A bidirectional personal thermal management fabric for heating and cooling and a method of making the same

Abstract

The application discloses a kind of heating and heat dissipation bidirectional personal thermal management fabric and preparation method thereof, belong to thermal management fabric design technical field.The main surface of fabric is sprayed with a layer of amorphous structure photonic crystal coating, the reflectivity of fabric in visible light near infrared band and the emissivity in mid-infrared band are improved, the physical coloring of no thermal burden is realized on the surface of fabric to meet the demand of diversification and beauty of textile, the MXene nanosheet of low emissivity is sprayed on the other side of fabric, the passive radiation heating performance, photothermal conversion performance and joule heating performance of MXene are used to realize the heating thermal management of fabric, the fabric of the application realizes dynamic personal thermal management, that is, compared with the temperature of simulated human skin, the temperature can be reduced by 10.2 DEG C in summer, and the temperature can be increased by 21.4 DEG C in winter by combining the heating effect of multiple modes, to provide greater flexibility for personal thermal management under different environmental conditions.

Description

Technical Field

[0001] This invention belongs to the field of thermal management fabric design technology, and specifically relates to a bidirectional personal thermal management fabric for both heating and heat dissipation and its preparation method. Background Technology

[0002] Today, extreme weather conditions and climate change caused by the greenhouse effect from fossil fuel combustion pose serious threats to human activities and public health. Extreme weather conditions such as extreme heat and cold exacerbate the need for effective ambient temperature regulation, especially for outdoor workers. Furthermore, there is an urgent need to develop energy-efficient and carbon-reducing thermal management technologies to mitigate the increasing frequency and severity of extreme weather events. Personal thermal management (PTM), focusing on energy management within the human body's microenvironment, is an effective strategy for improving thermal comfort while reducing energy consumption.

[0003] Traditional chemical colors (including dyes and pigments) are generated by the absorption of the visible spectrum by the sun, which often increases the radiative heat load. Balancing the heat generation effect caused by color with heat dissipation remains a significant challenge. Unlike chemical colors, structural colors obtained through the interaction of sunlight with nanostructures do not introduce additional heat input. Research by Zhang et al. has shown that a photonic thin film combined with a polymer micropyramid array mixed with random ceramic particles exhibits excellent cooling performance [ACS Nano 2018, 12(4), 3095-3102]. Notably, the synergistic effect of passive radiative cooling (PRC) properties and microstructure color can significantly improve cooling performance by reducing heat absorption and dissipating excess heat. Therefore, the photonic effect based on microstructures can be used to achieve colored surfaces without affecting cooling performance, and even generate a positive net radiative cooling effect.

[0004] Because the mid-infrared emission characteristics and the solar reflection characteristics in the passive radiant heating (PRH) region are contradictory, most existing PTM fabrics can only achieve a single cooling or insulating property. Unlike cooling textiles, passive radiant heating materials require high solar absorptivity to achieve effective solar heating (SH) and have low emissivity in the mid-infrared region. However, since ambient temperature and solar radiation intensity fluctuate with climate change and diurnal cycles, such single-function materials struggle to provide optimal comfort under varying external conditions. Therefore, it is necessary to develop an advanced temperature-adaptive PTM technology to adapt to ambient temperature and solar energy, thereby achieving all-weather comfort, even in environments with large diurnal temperature variations. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a bidirectional personal thermal management fabric for both heating and cooling, and its preparation method. The method primarily involves spraying an amorphous photonic crystal coating onto the fabric surface to enhance its reflectivity in the visible and near-infrared bands and its emissivity in the mid-infrared band. Simultaneously, it achieves heat-free physical coloring on the fabric surface, meeting the demands for textile diversity and aesthetics. Then, low-emissivity MXene nanosheets are sprayed onto the other side of the fabric. The passive radiative heating performance, photothermal conversion performance, and Joule heating performance of MXene are utilized to achieve heating and thermal management of the fabric, resulting in a bidirectional personal thermal management fabric for both heating and cooling. This fabric achieves dynamic personal thermal management, realizing both heating and cooling functions, and provides significant benefits for personal comfort, energy efficiency, and multi-scenario applications.

[0006] The present invention provides a personal thermal management fabric for both heating and heat dissipation, comprising: a fiber fabric substrate, an amorphous photonic crystal structure color coating disposed on one side of the fiber fabric substrate, and a nanomaterial coating disposed on the other side of the fiber fabric substrate.

[0007] In one embodiment of the present invention, the fiber fabric substrate is one of polylactic acid fiber fabric, cotton fabric, and polyester fiber fabric.

