Method for the preparation of multifunctional leather-based wearable materials based on dynamic thermal conversion

Abstract

The application discloses a preparation method of multifunctional leather-based wearable material based on dynamic heat conversion, specifically comprising the following steps: preparing a radiative cooling layer on the grain side of leather; mixing poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) solution, multi-walled carbon nanotube powder, trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane and PDMS, adding ethyl acetate, stirring, then ultrasonic stirring, spraying on the flesh side of the leather, and drying, so multifunctional leather-based wearable material is prepared.The multifunctional leather-based wearable material prepared by the application has excellent asymmetric wettability, flame retardancy, electrical conductivity, joule heating, electromagnetic shielding, physiological signal monitoring and switchable thermal management performance.The radiative cooling layer has a solar reflectance of about 90.13% and a mid-infrared emissivity of about 87.6%, and the heating layer has a solar absorptivity of about 89%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wearable material preparation, and particularly relates to a preparation method of multifunctional leather-based wearable material based on dynamic heat conversion. BACKGROUND

[0002] In order to alleviate the negative effects of extreme weather and maintain the comfort of body temperature, the importance of refrigeration and heating equipment is self-evident. However, the traditional heat management equipment can alleviate the discomfort of the human body to a certain extent, but it has the shortcomings of high energy consumption, low efficiency and inability to meet the outdoor body temperature regulation requirements. In order to overcome the above shortcomings, the daytime passive radiation cooling and solar heating technology with zero energy consumption have attracted the attention of researchers.

[0003] The principle of passive radiation cooling technology is high reflection of incident sunlight and high infrared emission of atmospheric transparent window. Solar heating technology is just the opposite, which is high absorption of incident sunlight, so as to realize the purpose of photo-thermal conversion. Based on this, researchers have developed and prepared various wearable fabrics for heat management. However, most of the wearable fabrics with heat management characteristics usually only have single heating or cooling function, and cannot effectively respond to the dynamic changes of seasons and weather, and the single heat management performance also greatly limits the application scenarios of wearable fabrics. Therefore, it is urgent to design a new type of multifunctional wearable fabric with temperature self-adaptability, which can switch between cooling and heating functions and has wide application scenarios. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of multifunctional leather-based wearable material based on dynamic heat conversion, which has excellent electrochemical sensing performance and can monitor human physiological signals.

[0005] The technical scheme adopted by the present application is a preparation method of multifunctional leather-based wearable material based on dynamic heat conversion, which is implemented according to the following steps:

[0006] Step 1: preparing a radiation cooling layer on the grain side of the leather;

[0007] Step 2: after step 1, preparing a solar heating layer on the flesh side of the leather to obtain the multifunctional leather-based wearable material;

[0008] Specifically, poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) solution, multi-walled carbon nanotube powder, trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane and PDMS are mixed, then ethyl acetate is added, stirring is performed, followed by ultrasonic stirring, to form a mixed solution, then the mixed solution is sprayed on the flesh side of the leather, and drying is performed, so as to prepare a solar heating layer on the flesh side of the leather, that is, the multifunctional leather-based wearable material.

[0009] The application also features that,

[0010] In step 1, specifically,

[0011] The magnesium phosphite powder is uniformly dissolved in the mixed solution of acetone and water, and cellulose acetate is slowly added under stirring, and the stirring is continued for 1-3h to obtain a mixed solution, and then the mixed solution is sprayed onto the grain side of the leather, and dried at 20-40℃ for 6-8h to prepare the radiative cooling layer on the grain side of the leather.

[0012] The mass ratio of magnesium phosphite and cellulose acetate is 0.4-0.8:1-3; the volume ratio of acetone to water in the acetone solution is 14-18:1-4.

[0013] In step 1, the thickness of the radiative cooling layer is 100-400μm.

[0014] In step 2, the mass ratio of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate), trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane, multi-walled carbon nanotube powder, PDMS, ethyl acetate is 0.5-1.5:0.045-0.135:0.09-0.45:0.09-0.27:8-10.

[0015] In step 2, the thickness of the solar heating layer is 100-400μm.

[0016] In step 2, the drying temperature is 55-65℃, and the drying time is 2-4h; the stirring time is 1-3h, and the ultrasonic stirring time is 5-15min.

[0017] The application has the following beneficial effects:

[0018] The multifunctional leather-based wearable material prepared by the application has excellent asymmetric wettability, flame retardancy, electrical conductivity, joule heating, electromagnetic shielding, physiological signal monitoring and switchable thermal management performance. The radiative cooling layer has a solar reflectivity of about 90.13% and a mid-infrared emissivity of about 87.6%, while the heating layer has a solar absorptivity of about 89%, and both of them show excellent thermal management characteristics in actual tests. It has broad application prospects in the fields of wearable thermal management, low-carbon travel and energy-saving building furniture; in addition, the preparation process of the application is simple, the operation process is simple, and it is conducive to large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The photograph of the actual object of the radiative cooling side of the multifunctional leather-based wearable material prepared by the application;

