CN110835526A - Material with thermochromic effect, preparation method thereof and thermochromic intelligent window - Google Patents

Abstract

The invention provides a material with a thermochromic effect, a preparation method thereof and a thermochromic intelligent window, wherein the method comprises the following steps of: taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_1‑xW_xO₂Powder; will V_1‑xW_xO₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_1‑xW_xO₂@SiO₂Composite powder; under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_1‑xW_xO₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_1‑xW_xO₂@SiO₂the/PNIPAM composite solution. The material has high visible light transmittance and high temperature change spectrum regulationEfficiency, photo-thermal stability, adaptability and the like.

Description

Material with thermochromic effect, preparation method thereof and thermochromic intelligent window

Technical Field

The invention relates to the field of intelligent energy-saving materials, in particular to a material with a thermochromic effect, a preparation method thereof and a thermochromic intelligent window.

Background

The window serves as a main passage for heat exchange between the building and the external environment, and occupies 50% of heat exchange energy in the building. Therefore, the key to building energy conservation is the building windows. Vanadium dioxide (VO)₂) The intelligent dimming material can selectively transmit, absorb or reflect specific spectrum to generate effects of adjusting light intensity, spectrum range and the like by changing the optical characteristics of the intelligent dimming material under the stimulation of external condition temperature, thereby realizing the adjustment of indoor temperature and achieving the purpose of energy conservation and temperature control. The transmittance of visible light hardly changes during the temperature transition. VO compared with traditional energy-saving glass and other types of intelligent window materials₂The film material can actively adjust the transmittance of sunlight according to the ambient temperature, and finally obtain a comfortable building environment in a warm-in-winter and cool-in-summer manner, thereby reducing energy consumption caused by refrigeration and heating and becoming the first choice of an intelligent temperature control material.

Chinese patent publication nos. CN 103205249A, CN 104725581a and CN 109293826a respectively describe vanadium dioxide material, poly-n-isopropylacrylamide and composite material thereof, but do not simultaneously achieve high visible light transmittance, high temperature solar spectrum regulation and control performance and phase transition temperature close to room temperature, and have low energy-saving efficiency. Therefore, practical use of thermochromic materials in smart windows that are sufficiently stable and effective has not been achieved at present.

Therefore, there is a need to provide a new solution.

Disclosure of Invention

The prepared thermochromic composite material can actively adjust the transmittance of sunlight according to the ambient temperature, and has the advantages of extremely high visible light transmittance, variable-temperature spectrum regulation and control efficiency, photo-thermal stability, adaptability and the like. The specific technical scheme is as follows:

in a first aspect, the present invention provides a method for preparing a material having a thermochromic effect, comprising the steps of:

s1, taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_1-xW_xO₂Powder;

s2, mixing V_1-xW_xO₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_1-xW_xO₂@SiO₂Composite powder;

s3, reacting V under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_1-xW_xO₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_1-xW_xO₂@SiO₂the/PNIPAM composite solution.

Further, step S1 specifically includes:

s11, adding 3-6g of vanadyl sulfate and 0.2-2g of ammonium tungstate into 160ml of distilled water of 120-;

s12, dropwise adding 0.6-1ml of hydrazine hydrate into the solution obtained in the step S11, and adjusting the pH value to 8-10 by using sodium hydroxide;

s13, centrifuging the solution obtained in the step S12 to obtain powder, and washing the powder with distilled water to obtain a powder raw material;

s14, putting the powder raw material into a hydrothermal reactorReacting in a reaction kettle, centrifuging, washing and drying to obtain powder V_{1- x}W_xO₂And (3) powder.

Further, in step S14, the reaction temperature is 240-270 ℃, the reaction time is 24-48h, the centrifugation is performed, then the washing is performed by sequentially adopting ethanol and distilled water, and the drying temperature is 40-80 ℃.

Further, in step S2, the solvent includes ethanol/the catalyst includes ammonia water, the reaction monomer includes tetraethyl orthosilicate, and the dispersant includes a silane coupling agent.

Further, step S2 specifically includes the following steps:

s21, converting the V obtained in the step S1_1-xW_xO₂Dispersing the powder in ethanol, stirring, adding ethanol and ammonia water diluent dropwise into the solution, and stirring for 30-120 min;

s22, adding tetraethyl orthosilicate into the solution obtained in the step S21 by a peristaltic pump, and stirring at room temperature for 4-12 hours;

s23, separating the solution obtained in the step S22 by a centrifugal machine, washing the separated solid by distilled water and alcohol in sequence, and drying at 50-80 ℃ for 6-24h to obtain powder A;

s24, dispersing the powder A in a mixed solution of ethanol, ammonia water and a silane coupling agent for reaction at room temperature, wherein the volume ratio of ethanol to ammonia water is 99: 1-80: 20;

s25, washing and centrifuging the reaction solution obtained in the step S24 by distilled water and alcohol, and drying at the temperature of 50-80 ℃ for 6-24h to obtain V_1-xW_xO₂@SiO₂And (3) composite powder.