[0008] In one embodiment of the present invention, the nanomaterial coating serves as a heating layer to provide a heating mode for the thermal management fabric, and the amorphous photonic crystal structure color coating serves as a heat dissipation layer to provide a heat dissipation mode for the thermal management fabric. Both the heating mode and the heat dissipation mode of the thermal management fabric can be used independently.

[0009] In one embodiment of the present invention, the amorphous photonic crystal structure color coating is a mixture of SiO2 nanospheres, polymethyl methacrylate-methacrylic acid (PA) nanoparticles, and nano-carbon black.

[0010] In one embodiment of the present invention, the particle size of SiO2 nanospheres is 180-300 nm.

[0011] In one embodiment of the present invention, the nanomaterial is one or more of graphene, AgNWs, carbon nanotubes, and MXene nanosheets.

[0012] In one embodiment of the present invention, the thickness of the amorphous photonic crystal structure color coating is 100-200 μm, and the thickness of the nanomaterial coating is 0.1-1.0 μm.

[0013] This invention provides a method for preparing the above-described bidirectional personal thermal management fabric for both heating and heat dissipation, specifically comprising the following steps:

[0014] (1) The fiber fabric substrate is hydrophilized;

[0015] (2) Anhydrous ethanol, water, ammonia, and tetraethyl orthosilicate were mixed in a volume ratio of 72:10:3:4-8, reacted, centrifuged, washed, and dried to obtain SiO2 microsphere powder; the SiO2 microsphere powder was dispersed in deionized water, and PA nanoparticles and nano carbon black were added sequentially to prepare SiO2 microsphere dispersion; finally, the SiO2 microsphere dispersion was sprayed onto the surface of a hydrophilic fiber fabric substrate and cured.

[0016] (3) Ti3AlC2 was etched with a mixed solution of HCl and LiF, washed with deionized water until the pH of the supernatant was 5-7, ultrasonically intercalated and centrifuged to obtain MXene dispersion, the MXene dispersion was sprayed on the other side of the fiber fabric substrate, and finally dried to obtain a bidirectional personal thermal management fabric for heating and heat dissipation.

[0017] In one embodiment of the present invention, in step (2), the mass ratio of SiO2 microsphere powder, PA nanoparticles and nano carbon black is 90-110:1-3:0.5-1.5.

[0018] In one embodiment of the present invention, in step (2), the mass fraction of SiO2 microsphere powder in the SiO2 microsphere dispersion is 10-30%.

[0019] In one embodiment of the present invention, in step (2), the spraying process is 15-20 seconds per spray, with an interval of 5-10 seconds.

[0020] In one embodiment of the present invention, in step (3), the concentration of HCl is 8-10M, and the ratio of HCl, LiF and Ti3AlC2 is 40mL:3.2-6.4g:2.0-4.0g.

[0021] In one embodiment of the present invention, in step (3), the ultrasonic intercalation solution is one or more of deionized water, anhydrous ethanol, N,N-dimethylformamide, dimethyl sulfoxide, and isopropanol.

[0022] In one embodiment of the present invention, in step (3), the mass fraction of the MXene dispersion is 10-30 mg / mL.

[0023] Beneficial effects:

[0024] (1) This invention designs a colored personal thermal management fabric integrating cooling and multi-mode heating management. The fabric is an asymmetric colored fabric formed by spraying a radiative cooling coating and a radiative heating coating, comprising a fiber fabric substrate, an amorphous photonic crystal structure color coating, and a coating constructed from low-emissivity nanomaterials. Therefore, the asymmetric colored personal thermal management fabric integrating cooling and multi-mode heating management can regulate the direction of heat transfer according to the ambient temperature or the wearer's needs. It provides warmth in cold weather and dissipates heat in hot weather, thus maintaining a suitable perceived temperature. This fabric achieves dynamic personal thermal management, achieving a 10.2°C temperature reduction in summer compared to simulated human skin temperature, and a 21.4°C temperature increase in winter due to the multi-mode heating effect, providing greater flexibility for personal thermal management under different environmental conditions.

[0025] (2) The color personal thermal management fabric with integrated cooling and multi-mode heating management designed in this invention uses photonic crystals and low emissivity materials to prepare thermal management textiles. Through passive thermal management technologies such as radiative heat dissipation, heat reflection and heat storage, it does not rely on traditional energy consumption, reduces the dependence on air conditioning and heating equipment, thereby significantly saving the consumption and use of fossil energy and promoting the development of the textile industry towards low carbon and sustainability.

