent color-changing particles provided by the invention greatly improve the color-changing performance of inorganic matters through organic-inorganic compounding, and provide a regular shape for color-changing substances;

in addition, the color change properties are combined with the environmental response properties of the particles, thereby making it possible to achieve a dual change; a creative breakthrough is made for developing novel intelligent materials;

the invention solves the problem of dispersion of inorganic color-changing components in response polymer particles through in-situ growth, controls the size of the inorganic color-changing substance through the interaction of the polymer and the inorganic color-changing substance, improves the color-changing performance and forms high-efficiency color-changing particles.

The preparation method of the intelligent color-changing particles provided by the invention is easy to control the process, is suitable for preparing the particles with different scales, and is particularly suitable for mass production and preparation.

Drawings

FIG. 1 is an SEM image of tungsten oxide/poly (N-isopropylacrylamide) smart color-changing particles prepared in example 1.

FIG. 2 is a photograph of the tungsten oxide/poly (N-isopropylacrylamide) smart color-changing particles prepared in example 1 under ultraviolet irradiation and a photograph under visible light irradiation.

Fig. 3 is a color change picture of the tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) smart color-changing particles prepared in example 2.

Detailed Description

The present invention will be described below with reference to specific examples, but the present invention is not limited thereto.

The experimental methods used in the following examples are all conventional methods unless otherwise specified; reagents, materials and the like used in the following examples are commercially available unless otherwise specified.

According to the present invention, there is provided a smart color changing particle comprising two parts, a responsive polymer and an inorganic substance.

The mass ratio of the inorganic substance to the responsive polymer can be 10:1-1:10000, and is preferably: 1:1 to 1:100, more preferably 0.5:1 to 1: 50;

the responsive polymer may be: n-ethyl acrylamide, N-ethyl-2-methyl acrylamide, N-diethyl acrylamide, N-dimethyl acrylamide, N-isopropyl methacrylamide, acrylic acid, methacrylic acid, ethacrylic acid, propyl acrylic acid, N-dimethylaminoethyl methacrylate, cyclopropyl methacrylamide, N-dimethylaminoethyl methacrylate, and the like, a polymer of N-vinyl caprolactam or a copolymer thereof with a crosslinking agent, or a copolymer thereof in any combination with other monomers;

the crosslinking agent is an olefin monomer having at least two double bonds, such as 1, 5-hexadiene, triallyl isocyanurate, ethylene glycol dimethacrylate, divinylbenzene, N N' -methylenebisacrylamide, 1, 6-hexanediol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, diacetone acrylamide, diethylene glycol diacrylate, tetraethylene glycol-diacrylate, etc.;

the other monomers in the copolymer with other monomers may be: olefin monomers containing carboxyl groups (such as acrylic acid, methacrylic acid, ethacrylic acid), acrylic esters (such as methyl methacrylate, ethyl methacrylate, butyl methacrylate), N-methylolacrylamide (NMA), N-hydroxyethyl acrylamide, N- (2-hydroxypropyl) methacrylamide, diacetone acrylamide (DAAM), Glycidyl Methacrylate (GMA), hydroxyethyl methacrylate (HEMA), ethyl acetoacetate methacrylate, acrylamide, N' -methylenebisacrylamide, styrene or vinylpyridine;

the polymer also includes derivative polymers obtained by further reaction on the polymer, such as sulfonation products of poly (N-isopropylacrylamide-styrene) and hydrolysis products of poly (N-isopropylacrylamide-methyl methacrylate).

The responsive polymer may specifically be: a polymer of N-isopropylacrylamide or a copolymer thereof with a crosslinking agent or a copolymer thereof with another monomer, such as any one of poly (N-isopropylacrylamide), poly (N-isopropylacrylamide-acrylic acid), poly (N-isopropylacrylamide-styrene), poly (N-isopropylacrylamide-methacrylic acid), or poly (N, N-diethylacrylamide-divinylbenzene).

When the responsive polymer is a copolymer of N-isopropylacrylamide and other monomers, the molar ratio of the N-isopropylacrylamide to the other monomers is not less than 50%.

When a crosslinking agent is contained, the addition amount of the crosslinking agent is 0.5 to 50 percent of the total amount of monomers for forming the polymer or the copolymer; preferably 2 to 20 percent.

