Radiation refrigeration mycelium material with biological simulation elephant skin structure and preparation method of radiation refrigeration mycelium material

Abstract

The invention discloses a radiation refrigeration mycelium material with a biological simulation elephant skin structure and a preparation method of the radiation refrigeration mycelium material, and belongs to the technical field of functional composite materials and green energy. The radiation refrigeration mycelium composite material is prepared by taking biological simulation mycelium as a substrate and loading double-layer nano-scale particles of a silicon dioxide layer and a PTFE layer, so that the problems that an existing radiation refrigeration material is low in radiation efficiency, a loading coating is easy to fall off, the environmental friendliness is poor and the like are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a radiation cooling mycelium material with a bio-simulated elephant skin structure and a preparation method thereof, and belongs to the field of functional composite materials and green energy technology. BACKGROUND

[0002] In recent years, with the intensification of global energy crisis, global climate warming and environmental pollution problems, the development of new energy-saving and environment-friendly materials has become a research hotspot. Among them, passive radiation cooling technology can achieve efficient cooling without external energy input, and has great potential in building energy saving, electronic equipment cooling and outdoor protection. However, traditional radiation cooling materials often use petroleum-based polymers and rare earth metals as substrates. Such materials are not renewable, difficult to degrade, consume a lot of energy and produce a large amount of carbon emissions, which will pose a long-term threat to the ecological environment.

[0003] Many existing patents have studied passive radiation cooling materials, such as Chinese patent CN118757939A which uses polyvinyl chloride and other composite materials as the substrate; Chinese patent CN120192570A uses ceramic as the substrate to load nano thin film; Chinese patent CN1144752220A uses a polydimethylsiloxane matrix composite material. These common radiation cooling materials are mostly non-degradable and produce a large amount of carbon dioxide and consume non-renewable energy during production, causing serious pollution to the ecological environment. Moreover, the applicant's experiments have found that single materials and single-layer loaded materials have poor radiation cooling potential.

[0004] Therefore, the development of a biodegradable material based on a biodegradable substrate with high-efficiency radiation cooling performance not only promotes the development of green cooling technology, but also reduces the negative impact of traditional materials on the ecological environment, which has important scientific significance and application value. SUMMARY

[0005] [TECHNICAL PROBLEM]

[0006] To solve the above problems, the present application uses a bio-simulated mycelium to load double-layer nano particles to prepare a radiation cooling mycelium composite material with a hydrophobic layer, in order to solve the problems of low radiation efficiency, easy peeling of the loaded coating and poor environmental friendliness of existing radiation cooling materials.

[0007] [TECHNICAL SCHEME]

[0008] The present application includes three aspects of innovation and improvement: first, the material itself is more green and sustainable and has natural radiation cooling performance; second, natural cooling examples are found in nature to improve the morphology of the material to enhance radiation cooling performance; third, double-layer particles are covered to help the interaction between particles for radiation cooling.

[0009] The mycelium composite material can achieve the standard of green and sustainable development. In addition, the traditional radiation cooling material mainly focuses on the emissivity of the first atmospheric window (8-13 microns), often ignoring the emissivity of the second atmospheric window (16-25 microns). The natural staggered three-dimensional structure in the mycelium can enhance the emissivity of the second atmospheric window, and the structure loaded with double-layer nanoparticles can improve the solar reflectivity and the emissivity of the double atmospheric window by using the refractive index difference.

[0010] The application provides a preparation method of a radiation cooling mycelium material.

[0011] (1) Preparation of an elephant skin mycelium substrate: inoculate the strain into a fungus bag containing culture material and cultivate for a period of time until the mycelium covers the fungus bag; then, lay the fungus bag loosely in an elephant skin mold and continue to cultivate for a period of time, demold, and obtain an elephant skin mycelium substrate;

[0012] (2) Pretreatment of the elephant skin mycelium substrate: soak the elephant skin mycelium substrate obtained in step (1) in an ethanol aqueous solution containing a silane coupling agent, and then dry;

