Multifunctional super fabric for radiation refrigeration and preparation method thereof

Abstract

The invention discloses a multifunctional super fabric for radiation refrigeration and a preparation method thereof.The fabric comprises a fabric layer, a bonding layer and an aerogel layer, and the fabric layer and the aerogel layer are compounded through the bonding layer; the aerogel layer is titanium dioxide aerogel with a three-dimensional pipeline-shaped structure, and a flaky electrostatic spinning fiber membrane containing magnetic core-shell particles is loaded on a framework of the aerogel layer. The multifunctional super fabric for radiation refrigeration has high solar reflectivity (0.90-0.98) and high infrared emissivity (0.90-0.97); the surface temperature lower than the temperature of the base material and the environment can be achieved under the condition of direct solar radiation at noon, and the excellent outdoor radiation refrigeration, flame-retardant and antibacterial capabilities are achieved.

Description

Technical Field

[0001] The invention relates to a multifunctional super fabric for radiative cooling and a preparation method thereof, belonging to the technical field of functional materials. Background Art

[0002] Passive daytime radiative cooling (PDRC) is completely environmentally friendly and does not require any additional energy consumption. It reflects sunlight (0.3-2.5 μm) and simultaneously emits its own energy to the ultra-cold outer space (3K) through the first atmospheric transparent window (8-13 μm), which is very promising to prevent the abuse of traditional compressed air-based refrigeration systems. In recent years, daytime radiative cooling has been demonstrated and developed, attracting the interest of researchers in this field. In principle, one of the key solutions to achieve passive subambient daytime radiative cooling is to reduce the negative impact of solar radiation on radiative coolers, because the magnitude of solar radiation power is much larger than that of radiative cooling. In addition, high temperatures in summer pose a serious challenge to human health, especially causing heat-induced diseases and related complications such as heat paralysis, skin cancer, and cardiovascular diseases. Therefore, the exploration of personal cooling technology has shown its significance where a lot of efforts have been invested recently. Personal thermoregulation provides a microclimate of thermal comfort for individuals by providing body cooling or heating, meeting the demand for innovative textiles that can help human body thermoregulation. Summary of the invention

[0003] Technical problem to be solved: The purpose of the present invention is to provide a multifunctional super fabric for radiant cooling and a preparation method thereof, which adopts scraping and interlayer composite technology to give the fabric outdoor radiant cooling capabilities.