Preferably, the responsive polymer is an N-isopropylacrylamide polymer containing a crosslinking agent, wherein the crosslinking agent specifically can be: ethylene glycol dimethacrylate, divinylbenzene, N N' -methylenebisacrylamide and the like; 1, 6-hexanediol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane triacrylate, diacetone acrylamide, diethylene glycol diacrylate, tetraethylene glycol diacrylate.

The inorganic substance may be at least one of metal oxide, metal hydroxide, metal oxyacid or metal salt thereof (such as sodium molybdate, potassium molybdate, sodium tungstate, potassium tungstate or tungstic acid, molybdic acid, etc.), metal carbonate and metal oxalate.

Wherein the metal at least comprises a metal with valence variation characteristics, and the metal with valence variation characteristics can be: at least one metal selected from tungsten, molybdenum, scandium, and rhodium.

The inorganic substance may specifically be: tungsten oxide (e.g., tungsten trioxide, tungsten dioxide), molybdenum oxide (e.g., molybdenum trioxide, molybdenum dioxide), rhodium oxide, rhodium hydroxide, sodium molybdate, sodium tungstate, potassium tungstate or tungstic acid, molybdic acid, scandium hydroxide, scandium oxide, etc., and may also be an oxalate or carbonate, such as scandium oxalate, rhodium oxalate, tungsten carbonate, tungsten oxalate, scandium carbonate, etc.; other inorganic components such as iron oxide, ferroferric oxide, titanium dioxide, zinc oxide, vanadium oxide, cobalt oxide, silicon dioxide, sodium oxide, potassium oxide, magnesium oxide, antimony trioxide, barium sulfate, etc. may also be included.

The intelligent color-changing particles can be specifically: tungsten oxide/poly (N-isopropylacrylamide) smart color-changing particles, tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) smart color-changing particles, molybdenum oxide/poly (N-isopropylacrylamide) smart color-changing particles, molybdenum oxide-titanium oxide/poly (N-isopropylacrylamide-acrylic acid) smart color-changing particles, rhodium hydroxide/poly (N-isopropylacrylamide-styrene) smart color-changing particles, scandium oxide/poly (N-methylethylacrylamide-methacrylic acid-styrene) smart color-changing particles, molybdenum oxide/poly (N, N-dimethylaminoethyl methacrylate-styrene) smart color-changing particles, tungstic oxide-vanadium oxide/poly (N-isopropylacrylamide-methacrylic acid) electrochromic particles, tungsten oxide-titanium oxide, Any one of tungsten oxide/poly (N, N-diethylacrylamide-divinylbenzene) smart color-changing particles.

The intelligent color-changing particles are prepared by the method comprising the following steps:

dispersing the responsive polymer particles in a solvent, adding the metal salt or soluble compound, and separating the particles after full contact to obtain intelligent color-changing particles; or

Dispersing the particles of the responsive polymer in a solvent, adding the salt or soluble compound of the metal, adding a precipitator, reacting, and separating out the particles to obtain the intelligently-changed particles.

In the above method, the solvent may be: water, ethanol, propanol, butanol, isopropanol, tetrahydrofuran, N-dimethylformamide, or a mixed solution thereof, preferably water or a mixed solution of water and alcohol.

The salt or soluble compound of the metal may be: tungstate, molybdate, rhodium oxide, scandium trichloride, trichlorinatedRhodium and hydrates thereof, K [ Rh (H)₂O)Cl₃]、K₂[Rh(H₂O)Cl₅]And rhodium oxide, or a zinc salt (such as zinc chloride, zinc sulfate, zinc nitrate) or at least one of a zincate, vanadate, cobalt salt or cobaltate

The mass ratio of the salt or soluble compound of the metal to the particles of the responsive polymer may be 0.01 to 100, and specifically may be 0.1 to 10.

The precipitating agent may be: at least one of hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

The poly (N-isopropylacrylamide) particles used in the following examples were prepared by the following method:

62 g of N-isopropylacrylamide and 6.2 g of N N' -methylenebisacrylamide crosslinker were added to 5L of water, 0.6 g of ammonium persulfate as an initiator was added, and the mixture was reacted under nitrogen for 8 hours to collect particles, thereby obtaining poly (N-isopropylacrylamide) particles.