[0013] (3) Loading of a silicon dioxide layer: mix tetraethyl orthosilicate (TEOS), anhydrous ethanol, deionized water and a catalyst to obtain a mixed solution; soak the pretreated elephant skin mycelium substrate in the mixed solution, dry after soaking, and obtain a mycelium loaded with silicon dioxide;

[0014] (4) Loading of a polytetrafluoroethylene (PTFE) layer: respectively disperse the adhesive and PTFE in water to obtain an adhesive solution and a PTFE dispersion; slowly drop the adhesive solution into the PTFE dispersion, stir, and obtain a mixed dispersion; soak the mycelium loaded with silicon dioxide obtained in step (3) in the mixed dispersion, dry and solidify after soaking, and obtain a radiation cooling mycelium material loaded with silicon dioxide and PTFE.

[0015] In an embodiment of the application, in step (1), the fungus bag containing culture material is prepared by the following method: mix cottonseed hulls, corn cobs, bran, soybean meal and flour, then add an aqueous solution containing potassium dihydrogen phosphate, soluble starch, glucose, calcium carbonate and peptone, stir uniformly to form culture material, and then load the culture material into a polypropylene fungus bag, sterilize, and obtain the fungus bag.

[0016] In an embodiment of the application, in the preparation process of the fungus bag, the mass ratio of cottonseed hulls, corn cobs, bran, soybean meal and flour is 6:2:1:0.5:0.5.

[0017] In an embodiment of the application, in the preparation process of the fungus bag, the water content of the culture material is 55-65%.

[0018] In one embodiment of the present invention, during the preparation of the spawn bag, the concentration of potassium dihydrogen phosphate in the aqueous solution is 0.75 g / L, the concentration of soluble starch is 15 g / L, the concentration of glucose is 20 g / L, the concentration of calcium carbonate is 2 g / L, and the concentration of peptone is 5 g / L.

[0019] In one embodiment of the present invention, the sterilization conditions during the preparation of the spawn bag are: high-pressure steam sterilization at 120°C and 0.1 MPa for 30 minutes.

[0020] In one embodiment of the present invention, in step (1), the inoculation method is as follows: inoculate the spawn onto the stick and then insert the stick into the spawn bag.

[0021] In one embodiment of the present invention, in step (1), the inoculation amount of the strain is 5%-10% of the weight of the substrate bag. Specifically, 8% is an option.

[0022] In one embodiment of the present invention, in step (1), the strain is a fungal strain. The fungal strain is selected from any one or more combinations of the following: oyster mushroom, Ganoderma lucidum, button mushroom, enoki mushroom, tea tree mushroom, morel mushroom, silver ear fungus, wood ear fungus, king oyster mushroom, straw mushroom, shiitake mushroom, Poria cocos, pleurotus ostreatus, white jade mushroom, button mushroom, and button mushroom.

[0023] In one embodiment of the present invention, in step (1), the inoculum is inoculated into a fungal bag containing culture medium at 25-30°C for 6-10 days until the mycelium fully grows on the fungal bag; then the fungal bag is loosely laid flat in an elephant skin mold at 25-30°C, humidity of 85%-96%, and CO2 concentration of 2-4% for 7-15 days.

[0024] In one embodiment of the present invention, in step (1), after demolding, a drying process can be performed at a temperature of 60°C for 1 to 2 hours.

[0025] In one embodiment of the present invention, in step (1), the strains introduced into the inoculation bag can be activated in advance, and the strains are inoculated on PDA culture medium plates and cultured in a constant temperature incubator until the mycelium covers the plate.

[0026] In one embodiment of the present invention, in step (2), the concentration of ethanol in the aqueous ethanol solution is 30 vol% to 50 vol%.

[0027] In one embodiment of the present invention, in step (2), the concentration of the silane coupling agent in the ethanol aqueous solution containing the silane coupling agent is 2wt%-5wt%.

[0028] In one embodiment of the present invention, in step (2), the silane coupling agent may specifically be 3-aminopropyltriethoxysilane.

[0029] In one embodiment of the present application, in step (2), the soaking time is 30 min.

[0030] In one embodiment of the present application, in step (2), the drying condition is 60 °C for 1-1.5 h.

