CN115011148B

CN115011148B - Sprayable solar thermal conversion functional gel and preparation method and application thereof

Info

Publication number: CN115011148B
Application number: CN202210461160.0A
Authority: CN
Inventors: 王振洋; 刘翠; 张淑东; 李年; 蒋长龙
Original assignee: Hefei Institutes of Physical Science of CAS
Current assignee: Hefei Institutes of Physical Science of CAS
Priority date: 2022-04-28
Filing date: 2022-04-28
Publication date: 2023-05-30
Anticipated expiration: 2042-04-28
Also published as: CN115011148A

Abstract

The invention discloses a sprayable solar thermal conversion functional gel and a preparation method and application thereof. The gel can be sprayed on any object such as glass, metal, building and the like through a spray gun, and a functional coating with a smooth and flat surface is formed, so that the problem of uneven dispersion of photo-thermal conversion nano material particles in the aqueous silica gel is solved. The method is simple to operate, raw materials are simple and easy to obtain, and the prepared solar thermal conversion functional gel has good photo-thermal conversion performance and excellent stability, and has wide application prospects in the fields of glass greenhouses, building energy conservation and the like.

Description

Sprayable solar thermal conversion functional gel and preparation method and application thereof

Technical Field

The invention relates to the field of preparation of solar thermal conversion functional gel, in particular to sprayable solar thermal conversion functional gel, and a preparation method and application thereof.

Background

The solar thermal conversion material is a nano material capable of converting solar energy into heat energy, and has wide application prospects in the fields of agriculture, buildings and the like. The preparation of the solar thermal conversion material into a sprayable functional coating is one of the best ways to realize the application of the solar thermal conversion material in the field of construction and agriculture. However, most of solar thermal conversion efficiency is inorganic nano materials at present, the dispersibility is poor, and a uniform coating cannot be formed; secondly, the preparation methods of the solar conversion functional coating mainly comprise methods such as vapor deposition, sputtering deposition, chemical plating, sol-gel method and the like, and the methods have the problems of complex operation, weak bonding strength of the functional coating and a substrate, inapplicability to large-area preparation and the like, so that development of a large-area preparation method of the photo-thermal functional gel with simplicity, high efficiency, uniform coating dispersion and strong bonding strength is needed.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide sprayable solar thermal conversion functional gel, a preparation method and application thereof, wherein the functional gel can be directly sprayed on the surface of a substrate to form a coating and has the characteristics of uniform coating dispersion and strong bonding strength.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the first aspect of the invention provides a preparation method of a sprayable solar thermal conversion functional gel, comprising the following steps:

(1) Surface modification of photothermal conversion material

Adding Polysuccinimide (PSI) into DMF, stirring under the heating condition of 60-80 ℃ until the polysuccinimide is completely dissolved to obtain polysuccinimide solution, adding oleylamine into the polysuccinimide solution for reaction for 10-15h to obtain oil aminated polysuccinimide, PSI-OAm for short, separating PSI-OAm from solvent, and dissolving the PSI-OAm in chloroform to obtain PSI-OAm/chloroform solution; dispersing the photo-thermal conversion nano material in water, adding PSI-OAm/chloroform solution into the nano material, performing solid-liquid separation on the nano material after ultrasonic treatment, and washing the obtained solid material with water to obtain the PSI-OAm modified photo-thermal conversion nano material.

Wherein: the photothermal conversion nano material is copper sulfide nano material, and the copper sulfide nano material can be Cu ₇ S ₄ The nano particles can also be CuS nano sheets and the like.

(2) Preparation of solar thermal conversion functional gel

Dripping tetraethyl orthosilicate into deionized water and ethanol solution, wherein the volume ratio of the tetraethyl orthosilicate to the deionized water is 18:9.32:4.475 regulating pH of the mixed solution to 4-5 with glacial acetic acid with concentration of 0.05-0.2mol/L, stirring at room temperature for reaction for 1-2h until the solution becomes clear from turbidity, and regulating pH of the solution to 7-8 with ammonia water with concentration of 0.05-0.2mol/L to obtain silica gel; adding the modified photo-thermal conversion material into the silica gel, adding water-based polyurethane (called water-based PU for short) after ultrasonic dispersion, and uniformly mixing to obtain the solar photo-thermal conversion functional gel. Preferably, the content of the aqueous PU in the solar thermal conversion functional gel is 1-5 wt%.