[0026] (3) The present invention designs a colored personal thermal management fabric that integrates cooling and multi-mode heating management. Its heating mode consists of three modes: passive radiation heating, photothermal heating and electric heating. By integrating multiple heating methods, it can meet the thermal management needs in different scenarios, achieve precise temperature control and reduce energy consumption, and has the advantages of high efficiency, energy saving, intelligence and flexibility and low carbon and environmental protection.

[0027] (4) The color personal thermal management fabric with integrated cooling and multi-mode heating management designed in this invention has good moisture permeability, which effectively improves the comfort of wearing it. The amorphous photonic crystal structure color layer has super hydrophilicity, while the low emissivity MXene nanosheet layer has a certain degree of hydrophobicity. In summer, the moisture and heat on the skin surface can be quickly diffused to the structure color layer and evaporated, realizing the unidirectional transmission of moisture and heat from the inside to the outside, further optimizing the cooling thermal management effect. Attached Figure Description

[0028] Figure 1 The microstructure of the amorphous photonic crystal structure in Example 1 is characterized, where (a, b) represents the microsphere distribution on the surface of the amorphous photonic crystal fabric and (c) represents the high-magnification amorphous photonic crystal fabric.

[0029] Figure 2 The diagram (a) shows the principle of radiation cooling of the amorphous photonic crystal structure (APC) in Example 1, and the reflectivity curves (b) of the near-infrared band and the emissivity curves of the mid-infrared band.

[0030] Figure 3 The transmittance and emissivity of the photonic crystal structures prepared for Example 1 and Comparative Example 1 are shown, where (a) is the transmittance and (b) is the emissivity;

[0031] Figure 4 Comparison of transmittance (a) and emissivity (b) in the visible and near-infrared bands and mid-infrared bands of the thermal management fabrics of Example 1 and Comparative Example 1;

[0032] Figure 5 The microstructure characterization of the MXene-loaded polyester fabric (MXene / PET) in Example 2 is shown, where (a) is MXene / PET and (b) is high-magnification MXene / PET.

[0033] Figure 6 The reflectance and emissivity curves of the MXene-loaded polyester fabric in the visible and near-infrared bands and the mid-infrared band are shown in Example 2.

[0034] Figure 7 Flowchart for the preparation of the color personal thermal management (CMPC) fabric with integrated cooling and multimodal heating management prepared in Example 3;

[0035] Figure 8 The cross-sectional morphology of the colored personal thermal management fabric with integrated cooling and multi-mode heating management prepared in Example 3 is characterized, wherein (a) is the cross-sectional micromorphology of the CMPC fabric and (b) is the cross-sectional mapping diagram of the CMPC fabric.

[0036] Figure 9 Reflectance in the visible near-infrared band and emissivity in the mid-infrared band of the colored personal thermal management fabric with integrated cooling and multi-mode heating management prepared for Example 3 (a); air permeability of the four fabrics (b).

[0037] Figure 10 To illustrate the heating and cooling tests conducted on the colored personal thermal management fabric with integrated cooling and multi-mode heating management prepared in Example 3 in an outdoor micro-environment, (a) is a schematic diagram of the micro-environment testing device, (b) is a physical image of the micro-environment testing device, (c) is a test of the cooling performance of the colored personal thermal management fabric with integrated cooling and multi-mode heating management, and (d) is a test of the heating performance of the colored personal thermal management fabric with integrated cooling and multi-mode heating management in multiple modes.

[0038] Figure 11 The images show (a, b) of the thermal insulation and heat dissipation bidirectional personal thermal management fabric prepared in Comparative Example 2 and (c) of the thermal insulation and heat dissipation bidirectional personal thermal management fabric prepared in Example 4.

[0039] Figure 12Comparison of transmittance (a) and emissivity (b) in the visible near-infrared band and mid-infrared band of the colored personal thermal management fabrics with integrated cooling and multi-mode heating management prepared in Examples 3, 4 and 5.

[0040] Figure 13 The heating performance of the colored personal thermal management fabrics with integrated cooling and multi-mode heating management prepared in Examples 3 and 5 is compared under outdoor conditions, wherein (a) is the fabric temperature change curve, (b) is the fabric temperature difference, and (c) is the ambient temperature and humidity. Detailed Implementation

[0041] The testing methods used in this invention:

[0042] Microscopic morphology characterization of samples: The microscopic morphology, particle size, and photonic crystal configuration of the microspheres were measured using a HITACHI SU8100 field emission scanning electron microscope (FESEM). Samples underwent pretreatment before testing. For microsphere samples, a microsphere dispersion was prepared by dispersing them in ultrapure water, then dropped onto a silicon wafer surface and dried before testing. For photonic crystal thin film samples, they were directly cut and attached to the sample platform for detection. Before testing, the sample stage was gold-plated to improve the conductivity of the samples, and the operating voltage was 4 kV.

