CN114801380A

CN114801380A - Preparation method of porous PDMS/PVA hydrogel composite refrigeration film

Info

Publication number: CN114801380A
Application number: CN202210228730.1A
Authority: CN
Inventors: 王建峰; 郭鑫怡; 靳秀秀; 王万杰
Original assignee: Zhengzhou University
Current assignee: Zhengzhou University
Priority date: 2022-03-10
Filing date: 2022-03-10
Publication date: 2022-07-29

Abstract

The invention discloses a preparation method of a porous PDMS/PVA hydrogel composite refrigeration film, which comprises the steps of mixing NaCl particles and an uncrosslinked PDMS raw material, stirring for 5-20 min, and then carrying out water bath ultrasound for 1-10min to remove bubbles; uniformly coating the obtained mixture on a glass plate to form a coating, and then placing the coating in an oven to be cured for 1-8 h; stripping the cured coating from the glass plate, placing the glass plate in deionized water at normal temperature for 1 to 3 days, and dissolving NaCl particles to form porous PDMS; adhering the porous PDMS and the PVA hydrogel to obtain a double-layer refrigeration polymer film; the skin cooling device has high emissivity and reflectivity, and radiation refrigeration and evaporation refrigeration are combined to meet the cooling requirement of human skin; according to the invention, the porous PDMS/PVA hydrogel composite refrigeration film with different radiation refrigeration and evaporation refrigeration efficiencies can be obtained by controlling the mass ratio of NaCl to the non-crosslinked PDMS raw material and the mass fraction of PVA, and the preparation process is simple and safe, and can be prepared in large scale in batch.

Description

Preparation method of porous PDMS/PVA hydrogel composite refrigeration film

Technical Field

The invention relates to the technical field of refrigeration and cooling films, in particular to a preparation method of a porous PDMS/PVA hydrogel composite refrigeration film.

Background

With the improvement of living standard, the pursuit of health and fitness of human beings is more urgent. Especially extreme high or low temperature weather caused by climate change is a major cause of harm to human health. In modern times with an increasing medical level, the emergence of various highly effective drugs and medical surgical protocols play an important role in the treatment of human diseases, but still face many challenges, such as the high cost of highly effective drugs and the complexity of surgical treatment. Researchers find that the cold therapy has great advantages in the aspect of treating partial diseases of human bodies and can make up for the defects of high-efficiency medicine and operation treatment. Based on this, more and more researchers are focusing on studying and developing materials or medical devices for thermal management of the human body. Heat management materials such as joule heating fabrics, photothermal conversion fabrics, radiation refrigeration and the like have played an increasingly important role in the treatment of diseases of different human body parts such as medical wounds, eyes, skin and the like.

In the field of radiation refrigeration, radiation refrigeration materials transport heat to outer space primarily through an atmospheric transparent window of 8-13 μm in the form of heat radiating electromagnetic waves. The materials for realizing the important performance are mainly infrared high-emission materials. And the other functional material is a sunlight high-reflection material which can reflect incident sunlight electromagnetic waves to the outer space, thereby reducing heat absorption and realizing the cooling effect. The intrinsically high emissivity of Polydimethylsiloxane (PDMS) makes it an ideal material for radiation refrigeration. In addition, the porous structure of the porous PDMS can increase multiple diffuse reflection of electromagnetic waves, and further the refrigeration effect of the porous PDMS is obviously improved.

In addition, evaporative cooling, which dissipates heat by evaporation of water, is a novel passive cooling technique that does not require power input. And the polyvinyl alcohol (PVA) hydrogel has wide prospects in the field of evaporative refrigeration due to excellent performance. However, the single effects of radiation refrigeration and evaporative refrigeration are still difficult to meet with the increasing demand for refrigeration and the increasingly complex refrigeration scenarios.

The present invention will provide a new solution to this problem.

Disclosure of Invention

In view of the above situation, the present invention aims to provide a method for preparing a porous PDMS/PVA hydrogel composite refrigeration film, in order to overcome the defects of the prior art.