In addition, a series of particles can be obtained by adjusting the ratio of N-isopropylacrylamide to N N' -methylenebisacrylamide crosslinker, or adjusting the molar ratio of N-isopropylacrylamide to another monomer and the amount of crosslinker added.

Example 1 preparation of tungsten oxide/poly (N-isopropylacrylamide) Smart color-changing particles

Adding 10g of poly (N-isopropylacrylamide) particles (containing N N '-methylenebisacrylamide crosslinker, wherein the mass ratio of N-isopropylacrylamide monomer to N N' -methylenebisacrylamide crosslinker is 10:1) into a 250mL flask, adding 150mL of water, fully dispersing, adding 1g of sodium tungstate, stirring for 10 minutes, adding 10mL of 10M hydrochloric acid, reacting for 1 hour, performing centrifugal separation, and fully washing with water to obtain the intelligent color-changing particles.

FIG. 1 is an SEM image of the prepared tungsten oxide/poly (N-isopropylacrylamide) smart color-changing particles.

FIG. 2 is a photograph of the tungsten oxide/poly (N-isopropylacrylamide) intelligent color-changing particles prepared under ultraviolet irradiation and a photograph of visible light irradiation.

As can be seen from the figure, the tungsten oxide/poly (N-isopropylacrylamide) particles become blue and dark blue under the ultraviolet irradiation, and the absorption wavelength is changed from 320nm to about 620 nm; the parts which are not illuminated are yellow.

Experimental example 2 preparation of tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) Smart color-changing particles

1g of poly (N-isopropylacrylamide-acrylic acid) (containing a divinylbenzene crosslinking agent, the molar ratio of N-isopropylacrylamide to acrylic acid is 10:1, and the addition amount of the divinylbenzene crosslinking agent is 2% of the total molar amount of two monomers) is added into a 250mL flask, 200mL of water is added, 2g of potassium tungstate is added after sufficient dispersion, 1M of hydrochloric acid is added after stirring for 1 hour, 10mL of hydrochloric acid is added after reaction for 10 hours, centrifugal separation is performed, and the intelligent particles are obtained by sufficient washing with water.

FIG. 3 is a color-changing picture of the prepared tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) intelligent color-changing particles,

as can be seen from the figure: after ultraviolet irradiation, the intelligent tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) color-changing particles turn into bluish blue, and the parts which are not irradiated are yellow.

EXAMPLE 3 preparation of Intelligent color-changing molybdenum oxide/Poly (N-isopropylacrylamide) particles

Dispersing 0.1g of poly (N-isopropylacrylamide) particles in 200mL of water; then adding 0.1g of potassium molybdate and 0.001 g of sodium zincate, stirring, adding 10mL of 1M hydrochloric acid, reacting for 1 hour, separating and washing to obtain the intelligent color-changing particles.

The resulting molybdenum oxide/poly (N-isopropylacrylamide) particles were irradiated with ultraviolet light, changing color from yellow to dark blue.

EXAMPLE 4 preparation of molybdenum oxide-titanium oxide/Poly (N-isopropylacrylamide-acrylic acid)

Dispersing 0.1g of poly (N-isopropylacrylamide-acrylic acid) copolymer particles (the molar ratio of two monomers is 5:1, a diethylene glycol diacrylate crosslinking agent is contained, and the addition amount of the crosslinking agent is 2 percent of the total moles of the monomers) in 200mL of water; then adding 0.1g of sodium molybdate and 0.001 g of potassium titanate, stirring, adding 10mL of 1M hydrochloric acid, reacting for 1 hour, separating and washing to obtain the intelligent color-changing particles.

The resulting particles were irradiated with ultraviolet light, changing the color from light yellow to sky blue.

EXAMPLE 5 preparation of rhodium hydroxide/Poly (N-isopropylacrylamide-styrene)

Adding 0.1g of poly (N-isopropylacrylamide-styrene) copolymer particles (the molar ratio of two monomers is 1:5, the trimethylolpropane triacrylate cross-linking agent is contained, and the addition amount of the cross-linking agent is 5 percent of the total molar number of the two monomers) into concentrated sulfuric acid, heating to 50 ℃, reacting for 2 hours, fully washing with water, and dispersing the particles in 20mL of water; then adding 0.1g of rhodium chloride, stirring, adding 2mL of 1M potassium hydroxide, reacting for 24 hours, separating and washing to obtain the intelligent color-changing particles.