Further, in step S3, the crosslinking agent includes an aqueous solution of N' N-methylene bisacrylamide, and the initiator includes a solution of ammonium persulfate.

Further, step S3 specifically includes:

s31, preparing a sodium dodecyl sulfate aqueous solution, and mixing the solution V_1-xW_xO₂@SiO₂Dispersing the composite powder in a sodium dodecyl sulfate aqueous solution, and stirring at normal temperature to obtain the product containing V_1-xW_xO₂@SiO₂Dodecyl sodium sulfate solution of composite powder;

s32, putting distilled water into a four-neck flask, vacuumizing, introducing nitrogen, heating,

s33, adding an aqueous solution of N-isopropylacrylamide and N' N-methylenebisacrylamide to the four-neck flask in the step S32;

s34, adding V_1-xW_xO₂@SiO₂Adding the sodium dodecyl sulfate solution of the composite powder into the step S33 with stirring to obtain a mixed solution, wherein each milliliter of the mixed solution contains V_1-xW_xO₂@SiO₂In the sodium dodecyl sulfate solution of composite powder, V_1-xW_xO₂@SiO₂The content of the composite powder is 0.0008-0.0032 g;

s35, adding an ammonium persulfate solution into the mixed solution obtained in the step S34, and stirring;

s36, adding N-isopropyl acrylamide and N' N-methylene bisacrylamide aqueous solution into the step S35, and reacting for 2-5h to obtain V_1-xW_xO₂@SiO₂the/PNIPAM composite solution has x not less than 0 and not more than 0.5.

Further, the step S3 is followed by: v obtained in step S36_1-xW_xO₂@SiO₂Forming a film by the PNIPAM composite solution and drying.

In a second aspect, the present invention also provides a material having a thermochromic effect, which is obtained by the method according to the first aspect.

In a third aspect, the invention further provides a material with a thermochromic effect, which is described in the second aspect, for application in a smart window.

The invention has the following beneficial effects:

1. the material with the thermochromic effect has high visible light transmittance and temperature-variable solar spectrum regulation and control performance, is composed of tungsten-doped vanadium dioxide and poly-nitrogen isopropyl acrylamide which are wrapped by silicon dioxide, can actively regulate the transmittance of sunlight according to the environmental temperature, and finally obtains a comfortable building environment in a warm-in-winter and cool-in-summer mode, thereby reducing energy consumption caused by refrigeration and heating. Meanwhile, the material has excellent thermal stability and adaptability, can be subjected to composition design and preparation according to the production requirements or the characteristics of conditions such as environmental temperature and the like, and has a very wide application prospect in the field of energy conservation.

2. The invention uses a hydrothermal reaction method and an emulsion polymerization method, and utilizes organic-inorganic composite solution and common glass to assemble and obtain the intelligent window with a sandwich structure.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic view of V prepared according to the present invention_0.8W_0.2O₂@SiO₂A PNIPAM dynamic light scattering particle size analysis chart;

FIG. 2 is a graph of V prepared according to the present invention_0.8W_0.2O₂@SiO₂A Transmission Electron Microscope (TEM) image of PNIPAM;

FIG. 3 is a V prepared according to the present invention_0.8W_0.2O₂@SiO₂PNIPAM and blank glass cooling test chart.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise. In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or may be connected through the interior of two elements or in interactive relation with one another. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Example 1

S1, taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_0.8W_0.2O₂And (3) powder.

Step S1 specifically includes the following steps:

s11, weighing the reagents according to the stoichiometric ratio: vanadyl sulfate 4.8g, ammonium tungstate 1.6g, was dissolved in 120 ml of distilled water to form a blue-green solution.

S12, 0.65ml of hydrazine hydrate is slowly dropped into the blue-green solution formed in the step S11 by using a peristaltic pump, and sodium hydroxide is added to adjust the pH value of the solution to 8.

S13, centrifuging the solution in the step S12 at the speed of 11000r/min to obtain powder, and washing the powder three times by using distilled water to obtain a powder raw material.

S14, transferring the powder raw material into a 100ml hydrothermal reaction kettle, preserving the heat for 36 hours at 260 ℃, and finally collecting the powder raw material by using a centrifugal machineWashing the powder with ethanol and distilled water for three times, and drying in an oven at 50 deg.C for 24 hr to obtain powder V_0.8W_0.2O₂(tungsten doped vanadium dioxide).