[0020] Figure 2A photograph of the solar side of the multifunctional leather-based wearable material made according to the present application;

[0021] Figure 3 A reflectivity plot of the radiative cooling side of the multifunctional leather-based wearable material made according to the present application in the solar spectral region;

[0022] Figure 4 A reflectivity plot of the radiative cooling side of the multifunctional leather-based wearable material made according to the present application in the atmospheric transparency window;

[0023] Figure 5 An absorptivity plot of the solar heating side of the multifunctional leather-based wearable material made according to the present application in the solar spectral region. DETAILED DESCRIPTION

[0024] The present application will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The present application is based on a method for preparing a multifunctional leather-based wearable material through dynamic heat conversion, which is implemented according to the following steps:

[0026] Step 1: preparing a radiative cooling layer on the grain side of the leather;

[0027] Specifically, magnesium phosphite powder is uniformly dissolved in a mixed solution of acetone and water, and cellulose acetate is slowly added under stirring, and the stirring is continued for 1-3 h to obtain a mixed solution, which is then sprayed onto the grain layer of the leather, and dried at 20-40℃ for 6-8 h to prepare the radiative cooling layer on the grain side of the leather.

[0028] The mass ratio of magnesium phosphite and cellulose acetate is 0.4-0.8:1-3, the volume ratio of acetone to water in the acetone solution is 14-18:1-4, and the thickness of the radiative cooling layer is 100-400μm;

[0029] The substrate layer used in the present application is a natural animal skin derived from biomass resources, which has excellent wearable performance and hygiene performance, and has the advantages of abundant resources, low cost, renewability and biodegradability, etc., and can effectively save fossil resources and protect the ecological environment;

[0030] Step 2: preparing a solar heating layer on the flesh side of the leather after step 1, to obtain a multifunctional leather-based wearable material;

[0031] Specifically, the poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) solution, multi-walled carbon nanotube powder, trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane, and PDMS are mixed, then the solvent ethyl acetate is added, and the mixture is stirred at room temperature for 1-3 h, followed by ultrasonic stirring for 5-15 min to form a mixed solution, and then the mixed solution is sprayed on the flesh side of the leather, and dried at 55-65 DEG C for 2-4 h to prepare a solar heating layer on the flesh side of the leather, that is, a multifunctional leather-based wearable material.

[0032] The mass ratio of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate), trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane, multi-walled carbon nanotube powder, PDMS, and ethyl acetate is 0.5-1.5:0.045-0.135:0.09-0.45:0.09-0.27:8-10.

[0033] The thickness of the solar heating layer is 100-400 microns.

[0034] The multifunctional leather-based wearable material prepared by the method has the advantages of cellulose acetate and nanometer magnesium subphosphate as passive radiation cooling materials on the cooling side, and a radiation cooling coating with a random porous structure is prepared. The inherent molecular vibration mode and the scattering of light by the porous structure of cellulose acetate and nanometer magnesium subphosphate make the radiation cooling side exhibit a high reflectivity of about 90.13% and a high emissivity of about 87.6%. The heating side is composed of a multi-walled carbon nanotube layer with high solar absorption capacity and electrical conductivity, which exhibits a light absorption rate of about 89%. In addition, hydrophobic polydimethylsiloxane and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and highly conductive poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) are added to the precursor solution. The multifunctional leather-based wearable material has excellent asymmetric wettability, flame retardancy, electrical conductivity, joule heating, electromagnetic shielding, physiological signal monitoring, and electrochemical sensing performance, can monitor human physiological signals, and has wide application prospects in the fields of wearable thermal management, low-carbon travel, and energy-saving building furniture.

[0035] Example 1

[0036] The application is a preparation method of multifunctional leather-based wearable material for dynamic heat conversion, specifically: uniformly dissolve 0.4 g of magnesium phosphite powder in a mixed solution of 14 mL of acetone and 4 mL of water, then slowly add 1 g of cellulose acetate while stirring, continue stirring at room temperature for 1 h, spray onto the grain side of the leather and dry at 20℃ for 8 h to obtain a radiative cooling layer. Take 0.5 g of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) solution, 0.09 g of multi-walled carbon nanotube powder, 0.045 g of trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane, and 0.09 g of PDMS into a beaker, then add 8 g of ethyl acetate as a solvent, stir magnetically at room temperature for 1 h and ultrasonically for 5 min. Spray onto the flesh side of the leather with the radiative cooling layer, dry at 55℃ for 2 h to obtain the multifunctional leather-based wearable material.

[0037] Example 2

[0038] The application is a preparation method of multifunctional leather-based wearable material for dynamic heat conversion, specifically: uniformly dissolve 0.4 g of magnesium phosphite powder in a mixed solution of 14 mL of acetone and 4 mL of water, then slowly add 1 g of cellulose acetate while stirring, continue stirring at room temperature for 1 h, spray onto the grain side of the leather and dry at 20℃ for 8 h to obtain a radiative cooling layer. Take 0.5 g of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) solution, 0.09 g of multi-walled carbon nanotube powder, 0.045 g of trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane, and 0.09 g of PDMS into a beaker, then add 8 g of ethyl acetate as a solvent, stir magnetically at room temperature for 1 h and ultrasonically for 5 min. Spray onto the flesh side of the leather with the radiative cooling layer, dry at 55℃ for 2 h to obtain the multifunctional leather-based wearable material.