[0004] Technical solution: A multifunctional super fabric for radiative cooling, the fabric comprising a fabric layer, a bonding layer and an aerogel layer, the fabric layer and the aerogel layer are compounded via the bonding layer, the aerogel layer is a titanium dioxide aerogel with a three-dimensional tubular structure and a sheet-like electrospun fiber membrane containing magnetic core-shell particles is loaded on the skeleton. Preferably, the method for preparing the multifunctional super fabric for radiative cooling comprises the following steps: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 10-30:15-25:1.5-3, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated fabric, titanium dioxide aerogel is loaded on the fabric surface to obtain a printed super fabric, which is then pre-baked and baked to obtain a multifunctional super fabric for radiant cooling. Preferably, the pretreated fabric is one of commercial cotton, polyester, nylon, linen, silk or spandex fabric, the pre-baking time is 5 to 10 minutes, the pre-baking temperature is 60 to 80°C, the baking time is 5 to 10 minutes, and the baking temperature is 120 to 150°C. Preferably, the preparation method of titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol and stirred to obtain a homogeneous solution A; S1-2. Mix water and anhydrous ethanol in a volume ratio of 1 to 3: 2 to 4, then add concentrated hydrochloric acid to adjust the pH to 1 to 3, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to the homogenized solution A, followed by the addition of the sheet-like electrospun fiber membrane, and the gel was obtained after magnetic stirring for 1 to 3 hours; S1-4. The gel obtained in S1-3 is placed in a magnetic field for 100 to 500 minutes, and then the device is removed to obtain a gel oriented along the direction of the sheet-like static spun fiber membrane; S1-5. Orient the gel obtained in S1-4 at -40 to -20°C and freeze-dry for 12 to 20 hours to obtain titanium dioxide aerogel. Preferably, the mass of tetrabutyl titanate in S1-1 is 55 to 70% of solution A, and the volume ratio of glacial acetic acid to anhydrous ethanol is 1 to 3:5 to 15. Preferably, the method for preparing the sheet-like electrospun fiber membrane in S1-3 comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 1 to 2.5:1 to 2.8, and stir magnetically at 40 to 60°C to obtain a homogeneous solution; S2-2. Add magnetic core-shell particles to the solution obtained in S2-1 and ultrasonically disperse to obtain an electrospinning solution with a mass fraction of 5 to 20 wt%; S2-3. The electrospinning solution obtained in S2-2 was electrospun at a voltage of 15 to 20 kV and a flow rate of 1 to 1.5 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a particle size of 1 to 2 mm. 2 Preferably, in S2-2, the method for preparing the magnetic core-shell particles comprises the following steps: S3-1. Take terephthalic acid and glacial acetic acid dihydrate in a mass ratio of 0.2 to 0.6:1 and add them to a triethylamine, DMF and ethanol solution in a volume ratio of 1 to 3:3 to 15:14 to 20 to obtain a mixed solution; S3-2. Add Fe3O4 suspension and inorganic particle suspension in a volume ratio of 1 to 3:2 to 5 to the mixed solution obtained in S3-1 and stir magnetically for 3 h; S3-3. The product obtained in S3-2 was centrifuged and washed to obtain Fe3O4@MOF-5@inorganic particles, and then the particles were dispersed in water to obtain a suspension A; S3-4. Mix water and titanium trichloride precursor in a volume ratio of 20:1, and then add a sodium bicarbonate solution having a concentration of 1 to 3 mol / L to adjust the pH to 2 to 5 to obtain a solution B; S3-5. Add the suspension A obtained in S3-3 to the solution B obtained in S3-4 and react for 10 to 50 minutes. After centrifugal washing and drying, magnetic core-shell particles are obtained. Preferably, the concentration ratio of the Fe3O4 suspension to the inorganic particle suspension in the S3-2 is 1-4:1-9, and the inorganic particle suspension is one or more of a BaSO4 suspension, a CaCO3 suspension, an Al2O3 suspension, a TiO2 suspension, a ZnO2 suspension, an AlPO4 suspension, a hollow glass microsphere suspension or a SiC suspension. Preferably, the ratio of the amount of Fe3O4@MOF-5@inorganic particles contained in the suspension A in S3-5 to the amount of ferric chloride precursor substance in the solution B is 1:15 to 1:70. Preferably, a multifunctional super fabric for radiative cooling is prepared by any of the methods described. Preferably, the multifunctional super fabric for radiative cooling prepared by any of the methods is used in personal thermal management, smart wearables, and energy-saving buildings. Beneficial effects: The multifunctional super fabric for radiative cooling prepared by the present invention has the following advantages: 1. The presence of the core-shell structure interface and the structural difference in the magnetic core-shell particles prepared by the present invention effectively expand the scattering cross section, promote the strong scattering of incident light, and thus improve the solar reflectivity. In addition, the presence of Fe3O4, inorganic particles and MOF-5 in the magnetic core-shell particles increases the surface area of ​​the material, further improving the scattering efficiency of sunlight and infrared emissivity, thereby improving the radiative cooling performance; 2. The tubular structure prepared by controlling the directional arrangement of the sheet-like electrospun fiber membrane in the present invention can be regarded as a pipe-like grating, which improves and expands the solar reflectivity. In addition, the presence of the sheet-like electrospun fiber membrane can enhance the mechanical stability of the aerogel while forming a porous structure, improve its adaptability to substrate deformation, and meet the actual use requirements; 3. The titanium dioxide aerogel prepared in the present invention has high porosity and large specific surface area, thereby improving the scattering ability of the solar spectrum. In addition, it has a high infrared emissivity in the atmospheric window band, which helps to effectively emit heat and thus improve the radiation cooling performance; 4. The coating prepared by the present invention has micro-pores formed by the volatilization of polytetrafluoroethylene during the baking process. According to the Mie scattering principle, due to the presence of the micro-nano pore structure, the coating has a strong ability to backscatter sunlight and enhance thermal radiation; 5. The multifunctional super fabric coating designed by the present invention for radiative cooling is suitable for personal thermal management and energy-saving building coatings. It has high solar reflectivity (0.90-0.97) and high infrared emissivity (0.94-0.98). The outdoor cooling effect can reach 7.2°C. It not only has excellent outdoor cooling capacity, but also has low thermal conductivity and resistance to environmental aging. 