S2, mixing V_0.8W_0.2O₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_0.8W_0.2O₂@SiO₂(tungsten doped vanadium dioxide coated with silicon dioxide) composite powder. Step S2 specifically includes the following steps:

s21, taking a certain amount of V prepared in the step S1_0.8W_0.2O₂The powder was dispersed in ethanol and stirred for 1 hour, 280ml of ethanol and 70 ml of aqueous ammonia dilution were added dropwise to the solution and stirred for 30 minutes.

S22, 0.5 ml of tetraethyl orthosilicate was added to the solution in step S21 using a peristaltic pump, and the mixture was stirred at room temperature for 4 hours.

S23, centrifuging the solution obtained in the step S22 by using a centrifuge to obtain powder, washing the separated solid by sequentially using distilled water and alcohol, and drying the washed solid at 80 ℃ for 12 hours to obtain powder A.

S24, dispersing 0.1 mg of the powder A obtained in the step S23 in a mixed solution of 100ml of ethanol, an ammonia water solution and 0.2 ml of a silane coupling agent, stirring for 4 hours at room temperature, wherein the volume ratio of ethanol to ammonia water is 99: 1.

s25, centrifuging the reaction solution of the step S24 by using distilled water and alcohol respectively to collect solid matters, and drying the solid matters at 80 ℃ for 12 hours to obtain V_0.8W_0.2O₂@SiO₂And (3) composite powder.

S3, reacting V under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_0.8W_0.2O₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_0.8W_0.2O₂@SiO₂PNIPAM (silica-coated tungsten doped vanadium dioxide and poly nitrogen isopropyl acrylamide) composite solution.Step S3 specifically includes the following steps:

s31, preparing 10ml of 0.19mol/L aqueous solution of sodium dodecyl sulfate, dispersing 0.005g of A powder in the aqueous solution, and stirring the mixture at normal temperature for 12 hours to obtain a solution containing V_0.8W_0.2O₂@SiO₂Dodecyl sodium sulfate solution of composite powder.

S32, putting 200 ml of distilled water into a four-neck flask, vacuumizing and introducing nitrogen, and heating the solution to 80 ℃.

S33, an aqueous solution containing 0.4g N-isopropylacrylamide and 7mg of N' N-methylenebisacrylamide was added to the four-necked flask.

S34, adding 1ml of solution containing 0.004g V while stirring_0.8W_0.2O₂@SiO₂The powdered sodium lauryl sulfate (sodium lauryl sulfate) solution is processed in step S33.

S35, 0.8ml of ammonium persulfate solution is added into the mixed solution of S33 to initiate reaction, and stirring is carried out for 1 minute.

S36, 3.5g N-isopropyl acrylamide and 168mg of N' N-methylene bisacrylamide aqueous solution are slowly dropped into the mixture by a peristaltic pump to react for 2 hours in the step S35, and V is obtained_0.8W_0.2O₂@SiO₂The PNIPAM composite solution is packaged by glass.

In one embodiment, the step S3 is followed by the following steps: v obtained in step S36_0.8W_0.2O₂@SiO₂Forming a film by the PNIPAM composite solution and drying.

The composite intelligent window material prepared in the embodiment can realize obvious thermochromism: at 20 ℃, the visible light transmittance can reach 92.46%, and the transmittance of the whole solar spectrum is 44.62%; at 40 ℃, the visible light transmittance can reach 29.05%, and the transmittance of the whole solar spectrum is 17.29%, so that the phase transition temperature of the material in the embodiment is 32 ℃, the variable-temperature spectrum regulation and control efficiency is 27.33%, and compared with blank glass, the temperature of the energy-saving test box can be reduced by 15.1 ℃.

Example 2

S1, taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_0.9W_0.1O₂And (3) powder.

Step S1 specifically includes the following steps:

s11, weighing the reagents according to the stoichiometric ratio: vanadyl sulfate 4.8g, ammonium tungstate 0.8g, was dissolved in 160ml of distilled water to form a blue-green solution.

S12, slowly dripping 1ml of hydrazine hydrate into the blue-green solution formed in the step S11 by using a peristaltic pump, adding sodium hydroxide, and adjusting the pH value of the solution to 9.

S13, centrifuging the solution in the step S12 at the speed of 11000r/min to obtain powder, and washing the powder three times by using distilled water to obtain a powder raw material.

S14, transferring the powder raw material into a 100ml hydrothermal reaction kettle, preserving heat for 24 hours at 260 ℃, finally collecting the powder by using a centrifugal machine, respectively washing the powder by using ethanol and distilled water for three times, and drying the powder in an oven at 60 ℃ for 48 hours to obtain powder V_0.9W_0.1O₂。

S2, mixing V_0.9W_0.1O₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_0.9W_0.1O₂@SiO₂And (3) composite powder. Step S2 specifically includes the following steps:

s21, taking a certain amount of V prepared in the step S1_0.9W_0.1O₂The powder was dispersed in ethanol and stirred for 1 hour, 280ml of ethanol and 70 ml of aqueous ammonia dilution were added dropwise to the solution and stirred for 30 minutes.