The technical scheme for solving the problem is as follows: a preparation method of a porous PDMS/PVA hydrogel composite refrigeration film comprises the following steps:

1) crushing NaCl particles for 1-30 min, and screening by a mesh screen to obtain NaCl particles with corresponding sizes for subsequent use;

2) mixing the NaCl particles obtained in the step 1) with the non-crosslinked PDMS raw material, stirring for 5-20 min, and then performing water bath ultrasound for 1-10min to remove bubbles;

3) uniformly coating the mixture obtained in the step 2) on a glass plate to form a coating, and then placing the coating in an oven to be cured for 1-8 hours;

4) stripping the cured coating from the glass plate, placing the glass plate in deionized water at normal temperature for 1-3 days, and dissolving NaCl particles to form porous PDMS;

5) weighing a certain mass of PVA polymer and deionized water, mixing in a container, and then placing the container in a water bath kettle for magnetic stirring for 0.5-3h to completely dissolve the PVA to form a PVA aqueous solution;

6) ultrasonically treating the PVA aqueous solution obtained in the step 5) in a water bath for 5-30min to remove bubbles, and preserving the heat for 10min at the temperature of 75-98 ℃;

7) scraping the PVA aqueous solution on a glass plate, freezing for 8-24h, and then unfreezing at normal temperature for 8-24 h;

8) repeating the freezing-unfreezing cycle in the step 7) for 3-5 times until PVA hydrogel is obtained;

9) and (3) adhering the porous PDMS and the PVA hydrogel obtained in the steps (4) and (8) to obtain the double-layer refrigeration polymer film.

Preferably, the pore size of the mesh screen in the step 1) is 50 to 500 meshes.

Preferably, the mass ratio of the NaCl particles to the uncrosslinked PDMS raw material in the step 2) is 1:5 to 5: 1.

Preferably, the uncrosslinked PDMS material is selected from Dow Corning Sylgard 184 or Meiji RTV615 PDMS.

Preferably, the thickness of the coating in the step 3) is 25-1000 μm, and the curing temperature is 50-150 ℃.

Preferably, the temperature of the water bath in the step 5) is set to 75-98 ℃.

Preferably, the mass fraction of the aqueous PVA solution in the step 5) is 5-20%.

Preferably, the PVA hydrogel in the step 8) has a thickness of 25 to 1000. mu.m.

As a further improvement of the invention, the PVA polymer in said step 5) can also be replaced by a PAA polymer.

Through the technical scheme, the invention has the beneficial effects that:

1. the invention combines radiation refrigeration and evaporation refrigeration technologies to prepare a double-layer refrigeration polymer film, namely a porous PDMS/PVA hydrogel composite refrigeration film, which has high emissivity and reflectivity, and the radiation refrigeration and evaporation refrigeration performances meet the cooling requirements of human skin;

2. according to the invention, the porous PDMS/PVA hydrogel composite refrigeration film with different radiation refrigeration and evaporation refrigeration efficiencies can be obtained by controlling the mass ratio of NaCl to the non-crosslinked PDMS raw material and the mass fraction of PVA, the preparation process is simple and safe, and the large-scale batch preparation can be realized.

Drawings

Fig. 1 is a surface scanning electron micrograph of porous PDMS prepared according to example 1.

Fig. 2 is a cross-sectional scanning electron micrograph of porous PDMS prepared according to example 1.

FIG. 3 is a graph comparing the emissivity of the porous PDMS/PVA hydrogel composite refrigeration film prepared in example 1 with that of a common PDMS film at 8-13 μm.

FIG. 4 is a temperature drop curve diagram of the porous PDMS/PVA hydrogel composite refrigeration film prepared in example 1 in an outdoor environment.

Detailed Description

The foregoing and other technical matters, features and effects of the present invention will be apparent from the following detailed description taken in conjunction with the accompanying fig. 1 to 4. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The application of the principles of the present invention will now be described in detail with reference to the following examples.