6. The present invention designs a multifunctional super fabric for radiant cooling that can withstand long-term ultraviolet radiation without changing color, has good physical and chemical stability, strong durability, and long service life, and achieves long-term stable refrigeration performance. In addition, the super fabric coating is endowed with multifunctional effects of being waterproof (contact angle of 141.6°), flame retardant (LOI of 30.1%), and antibacterial (antibacterial rate of 98.2%). BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 For indoor refrigeration evaluation: (a) Diagram of the homemade refrigeration evaluation device, (b) Temperature change of the sample under an indoor xenon lamp simulating 1 sun; Figure 2 The temperature change curve of cotton and the sample of Example 1 worn by a human body outdoors under sunlight; Figure 3 Environmental conditions for the outdoor test day: (a) wind speed and relative humidity, (b) solar radiation power. DETAILED DESCRIPTION The present invention will be further described below in conjunction with embodiments, which are explanations of the present invention and are not limited to the following embodiments: Example 1 A multifunctional super fabric for radiative cooling, the preparation method comprising the following steps: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 10:15:1.5, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated commercial cotton, the aerogel is loaded on the surface of the fabric to obtain a printed superfabric, which is pre-baked at 60°C for 5 minutes and then baked at 120°C for 5 minutes to obtain a multifunctional superfabric for radiative cooling; The method for preparing the titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol, the volume ratio of glacial acetic acid to anhydrous ethanol was 1:5, and the mass fraction of tetrabutyl titanate solution A was obtained after stirring; S1-2. Mix water and anhydrous ethanol in a volume ratio of 1:2, then add concentrated hydrochloric acid to adjust the pH to 1, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to solution A, and then a sheet of electrospun fiber membrane was added, and a gel was obtained after magnetic stirring for 1 hour; S1-4. The gel obtained in S1-3 was placed in a magnetic field for 100 minutes, and then the device was removed to obtain a gel oriented along the direction of the sheet of electrospun fiber membrane; S1-5. The gel obtained in S1-4 was oriented at -40 ° C and freeze-dried for 12 h to obtain titanium dioxide aerogel; Wherein, in said S1-3, the method for preparing the sheet-like electrospun fiber membrane comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 1:1 and stir magnetically at 40°C to obtain a homogeneous solution; S2-2. Add magnetic core-shell particles to the solution obtained in S2-1 and disperse by ultrasonic to obtain an electrospinning solution with a mass fraction of 5 wt %; S2-3. Use the electrospinning solution obtained in S2-2 to electrospin at a voltage of 15 kV and a flow rate of 1 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a particle size of 1 mm. 2 Sheet-like electrospun fiber membrane; Wherein, in said S2-2, the method for preparing magnetic core-shell particles comprises the following steps: S3-1. Take terephthalic acid and glacial acetic acid dihydrate in a mass ratio of 0.2:1 and add triethylamine, DMF and ethanol solution in a volume ratio of 1:3:14 to obtain a mixed solution; S3-2. The Fe3O4 suspension and the BaSO4 suspension having a volume ratio of 1:2 and a concentration ratio of 1:1 were added to the mixed solution obtained in S3-1 and magnetically stirred for 3h; S3-3. The product obtained in S3-2 was centrifuged and washed to obtain Fe3O4@MOF-5@BaSO4, and then the particles were dispersed in water to obtain a suspension A; S3-4. Mix water and titanium trichloride precursor in a volume ratio of 20:1, and then add a 1 mol / L sodium bicarbonate solution to adjust the pH to 2 to obtain solution B; S3-5. Add the suspension A obtained in S3-3 to the solution B obtained in S3-4, the ratio of the amount of Fe3O4@MOF-5@BaSO4 to the ferric chloride precursor in solution B is 1:1, react for 10 minutes, centrifuge, wash and dry to obtain core-shell structured magnetic particles. Example 2 A multifunctional super fabric for radiative cooling, the preparation method comprising the following steps: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 30:25:3, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated commercial cotton, the aerogel is loaded on the surface of the fabric to obtain a printed superfabric, which is pre-baked at 80°C for 10 min and then baked at 150°C for 10 min to obtain a multifunctional superfabric for radiative cooling; The method for preparing the titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol, the volume ratio of glacial acetic acid to anhydrous ethanol was 3:15, and after stirring, a tetrabutyl titanate solution A having a mass fraction of 70wt% was obtained; S1-2. Mix water and anhydrous ethanol in a volume ratio of 3:4, then add concentrated hydrochloric acid to adjust the pH to 3, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to solution A, followed by the addition of a sheet of electrospun fiber membrane, and a gel was