S22, 0.5 ml of tetraethyl orthosilicate was added to the solution in step S21 using a peristaltic pump, and the mixture was stirred at room temperature for 4 hours.

S23, centrifuging the solution obtained in the step S22 by using a centrifuge to obtain powder, washing the separated solid by sequentially using distilled water and alcohol, and drying the washed solid at 80 ℃ for 12 hours to obtain powder A.

S24, dispersing 0.1 mg of the powder A obtained in the step S23 in a mixed solution of 100ml of ethanol, an ammonia water solution and 0.2 ml of a silane coupling agent, stirring for 4 hours at room temperature, wherein the volume ratio of ethanol to ammonia water is 99: 1.

s25, centrifuging the reaction solution of the step S24 by using distilled water and alcohol respectively to collect solid matters, and drying the solid matters at 80 ℃ for 12 hours to obtain V_0.9W_0.1O₂@SiO₂And (3) composite powder.

S3, reacting V under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_0.9W_0.1O₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_0.9W_0.1O₂@SiO₂the/PNIPAM composite solution. Step S3 specifically includes the following steps:

s31, preparing 10ml of 0.19mol/L aqueous solution of sodium dodecyl sulfate, dispersing 0.005g of A powder in the aqueous solution, and stirring the mixture at normal temperature for 12 hours to obtain a solution containing V_0.9W_0.1O₂@SiO₂Dodecyl sodium sulfate solution of composite powder.

S32, putting 200 ml of distilled water into a four-neck flask, vacuumizing and introducing nitrogen, and heating the solution to 80 ℃.

S33, an aqueous solution containing 0.4g N-isopropylacrylamide and 7mg of N' N-methylenebisacrylamide was added to the four-necked flask.

S34, adding 1ml of solution containing 0.0008g V while stirring_0.9W_0.1O₂@SiO₂The powdered sodium lauryl sulfate (sodium lauryl sulfate) solution is processed in step S33.

S35, 0.8ml of ammonium persulfate solution is added into the mixed solution of S33 to initiate reaction, and stirring is carried out for 1 minute.

S36, 3.5g N-isopropyl acrylamide and 168mg of N' N-methylene bisacrylamide aqueous solution are slowly dropped into the mixture by a peristaltic pump to react for 2 hours in the step S35, and V is obtained_0.9W_0.1O₂@SiO₂The PNIPAM composite solution is packaged by glass.

In one embodimentIn (c), the step S3 is followed by the steps of: v obtained in step S36_0.9W_0.1O₂@SiO₂Forming a film by the PNIPAM composite solution and drying.

The composite intelligent window material prepared in the embodiment can realize obvious thermochromism: at 20 ℃, the visible light transmittance can reach 73.40%, and the transmittance of the whole solar spectrum is 38.20%; at 40 ℃, the visible light transmittance is 0.02%, and the transmittance of the whole solar spectrum is 0.04%, so that the phase transition temperature of the material in this example is 41 ℃, and the temperature-variable spectrum regulation efficiency is 38.16%.

Example 3

S1, taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_0.7W_0.3O₂And (3) powder.

Step S1 specifically includes the following steps:

s11, weighing the reagents according to the stoichiometric ratio: vanadyl sulfate 4.8g, ammonium tungstate 0.24g, was dissolved in 150 ml of distilled water to form a blue-green solution.

S12, 0.8ml of hydrazine hydrate is slowly dropped into the blue-green solution formed in the step S11 by using a peristaltic pump, and sodium hydroxide is added to adjust the pH value of the solution to 9.5.

S13, centrifuging the solution in the step S12 at the speed of 11000r/min to obtain powder, and washing the powder three times by using distilled water to obtain a powder raw material.

S14, transferring the powder raw material into a 100ml hydrothermal reaction kettle, preserving heat for 48 hours at 260 ℃, finally collecting the powder by using a centrifugal machine, respectively washing the powder by using ethanol and distilled water for three times, and drying the powder in a 50 ℃ oven for 24 hours to obtain powder V_0.7W_0.3O₂。

S2, mixing V_0.7W_0.3O₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_0.7W_0.3O₂@SiO₂And (3) composite powder. Step S2 specifically includes the following steps:

s21, taking a certain amount of stepsV obtained in step S1_0.7W_0.3O₂The powder was dispersed in ethanol and stirred for 1 hour, 280ml of ethanol and 70 ml of aqueous ammonia dilution were added dropwise to the solution and stirred for 30 minutes.

