阅读说明：本技术 一种掺杂ZrO2粒子的PDMS辐射制冷薄膜的制备方法 (Preparation method of ZrO2 particle-doped PDMS radiation refrigeration film ) 是由 谭新玉 张玉博 齐贵广 杨雄波 胡蝶 王云宽 于 2020-11-05 设计创作，主要内容包括：本文提供一种掺杂ZrO-2粒子的PDMS辐射制冷薄膜的制备方法。该辐射制冷薄膜主要以PDMS为基底掺杂ZrO-2粒子组成辐射制冷薄膜。其制备方法为：将PDMS加入到正己烷溶液中,磁力搅拌后形成均一溶液；将二氧化锆加入到上述溶液中,再加入Sylgard 184硅橡胶固化剂,磁力搅拌后使其分散均匀得到白色溶液。用洗衣水清洗亚克力片,在清水中超声后用无水乙醇清洗,再用去离子水清洗后烘干待用。首先在平整桌面放置一张A4纸,校正KTQ-Ⅱ可调节刮刀,将溶液滴到亚克力片表面,然后以匀速缓慢划过样品,形成平整涂层,最后将样品放置烘箱中烘干即可。因为发明材料价格低廉且制备方法简单,该薄膜在建筑、太阳能电池、太空建设领域中有广阔应用前景。(A doped ZrO is provided herein 2 A preparation method of a PDMS radiation refrigeration film of particles. The radiation refrigeration film mainly takes PDMS as a substrate to be doped with ZrO 2 The particles constitute the radiation refrigeration film. The preparation method comprises the following steps: adding PDMS into a normal hexane solution, and magnetically stirring to form a uniform solution; adding zirconium dioxide into the solution, adding Sylgard 184 silicon rubber curing agent, and dispersing the mixture evenly after magnetic stirring to obtain white solution. Washing the acrylic sheet with washing water, ultrasonically treating the acrylic sheet in clear water, washing the acrylic sheet with absolute ethyl alcohol, washing the acrylic sheet with deionized water, and drying the acrylic sheet for later use. Firstly, placing a piece of A4 paper on a flat table top, correcting a KTQ-II adjustable scraper, dripping solution on the surface of an acrylic sheet, slowly scratching a sample at a constant speed to form a flat coating, and finally, placing the sample in an oven to dry. Because the material of the invention is low in price and the preparation method is simple, the film has wide application prospect in the fields of building, solar cell and space construction.)

1. Doped ZrO (ZrO)₂The preparation method of the PDMS radiation refrigeration film of the particles is characterized in that: the radiation refrigeration film is formed by doping ZrO on a PDMS substrate₂Particle composition comprising the following preparation steps:

(1) preparation of PDMS solution: adding PDMS into n-hexane solution, and magnetically stirring for 8-15min to form uniform solution;

(2) preparing a coating stock solution: adding zirconium dioxide into the solution obtained in the step (1), adding Sylgard 184 silicon rubber curing agent, and finally performing magnetic stirring to uniformly disperse the zirconium dioxide to obtain a white solution;

(3) film forming of a coating: dripping the white solution obtained in the step (2) on the surface of the cleaned acrylic sheet, scraping the solution at a constant speed by adopting a scraper to form a flat coating, finally placing the sample in an oven, baking for 40-60min at 90-110 ℃ to obtain the ZrO-doped ZrO₂The PDMS of the particles radiates the refrigeration membrane.

2. Doped ZrO according to claim 1₂The preparation method of the particle PDMS radiation refrigeration film is characterized in that PDMS, Sylgard 184 silicon rubber curing agent and ZrO₂The addition mass ratio of (A) to (B) is 1-4: 0.1-0.5: 1.

3. the doped ZrO of claim 1₂The preparation method of the particle PDMS radiation refrigeration film is characterized in that ZrO in the step (2)₂The particle size of (1) is 500-600 nm.

4. The doped ZrO of claim 1₂The preparation method of the particle PDMS radiation refrigeration film is characterized in that the baking temperature in the step (3) is 100 ℃, and the baking time is 50 min.

5. The doped ZrO of claim 1₂The preparation method of the particle PDMS radiation refrigeration film is characterized in that ZrO is doped₂P of the particleZrO in DMS radiation refrigeration films₂The particles account for less than 10% of the volume of the PDMS radiation refrigeration film.