In the preparation process of the solar thermal conversion functional gel, the pH value of the mixed solution is adjusted to be 4-5, so that a proper acid environment is provided for preparing the silica gel. After the reaction is finished, i.e. the solution is clarified from turbidity, the pH value of the solution is adjusted to 7-8, and the solution is near neutral and is easy to react between the silica gel and the aqueous PU and photothermal conversion nano material. In the above reaction, the pH of the solution is biased to cause aggregation of the photo-thermal conversion nanoparticles, and the pH of the solution is biased to cause gelation of the composite sol.

Because the photo-thermal conversion material copper sulfide nano particles have higher surface activity, the photo-thermal conversion material copper sulfide nano particles are easy to agglomerate in the application of the functional coating, so that the photo-thermal conversion performance and the stability of the coating are influenced, and the dispersibility of the photo-thermal conversion material copper sulfide nano particles in the silica gel is improved by a surface modification technology. Because the surface of the copper sulfide nano particle is electronegative, the invention firstly prepares the PSI-OAm with amphipathy, wherein the positively charged and hydrophobic oleyl amine group and the negatively charged copper sulfide are subjected to electrostatic adsorption, and the hydrophilic end of the PSI enables the modified copper sulfide to be uniformly dispersed in water, so that the dispersibility of the copper sulfide nano particle in the silica gel is improved, and the stable functional gel is obtained.

In addition, in the preparation of functional coatings, the composite solution of inorganic copper sulfide nanoparticles and silica gel is susceptible to layering after heat treatment due to the presence of surface tension. In order to avoid layering, the invention selects the water-based PU, utilizes the water-based PU to contain a large amount of polar groups in the molecule, has strong intermolecular acting force and excellent film forming capability, combines the water-based PU with the photothermal conversion material and the silica gel, optimizes the film forming effect of the functional gel and finally forms a uniform and stable coating.

In a second aspect, the invention provides a sprayable solar thermal conversion functional gel prepared according to the preparation method provided in the first aspect.

The third aspect of the invention provides an application of the solar thermal conversion functional gel as a functional coating, comprising the steps of spraying the solar thermal conversion functional gel onto a substrate by using a spray pen, keeping the direction of a spray head hair line perpendicular to the surface of the substrate, and then drying to obtain the functional coating on the surface of the substrate. Further preferably, the substrate is glass, metal or a building.

Compared with the prior art, the invention has the beneficial effects that:

1. the preparation method of the sprayable solar thermal conversion functional gel successfully disperses the photo-thermal conversion material in the silica gel by carrying out surface modification on the photo-thermal conversion material, so as to prepare the photo-thermal conversion functional gel.

2. The solar thermal conversion functional gel can be sprayed on the surfaces of various substrates, such as glass, metal, buildings and the like by using a spray gun. The invention has simple operation and easily obtained raw materials, can be prepared in a general chemistry laboratory, is easy to popularize and is convenient for application in agricultural glass greenhouses, buildings and the like.

Drawings

FIG. 1 shows PSI-OAm modified Cu prepared in example 1 ₇ S ₄ SEM image of nanoparticles;

fig. 2 is a tyndall phenomenon of the solar thermal conversion functional gel prepared in example 1;

FIG. 3 is Cu ₇ S ₄ Nanoparticle (A) and PSI-OAm modified Cu ₇ S ₄ Comparison of dispersion stability of nanoparticles (B) in silica gel;

FIG. 4 is an optical photograph of the functional coating-loaded glass sheet prepared in example 1;

FIG. 5 is a cross-sectional SEM of the glass sheet of FIG. 4;

fig. 6 is a tyndall phenomenon of the solar thermal conversion functional gel prepared in example 2;

FIG. 7 is an optical photograph of the functional coating-loaded glass sheet prepared in example 2;

fig. 8 is a tyndall phenomenon of the solar thermal conversion functional gel prepared in example 3;

fig. 9 is an optical photograph of the functional coating-loaded glass sheet prepared in example 3.

Detailed Description

The technical scheme in the embodiment of the invention is further described in detail by combining the drawings in the embodiment of the invention. The following specific examples are given for the purpose of illustration only and are not intended to be limiting.

The reagents and starting materials used in the following examples were commercially available. Wherein: the aqueous polyurethane is made of aqueous polyurethane of the model F0401 manufactured by Shenzhen Jitian chemical Co., ltd. The above reagents are merely provided to illustrate the sources and ingredients of the reagents used in the experiments of the present invention, and are not meant to be limiting in that the present invention may not be practiced using other reagents of the same type or provided by other suppliers.