S22, 0.5 ml of tetraethyl orthosilicate was added to the solution in step S21 using a peristaltic pump, and the mixture was stirred at room temperature for 4 hours.

S23, centrifuging the solution obtained in the step S22 by using a centrifuge to obtain powder, washing the separated solid by sequentially using distilled water and alcohol, and drying the washed solid at 80 ℃ for 12 hours to obtain powder A.

S24, dispersing 0.1 mg of the powder A obtained in the step S23 in a mixed solution of 100ml of ethanol, an ammonia water solution and 0.2 ml of a silane coupling agent, stirring for 4 hours at room temperature, wherein the volume ratio of ethanol to ammonia water is 99: 1.

s25, centrifuging the reaction solution of the step S24 by using distilled water and alcohol respectively to collect solid matters, and drying the solid matters at 80 ℃ for 12 hours to obtain V_0.7W_0.3O₂@SiO₂And (3) composite powder.

S3, reacting V under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_0.7W_0.3O₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_0.7W_0.3O₂@SiO₂the/PNIPAM composite solution. Step S3 specifically includes the following steps:

s31, preparing 10ml of 0.19mol/L aqueous solution of sodium dodecyl sulfate, dispersing 0.005g of A powder in the aqueous solution, and stirring the mixture at normal temperature for 12 hours to obtain a solution containing V_0.7W_0.3O₂@SiO₂Dodecyl sodium sulfate solution of composite powder.

S32, putting 200 ml of distilled water into a four-neck flask, vacuumizing and introducing nitrogen, and heating the solution to 80 ℃.

S33, an aqueous solution containing 0.4g N-isopropylacrylamide and 7mg of N' N-methylenebisacrylamide was added to the four-necked flask.

S34, adding 1ml of the mixture during stirringContains 0.0016g V_0.7W_0.3O₂@SiO₂The powdered sodium lauryl sulfate (sodium lauryl sulfate) solution is processed in step S33.

S35, 0.8ml of ammonium persulfate solution is added into the mixed solution of S33 to initiate reaction, and stirring is carried out for 1 minute.

S36, 3.5g N-isopropyl acrylamide and 168mg of N' N-methylene bisacrylamide aqueous solution are slowly dropped into the mixture by a peristaltic pump to react for 2 hours in the step S35, and V is obtained_0.7W_0.3O₂@SiO₂The PNIPAM composite solution is packaged by glass.

In one embodiment, the step S3 is followed by the following steps: v obtained in step S36_0.7W_0.3O₂@SiO₂Forming a film by the PNIPAM composite solution and drying.

The composite intelligent window material prepared in the embodiment can realize obvious thermochromism: at 20 ℃, the visible light transmittance can reach 81.61%, and the transmittance of the whole solar spectrum is 40.99%; at 40 ℃, the visible light transmittance can reach 0.03%, and the transmittance of the whole solar spectrum is 0.96%, so that in the embodiment, the phase transition temperature of the material is 25 ℃, and the variable-temperature spectrum regulation and control efficiency is 40.03%.

Example 4

S1, taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_0.8W_0.2O₂And (3) powder.

Step S1 specifically includes the following steps:

s11, weighing the reagents according to the stoichiometric ratio: vanadyl sulfate 4.8g, ammonium tungstate 1.6g, was dissolved in 120 ml of distilled water to form a blue-green solution.

S12, 0.65ml of hydrazine hydrate is slowly dropped into the blue-green solution formed in the step S11 by using a peristaltic pump, and sodium hydroxide is added to adjust the pH value of the solution to 8.

S13, centrifuging the solution in the step S12 at the speed of 11000r/min to obtain powder, and washing the powder three times by using distilled water to obtain a powder raw material.

S14, transferring the powder raw material into a 100ml hydrothermal reaction kettle, preserving heat for 36 hours at 260 ℃, finally collecting the powder by using a centrifugal machine, respectively washing the powder by using ethanol and distilled water for three times, and drying the powder in a 50 ℃ oven for 24 hours to obtain powder V_0.8W_0.2O₂。

S2, mixing V_0.8W_0.2O₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_0.8W_0.2O₂@SiO₂And (3) composite powder. Step S2 specifically includes the following steps:

s21, taking a certain amount of V prepared in the step S1_0.8W_0.2O₂The powder was dispersed in ethanol and stirred for 1 hour, 280ml of ethanol and 70 ml of aqueous ammonia dilution were added dropwise to the solution and stirred for 30 minutes.

S22, 0.5 ml of tetraethyl orthosilicate was added to the solution in step S21 using a peristaltic pump, and the mixture was stirred at room temperature for 4 hours.

S23, centrifuging the solution obtained in the step S22 by using a centrifuge to obtain powder, washing the separated solid by sequentially using distilled water and alcohol, and drying the washed solid at 80 ℃ for 12 hours to obtain powder A.