[0043] Optical and radiation properties testing: The spectral properties of thermal insulation and heat dissipation personal thermal management fabrics were tested, including the characterization of their transmission and reflection. The spectrum in the solar radiation band (0.3-2.5μm) was characterized by a spectrophotometer, and the emissivity, reflectivity and absorptivity in the mid-infrared band were characterized by an integrating sphere mode Fourier transform infrared spectrometer.

[0044] Outdoor heating and cooling performance testing: Tests were conducted using a self-built microenvironment test chamber. Figure 10 a, b), the test was conducted in Wuxi, Jiangsu Province, China (31°N, 120°E), at 121 W m -2 The heater and silicone rubber are used to simulate the daily heat dissipation behavior of human skin, and thermocouples are attached under the test sample to monitor the sample temperature in real time. At the same time, a weather station is set up to monitor the real-time ambient temperature, humidity, wind speed and light irradiance.

[0045] Air permeability test: According to the national standard (GB / T 13764), the moisture permeability of CMPC, APC / PET, MXene / PET, and PET was tested using the positive cup evaporation method. A permeability cup containing distilled water and a sealed fabric sample was placed in a sealed environment. The temperature and humidity of the sealed environment were 38±2℃ and 40±2%, respectively.

[0046] The polymethyl methacrylate-methacrylic acid (PA) nanoparticles used below have a particle size of 20-50 nm; the structural color coating thickness is 100-200 μm; and the nanomaterial coating thickness is 0.1-1.0 μm.

[0047] Example 1

[0048] (1) After washing with deionized water, the polyester fabric is placed in ethanol solvent to treat the fabric surface, dissolve the oil and chemical residues on the fabric surface, expose the hydrophilic groups, and dry in an oven at 60°C for later use.

[0049] (2) Adopt Monodisperse SiO2 microspheres were prepared by adding 10 mL of deionized water and 3 mL of ammonia to 72 mL of anhydrous ethanol and stirring thoroughly at room temperature. Then, 4 mL of tetraethyl orthosilicate was slowly added dropwise. After reacting for 8 hours, the mixture was centrifuged, washed, and dried to obtain SiO2 microsphere powder. The SiO2 microsphere powder was dispersed in deionized water, and PA nanoparticles and nano-carbon black were added sequentially to prepare a microsphere dispersion. The mass fraction of the microspheres was 20 wt%, and the mass ratio of SiO2 microsphere powder, PA nanoparticles, and nano-carbon black in the microsphere dispersion was 100:2:1. Finally, the microsphere dispersion was sprayed onto the surface of hydrophilically treated polyester fabric. The spraying process was 20 seconds per spray, with a 10-second interval. The microspheres were then cured in an oven at 80°C to obtain a fabric with cooling properties.

[0050] Figure 1 The image shows the microstructure of an amorphous photonic crystal structure prepared by a spraying method. The SiO2 microspheres have a particle size of 208.7 nm and exhibit a short-range ordered, long-range disordered distribution. Due to the quasi-periodic structure of the APC, multiple scattering of visible light forms photonic pseudobands. The scattered light, due to its high scattering intensity, is relatively random and isotropic, corresponding to... Figure 1 (c) shows a ring-shaped, centrally symmetrical pattern. Because light undergoes strong multiple scattering in the quasi-periodic APC, it can effectively increase solar reflectivity and enhance scattering performance in the infrared band, thereby increasing radiative heat dissipation, such as... Figure 2 As shown, the introduction of color based on physical structure not only does not increase the thermal burden of thermal management fabric, but also helps to further improve the cooling effect, demonstrating excellent radiative cooling performance.

[0051] Comparative Example 1

[0052] This comparative example demonstrates the preparation of a colored radiation-cooled fabric with a crystalline photonic crystal structure. The specific preparation method is as follows:

[0053] (1) After washing with deionized water, the polyester fabric is placed in ethanol solvent to treat the fabric surface, dissolve the oil and chemical residues on the fabric surface, expose the hydrophilic groups, and dry in an oven at 60°C for later use.

[0054] (2) Adopt Monodisperse SiO2 microspheres were prepared by adding 10 mL of deionized water and 3 mL of ammonia to 72 mL of anhydrous ethanol and stirring thoroughly at room temperature. Then, 4 mL of tetraethyl orthosilicate was slowly added dropwise. After reacting for 8 h, the mixture was centrifuged, washed, and dried for later use. The SiO2 microsphere powder was dispersed in deionized water to prepare a microsphere dispersion with a microsphere mass fraction of 1 wt%. A crystalline photonic crystal structure was constructed on the surface of polyester fabric using a vertical deposition method. The oven temperature was 60 °C, the humidity was 50%, and the deposition time was 36 h. The microspheres were then cured in an oven at 80 °C to stabilize the photonic crystal structure, resulting in a fabric with cooling properties.