Technical Field

Doped ZrO (ZrO)₂A preparation method of a particle PDMS radiation refrigeration film belongs to the field of materials and energy, mainly relates to the refrigeration problem of environmental temperature, and can effectively reduce the capability of sub-environmental temperature through the radiation refrigeration film.

Background

The control of cold and heat in buildings is an important topic to be considered for the pursuit of comfortable life for human beings. Particularly in the case of summer refrigeration, currently, common refrigeration methods include: vapor compression refrigeration, absorption refrigeration, and commercial air conditioning refrigeration, while effective, consume large amounts of energy and thus also pose serious environmental pollution problems. Radiation refrigeration is a zero-energy-consumption technology for passively dissipating earth heat to outer space through a radiation refrigeration film through heat radiation, the heat radiation is dissipated to the outer space through an atmosphere transparent window (8-13 mu m), and the temperature of the outer space is about 2.7K, so that the radiation refrigeration is considered to be an ideal radiator. Radiation refrigeration has been extensively studied during the last decade and its applicability has been well proven. Daytime cooling is more of a research interest and more challenging as it is generally daytime when considering the need for cooling. The requirement for a radiation cooler is to select emission only at the atmospheric window and suppress absorption or emission outside this band. A good design or material can realize satisfactory sub-environment refrigeration effect, and the net refrigeration power can reach 100W/m under sunny and cloudless weather². Therefore, radiation refrigeration can become a refrigeration technology with great potential in the fields of buildings, solar cells and space construction.

Disclosure of Invention

Doped ZrO (ZrO)₂A preparation method of a particle PDMS radiation refrigeration film. The radiation refrigeration film is used for calculating PDMS and ZrO₂Proportioned and prepared by a knife coating method, samples exhibiting a reflectance of 93.55% (0.3-1.35 μm) and an emissivity of 92.25% (3-25 μm), wherein the maximum average temperature drop achieved by the radiation-cooled film was 9.8 ℃ during the day, 4.4 ℃ lower than that achieved by commercial white paint (Guangdong III and chemical, color number: 40) and 2.9 ℃ at night. Finally, make a dieThe house-like experiment shows that the average temperature of the sample is reduced to 4.2 ℃ compared with the commercial white paint coating. Because the material of the invention has low price and the preparation method is simple, the film has wide application prospect in building refrigeration.

Doped ZrO (ZrO)₂A preparation method of a particle PDMS radiation refrigeration film. The preparation method of the paint coating comprises the following steps: PDMS solution (PDMS as component A, Sylgard 184 silicon rubber as component B, Shanghai Deng Shanghai) and submicron zirconium dioxide (Hebei Huacheng Metallurgical). The preparation method comprises the following specific steps:

(1) preparation of PDMS solution: adding PDMS into n-hexane solution, and magnetically stirring for 8-15min to form uniform solution;

(2) preparing a coating stock solution: adding zirconium dioxide into the solution obtained in the step (1), adding Sylgard 184 silicon rubber curing agent, and finally performing magnetic stirring to uniformly disperse the zirconium dioxide to obtain a white solution;

(3) film forming of a coating: dripping the white solution obtained in the step (1) on the surface of a cleaned acrylic sheet, scraping the solution at a constant speed by adopting a scraper to form a flat coating, finally placing the sample in an oven, baking for 40-60min at 90-110 ℃ to obtain the ZrO-doped ZrO₂The PDMS of the particles radiates the refrigeration membrane.

The PDMS, Sylgard 184 silicon rubber curing agent and ZrO₂The addition mass ratio of (A) to (B) is 1-4: 0.1-0.5: 1.

ZrO in step (2)₂The particle size of (1) is 500-600 nm.

The preferable scheme in the step (3) is that the baking temperature is 100 ℃, and the baking time is 50 min.

The resulting doped ZrO prepared₂In PDMS radiation-cooled films of particles, ZrO₂The particles account for less than 10% of the volume of the PDMS radiation refrigeration film.

The advantages of the patent are as follows:

the PDMS radiation refrigeration film prepared by doping zirconia particles effectively improves the radiation capability of PDMS at the atmosphere transparent window of the mid-infrared light band (8-13 um), so that the radiation refrigeration film is in the whole solar band: the visible light wave band (0.3-1.35 um) has high reflectivity, and the medium and far infrared light wave bands (3-25 um) have high emissivity. So that the radiation refrigeration film has good radiation refrigeration effect.