Example 1:

1) placing NaCl particles in a high-speed multifunctional pulverizer to pulverize for 5min, placing pulverized NaCl powder in a 200-mesh sieve to obtain NaCl particles with corresponding sizes for subsequent use; 2) mixing NaCl particles and a Dow Corning Sylgard 184 raw material in a mass ratio of 1:2, stirring for 5min, and performing water bath ultrasound for 10min to remove bubbles; wherein the mass ratio of the PDMS polymer to the cross-linking agent in the Dow Corning Sylgard 184 raw material is 10: 1; 3) uniformly coating the mixture obtained in the step 2) on a glass plate in a scraping way, wherein the thickness of the coating is 300 mu m, and curing the coating in an oven at 80 ℃ for 8 h; 4) stripping the cured coating from the glass plate, and placing the glass plate in deionized water at normal temperature for 3 days to dissolve NaCl particles to form porous PDMS; 5) weighing a certain mass of PVA polymer and deionized water, mixing in a beaker, placing in a water bath kettle at 98 ℃, and magnetically stirring for 2 hours to completely dissolve the PVA to form a PVA aqueous solution with the mass fraction of 13%; 6) carrying out water bath ultrasound on the PVA aqueous solution obtained in the step 5) for 15min to remove bubbles, and carrying out heat preservation for 10min at the temperature of 98 ℃; 7) scraping the PVA aqueous solution on a glass plate, freezing for 8h, and then unfreezing for 12h at normal temperature; 8) repeating the freezing-unfreezing cycle in the step 7) for 3 cycles to obtain PVA hydrogel with the thickness of 300 mu m; 9) and (3) adhering the porous PDMS and the PVA hydrogel obtained in the steps 4) and 8) to obtain a double-layer refrigerating polymer film, namely the porous PDMS/PVA hydrogel composite refrigerating film.

Example 2:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 1:1, other conditions are not changed, and PDMS and PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 3:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 3:2, other conditions are not changed, and PDMS and PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 4:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 1:5, other conditions are not changed, and PDMS and PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 5:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 5:1, other conditions are not changed, and PDMS and PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 6:

the mass fraction of the PVA aqueous solution in the example 1 is replaced by 5%, other conditions are not changed, and PDMS and PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 7:

the mass fraction of the PVA aqueous solution in the example 1 is replaced by 20%, other conditions are not changed, and PDMS and PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 8:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 1:5, the coating thickness in the step 3) is 25 μm, the curing temperature is 50 ℃, the water bath temperature in the step 5) is set to be 75 ℃, the mass fraction of the PVA aqueous solution is 5%, and other conditions are not changed, and PDMS and PVA hydrogel are prepared to be adhered to obtain the double-layer refrigeration polymer film.

Example 9:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 5:1, the coating thickness in the step 3) is 1000 μm, the curing temperature is 150 ℃, the water bath temperature in the step 5) is set to be 98 ℃, the mass fraction of the PVA aqueous solution is 20%, and other conditions are not changed, and PDMS and PVA hydrogel are prepared to be adhered to obtain the double-layer refrigeration polymer film.

Example 10:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 3:2, the coating thickness in the step 3) is 25 μm, the curing temperature is 50 ℃, the water bath temperature in the step 5) is set to be 75 ℃, the mass fraction of the PVA aqueous solution is 5%, and other conditions are not changed, and PDMS and PVA hydrogel are prepared to be adhered to obtain the double-layer refrigeration polymer film.

Example 11:

the mass ratio of the NaCl particles to the Dow Corning Sylgard 184 raw material in the example 1 is replaced by 3:2, the coating thickness in the step 3) is 1000 μm, the curing temperature is 150 ℃, the water bath temperature in the step 5) is set to be 98 ℃, the mass fraction of the PVA aqueous solution is 20%, and other conditions are not changed, and PDMS and PVA hydrogel are prepared to be adhered to obtain the double-layer refrigeration polymer film.