The photothermal conversion material used in the following examples was hollow Cu ₇ S ₄ Nanoparticles, which are relatively mature products, can be prepared by a variety of methods, and the preparation method adopted by the invention is as follows:

respectively weighing 0.2g of copper acetate and 0.2g of polyvinylpyrrolidone, dissolving in 30mL of water, then adding 10mL of 1M sodium hydroxide solution, stirring for reaction for 30min to obtain a brick red precipitate, quickly adding 10mL of 0.3M ascorbic acid, heating to 55 ℃ for reaction for 1h, respectively washing the obtained mixed solution with water and ethanol for 3 times, and drying for later use.

Example 1

A preparation method of sprayable solar thermal conversion functional gel comprises the following steps:

(1) Surface modification of photothermal conversion material

1g of PSI was dissolved in 20mL of DMF and stirred under heating at 60℃until complete dissolution to give a polysuccinimide solution, to which 1mL of oleylamine was added for reaction for 12h to give an oil aminated polysuccinimide, PSI-OAm. Adding methanol into the solution to separate PSI-OAm from the solution to obtain a mixed material, andit is subjected to solid-liquid separation to obtain PSI-OAm. PSI-OAm was dissolved in chloroform to give 20mg/mL of PSI-OAm/chloroform solution; then 10mgCu is added ₇ S ₄ Dispersing the nano particles in 20mL of water, adding 5mL of PSI-OAm/chloroform solution, performing solid-liquid separation after ultrasonic treatment, and washing the obtained solid material with water to obtain PSI-OAm modified Cu ₇ S ₄ And (3) nanoparticles.

(2) Preparation of solar thermal conversion functional gel

18mL of deionized water and 9.32mL of ethanol are mixed to obtain an ethanol aqueous solution, 4.475mL of tetraethyl orthosilicate is dropwise added to the ethanol aqueous solution, then the pH of the mixed solution is regulated to 4.5 by 0.1mol/L glacial acetic acid to obtain a mixed solution, the mixed solution is stirred at room temperature for reaction until the mixed solution becomes clear from turbidity, and then the pH of the solution is regulated to 7.0 by 0.1mol/L ammonia water to obtain silica gel. 2mL of silica gel was taken and 10mg of PSI-OAm modified Cu was added ₇ S ₄ After the nano particles are treated for 15min by ultrasonic, adding water-based polyurethane (water-based PU), and continuously stirring for 15min at room temperature to obtain the solar thermal conversion functional gel with the water-based PU content of 1 wt%; PSI-OAm modified Cu in obtained solar thermal conversion functional gel ₇ S ₄ The content of the nanoparticle was 5mg/mL.

The prepared gel with the solar thermal conversion function is sprayed on a glass sheet by using a spray pen, the diameter of the spray pen is 1mm, the pressure value of a pressurizing pump of the spray pen is 10MPa, and the direction of a hairline of a spray head is kept to be perpendicular to the glass sheet, and the distance is 20cm. The solar thermal conversion functional gel with the volume of 5mL is sprayed on the surface of the glass sheet for three times uniformly, the glass sheet is dried at 80 ℃ for 10min after each spraying, then the spraying process is repeated, and finally the obtained sheet is kept at 110 ℃ for 30min, so that the functional coating formed by the solar thermal conversion functional gel can be obtained on the glass sheet.

FIG. 1 is a PSI-OAm modified Cu prepared in step (1) of example 1 ₇ S ₄ SEM image of nanoparticles, as can be seen from fig. 1, modified Cu ₇ S ₄ The nanoparticles can be uniformly dispersed. The PSI-OAm modified Cu ₇ S ₄ Nanometer scaleThe particles were uniformly dispersed in the silica gel and the tyndall effect was seen after irradiation with the laser, and a bright light path was observed in the gel (fig. 2). Unmodified Cu ₇ S ₄ The nano particles are precipitated in the silica gel (figure 3A), and the dispersibility of the modified photo-thermal conversion functional gel is not changed after the modified photo-thermal conversion functional gel is placed for a week (figure 3B), which shows that the stability of the photo-thermal conversion functional gel prepared by modifying the surface of the photo-thermal conversion nano material is better. Fig. 4 is an optical photograph of the solar thermal conversion functional gel prepared in example 1 after being sprayed on the surface of a glass sheet, and it can be seen that the functional coating formed on the surface of the glass sheet is relatively smooth. Fig. 5 is a cross-sectional SEM image of a glass sheet loaded with a functional coating, which can be seen from fig. 5 to a thickness of about 5 μm.