Drawings

FIG. 1 is a graph showing the scattering coefficient of the particle diameter of zirconia in example 1.

FIG. 2 is a reflectance chart of the particle diameter of zirconia in example 1.

Figure 3 volume fraction test chart of example 2 zirconia.

FIG. 4 example 3 PDMS and ZrO₂The addition mass ratio diagram of (1).

FIG. 5 is a graph of a test object of example 4 of a radiation-cooled film and a commercial white paint, wherein A is the commercial white paint and B is doped ZrO₂The PDMS of the particles radiates the refrigeration membrane.

Figure 6 example 4 radiation refrigeration film and commercial white paint test equipment and location diagram.

FIG. 7 test temperature profile during the day of the radiant refrigeration film and commercial white paint test of example 4.

FIG. 8 test temperature profiles at night for example 4 radiation refrigeration films and commercial white paint testing.

Figure 9 is a picture of a test object of example 5 radiation-cooled film in a simulated building.

FIG. 10 test set-up and position diagram of example 5 radiation-cooled membranes in a simulated building, A commercial white paint and B doped ZrO₂The PDMS of the particles radiates the refrigeration membrane.

Figure 11 test temperature profiles of example 5 radiation-cooled membranes during the day of a simulated building.

Figure 12 test vs. temperature plot of example 5 radiation-cooled membranes during the day of a simulated building.

Figure 13 test temperature profiles of example 5 radiation-cooled membranes at night in a simulated building.

Figure 14 test vs. temperature profile of example 5 radiation-cooled membranes at night in a simulated building.

Detailed Description

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention.

Example 1

Influence of different zirconia particle sizes on radiation refrigeration film

(1) By setting the volume fraction of the doped zirconia particles in the PDMS solution to 4% and the thickness of the radiation refrigeration film to 500 μm through simulation experiments, the scattering coefficient of the film was investigated when the zirconia particles had particle sizes of 0.2 μm, 0.4 μm, 0.5 μm, 0.6 μm, and 0.8 μm, respectively, as shown in fig. 1, it can be seen that as the particle size increased, the scattering peak was shifted to a direction where the wavelength was longer, and the scattering peak became smaller and wider, which means that as the particle size increased, the relationship between the scattering coefficient and the wavelength became weaker.

(2) Then, the film reflectance was obtained by tracing 100000 energy beams through MC simulation. As shown in fig. 2, with the AM1.5 global oblique solar spectrum as the background, it can be seen that, for the minimum particle size of 0.2 μm, the reflectance is maximum at the maximum solar irradiance, but as the wavelength increases, the reflectance drops rapidly, which corresponds to its scattering peak; in other particle sizes, the reflectance tends to increase and decrease as the particle size increases due to the shift of the scattering peak.

(3) By combining with the standard solar spectrum, we finally determined to take 0.5 μm as the optimal particle size by the simulated analysis of scattering coefficient and reflectivity.

Example 2

Effect of different zirconia volume fractions on radiation refrigeration films

(1) According to the invention, the influence of the volume fraction of the zirconia particles on the optical properties of the film is researched (namely the volume fraction of the zirconia particles obtained after the preparation of the PDMS radiation refrigeration film is increased), the research objects are considered to be sparse particle swarms, and the volume fraction is set to be not more than 10%. And the optical properties of the films were simulated for both 4% and 10% volume fractions.

(2) Through simulation experiment data and results, as shown in fig. 3, by increasing the volume fraction of the zirconia particles in the PDMS radiation refrigeration film, the reflectivity of the visible light band can be increased, and the defect of the reflectivity decrease of the infrared band can be reduced.

(3) Through the simulation experiment, compared with the volume fraction of 4% and 10% of the zirconia particles, the volume fraction of 4% of the zirconia particles is obviously better than the volume fraction of 10%, so that the volume fraction of 4% of the zirconia particles is better.

Example 3

Influence of different proportions on radiation refrigeration film

(1) PDMS is chosen as the radiation refrigeration medium, because the extinction coefficient of the solar band is almost 0, the electromagnetic wave will pass through the medium, so the absorption of the solar band is very little, and in the atmospheric window band, the extinction coefficient is large, namely the electromagnetic wave will be attenuated rapidly when passing through the medium, so the PDMS has high absorption rate in the solar band.