S24, dispersing 0.1 mg of the powder A obtained in the step S23 in a mixed solution of 100ml of ethanol, an ammonia water solution and 0.2 ml of a silane coupling agent, stirring for 4 hours at room temperature, wherein the volume ratio of ethanol to ammonia water is 99: 1.

s25, centrifuging the reaction solution of the step S24 by using distilled water and alcohol respectively to collect solid matters, and drying the solid matters at 80 ℃ for 12 hours to obtain V_0.8W_0.2O₂@SiO₂And (3) composite powder.

S3, reacting V under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_0.8W_0.2O₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_0.8W_0.2O₂@SiO₂the/PNIPAM composite solution. The step S3 specifically includes the following stepsThe method comprises the following steps:

s31, preparing 10ml of 0.19mol/L aqueous solution of sodium dodecyl sulfate, dispersing 0.005g of A powder in the aqueous solution, and stirring the mixture at normal temperature for 12 hours to obtain a solution containing V_0.8W_0.2O₂@SiO₂Dodecyl sodium sulfate solution of composite powder.

S32, putting 200 ml of distilled water into a four-neck flask, vacuumizing and introducing nitrogen, and heating the solution to 80 ℃.

S33, an aqueous solution containing 0.4g N-isopropylacrylamide and 7mg of N' N-methylenebisacrylamide was added to the four-necked flask.

S34, adding 1ml of solution containing 0.0024g V while stirring_0.8W_0.2O₂@SiO₂The powdered sodium lauryl sulfate (sodium lauryl sulfate) solution is processed in step S33.

S35, 0.8ml of ammonium persulfate solution is added into the mixed solution of S33 to initiate reaction, and stirring is carried out for 1 minute.

S36, 3.5g N-isopropyl acrylamide and 168mg of N' N-methylene bisacrylamide aqueous solution are slowly dropped into the mixture by a peristaltic pump to react for 2 hours in the step S35, and V is obtained_0.8W_0.2@SiO₂The PNIPAM composite solution is packaged by glass.

In one embodiment, the step S3 is followed by the following steps: v obtained in step S36_0.8W_0.2@SiO₂Forming a film by the PNIPAM composite solution and drying.

The composite intelligent window material prepared in the embodiment can realize obvious thermochromism: at 20 ℃, the visible light transmittance can reach 88.12%, and the transmittance of the whole solar spectrum is 43.17%; at 40 ℃, the visible light transmittance can reach 0.04%, and the transmittance of the whole solar spectrum is 1.27%, so that the phase transition temperature of the material in the embodiment is 32 ℃, and the variable-temperature spectrum regulation efficiency is 41.90%.

Example 5

S1, taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_0.8W_0.2O₂And (3) powder.

Step S1 specifically includes the following steps:

s11, weighing the reagents according to the stoichiometric ratio: vanadyl sulfate 4.8g, ammonium tungstate 1.6g, was dissolved in 120 ml of distilled water to form a blue-green solution.

S12, 0.65ml of hydrazine hydrate is slowly dropped into the blue-green solution formed in the step S11 by using a peristaltic pump, and sodium hydroxide is added to adjust the pH value of the solution to 8.

S13, centrifuging the solution in the step S12 at the speed of 11000r/min to obtain powder, and washing the powder three times by using distilled water to obtain a powder raw material.

S14, transferring the powder raw material into a 100ml hydrothermal reaction kettle, preserving heat for 36 hours at 260 ℃, finally collecting the powder by using a centrifugal machine, respectively washing the powder by using ethanol and distilled water for three times, and drying the powder in a 50 ℃ oven for 24 hours to obtain powder V_0.8W_0.2O₂。

S2, mixing V_0.8W_0.2O₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_0.8W_0.2O₂@SiO₂And (3) composite powder. Step S2 specifically includes the following steps:

s21, taking a certain amount of V prepared in the step S1_0.8W_0.2O₂The powder was dispersed in ethanol and stirred for 1 hour, 280ml of ethanol and 70 ml of aqueous ammonia dilution were added dropwise to the solution and stirred for 30 minutes.

S22, 0.5 ml of tetraethyl orthosilicate was added to the solution in step S21 using a peristaltic pump, and the mixture was stirred at room temperature for 4 hours.

S23, centrifuging the solution obtained in the step S22 by using a centrifuge to obtain powder, washing the separated solid by sequentially using distilled water and alcohol, and drying the washed solid at 80 ℃ for 12 hours to obtain powder A.