[0055] Figure 1 The paper demonstrates that the amorphous photonic crystal structure prepared by the spraying method exhibits quasi-periodicity. Figure 3 The image shows a highly ordered photonic crystal structure prepared by vertical deposition, with microspheres arranged in a regular hexagonal array. The corresponding Fast Fourier Transform (FFT) diagram shows a hexagonal symmetrical lattice structure exhibiting anisotropy. In periodic photonic crystals, light scattering intensity is weak and the scattering range is narrow, mainly concentrated in a specific wavelength region matching its photonic bandgap. Therefore, it exhibits weaker solar reflectance and infrared radiation performance. Figure 4 ).

[0056] Example 2

[0057] (1) After washing with deionized water, the polyester fabric is placed in ethanol solvent to treat the fabric surface, dissolve the oil and chemical residues on the fabric surface, expose the hydrophilic groups, and dry in an oven at 60°C for later use.

[0058] (2) MXene nanosheets were prepared by MILD method. 3.2g of lithium fluoride was added to 40mL of 9M HCl and stirred at room temperature for 5-10min. Then, 2.0g of Ti3AlC2 powder was slowly added. After etching for 24h, the supernatant was washed with deionized water until the pH of the supernatant was ~6. Ultrasonic intercalation was performed at 5-8℃ with deionized water as the ultrasonic intercalation solvent. The MXene dispersion was obtained by centrifugation at 3500rpm for 5min. 20mg / mL of MXene dispersion was sprayed onto one side of polyester fabric and dried in an oven at 60℃ to obtain a fabric with heat preservation properties.

[0059] like Figure 5 As shown, MXene nanosheets prepared by the MILD method are uniformly distributed on the surface of polyester fabric. The resulting MXene / PET fabric exhibits excellent solar energy absorption capacity, and the low emissivity of MXene itself endows MXene / PET with excellent radiative heating performance. Figure 6 ).

[0060] Example 3

[0061] A bidirectional personal thermal management fabric for both heating and cooling includes: a polyester fabric substrate; an amorphous photonic crystal structure color coating disposed on one side of the polyester fabric substrate, constructed from a mixture of SiO2 nanospheres, polymethyl methacrylate-methacrylic acid (PA) nanoparticles, and nano-carbon black; and a coating disposed on the other side of the polyester fabric substrate, constructed from MXene nanosheets. The specific preparation method is as follows: Figure 7 As shown:

[0062] (1) After washing with deionized water, the polyester fabric is placed in ethanol solvent to treat the fabric surface, dissolve the oil and chemical residues on the fabric surface, expose the hydrophilic groups, and dry in an oven at 60°C for later use.

[0063] (2) Adopt Monodisperse SiO2 microspheres (particle size 242 nm) were prepared by adding 10 mL of deionized water and 3 mL of ammonia to 72 mL of anhydrous ethanol and stirring at room temperature until fully mixed. Then, 7 mL of tetraethyl orthosilicate was slowly added dropwise. After reacting for 8 h, the SiO2 microsphere powder was centrifuged, washed, and dried to obtain SiO2 microsphere powder dispersed in deionized water. PA nanoparticles and carbon black nanoparticles were added sequentially to prepare a microsphere dispersion, wherein the mass fraction of microspheres was 20 wt%, and the mass ratio of SiO2 microsphere powder, PA nanoparticles and carbon black nanoparticles in the microsphere dispersion was 100:3:1. The microsphere dispersion was sprayed onto the surface of hydrophilically treated polyester fabric. The spraying process parameters were 20 s for each spray and 5 s for each interval. The microspheres were cured in an oven at 80 °C.

[0064] (3) MXene nanosheets were prepared by MILD method. 3.2g of lithium fluoride was added to 40mL of 9M HCl and stirred at room temperature for 5-10min. Then, 2.0g of Ti3AlC2 powder was slowly added. After etching for 24h, the supernatant was washed with deionized water until the pH of the supernatant was ~6. Ultrasonic intercalation was performed at 5-8℃ with deionized water as the ultrasonic intercalation solvent. The MXene dispersion was obtained by centrifugation at 3500rpm for 5min. The MXene dispersion with a mass fraction of 30mg / mL was sprayed onto the other side of the polyester fabric and dried in an oven at 60℃ to obtain a colored personal thermal management fabric (CMPC) with integrated cooling and multi-mode heating management.