(2) The zirconia particles and the silica have high refractive indexes, can strongly reflect solar radiation in visible light and near infrared bands, and have larger extinction coefficient in ultraviolet bands compared with the silica, which means that more absorption exists. Therefore, the zirconium oxide is selected as the doping particles to optimize the PDMS radiation refrigeration film.

(3) When the mass ratios of zirconia are respectively set to 20.5%, 29.5% and 37.5% (mass fraction of zirconia in the PDMS reagent), as shown in fig. 4, three different reflectance curves are obtained, and when the mass ratio of doped zirconia can be obtained by curve group to be 37.5%, the radiation refrigeration effect of the obtained PDMS film is the best, so the selection ratio is 37.5%, and considering that the condition that the mass ratio of zirconia is more than 37.5% and more will seriously restrict the product cost, and the product is difficult to be commercially used and popularized, so the mass ratio of zirconia more than 37.5% and more is not considered.

Example 4

Comparison of radiation refrigeration coatings with commercial white paint coatings

The first step is as follows: preparation of PDMS solution: adding 2.5 g of PDMS into 1 g of n-hexane solution, and magnetically stirring for 8-15min to form a uniform solution;

the second step is that: preparing a coating stock solution: 1.0 g of zirconium dioxide with the particle size of 500nm is added into the solution, then 0.25g of Sylgard 184 silicon rubber reagent is added, and finally, the mixture is magnetically stirred for 60min to be uniformly dispersed, so that white solution is obtained.

The third step: cleaning acrylic sheets: firstly, washing acrylic tablets with washing water, then carrying out ultrasonic treatment in clear water, then washing with absolute ethyl alcohol, then washing with deionized water, and finally drying for later use.

The fourth step: film forming of a coating: firstly, placing a piece of A4 paper on a flat table top, correcting a KTQ-II adjustable scraper, setting the thickness to be 1800 mu m, dripping a solution on the surface of an acrylic sheet, slowly scratching a sample at a constant speed to form a flat coating, finally placing the sample in an oven, baking for 40-60min at 100 ℃ to obtain the ZrO-doped ZrO₂The PDMS of the particles radiates the refrigeration membrane.

The fifth step: two identical devices were set up to compare the refrigeration performance of the samples produced with a commercial white paint coating (Guangdong III and Chemicals, color number 40). The overall size of the test box is 30cm multiplied by 10cm, a hollow hole is arranged at the center of the top, and the size of the hollow hole is 15cm multiplied by 2cm and is used as an isolation space for sample test.

And a sixth step: the experiment was carried out in 8 months of clear weather in Yichang area, the test chamber was horizontally placed as shown in FIG. 5, wherein A is commercial white paint and B is doped ZrO₂Comparative examples of PDMS radiation-cooled films of particles, the apparatus embodied in the test chamber as shown in fig. 6, were tested continuously for three days (2020.8.26-2020.8.28), the results of the tests are shown in fig. 7, the temperature change from 9:40 to 14:40 was recorded during the day test, and the sub-ambient temperature (i.e. the temperature of the cavity where the sample is located), the sample temperature and the temperature of the commercial white paint (Guangdong III and Chemicals, color number: 40) were detected by the thermocouple in the test chamber in fig. 7. In FIG. 7, the sample temperature was reduced by 9.8 deg.C, 8.4 deg.C and 8.2 deg.C, respectively, on average, compared to the sub-ambient temperature of the blank sample for three days of testing, and by 4.4 deg.C, 4.5 deg.C and 4.5 deg.C, respectively, compared to the commercial white paint temperature for three days of testing. The humidity is about 30% and the wind speed is 2.5m/s for three days.

The seventh step: the change in temperature at night three days after the test is shown in FIG. 8. the sample temperature for three days after the test is reduced by 2.9 deg.C, 2.9 deg.C and 1.6 deg.C respectively compared with the sub-ambient temperature. The humidity was approximately 28% during the three days and night of the test. The windless condition is present in all the periods.

Eighth step: the above tests of radiation refrigeration coatings and commercial white paint coatings gave: the sample temperature was reduced by an average of 9.8 deg.C, 8.4 deg.C and 8.2 deg.C over sub-ambient temperature three days during the day test, and by an average of 4.4 deg.C, 4.5 deg.C and 4.5 deg.C over commercial white paint temperature three days during the day test. The sample temperature was reduced by an average of 2.9 deg.C, 2.9 deg.C and 1.6 deg.C, respectively, over sub-ambient temperatures for three days of testing at night. Compared with commercial white paint, the radiation refrigeration film has a relatively obvious radiation refrigeration effect.