S24, dispersing 0.1 mg of the powder A obtained in the step S23 in a mixed solution of 100ml of ethanol, an ammonia water solution and 0.2 ml of a silane coupling agent, stirring for 4 hours at room temperature, wherein the volume ratio of ethanol to ammonia water is 99: 1.

s25, centrifuging the reaction solution of the step S24 by using distilled water and alcohol respectively to collect solid matters, and drying the solid matters at 80 ℃ for 12 hours to obtain V_0.8W_0.2O₂@SiO₂And (3) composite powder.

S3, reacting V under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_0.8W_0.2O₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_0.8W_0.2O₂@SiO₂the/PNIPAM composite solution. Step S3 specifically includes the following steps:

s31, preparing 10ml of 0.19mol/L aqueous solution of sodium dodecyl sulfate, dispersing 0.005g of A powder in the aqueous solution, and stirring the mixture at normal temperature for 12 hours to obtain a solution containing V_0.8W_0.2O₂@SiO₂Dodecyl sodium sulfate solution of composite powder.

S32, putting 200 ml of distilled water into a four-neck flask, vacuumizing and introducing nitrogen, and heating the solution to 80 ℃.

S33, an aqueous solution containing 0.4g N-isopropylacrylamide and 7mg of N' N-methylenebisacrylamide was added to the four-necked flask.

S34, adding 1ml of solution containing 0.0032g V during stirring_0.8W_0.2O₂@SiO₂The powdered sodium lauryl sulfate (sodium lauryl sulfate) solution is processed in step S33.

S35, 0.8ml of ammonium persulfate solution is added into the mixed solution of S33 to initiate reaction, and stirring is carried out for 1 minute.

S36, 3.5g N-isopropyl acrylamide and 168mg of N' N-methylene bisacrylamide aqueous solution are slowly dropped into the mixture by a peristaltic pump to react for 2 hours in the step S35, and V is obtained_0.8W_0.2O₂@SiO₂The PNIPAM composite solution is packaged by glass.

In one embodiment, the step S3 is followed by the following steps: v obtained in step S36_0.8W_0.2O₂@SiO₂Forming a film by the PNIPAM composite solution and drying.

The composite intelligent window material prepared in the embodiment can realize obvious thermochromism: at 20 ℃, the visible light transmittance can reach 91.41 percent, and the transmittance of the whole solar spectrum is 44.76 percent; at 40 ℃, the visible light transmittance can reach 12.15%, and the transmittance of the whole solar spectrum is 11.99%, so that the phase transition temperature of the material in the embodiment is 32 ℃, and the temperature-variable spectrum regulation efficiency is 32.77%.

Example 6

The invention also provides a material with thermochromic effect, which is prepared by the method of the embodiment 1 to the embodiment 5.

Example 7

The invention also provides a thermochromic intelligent window, which comprises glass and the material in the embodiment 6, wherein the material is packaged between interlayers of the glass. It should be noted that the material with thermochromic effect of the present invention is not limited to the application in smart windows.

Referring to FIGS. 1 to 3, FIG. 1 shows a V prepared according to the present invention_0.8W_0.2O₂@SiO₂A PNIPAM dynamic light scattering particle size analysis chart; FIG. 2 is a graph of V prepared according to the present invention_0.8W_0.2O₂@SiO₂TEM image of/PNIPAM; FIG. 3 is a V prepared according to the present invention_0.8W_0.2O₂@SiO₂PNIPAM and blank glass cooling test chart. As shown in fig. 1 to fig. 3, the thermochromic composite material provided by the present invention can actively adjust the transmittance of sunlight according to the ambient temperature, and has the advantages of very high visible light transmittance, variable-temperature spectrum regulation efficiency, photo-thermal stability, adaptability, and the like.

The invention has the following beneficial effects:

1. the material with the thermochromic effect has high visible light transmittance and temperature-variable solar spectrum regulation and control performance, is composed of tungsten-doped vanadium dioxide and poly-nitrogen isopropyl acrylamide which are wrapped by silicon dioxide, can actively regulate the transmittance of sunlight according to the environmental temperature, and finally obtains a comfortable building environment in a warm-in-winter and cool-in-summer mode, thereby reducing energy consumption caused by refrigeration and heating. Meanwhile, the material has excellent thermal stability and adaptability, can be subjected to composition design and preparation according to the production requirements or the characteristics of conditions such as environmental temperature and the like, and has a very wide application prospect in the field of energy conservation.

2. The invention uses a hydrothermal reaction method and an emulsion polymerization method, and utilizes organic-inorganic composite solution and common glass to assemble and obtain the intelligent window with a sandwich structure.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.

While embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications and variations may be made therein by those of ordinary skill in the art within the scope of the present invention.