[0031] In one embodiment of the present application, in step (3), the catalyst includes, but is not limited to, any one or a combination of more than one of the following: ammonia, tetramethylammonium hydroxide (TMAH), triethylamine (TEA), ammonium carbonate, acetic acid, hydrochloric acid, nitric acid, and silicatein.

[0032] In one embodiment of the present application, in step (3), the catalyst is ammonia, and the volume ratio of TEOS, anhydrous ethanol, deionized water, and ammonia is 1:4:4:0.1.

[0033] Further, the catalyst is 0.1 M ammonia.

[0034] In one embodiment of the present application, in step (3), the pH of the mixed solution is 8-9.

[0035] In one embodiment of the present application, in step (3), the soaking condition is 40 °C for 1-2 h.

[0036] In one embodiment of the present application, in step (3), the drying condition is 60 °C for 1-1.5 h.

[0037] In one embodiment of the present application, in step (4), the binder includes, but is not limited to, any one or a combination of more than one of the following: polyvinyl alcohol (PVA), water-based polyurethane (WPU), chitosan, sodium alginate, lignin sulfonate, silane coupling agent (APTES), and polyethylene glycol (PEG). Polyvinyl alcohol is preferred.

[0038] In one embodiment of the present application, in step (4), the concentration of the binder solution is 2 wt%-10 wt%. Further, 3-5 wt% is preferred.

[0039] In one embodiment of the present application, in step (4), the concentration of the PTFE dispersion liquid is 20 wt%-30 wt%. Specifically, 25 wt% can be selected.

[0040] In one embodiment of the present application, in step (4), the volume ratio of the binder solution to the PTFE dispersion liquid is 5-10:1. Specifically, 9:1 can be selected.

[0041] In an embodiment of the present application, in step (4), the stirring condition is 200-300 rpm, 30-40℃, and 15-20 min.

[0042] In an embodiment of the present application, in step (4), the soaking condition is 30-40℃, 1-2 h.

[0043] In an embodiment of the present application, in step (4), the solidification temperature is 60℃, and the time is 1-2 h.

[0044] The present application provides a radiation cooling mycelium material prepared based on the above method.

[0045] The present application also provides the application of the above radiation cooling mycelium material in the fields of building energy saving, electronic equipment heat dissipation, and outdoor protection.

[0046] Advantages:

[0047] The present application uses biological simulated mycelium as a substrate, and loads double-layer nano particles of silica layer and PTFE layer to prepare a radiation cooling mycelium composite material. The present application uses mycelium as a substrate, which is green and sustainable, and the obtained composite material has an infrared emissivity of 96.4%, a solar reflectivity of 89.3%, a thermal conductivity as low as 0.04 W / m*k, and a net radiation cooling power of 48.5 W / m 2 , and has excellent radiation cooling effect. The present application loads silica by in-situ synthesis, so that the surface covering layer is firm and not easy to fall off, and solves the problems of low radiation efficiency, easy falling off of the loaded coating, and poor environmental friendliness of the existing radiation cooling materials. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 Fig. 1 is a structural schematic diagram of the radiation cooling mycelium material with a biological simulated elephant skin structure of the present application. The mycelium substrate is loaded with a silica layer and a PTFE layer. DETAILED DESCRIPTION

[0049] In order to better understand the present application, the present application will be further described in detail in combination with examples, but the scope of protection claimed by the present application is not limited to the scope represented by the examples.

[0050] The following access to the strain of the fungus package can be activated in advance, the specific activation process includes: 200g / L potato powder, 20g / L glucose, 18g / L agar and water are mixed, pH is 5-6, 120℃ high temperature sterilization 20min. Cool to 55℃ at room temperature, pour into the plate, make PDA plate. The strain is inoculated into the plate before activation, and the flame sterilization is required. A small amount of strain is taken with a inoculation ring, and a "Z" shape is drawn on the PDA plate. Burn the inoculation ring after each draw, and cool it down before taking the strain again. The prepared medium is cultured at 28℃ for 3-6 days, and the surface is observed to be covered with white velvet mycelium.