[0065] from Figure 8 The structure of the colored personal thermal management fabric with integrated cooling and multi-mode heating management can be clearly seen in the cross-sectional SEM image of (a). Figure 8The mapping distribution in (b) further illustrates the structural distribution of the fabric. Si elements are distributed in the upper layer, and Ti elements are distributed in the lower layer, which can be attributed to SiO2 APC and MXene, respectively. Figure 9 As shown in (a), the two sides of the fabricated colored personal thermal management fabric with integrated cooling and multi-mode heating management exhibit different optical properties. The SiO2 APC cooling layer shows high solar reflectivity (79.85%) and high emissivity (92.03%), while the MXene heating layer shows the opposite: high solar absorptivity (80.33%) and low emissivity (18.24%). Figure 9 As shown in (b), the prepared two-way personal thermal management fabric with both heat insulation and heat dissipation exhibits good air permeability, with a water vapor transmission rate of 3722.2 gm. -2 day -1 It demonstrates good comfort when taken.

[0066] use Figure 10 The apparatus shown in (a) and (b) further characterizes the cooling and heating effects of CMPC fabrics in a microenvironment. The results show that, as Figure 10 As shown in (c), in cooling mode, the surface temperature of the CMPC fabric is significantly lower than that of simulated skin and ordinary cotton fabric, demonstrating a good cooling effect; Figure 10 As shown in (d), in heating mode, by synergistically controlling the passive radiative heating, photothermal performance, and electrothermal performance of the heating layer, the surface temperature of the CMPC fabric is 21.4℃ and 28.5℃ higher than that of simulated skin and ordinary cotton fabric, respectively. This demonstrates that the prepared colored personal thermal management fabric with integrated cooling and multi-mode heating management can adapt to changes in ambient temperature or human needs by altering its thermal management mode and regulating the direction of heat transfer. It provides warmth in cold weather and dissipates heat in hot weather, thereby maintaining a suitable perceived temperature.

[0067] Example 4

[0068] A bidirectional personal thermal management fabric for both heating and heat dissipation includes: a polyester fabric substrate; an amorphous photonic crystal structure color coating disposed on one side of the polyester fabric substrate, constructed from a mixture of SiO2 nanospheres, polymethyl methacrylate-methacrylic acid (PA) nanoparticles, and nano-carbon black; and a coating disposed on the other side of the polyester fabric substrate, constructed from MXene nanosheets. The preparation method includes:

[0069] (1) After washing with deionized water, the polyester fabric is placed in ethanol solvent to treat the fabric surface, dissolve the oil and chemical residues on the fabric surface, expose the hydrophilic groups, and dry in an oven at 60°C for later use.

[0070] (2) Adopt Monodisperse SiO2 microspheres (particle size 242 nm) were prepared by adding 10 mL of deionized water and 3 mL of ammonia to 72 mL of anhydrous ethanol and stirring thoroughly at room temperature. Then, 7 mL of tetraethyl orthosilicate was slowly added dropwise. After reacting for 8 h, the mixture was centrifuged, washed, and dried for later use. The SiO2 microsphere powder was dispersed in deionized water, and PA nanoparticles and carbon black nanoparticles were added sequentially to prepare a microsphere dispersion. The mass fraction of the microspheres was 30 wt%, and the mass ratio of SiO2 microsphere powder, PA nanoparticles and carbon black nanoparticles in the microsphere dispersion was 100:2:1. The microsphere dispersion was sprayed onto the surface of hydrophilically treated polyester fabric. The spraying process parameters were 20 s spraying followed by a 5 s interval, and the microspheres were cured in an oven at 80 °C.

[0071] (3) MXene nanosheets were prepared by the MILD method. The specific preparation method was as follows: 3.2g of lithium fluoride was added to 40mL of 9M HCl, and after stirring at room temperature for 5-10min, 2.0g of Ti3AlC2 powder was slowly added. After etching for 24h, the supernatant was washed with deionized water until the pH of the supernatant was ~6. Ultrasonic intercalation was performed at 5-8℃, and deionized water was used as the ultrasonic intercalation solvent. The MXene dispersion was obtained by centrifugation at 3500rpm for 5min. The MXene dispersion with a mass fraction of 10mg / mL was sprayed onto the other side of the polyester fabric and dried in an oven at 60℃ to obtain a colored personal thermal management fabric with integrated cooling and multi-mode heating management.