Claims (10)

1. A method for preparing a material with a thermochromic effect is characterized by comprising the following steps:

s1, taking vanadyl sulfate and ammonium tungstate as raw materials, and obtaining V through hydrothermal reaction_1-xW_xO₂Powder;

s2, mixing V_1-xW_xO₂Dispersing the powder in a solvent, adding a reaction monomer and a dispersant under the action of a catalyst to perform hydrolysis and condensation reaction to obtain V_1-xW_xO₂@SiO₂Composite powder;

s3, reacting V under the action of a crosslinking agent and an initiator under the conditions of nitrogen and heating_1-xW_xO₂@SiO₂The composite powder and N-isopropyl acrylamide are subjected to emulsion polymerization to prepare V_1-xW_xO₂@SiO₂the/PNIPAM composite solution.

2. The method according to claim 1, wherein step S1 specifically comprises:

s11, adding 3-6g of vanadyl sulfate and 0.2-2g of ammonium tungstate into 160ml of distilled water of 120-;

s12, dropwise adding 0.6-1ml of hydrazine hydrate into the solution obtained in the step S11, and adjusting the pH value to 8-10 by using sodium hydroxide;

s13, centrifuging the solution obtained in the step S12 to obtain powder, and washing the powder with distilled water to obtain a powder raw material;

s14, putting the powder raw material into a hydrothermal reaction kettle for reaction, centrifuging, washing and drying to obtain V_1-xW_xO₂And (3) powder.

3. The method as claimed in claim 2, wherein the reaction temperature is 240-270 ℃ and the reaction time is 24-48h in step S14, and the centrifugation is followed by washing with ethanol and distilled water in sequence, and the drying temperature is 40-80 ℃.

4. The method according to claim 1, wherein in step S2, the solvent comprises ethanol/the catalyst comprises ammonia water, the reactive monomer comprises tetraethyl orthosilicate, and the dispersant comprises a silane coupling agent.

5. The method according to claim 4, wherein step S2 specifically comprises the steps of:

s21, converting the V obtained in the step S1_1-xW_xO₂Dispersing the powder in ethanol, stirring, adding ethanol and ammonia water diluent dropwise into the solution, and stirring for 30-120 min;

s22, adding tetraethyl orthosilicate into the solution obtained in the step S21 by a peristaltic pump, and stirring at room temperature for 4-12 hours;

s23, separating the solution obtained in the step S22 by a centrifugal machine, washing the separated solid by distilled water and alcohol in sequence, and drying at 50-80 ℃ for 6-24h to obtain powder A;

s24, dispersing the powder A in a mixed solution of ethanol, ammonia water and a silane coupling agent for reaction at room temperature, wherein the volume ratio of ethanol to ammonia water is 99: 1-80: 20;

s25, washing and centrifuging the reaction solution obtained in the step S24 by distilled water and alcohol, and drying at the temperature of 50-80 ℃ for 6-24h to obtain V_1-xW_xO₂@SiO₂And (3) composite powder.

6. The method of claim 1, wherein the cross-linking agent in step S3 comprises an aqueous solution of N' N-methylene bisacrylamide, and the initiator comprises a solution of ammonium persulfate.

7. The method according to claim 6, wherein step S3 specifically comprises:

s31, preparing a sodium dodecyl sulfate aqueous solution, and mixing the solution V_1-xW_xO₂@SiO₂Dispersing the composite powder in a sodium dodecyl sulfate aqueous solution, and stirring at normal temperature to obtain the product containing V_1-xW_xO₂@SiO₂Dodecyl sodium sulfate solution of composite powder;

s32, putting distilled water into a four-neck flask, vacuumizing, introducing nitrogen, heating,

s33, adding an aqueous solution of N-isopropylacrylamide and N' N-methylenebisacrylamide to the four-neck flask in the step S32;

s34, adding V_1-xW_xO₂@SiO₂Adding the sodium dodecyl sulfate solution of the composite powder into the step S33 with stirring to obtain a mixed solution, wherein each milliliter of the mixed solution contains V_1-xW_xO₂@SiO₂Dodecyl sodium sulfate solution of composite powderIn liquid, V_1-xW_xO₂@SiO₂The content of the composite powder is 0.0008-0.0032 g;

s35, adding an ammonium persulfate solution into the mixed solution obtained in the step S34, and stirring;

s36, adding N-isopropyl acrylamide and N' N-methylene bisacrylamide aqueous solution into the step S35, and reacting for 2-5h to obtain V_1-xW_xO₂@SiO₂the/PNIPAM composite solution has x not less than 0 and not more than 0.5.

8. The method according to claim 7, wherein the step S3 is followed by further comprising: v obtained in step S36_1-xW_xO₂@SiO₂Forming a film by the PNIPAM composite solution and drying.

9. A material having a thermochromic effect, characterised in that it is obtained by a method according to any of claims 1-8.

10. A thermochromic smart window, comprising: the smart window comprises glass and the material of claim 9, the material being encapsulated between interlayers of the glass.

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