Example 5

Application of radiation refrigeration film in building

The first step is as follows: preparation of PDMS solution: adding 4g of PDMS reagent into 2 g of n-hexane solution, and magnetically stirring for 8-15min to form a uniform solution;

the second step is that: preparing a coating stock solution: 2.4g of zirconium dioxide with the particle size of 500nm is added into the solution, 0.35g of Sylgard 184 silicon rubber reagent is added, and finally, the mixture is magnetically stirred for 60min to be uniformly dispersed, so that white solution is obtained.

The third step: cleaning acrylic sheets: firstly, washing acrylic tablets with washing water, then carrying out ultrasonic treatment in clear water, then washing with absolute ethyl alcohol, then washing with deionized water, and finally drying for later use.

The fourth step: film forming of a coating: firstly, placing a piece of A4 paper on a flat table top, correcting a KTQ-II adjustable scraper, setting the thickness to be 1800 mu m, dripping solution on the surface of an acrylic sheet, slowly scratching a sample at a constant speed to form a flat coating, and finally placing the sample in an oven, baking for 40-60min at 100 ℃ to dry.

The fifth step: two identical box simulated houses were made, as shown in fig. 9. The boxes consisted of acrylic sheets with light transmission on four sides and foam on the bottom to reduce parasitic heat loss inside the box, the top of the two boxes was sample and commercial white paint (Guangdong III and chemical, color number: 40) in this example, respectively, with two temperature measurement points on each box, top and center of the house, respectively. Radiation-cooled rooms and with reference to interior detailsThe test equipment is shown in figure 10, wherein A is commercial white paint and B is doped ZrO₂The PDMS of the particles radiates the refrigeration membrane.

And a sixth step: the amount of temperature change between the radiation-cooled room and the reference room on two days (2020.9.3, 2020.9.5) is shown in fig. 11, the daytime test records the temperature change from 11:15 to 14:15, the temperature change shown in fig. 11 (# 1 is the temperature of the sample on the radiation-cooled roof part tested by the thermocouple, #2 is the temperature inside the radiation-cooled room, #3 is the temperature of the commercial white paint on the reference roof part tested by the thermocouple, #4 is the temperature inside the reference room), and the relative change in temperature is shown in fig. 12, where #1 and #2 are #2 and the temperature inside the radiation-cooled room is lower than the temperature of the radiation-cooled roof of #1 by about 4 ℃. The temperatures of #3 and #4 in the interior of the reference room #4 were about 2c higher than the temperature of the commercial white paint on the roof of the reference room #3 because the commercial white paint had no radiant cooling capability and the heat in the reference room could not be dissipated by the radiant cooling of the white paint. In the case of #4 and #2, the temperature inside the reference room was about 5 ℃ higher than the temperature inside the radiation-cooled room of #2, the humidity was about 30% on two days of the test, and the average wind speed was 2 m/s.

The seventh step: the night test result is shown in figure 13, the relative temperature change is shown in figure 14, and in the figure, #1 and #2, the temperature inside the radiation refrigeration room #2 is about 2 ℃ lower than the temperature of the radiation refrigeration roof # 1; the temperatures of #3 and #4 in the interior of the reference room #4 were about 2c higher than the temperature of the commercial white paint on the roof of the reference room #3 because the commercial white paint had no radiant cooling capability and the heat in the reference room could not be dissipated by the radiant cooling of the white paint. In the case of #2 and #4, the temperature inside the reference room was 4 ℃ higher than the temperature inside the radiation-cooled room of #2, and the humidity was about 50% and the average wind speed was 2m/s in the test two days.

Eighth step: the test of the simulated radiation refrigeration film on the building can obtain the following results: the interior of the house covered by the radiant refrigeration film was 4 c cooler than the roof temperature during the day and 5c cooler than the reference house covered by commercial white paint.

The cold film covered house interior was 2c cooler than the roof temperature and 4 c cooler than the commercial white paint covered reference house interior at night. Compared with commercial white paint, the radiation refrigeration film has a relatively obvious radiation refrigeration effect.