[0072] Comparative Example 2

[0073] A bidirectional personal thermal management fabric for both heating and heat dissipation includes: a polyester fabric substrate, an amorphous photonic crystal structure color coating constructed from SiO2 nanospheres disposed on one side of the polyester fabric substrate, and a coating constructed from MXene nanosheets disposed on the other side of the polyester fabric substrate. The preparation method includes:

[0074] (4) Place the polyester fabric washed with deionized water in an ethanol solvent to treat the fabric surface, dissolve the oil and chemical residues on the fabric surface, expose the hydrophilic groups, and dry it in a 60°C oven for later use.

[0075] (5) Adopt Monodisperse SiO2 microspheres (particle size 242 nm) were prepared by adding 10 mL of deionized water and 3 mL of ammonia to 72 mL of anhydrous ethanol and stirring thoroughly at room temperature. Then, 7 mL of tetraethyl orthosilicate was slowly added dropwise. After reacting for 8 h, the mixture was centrifuged, washed, and dried for later use. The SiO2 microsphere powder and carbon black nanoparticles were dispersed in deionized water, with the microspheres having a mass fraction of 30 wt%, ensuring a mass ratio of 100:1 between the SiO2 microspheres and carbon black nanoparticles. The microsphere dispersion was sprayed onto the surface of hydrophilically treated polyester fabric. The spraying process parameters were 20 s per spray, with a 5 s interval, and the microspheres were cured in an oven at 80 °C.

[0076] (6) MXene nanosheets were prepared by the MILD method. The specific preparation method was as follows: 3.2g of lithium fluoride was added to 40mL of 9M HCl, and after stirring at room temperature for 5-10min, 2.0g of Ti3AlC2 powder was slowly added. After etching for 24h, the supernatant was washed with deionized water until the pH of the supernatant was ~6. Ultrasonic intercalation was performed at 5-8℃, and deionized water was used as the ultrasonic intercalation solvent. The MXene dispersion was obtained by centrifugation at 3500rpm for 5min. The MXene dispersion with a mass fraction of 10mg / mL was sprayed onto the other side of the polyester fabric and dried in an oven at 60℃ to obtain a colored personal thermal management fabric with integrated cooling and multi-mode heating management.

[0077] like Figure 11 As shown in (a, b), in the process of preparing the CMPC fabric in Comparative Example 2, when no PA binder was added to the microsphere dispersion, applying indentations or scratches to the fabric surface would damage the APC structure and cause the structural color to disappear. However, in the CMPC fabric of Example 4, the surface showed almost no damage when scratches and indentations were applied. Figure 11 c).

[0078] Example 5

[0079] A personal thermal management fabric with both heat insulation and heat dissipation functions includes: a polyester fabric substrate; an amorphous photonic crystal structure color coating constructed from a mixture of SiO2 nanospheres, polymethyl methacrylate-methacrylic acid (PA) nanoparticles, and nano-carbon black on one side of the polyester fabric substrate; and a coating constructed from MXene nanosheets on the other side of the polyester fabric substrate. The preparation method includes:

[0080] (1) After washing with deionized water, the polyester fabric is placed in ethanol solvent to treat the fabric surface, dissolve the oil and chemical residues on the fabric surface, expose the hydrophilic groups, and dry in an oven at 60°C for later use.

[0081] (2) Adopt Monodisperse SiO2 microspheres (particle size 294 nm) were prepared by adding 10 mL of deionized water and 3 mL of ammonia to 72 mL of anhydrous ethanol and stirring thoroughly at room temperature. Then, 8 mL of tetraethyl orthosilicate was slowly added dropwise. After reacting for 8 h, the mixture was centrifuged, washed, and dried for later use. The SiO2 microsphere powder was dispersed in deionized water, and PA nanoparticles and carbon black nanoparticles were added sequentially to prepare a microsphere dispersion. The mass fraction of the microspheres was 20 wt%, and the mass ratio of SiO2 microsphere powder, PA nanoparticles and carbon black nanoparticles in the microsphere dispersion was 100:2:1. The microsphere dispersion was sprayed onto the surface of hydrophilically treated polyester fabric. The spraying process parameters were 20 s for each spray and 10 s for each interval. The microspheres were cured in an oven at 80 °C.

[0082] (3) MXene nanosheets were prepared by the MILD method. The specific preparation method was as follows: 3.2g of lithium fluoride was added to 40mL of 9M HCl. After stirring at room temperature for 5-10min, 2.0g of Ti3AlC2 powder was slowly added. After etching for 24h, the supernatant was washed with deionized water until the pH of the supernatant was ~6. Ultrasonic intercalation was performed at 5-8℃. The ultrasonic intercalation solvent was deionized water. The MXene dispersion was obtained by centrifugation at 3500rpm for 5min. The MXene dispersion with a mass fraction of 20mg / mL was sprayed onto the other side of the polyester fabric and dried in an oven at 60℃ to obtain a colored personal thermal management fabric with integrated cooling and multi-mode heating management.