[0051] The specific operation steps of inoculating the strain on the wooden stick are as follows: select a certain number of wooden sticks about 10cm long, first soak in water for more than 48 hours; then mix the bran and starch evenly, evenly cover the surface of each wooden stick, sterilize and cool after completion; then take the Ganoderma applanatum strain from the PDA medium and inoculate it on the wooden stick, and culture it at 28℃ for 5-7 days. After the surface of the wooden stick is covered with mycelium, insert it into the fungus package in a sterile environment in a clean bench.

[0052] Example 1: Preparation of radiation cooling mycelium material

[0053] (1) Preparation of biomimetic elephant skin mycelium substrate: 60wt% cottonseed hulls, 20wt% corn cob, 10wt% bran, 5wt% soybean meal, 5wt% flour are mixed, then water is added to make the culture medium contain about 65wt% water, and the water contains exogenous nutrients potassium dihydrogen phosphate 0.75g / L, soluble starch 15g / L, glucose 20g / L, calcium carbonate 2g / L, and peptone 5g / L. The uniformly stirred culture medium is filled into a polypropylene fungus bag, and steam sterilized at a temperature of 120℃ and a pressure of 0.1Mpa for 30min. After sterilization, the fungus package is prepared, and the weight of Ganoderma applanatum strain is 8% on the 10cm wooden stick. The wooden stick is inserted into the fungus package and cultured at 27℃ for 10d until the mycelium covers the fungus package. The fungus package is spread flat in the elephant skin mold, and cultured at a temperature of 27℃, a humidity of 90%, a CO2 concentration of 2.5%, and no light for 10d, then demolded to obtain the biomimetic elephant skin mycelium substrate.

[0054] (2) Pretreatment of biomimetic elephant skin mycelium substrate: the biomimetic elephant skin mycelium substrate obtained in step (1) is soaked in 45vol% ethanol aqueous solution containing 2wt% silane coupling agent (3-aminopropyl triethoxysilane) for 30min, and the mycelium is pretreated, then dried in a 60℃ oven for 45min.

[0055] (3) Silica loading layer: TEOS, anhydrous ethanol, deionized water, ammonia water were mixed in a volume ratio of 1:4:4:0.1 to obtain a mixed solution; wherein the ammonia water concentration was about 0.1M, and the measured solution pH was about 8-9; the pretreated biomimetic elephant skin mycelium substrate was soaked in the mixed solution for 1h at a temperature of 40℃, and then dried in a 60℃ oven for 1h to obtain a mycelium loaded with silica.

[0056] (4) PTFE loading layer: 5g of polyvinyl alcohol particles were dissolved in 95ml of deionized water, heated to 90℃ in a water bath, and stirred for 1h until completely dissolved to prepare a 5wt% polyvinyl alcohol solution; a 60% solid content PTFE aqueous solution was mixed with deionized water to prepare a 25wt% PTFE dispersion; the 5% polyvinyl alcohol solution and the 25wt% PTFE dispersion were mixed in a volume ratio of 9:1, the polyvinyl alcohol solution was slowly added to the PTFE dispersion, and magnetic stirring was carried out at a speed of 300rpm and a temperature of 30℃ for 15min to obtain a mixed dispersion; the mycelium loaded with silica obtained in step (3) was soaked in the mixed dispersion for 2h at 30℃, and then solidified in a 60℃ oven for 1h after soaking to obtain a mycelium radiative cooling material loaded with silica and PTFE.

[0057] Example 2

[0058] Effect of different catalysts on the radiative cooling performance of the material when loading a silica layer

[0059] Referring to Example 1, only the type of catalyst in step (3) was different, and the catalyst was replaced with tetramethylammonium hydroxide, acetic acid, hydrochloric acid, and silicic acid esterase, respectively, and other conditions were the same to prepare different radiative cooling mycelium materials.

[0060] The solar reflectivity, infrared emissivity, and net radiative cooling power of the mycelium radiative cooling materials obtained using different catalysts were tested, and the results are shown in Table 1.