The resulting particles were irradiated with uv light and changed in color from light yellow to blue.

EXAMPLE 6 preparation of scandia/poly (N-methylethylacrylamide-methacrylic acid-styrene)

Dispersing 1g of poly (N-isopropylacrylamide-methacrylic acid-styrene) copolymer particles (the molar ratio of the three monomers is 5: 5:1 in sequence) in 50mL of water; then 0.05g of scandium trichloride is added, 1mL of 2M hydrochloric acid is added after stirring, and separation and washing are carried out after 48-hour reaction to obtain the intelligent color-changing particles.

The resulting particles were irradiated with ultraviolet light, changing the color from light yellow to sky blue.

EXAMPLE 7 preparation of molybdenum oxide/Poly (N, N-dimethylaminoethyl methacrylate-styrene)

Adding 10g of poly (N, N-dimethylaminoethyl methacrylate-styrene) copolymer particles (the molar ratio of two monomers is 1: 2) into concentrated sulfuric acid, heating to 40 ℃ for reaction for 4 hours, fully washing with water, and dispersing the particles in 200mL of water; then adding 0.1g of sodium molybdate and 0.01 g of potassium zincate, stirring, adding 10mL of 1M hydrochloric acid, reacting for 1 hour, separating and washing to obtain the intelligent color-changing particles.

The resulting particles were irradiated with uv light and changed in color from light yellow to blue.

Experimental example 8 preparation of tungstic acid oxide-vanadium oxide/poly (N-isopropylacrylamide-methacrylic acid)

1g of poly (N-isopropylacrylamide-methacrylic acid) copolymer particles (molar ratio of the two monomers 10:1) were dispersed in 200mL of water; then 0.1g of sodium tungstate and 0.001 g of sodium metavanadate are added, 10mL of 1M hydrochloric acid is added after stirring, and separation and washing are carried out after 1 hour of reaction to obtain the electrochromic intelligent particles (light yellow color is obtained when the electricity is not electrified, and dark blue color is obtained after the electricity is electrified).

Example 9 preparation of tungsten oxide/Poly (N, N-Diethylacrylamide-Divinylbenzene) Smart particles

10g of poly (N, N-diethylacrylamide-divinylbenzene) (the molar ratio of the two monomers is 10:1, 150mL of water is added, 10g of potassium tungstate is added after full dispersion, 10mL of 10M hydrochloric acid is added after stirring for 10 minutes, reaction is carried out for 1 hour, centrifugal separation is carried out, and the intelligent color-changing particles are obtained after full washing with water.

The resulting particles were irradiated with ultraviolet light and changed in color from yellow to blue-brown.

Comparative example 1

Referring to the preparation method of example 2, instead of poly (N-isopropylacrylamide-acrylic acid) (containing a divinylbenzene crosslinking agent, the molar ratio of N-isopropylacrylamide to acrylic acid is 2:1, and the amount of the divinylbenzene crosslinking agent added is 2% of the total molar amount of the two monomers) in example 2, the obtained tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) particles were prepared to be pale yellow in the dark or light, and the color change was not significant under visible light or ultraviolet light.

Comparative example 2

Referring to the preparation method of example 2, instead of poly (N-isopropylacrylamide-acrylic acid) (containing a divinylbenzene crosslinking agent, the molar ratio of N-isopropylacrylamide to acrylic acid is 2:1, and the amount of the divinylbenzene crosslinking agent added is 2% of the total molar amount of the two monomers) in example 2, the obtained tungsten oxide/poly (N-isopropylacrylamide-acrylic acid) particles were prepared to be pale yellow in the dark or light, and the color change was not significant under visible light or ultraviolet light.

The inventor of the present invention found in research that when the responsive polymer is a copolymer of N-isopropylacrylamide and another monomer, and the molar ratio of N-isopropylacrylamide to the other monomer is 50% or more, the color-changing property of the prepared color-changing particles is remarkable.