[0083] Figure 12 The solar absorptivity and infrared emissivity of CMPC fabrics with different MXene loadings are shown. The results show that the solar absorptivity does not change significantly with the increase of MXene loading. The weighted absorptivity of CMPC fabrics with MXene loadings of 10 mg / mL (Example 4), 20 mg / mL (Example 5), and 30 mg / mL (Example 3) in the visible and near-infrared bands are 80.55%, 80.56%, and 80.33%, respectively. The emissivity shows a trend of first increasing and then decreasing with the increase of loading. This is because when the coating thickness reaches a certain level, the surface smoothness of the material increases, resulting in more mid-infrared electromagnetic waves being absorbed rather than reflected, thus showing a decrease in emissivity. Figure 13 The thermal performance of CMPC fabrics with loadings of 20 mg / mL and 30 mg / mL was compared in an outdoor environment. The results showed that the CMPC fabric with a low emissivity and a 20% loading exhibited better thermal performance, with an average temperature higher than that of the CMPC fabric with a loading of 30 mg / mL. However, since the increase in loading can lead to a significant increase in electrothermal performance, the CMPC fabric with a loading of 30 mg / mL MXene was ultimately selected as the optimal amount to prepare a personal thermal management fabric with better thermal performance.

[0084] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A personal thermal management fabric that combines heating and heat dissipation, characterized in that, include: The fiber fabric substrate, the amorphous photonic crystal structure color coating disposed on one side of the fiber fabric substrate, and the nanomaterial coating disposed on the other side of the fiber fabric substrate; The fiber fabric substrate is one of polylactic acid fiber fabric, cotton fabric, or polyester fiber fabric; the amorphous photonic crystal structure color coating is a mixture of SiO2 nanospheres, polymethyl methacrylate-methacrylic acid nanoparticles, and nano-carbon black; the nanomaterial is MXene nanosheets. The method for preparing the aforementioned bidirectional heating and cooling personal thermal management fabric includes the following steps: (1) The fiber fabric substrate is hydrophilized; (2) Anhydrous ethanol, water, ammonia, and tetraethyl orthosilicate were mixed and reacted. After centrifugation, washing, and drying, SiO2 microsphere powder was obtained. The SiO2 microsphere powder was dispersed in deionized water, and polymethyl methacrylate-methacrylic acid nanoparticles and carbon black nanoparticles were added sequentially to prepare SiO2 microsphere dispersion. Finally, the SiO2 microsphere dispersion was sprayed onto the surface of a hydrophilically treated fiber fabric substrate and cured. The volume ratio of anhydrous ethanol, water, ammonia, and tetraethyl orthosilicate was 72:10:3:4-8. The mass ratio of SiO2 microsphere powder, polymethyl methacrylate-methacrylic acid nanoparticles, and carbon black nanoparticles was 90-110:1-3:0.5-1.

5. The mass fraction of SiO2 microsphere powder in the SiO2 microsphere dispersion was 10-30%. (3) Ti3AlC2 was etched with a mixed solution of HCl and LiF, washed with deionized water until the pH of the supernatant was 5-7, ultrasonically intercalated and centrifuged to obtain MXene dispersion with a concentration of 10-30 mg / mL. The MXene dispersion was sprayed onto the other side of the fiber fabric substrate and finally dried to obtain a bidirectional personal thermal management fabric for heating and heat dissipation.

2. The personal thermal management fabric for both heating and heat dissipation according to claim 1, characterized in that, The nanomaterial coating serves as a heating layer to provide a heating mode for the thermal management fabric, while the amorphous photonic crystal structure color coating serves as a heat dissipation layer to provide a heat dissipation mode for the thermal management fabric. Both the heating mode and the heat dissipation mode of the thermal management fabric can be used independently.

3. The personal thermal management fabric for both heating and heat dissipation according to claim 1, characterized in that, The thickness of the amorphous photonic crystal structure color coating is 100-200μm, and the thickness of the nanomaterial coating is 0.1-1.0μm.

4. The personal thermal management fabric for both heating and heat dissipation according to claim 1, characterized in that, In step (3), the concentration of HCl is 8-10 M; the ratio of HCl, LiF and Ti3AlC2 is 40 mL: 3.2-6.4 g: 2.0-4.0 g.

5. The personal thermal management fabric for both heating and heat dissipation according to claim 1, characterized in that, In step (3), the ultrasonic intercalation solution is one or more of deionized water, anhydrous ethanol, N,N-dimethylformamide, dimethyl sulfoxide, and isopropanol.

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