Example 12:

the thickness of the PVA hydrogel in the example 1 is replaced by 25 μm, other conditions are not changed, and PDMS and the PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 13:

the thickness of the PVA hydrogel in the example 1 is replaced by 1000 μm, other conditions are not changed, and PDMS and the PVA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Example 14: the PVA in example 1 is replaced by PAA, other conditions are not changed, PDMS and PAA hydrogel are prepared and adhered to obtain the double-layer refrigeration polymer film.

Comparative example 1: common PDMS film (thickness 300 μm)

Comparative example 2: common PDMS film (thickness 25 μm)

Comparative example 3: common PDMS film (thickness 1000 μm)

The test methods and evaluation criteria involved in the above examples are as follows:

scanning electron microscope analysis: scanning electron microscope images (SEMs) were collected using a scanning electron microscope (JSM-5900 LVSEM) at a voltage of 5.0 kV. As can be seen from fig. 1 and 2, the surface of the PDMS film has uniformly distributed pores, which illustrates the successful preparation of the porous PDMS film.

The porous PDMS/PVA hydrogel composite refrigeration film is used for testing the refrigeration performance of the eyelid:

and recording the temperature change of the porous PDMS/PVA hydrogel composite refrigeration film under the dual mechanisms of radiation refrigeration/evaporation refrigeration by using a thermoelectric even data recorder (model TC-08).

Emissivity (epsilon) test:

infrared reflectance (. rho.) and transmittance (. tau.) of the composite refrigeration film of ordinary PDMS film and porous PDMS/PVA hydrogel an FTIR spectrometer (Spotlight 200 i) with an external infrared integrating sphere was used. According to the emissivity formula of the transparent object:

ε=1-ρ-τ

obtaining the emissivity of the common PDMS film and the porous PDMS/PVA hydrogel composite refrigeration film. As can be seen from FIG. 3, the emissivity of the porous PDMS/PVA hydrogel composite refrigeration film is improved to a certain extent in the range of 8-13 μm of infrared wave compared with that of the common PDMS film.

Outdoor radiation refrigeration/evaporative refrigeration testing:

and recording the refrigerating performance of the porous PDMS/PVA hydrogel composite refrigerating film by using a thermoelectric even data recorder (model TC-08).

TABLE 1 average refrigerating temperature of porous PDMS/PVA hydrogel composite refrigerating film in outdoor environment

Examples	Average refrigerating temperature (. degree.C.)
		Example 1	6.41
Example 2	6.80
		Example 3	7.50
Example 4	6.20
		Example 5	9.82
Example 6	5.20
		Example 7	8.67
Example 8	4.60
		Example 9	13.2
Example 10	7.20
		Example 11	8.90
Example 12	6.00
		Example 13	6.90
Example 14	6.32
		Comparative example 1	6.26
Comparative example 2	5.20
		Comparative example 3	6.52

As can be seen from Table 1, the outdoor refrigeration effect is related to the mixture ratio of the raw materials and the mass fraction of PVA. As can be seen from the data of examples 1-5, as the mass ratio of NaCl particles to Dow Corning Sylgard 184 feed increased, the outdoor refrigeration temperature increased; as can be seen from the data of examples 6-7 and examples 12-13, as the mass fraction and thickness of the PVA hydrogel increased, the corresponding outdoor refrigeration temperature increased; as can be seen from the comparison of the data of examples 1-5 and comparative example 1, the refrigeration effect of the porous PDMS/PVA hydrogel composite refrigeration film is superior to that of the common PDMS film. As can be seen from the comparison of the data of examples 1-5 and comparative examples 1-3, the thickness of the porous PDMS film affects the refrigeration effect, and the larger the thickness is, the better the refrigeration effect is. From the data results of example 12 and comparative example 2, it can be seen that the refrigeration effect of the porous PDMS/PVA hydrogel composite refrigeration film in the open air is 0.8 ℃ lower than that of the control sample.