Example 2

Unlike example 1, this example was modified Cu by changing PSI-OAm in the step of preparing a solar thermal conversion functional gel ₇ S ₄ The addition amount of the nano particle material ensures that the final obtained Cu modified by PSI-OAm in the middle solar thermal conversion functional gel ₇ S ₄ The nanoparticle content was 10mg/mL, and the color of the prepared photothermal conversion functional gel was darker than that of example 1, and the brightness of the optical path was weaker than that of example 1 (FIG. 6). When it was sprayed on a glass sheet, the optical photograph thereof was as shown in FIG. 7, the color of the surface of the glass was significantly increased as compared with example 1, and the transmittance thereof was reduced. This is because the photo-thermal conversion nanoparticles are black in color, and an increase in the content thereof results in a decrease in transmittance of the glass, and an increase in absorption of solar energy, and thus an increase in the glass surface temperature and photo-thermal conversion efficiency.

Example 3

Unlike example 1, this example was modified Cu by changing PSI-OAm in the step of preparing a solar thermal conversion functional gel ₇ S ₄ The addition amount of the nano particles ensures that the Cu modified by PSI-OAm in the finally obtained solar thermal conversion functional gel ₇ S ₄ The nanometer particles are 20mg/mL, the prepared photo-thermal conversion functional gel has darker color than that of the example 1 and the example 2, and noA complete beam can be observed (fig. 8). It was sprayed on a glass sheet, the optical photograph of which is shown in FIG. 9, and the color of the glass surface was significantly darker than that of examples 1 and 2, because of Cu ₇ S ₄ The content of the nano particles is further deepened, so that the laser beam cannot pass through the functional gel, the content of the nano particles is also increased on the surface of the glass, and the color of the surface of the glass is also deepened.

The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.

Claims

1. A preparation method of sprayable solar thermal conversion functional gel is characterized in that: the method comprises the following steps:

(1) Surface modification is carried out on the photothermal conversion material: dissolving polysuccinimide in a solvent to obtain polysuccinimide solution, adding oleylamine into the polysuccinimide solution to react to obtain oil aminated polysuccinimide, namely PSI-OAm, separating PSI-OAm from the solvent, and dissolving the PSI-OAm in chloroform to obtain PSI-OAm/chloroform solution; dispersing the photo-thermal conversion nano material in water, adding PSI-OAm/chloroform solution into the nano material, performing solid-liquid separation after ultrasonic treatment, and washing the obtained solid material with water to obtain the PSI-OAm modified photo-thermal conversion nano material; the photothermal conversion nano material is copper sulfide nano material;

(2) Preparing a solar thermal conversion functional gel: adding tetraethyl orthosilicate into an ethanol water solution, and then adding acid to adjust the pH value to be acidic to obtain a mixed solution; stirring the mixed solution at room temperature until the mixed solution becomes clear from turbidity, and then adding alkali to adjust the pH value to 7-8 to obtain silica gel; adding PSI-OAm modified photo-thermal conversion nano material into the silica gel, adding water-based polyurethane after ultrasonic dispersion, and uniformly mixing to obtain a solar photo-thermal conversion functional gel; the content of the water-based polyurethane in the solar thermal conversion functional gel is 1-5 wt%.

2. The method for preparing a sprayable solar thermal conversion functional gel according to claim 1, wherein: in the step (1), the solvent is N, N-dimethylformamide; the temperature of the solvent is 60-80 ℃; the reaction time of adding oleylamine is 10-15h.

3. The method for preparing a sprayable solar thermal conversion functional gel according to claim 1, wherein: in the step (2), the acid is glacial acetic acid with the concentration of 0.05-0.2mol/L, the pH value of the mixed solution is 4-5, and the mixed solution is stirred for 2-5h at room temperature.

4. The method for preparing a sprayable solar thermal conversion functional gel according to claim 1, wherein: in the step (2), the alkali is ammonia water with the concentration of 0.05-0.2 mol/L.

5. A sprayable solar thermal conversion functional gel, characterized in that: which is prepared by the preparation method as claimed in any one of claims 1 to 4.

6. Use of a sprayable solar thermal conversion functional gel according to claim 5 as a functional coating, characterized in that: the method comprises the following steps of spraying solar thermal conversion functional gel onto the surface of a substrate, and drying to obtain a functional coating on the surface of the substrate.

7. The use of a sprayable solar thermal conversion functional gel according to claim 6 as a functional coating, characterized in that: the specific method for spraying comprises the following steps: and spraying the gel with the solar thermal conversion function onto the substrate by using a spray pen, keeping the hairline direction of the spray head vertical to the surface of the substrate, and then drying.

8. The use of a sprayable solar thermal conversion functional gel according to claim 6 as a functional coating, characterized in that: the substrate is glass, metal or a building.