obtained after magnetic stirring for 3 h; S1-4. The gel obtained in S1-3 was placed in a magnetic field for 500 min, and then the device was removed to obtain a gel oriented along the direction of the sheet-like static spun fiber membrane; S1-5. The gel obtained in S1-4 was oriented at -20°C and freeze-dried for 20 h to obtain titanium dioxide aerogel; Wherein, in said S1-3, the method for preparing the sheet-like electrospun fiber membrane comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 2.5:2.8 and stir magnetically at 60°C to obtain a homogeneous solution; S2-2. Add magnetic core-shell particles to the solution obtained in S2-1 and disperse by ultrasonic to obtain an electrospinning solution with a mass fraction of 20 wt %; S2-3. Use the electrospinning solution obtained in S2-2 to electrospin at a voltage of 20 kV and a flow rate of 1.5 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a size of 2 mm 2 Sheet-like electrospun fiber membrane; Wherein, in said S2-2, the method for preparing magnetic core-shell particles comprises the following steps: S3-1. Take terephthalic acid and glacial acetic acid dihydrate in a mass ratio of 0.6:1 and add triethylamine, DMF and ethanol solution in a volume ratio of 3:15:20 to obtain a mixed solution; S3-2. The Fe3O4 suspension and the BaSO4 suspension having a volume ratio of 3:5 and a concentration ratio of 4:9 were added to the mixed solution obtained in S3-1 and magnetically stirred for 3h; S3-3. The product obtained in S3-2 was centrifuged and washed to obtain Fe3O4@MOF-5@BaSO4, and then the particles were dispersed in water to obtain a suspension A; S3-4. Mix water and titanium trichloride precursor in a volume ratio of 20:1, and then add a 3 mol / L sodium bicarbonate solution to adjust the pH to 5 to obtain solution B; S3-5. The suspension A obtained in S3-3 was added to the solution B obtained in S3-4, the ratio of the amount of Fe3O4@MOF-5@BaSO4 to the ferric chloride precursor in solution B was 15:70, and after reacting for 50 minutes, the core-shell structured magnetic particles were obtained after centrifugal washing and drying. Example 3 A multifunctional super fabric for radiative cooling, the preparation method comprising the following steps: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 15:23:3, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated commercial cotton, the aerogel is loaded on the surface of the fabric to obtain a printed superfabric, which is pre-baked at 70°C for 8 minutes and then baked at 130°C for 10 minutes to obtain a multifunctional superfabric for radiative cooling; The method for preparing the titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol, the volume ratio of glacial acetic acid to anhydrous ethanol was 3:15, and after stirring, a mass fraction of 60wt% tetrabutyl titanate solution A was obtained; S1-2. Mix water and anhydrous ethanol in a volume ratio of 2:3, then add concentrated hydrochloric acid to adjust the pH to 2, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to solution A, followed by the addition of a sheet of electrospun fiber membrane, and a gel was obtained after magnetic stirring for 3 h; S1-4. The gel obtained in S1-3 was placed in a magnetic field for 400 min, and then the device was removed to obtain a gel oriented along the direction of the sheet-like static spun fiber membrane; S1-5. The gel obtained in S1-4 was oriented at -30°C and freeze-dried for 20 h to obtain titanium dioxide aerogel; Wherein, in said S1-3, the method for preparing the sheet-like electrospun fiber membrane comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 2:2.8 and stir them under magnetic stirring at 50°C to obtain a homogeneous solution; S2-2. Magnetic core-shell particles were added to the solution obtained in S2-1 and ultrasonically dispersed to obtain an electrospinning solution with a mass fraction of 15 wt %; S2-3. The electrospinning solution obtained in S2-2 was electrospun at a voltage of 18 kV and a flow rate of 1.3 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a size of 2 mm 2 Sheet-like electrospun fiber membrane; Wherein, in said S2-2, the method for preparing magnetic core-shell particles comprises the following steps: S3-1. Take terephthalic acid and glacial acetic acid dihydrate in a mass ratio of 0.5:1 and add triethylamine, DMF and ethanol solution in a volume ratio of 3:15:20 to obtain a mixed solution; S3-2. The Fe3O4 suspension and ZnO2 suspension with a volume ratio of 3:5 and a concentration ratio of 2:9 were added to the mixed solution obtained in S3-1 and magnetically stirred for 3h; S3-3. The product obtained in S3-2 was centrifuged and washed to obtain Fe3O4@MOF-5@ZnO2, and then the particles were dispersed in water to obtain a suspension A; S3-4. Mix water and titanium trichloride precursor in a volume ratio of 20:1, and then add a 2 mol / L sodium bicarbonate solution to adjust the pH to 5 to obtain solution B; S3-5. The suspension A obtained in S3-3 was added to the solution B obtained in S3-4, the ratio of the amount of Fe3O4@MOF-5@BaSO4 to the ferric chloride precursor in solution B was 13:70, and after reacting for 50 minutes, the core-shell structured magnetic particles were obtained after centrifugal washing and drying. Example 4 A multifunctional super fabric for radiative cooling, the preparation method comprising the following steps: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 20:17:2, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated commercial cotton, the aerogel is loaded on the surface of the fabric to obtain a printed superfabric, which is pre-baked at 75°C for 8 minutes and then baked at 160°C for 10 minutes to obtain a multifunctional superfabric for radiative cooling; The method for preparing the titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol, the volume ratio of glacial acetic acid to anhydrous ethanol was 3:15, and after stirring, a mass fraction of 60wt% tetrabutyl titanate solution A was obtained; S1-2. Mix water and anhydrous ethanol in a volume ratio of 2:3, then add concentrated hydrochloric acid to adjust the pH to 3, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to solution A, followed by the addition of a sheet of electrospun fiber membrane, and a gel was obtained after magnetic stirring for 3 h; S1-4. The gel obtained in S1-3 was placed in a magnetic field for 200 min, and then the device was removed to obtain a gel oriented along the direction of the sheet-like static spun fiber membrane; S1-5. The gel obtained in S1-4 was oriented at -35°C and freeze-dried for 18h to obtain titanium dioxide aerogel; Wherein, in said S1-3, the method for preparing the sheet-like electrospun fiber membrane comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 2:2.3 and stir them under magnetic stirring at 50°C to obtain a homogeneous solution; S2-2. Add magnetic core-shell particles to the solution obtained in S2-1 and disperse by ultrasonic to obtain an electrospinning solution with a mass fraction of 20 wt %; S2-3. Use the electrospinning solution obtained in S2-2 to electrospin at a voltage of 18 kV and a flow rate of 1.5 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a size of 1.5 mm 2 Sheet-like electrospun fiber membrane; Wherein, in said S2-2, the method for preparing magnetic core-shell particles comprises the following steps: S3-1. Take terephthalic acid and glacial acetic acid dihydrate in a mass ratio of 0.5:1 and add triethylamine, DMF and ethanol solution in a volume ratio of 3:15:20 to obtain a mixed solution; S3-2. The Fe3O4 suspension and the TiO2 suspension having a volume ratio of 2:5 and a concentration ratio of 2:9 were added to the mixed solution obtained in S3-1 and magnetically stirred for 3h; S3-3. The product obtained in S3-2 was centrifuged and washed to obtain Fe3O4@MOF-5@TiO2, and then the particles were dispersed in water to obtain a suspension A; S3-4. Mix water and titanium trichloride precursor in a volume ratio of 20:1, and then add 2.5 mol / L sodium bicarbonate solution to adjust the pH to 5 to obtain solution B; S3-5. Add the suspension A obtained in S3-3 to the solution B obtained in S3-4, the ratio of the amount of Fe3O4@MOF-5@TiO2 to the ferric chloride precursor in solution B is 10:65, react for 40 minutes, centrifuge, wash and dry to obtain core-shell structured magnetic particles. Example 5 A multifunctional super fabric for radiative cooling, the preparation method comprising the following steps: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 25:25:2, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated commercial cotton, the aerogel is loaded on the surface of the fabric to obtain a printed superfabric, which is pre-baked at 65°C for 8 minutes and then baked at 160°C for 9 minutes to obtain a multifunctional superfabric for radiative cooling; The method for preparing the titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol, the volume ratio of glacial acetic acid to anhydrous ethanol was 3:15, and after stirring, a mass fraction of 65wt% tetrabutyl titanate solution A was obtained; S1-2. Mix water and anhydrous ethanol in a volume ratio of 2:3, then add concentrated hydrochloric acid to adjust the pH to 3, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to solution A, followed by the addition of a sheet of electrospun fiber membrane, and a gel was obtained after magnetic stirring for 3 h; S1-4. The gel obtained in S1-3 was placed in a magnetic field for 300 min, and then the device was removed to obtain a gel oriented along the direction of the sheet-like static spun fiber membrane; S1-5. The gel obtained in S1-4 was oriented at -20°C and freeze-dried for 16 h to obtain titanium dioxide aerogel; Wherein, in said S1-3, the method for preparing the sheet-like electrospun fiber membrane comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 2:2.8 and stir magnetically at 55°C to obtain a homogeneous solution; S2-2. Add magnetic core-shell particles to the solution obtained in S2-1 and disperse by ultrasonic to obtain an electrospinning solution with a mass fraction of 15 wt %; S2-3. Use the electrospinning solution obtained in S2-2 to electrospin at a voltage of 20 kV and a flow rate of 1.2 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a particle size of 1 mm. 2 Sheet-like electrospun fiber membrane; Wherein, in said S2-2, the method for preparing magnetic core-shell particles comprises the following steps: S3-1. Take terephthalic acid and glacial acetic acid dihydrate in a mass ratio of 0.5:1 and add triethylamine, DMF and ethanol solution in a volume ratio of 2:13:17 to obtain a mixed solution; S3-2. The Fe3O4 suspension and the CaCO3 suspension having a volume ratio of 2:5 and a concentration ratio of 3:8 were added to the mixed solution obtained in S3-1 and magnetically stirred for 3h; S3-3. The product obtained in S3-2 was centrifuged and washed to obtain Fe3O4@MOF-5@CaCO3, and then the particles were dispersed in water to obtain a suspension A; S3-4. Mix water and titanium chloride precursor in a volume ratio of 20:1, and then add a 2.5 mol / L sodium bicarbonate solution to adjust the pH to 5 to obtain solution B; S3-5. The suspension A obtained in S3-3 was added to the solution B obtained in S3-4, the ratio of the amount of Fe3O4@MOF-5@CaCO3 to the ferric chloride precursor in solution B was 10:55, and after reacting for 45 minutes, the core-shell structured magnetic particles were obtained after centrifugal washing and drying. Comparative Example 1 The difference between Comparative Example 1 and Example 5 is that no magnetic core-shell structure particles are added to the titanium dioxide aerogel. A multifunctional super fabric for radiative cooling, the preparation method comprising the following steps: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 25:25:2, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated commercial cotton, the aerogel is loaded on the surface of the fabric to obtain a printed superfabric, which is pre-baked at 65°C for 8 minutes and then baked at 160°C for 9 minutes to obtain a multifunctional superfabric for radiative cooling; The method for preparing the titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol, the volume ratio of glacial acetic acid to anhydrous ethanol