As can be seen from fig. 4, compared with the ambient temperature, the temperature measured by the experiment of the porous PDMS/PVA hydrogel composite refrigeration film is much lower than the ambient temperature, which indicates that the double-layer porous PDMS/PVA hydrogel composite refrigeration film has a good refrigeration effect. The average temperature of the porous PDMS/PVA hydrogel composite refrigeration film in 8 hours is-5.88 ℃, 6.41 ℃ lower than the outdoor average temperature (0.53 ℃), and 0.15 ℃ lower than the average temperature (-5.73 ℃) of the PDMS/PVA film compared with a control sample.

In conclusion, the invention combines the radiation refrigeration and the evaporation refrigeration technology, namely a double-layer refrigeration polymer film is prepared, the double-layer polymer film is composed of porous PDMS and PVA, the porous PDMS provides radiation refrigeration performance, and heat can be transmitted to the outer space through the atmosphere transparent window in both day and night; and PVA cools the human body by evaporation in the daytime, and can be restored to the original state by the reabsorption of water vapor at night. The porous PDMS/PVA hydrogel composite refrigeration film with different radiation refrigeration and evaporation refrigeration efficiencies can be obtained by controlling the mass ratio of NaCl to the non-crosslinked PDMS raw material and the mass fraction of PVA, the preparation process is simple and safe, large-scale batch preparation can be realized, the prepared porous PDMS/PVA hydrogel composite refrigeration film has higher emissivity and reflectivity, and the radiation refrigeration and evaporation refrigeration performance can meet the cooling requirement of human skin.

For a further improvement of the above solution, the hydrogel may be PAA or other hydrogels.

The present invention has been described in further detail with reference to the embodiments, and it is not to be construed that the embodiments are limited thereto; for those skilled in the art to which the present invention pertains and related technologies, the extension, operation method and data replacement should fall within the protection scope of the present invention based on the technical solution of the present invention.

Claims

1. A preparation method of a porous PDMS/PVA hydrogel composite refrigeration film is characterized by comprising the following steps:

3) uniformly coating the mixture obtained in the step 2) on a glass plate to form a coating, and then placing the coating in a drying oven for curing for 1-8 h;

4) stripping the cured coating from the glass plate, placing the glass plate in deionized water at normal temperature for 1 to 3 days, and dissolving NaCl particles to form porous PDMS;

9) and (5) adhering the porous PDMS and the PVA hydrogel obtained in the steps (4) and (8) to obtain the double-layer refrigeration polymer film.

2. The method for preparing the porous PDMS/PVA hydrogel composite refrigeration film according to claim 1, wherein: the aperture of the mesh screen in the step 1) is 50-500 meshes.

3. The method for preparing the porous PDMS/PVA hydrogel composite refrigeration film according to claim 1, wherein: the mass ratio of the NaCl particles to the non-crosslinked PDMS raw material in the step 2) is 1: 5-5: 1.

4. The method for preparing the porous PDMS/PVA hydrogel composite refrigeration film according to claim 3, wherein: the uncrosslinked PDMS material may be selected from Dow Corning Sylgard 184 or Mylar RTV615 PDMS.

5. The method for preparing the porous PDMS/PVA hydrogel composite refrigeration film according to claim 4, wherein: the thickness of the coating in the step 3) is 25-1000 μm, and the curing temperature is 50-150 ℃.

6. The method for preparing the porous PDMS/PVA hydrogel composite refrigeration film according to claim 5, wherein: the temperature of the water bath in the step 5) is set to be 75-98 ℃.

7. The method for preparing the porous PDMS/PVA hydrogel composite refrigeration film according to claim 6, wherein: the mass fraction of the PVA aqueous solution in the step 5) is 5-20%.

8. The method for preparing the porous PDMS/PVA hydrogel composite refrigeration film according to claim 7, wherein: the thickness of the PVA hydrogel in the step 8) is 25-1000 μm.

9. The method for preparing a porous PDMS/PVA hydrogel composite refrigeration film according to any one of claims 1 to 8, wherein: the PVA polymer in said step 5) can also be replaced by a PAA polymer.