[0039] Example 3

[0040] The application is based on a preparation method of multifunctional leather-based wearable material through dynamic heat conversion, specifically: 0.8g of magnesium phosphite powder is first uniformly dissolved and dispersed in a mixed solution of 18mL of acetone and 0mL of water, then 3g of cellulose acetate is slowly added while stirring, and the stirring is continued at room temperature for 2h. Spray to the leather grain layer and dry at 40℃ for 6h to obtain the radiative cooling layer. Take 1.5g of poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) solution, 0.45g of multi-walled carbon nanotube powder, 0.135g of trimethoxy(1H,1H,2H,2H-hexadecafluorodecyl)silane, 0.27g of PDMS into a beaker, then add 10g of ethyl acetate as a solvent, stir for 3h at room temperature and ultrasonic stir for 15min, spray to the leather flesh side layer with the radiative cooling layer, dry at 65℃ for 4h to obtain the multifunctional leather-based wearable material.

[0041] Figure 1 The physical map of the radiative cooling side of the prepared multifunctional leather-based wearable material is shown in the figure, and it can be seen that the cooling side is highly white. White materials generally have high light reflectivity, so this is one of the reasons why the radiative cooling side has high reflectivity in the solar spectrum. Figure 2 The physical map of the solar heating side of the prepared multifunctional leather-based wearable material is shown in the figure, and it can be seen that the heating side is black as a whole, which is in sharp contrast to the radiative cooling side. Black materials have better light absorption than other colors under the same conditions, so the heating side can fully absorb sunlight and achieve the purpose of heating.

[0042] Figure 3 The reflectivity curve of the radiative cooling side in the solar spectrum is shown in the figure. It can be found that the radiative cooling side has excellent light reflectivity in the visible light band. Calculation shows that the reflectivity of the radiative cooling side of the multifunctional leather-based wearable material to incident sunlight is about 90.16%. Figure 4 The corresponding reflectivity of the radiative cooling side is shown in the figure, and the emissivity is indirectly calculated by subtracting the reflectivity from 1. High emissivity is a necessary condition for realizing radiative cooling. Only by emitting its own heat and cooperating with high solar reflectivity can the cooling effect be maximized. Calculation shows that the overall emissivity of the solar heating side of the multifunctional leather-based wearable material is about 87.6%. Figure 5 The light absorption rate of the solar heating side is shown in the figure. Light and heat can be converted accordingly, so the greater the light absorption, the faster the temperature rises. Calculation shows that the light absorption rate of the heating layer is about 89%, which can basically meet the use requirements.

Claims

1. A method for preparing multifunctional leather-based wearable materials based on dynamic thermal conversion, characterized in that, The specific steps are as follows: Step 1: Prepare a radiation cooling layer on the grain side of the leather; specifically: Magnesium phosphite powder is uniformly dissolved in a mixture of acetone and water. Cellulose acetate is slowly added while stirring, and stirring is continued for 1-3 hours to obtain a mixture. The mixture is then sprayed onto the leather grain surface and dried at 20-40℃ for 6-8 hours to prepare a radiation cooling layer on the leather grain side. The thickness of the radiation cooling layer is 100-400 μm. The mass ratio of magnesium phosphite to cellulose acetate is 0.4-0.8:1-3; the volume ratio of acetone to water in the acetone solution is 14-18:1-4. Step 2: After step 1, a solar heating layer is prepared on the flesh side of the leather to obtain a multifunctional leather-based wearable material. Specifically, the following steps are taken: a poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) solution, multi-walled carbon nanotube powder, trimethoxy(1H,1H,2H,2H-hexadecylfluorodecyl)silane, and PDMS are mixed, then ethyl acetate is added, and the mixture is stirred and ultrasonically stirred to form a mixture. The mixture is then sprayed onto the flesh side of the leather and dried to prepare a solar heating layer on the flesh side of the leather, which is a multifunctional leather-based wearable material; the thickness of the solar heating layer is 100-400 μm.

2. The method for preparing the multifunctional leather-based wearable material based on dynamic thermal conversion according to claim 1, characterized in that, In step 2, the mass ratio of poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate), trimethoxy(1H,1H,2H,2H-hexadecylfluorodecyl)silane, multi-walled carbon nanotube powder, PDMS, and ethyl acetate is 0.5-1.5:0.045-0.135:0.09-0.45:0.09-0.27:8-10.

3. The method for preparing the multifunctional leather-based wearable material based on dynamic thermal conversion according to claim 1, characterized in that, In step 2, the drying temperature is 55-65℃, the drying time is 2-4h, the stirring time is 1-3h, and the ultrasonic stirring time is 5-15min.

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