was 3:15, and after stirring, a mass fraction of 65wt% tetrabutyl titanate solution A was obtained; S1-2. Mix water and anhydrous ethanol in a volume ratio of 2:3, then add concentrated hydrochloric acid to adjust the pH to 3, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to solution A, followed by the addition of a sheet of electrospun fiber membrane, and a gel was obtained after magnetic stirring for 3 h; S1-4. The gel obtained in S1-3 was placed in a magnetic field for 300 min, and then the device was removed to obtain a gel oriented along the direction of the sheet-like static spun fiber membrane; S1-5. The gel obtained in S1-4 was oriented at -20°C and freeze-dried for 16 h to obtain titanium dioxide aerogel; Wherein, in said S1-3, the method for preparing the sheet-like electrospun fiber membrane comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 2:2.8 and stir magnetically at 55°C to obtain a homogeneous solution; S2-2. Fe3O4@MOF-5 particles and CaCO3 particles in a mass ratio of 1:1 were added to the solution obtained in S2-1 and ultrasonically dispersed to obtain an electrospinning solution with a mass fraction of 15 wt%; S2-3. The electrospinning solution obtained in S2-2 was electrospun at a voltage of 20 kV and a flow rate of 1.2 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a particle size of 1 mm. 2 Sheet-like electrospun fiber membrane. Comparative Example 2 The difference between Comparative Example 2 and Example 5 is that magnetic core-shell particles are added to the titanium dioxide aerogel without adding a sheet-like electrospinning membrane. Comparative Example 3 The difference between Comparative Example 3 and Example 5 is that the sheet-like electrospun fiber membrane in the titanium dioxide aerogel is not oriented. Comparative Example 4 The difference between Comparative Example 4 and Example 5 is that the titanium dioxide aerogel is dispersed in the adhesive layer for scraping. Comparative Example 5 The difference between Comparative Example 5 and Example 5 is that the titanium dioxide aerogel is not subjected to directional freeze-drying. Performance Testing The following is a performance test of the samples prepared in Examples 1-5 of the present invention and Comparative Examples 1-5. It can be seen from Table 1 that compared with the comparative example, the multifunctional super fabric radiant cooling coating of each embodiment has better cooling effect and longer service life performance, the emissivity of 8μm-13μm is greater than 95%, and the reflectivity of 0.3μm-2.5μm is greater than 96%. The emissivity and reflectivity of the samples in Table 1 It can be seen from Table 2 that the test results of Example 5 are the best, showing good flame retardant and waterproof effects. Table 2 Flame retardant and waterproof test results Smoldering time(s) Limiting oxygen index (%) Contact angle (°) Hydrostatic pressure resistance Example 1 0.7 26.1 135 11.22 Example 2 1 25 131.5 10.09 Example 3 0.8 27 133.1 10.03 Example 4 0.9 26.7 134.8 10.11 Example 5 0.4 30.1 141.6 13.52 Comparative Example 1 1.2 24.8 130 10.10 Comparative Example 2 0.8 27.1 135.2 10.86 Comparative Example 3 0.7 26.3 131.2 10.53 Comparative Example 4 0.9 25.8 131.8 11.02 Comparative Example 5 0.8 26.8 130.1 11.17 It can be seen from Table 3 that Example 5 has the best antibacterial effect, with an antibacterial rate of 98.72% against Staphylococcus aureus. Table 3 Antibacterial performance test of different samples Note: 1. AM1.5 solar spectrum reflectance test: The spectral reflectance in the band of 200-2500nm is tested and characterized. The test instrument used is UV3600 of Shimadzu Corporation of Japan, and the standard backplane used in the test is BaSO4 backplane; 2.8μm-13μm band emissivity test method: Use infrared spectroscopy to test, the test instrument is Fourier transform infrared spectrometer, test the infrared emissivity of 8μm-13μm band, the test interval is 1nm, the emissivity of 8μm-13μm band is the atmospheric window emissivity; 3. Refrigeration performance evaluation: All temperature measurements were recorded using TA612C thermocouples, and the relative error between thermocouples was less than 0.5°C. Figure 1 The measurement device includes a polystyrene foam box wrapped in aluminum foil to minimize heat transfer and reflect sunlight. The test fabric samples are visualized in real time using an infrared thermal imager (UTi320E). Combined with a real human outdoor experiment, volunteers wearing the test samples (different fabrics on the left and right sides of the clothes, i.e., one side of the super fabric and one side of the pure cotton fabric) face the direction of the sun. The temperature of the fabrics of different fabrics and the skin temperature with or without super fabric coverage are recorded using thermocouples. The environmental conditions on the day of the experiment, such as temperature and humidity, wind speed, solar radiation power, etc., are also recorded. 4. Flame retardant test: Test the vertical combustion of super fabrics according to the national standard GB / T5455 and the limiting oxygen index of super fabrics according to CB / T5454; 5. Waterproof test: Use a contact angle meter to test the contact angle of the super fabric; use the YG(B)812Q textile hydrostatic pressure tester to test the hydrostatic pressure resistance of the super fabric in accordance with GB / T4744-2013 "Hydrostatic pressure test for detection and evaluation of waterproof performance of textiles". 6. Antibacterial test: Test the antibacterial properties of the super fabric according to the national standard GB / T 20944. Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A multifunctional super fabric for radiative cooling, characterized in that: The fabric comprises a fabric layer, a bonding layer and an aerogel layer, wherein the fabric layer and the aerogel layer are compounded via the bonding layer, and the aerogel layer is a titanium dioxide aerogel with a three-dimensional tubular structure and a sheet-like electrostatically spun fiber membrane containing magnetic core-shell particles is loaded on the skeleton.

2. The method for preparing the multifunctional super fabric for radiative cooling according to claim 1, characterized in that: The following steps are involved: S1. Take polytetrafluoroethylene emulsion, binder and thickener in a mass ratio of 10 to 30:15 to 25:1.5 to 3, stir evenly to obtain a color paste; S2. After the color paste is evenly scraped onto the pretreated fabric, titanium dioxide aerogel is loaded on the fabric surface to obtain a printed super fabric, which is then pre-baked and baked to obtain a multifunctional super fabric for radiant cooling.

3. The method for preparing the multifunctional super fabric for radiative cooling according to claim 2, characterized in that: The pretreated fabric is one of commercial cotton, polyester, nylon, linen, silk or spandex fabrics, the pre-baking time is 5 to 10 minutes, the pre-baking temperature is 60 to 80°C, the baking time is 5 to 10 minutes, and the baking temperature is 120 to 150°C.

4. The method for preparing the multifunctional super fabric for radiative cooling according to claim 2, characterized in that: The preparation method of the titanium dioxide aerogel in S2 comprises the following steps: S1-1. After tetrabutyl titanate and glacial acetic acid were mixed, they were added to anhydrous ethanol and stirred to obtain a homogeneous solution A; S1-2. Mix water and anhydrous ethanol in a volume ratio of 1 to 3: 2 to 4, then add concentrated hydrochloric acid to adjust the pH to 1 to 3, and stir to obtain solution B; S1-3. Solution B was slowly added dropwise to the homogenized solution A, followed by the addition of the sheet-like electrospun fiber membrane, and the gel was obtained after magnetic stirring for 1 to 3 hours; S1-4. The gel obtained in S1-3 is placed in a magnetic field for 100 to 500 minutes, and then the device is removed to obtain a gel oriented along the direction of the sheet-like static spun fiber membrane; S1-5. Orient the gel obtained in S1-4 at -40 to -20°C and freeze-dry for 12 to 20 hours to obtain titanium dioxide aerogel.

5. The method for preparing the multifunctional super fabric for radiative cooling according to claim 4, characterized in that: The mass of tetrabutyl titanate in S1-1 is 55-70% of that in solution A, and the volume ratio of glacial acetic acid to anhydrous ethanol is 1-3:5-15.

6. The method for preparing the multifunctional super fabric for radiative cooling according to claim 4, characterized in that: The method for preparing the sheet-like electrospun fiber membrane in S1-3 comprises the following steps: S2-1. Take tetrabutyl titanate and glacial acetic acid in a molar ratio of 1 to 2.5:1 to 2.8, and stir magnetically at 40 to 60°C to obtain a homogeneous solution; S2-2. Add magnetic core-shell particles to the solution obtained in S2-1 and ultrasonically disperse to obtain an electrospinning solution with a mass fraction of 5 to 20 wt%; S2-3. The electrospinning solution obtained in S2-2 was electrospun at a voltage of 15 to 20 kV and a flow rate of 1 to 1.5 mL / h to obtain an electrospun fiber membrane; S2-4. The electrospun fiber membrane obtained in S2-3 was crushed to obtain a particle size of 1 to 2 mm. 2 Sheet-like electrospun fiber membrane.

7. The method for preparing the multifunctional super fabric for radiative cooling according to claim 6, characterized in that: The method for preparing the magnetic core-shell particles in S2-2 comprises the following steps: S3-1. Take terephthalic acid and glacial acetic acid dihydrate in a mass ratio of 0.2 to 0.6:1 and add them to a triethylamine, DMF and ethanol solution in a volume ratio of 1 to 3:3 to 15:14 to 20 to obtain a mixed solution; S3-2. Add Fe3O4 suspension and inorganic particle suspension in a volume ratio of 1 to 3:2 to 5 to the mixed solution obtained in S3-1 and stir magnetically for 3 h; S3-3. The product obtained in S3-2 was centrifuged and washed to obtain Fe3O4@MOF-5@inorganic particles, and then the particles were dispersed in water to obtain a suspension A; S3-4. Mix water and titanium trichloride precursor in a volume ratio of 20:1, and then add a sodium bicarbonate solution having a concentration of 1 to 3 mol / L to adjust the pH to 2 to 5 to obtain a solution B; S3-5. Add the suspension A obtained in S3-3 to the solution B obtained in S3-4 and react for 10 to 50 minutes. After centrifugal washing and drying, magnetic core-shell particles are obtained.

8. The method for preparing the multifunctional super fabric for radiative cooling according to claim 7, characterized in that: The concentration ratio of the Fe3O4 suspension to the inorganic particle suspension in the S3-2 is 1-4:1-9, and the inorganic particle suspension is one or more of a BaSO4 suspension, a CaCO3 suspension, an Al2O3 suspension, a TiO2 suspension, a ZnO2 suspension, an AlPO4 suspension, a hollow glass microsphere suspension or a SiC suspension.

9. The method for preparing the multifunctional super fabric for radiative cooling according to claim 8, characterized in that: The ratio of the amount of Fe3O4@MOF-5@inorganic particles contained in the suspension A in S3-5 to the amount of ferric chloride precursor substance in the solution B is 1:15 to 1:70.

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