[0061] Solar reflectivity test: an ultraviolet-visible-near infrared spectrophotometer (UV-Vis-NIR) was used to measure the reflectance spectrum in the wavelength range of 250-2500nm with an integrating sphere. The calculation formula is:

[0062] Infrared emissivity test: a Fourier transform infrared spectrometer (FTIR) was used to measure the emission spectrum in the wavelength range of 4-25 microns with an integrating sphere. The calculation formula is:

[0063] Net radiative cooling power calculation formula: P cool = P rad - P atm - P solar - P conv+cond

[0064] Among them, P rad P represents the radiated power of a material into space. atm For atmospheric back radiation, P solar To absorb solar radiation, P conv+cond This is due to heat loss through conduction.

[0065] Table 1: Effect of different catalysts on the radiative cooling performance of materials in Examples 1-5

[0066]

[0067] Different catalysts have different effects on the radiation cooling performance of mycelium. As shown in Table 1, ammonia water has the best effect on the radiation cooling performance of mycelium.

[0068] Example 3

[0069] Effect of different catalyst concentrations on the radiative cooling performance of materials coated with silica layers

[0070] Referring to Example 1, only the catalyst concentration in step (3) is different, being replaced with 0.05M, 0.2M, and 0.5M respectively, while other conditions remain the same, different radiation-cooled mycelial materials can be prepared.

[0071] The silica layer, solar reflectance, infrared emissivity, and net radiative cooling power of mycelia catalyzed by different catalyst concentrations were tested, and the results are shown in Table 2.

[0072] Silica layer: Obtained from SEM scan image analysis.

[0073] Table 2: Effect of different catalyst concentrations on the radiative cooling performance of the material

[0074]

[0075]

[0076] Different catalyst concentrations have different effects on the radiative cooling performance of mycelium. If the concentration is too low, the silica layer is too thin, and if the concentration is too high, the silica layer is too thick. As shown in Table 2, 0.1M ammonia water has the best effect on the radiative cooling performance of mycelium.

[0077] Example 4

[0078] Effect of different immersion times on the radiative cooling performance of materials coated with silica layers

[0079] Referring to Example 1, only the soaking time in step (3) is different. The soaking time is replaced with 0.5h, 2h and 4h respectively, while other conditions are the same, and different radiation-cooled mycelial materials can be obtained.

[0080] The mycelium of different soaking time was tested for silicon dioxide layer, solar reflectivity, and infrared emissivity, and the results are shown in Table 3.

[0081] Table 3: Effect of different soaking time on the radiation cooling performance of the material

[0082]

[0083] The mycelium of different soaking time was tested for silicon dioxide layer, solar reflectivity, and infrared emissivity, and the results are shown in Table 3.

[0084] Example 5

[0085] Effect of different soaking temperature on the radiation cooling performance of the material when loaded with a silicon dioxide layer

[0086] Referring to Example 1, only the soaking temperature in step (3) is different, and the soaking time is replaced with 25°C and 60°C, respectively, and other conditions are consistent, different radiation cooling mycelium materials can be prepared.

[0087] The mycelium of different soaking temperature was tested for solar reflectivity and infrared emissivity, and the results are shown in Table 4.

[0088] Table 4: Effect of different soaking temperature on the radiation cooling performance of the material

[0089]

[0090]

[0091] The mycelium of different soaking temperature was tested for solar reflectivity and infrared emissivity, and the results are shown in Table 4.

[0092] Example 6

[0093] Effect of different adhesives on the radiation cooling performance of the material when loaded with a PTFE layer

[0094] Referring to Example 1, only the adhesive in step (4) is different, and the adhesive is replaced with water-based polyurethane, acrylic, chitosan, and epoxy resin, respectively, and other conditions are consistent, different radiation cooling mycelium materials can be prepared.

[0095] The mycelium of different adhesives was tested for solar reflectivity and infrared emissivity, and the results are shown in Table 5.

[0096] Table 5: Effect of different adhesives on the radiation cooling performance of the material

[0097] Adhesive Solar reflectance Infrared emittance Polyvinyl alcohol (Example 1) 89.3％ 96.4％ Aqueous polyurethane 80.1％ 89.2％ Acrylic 75.5％ 86.5％ Chitosan 73.9％ 91.7％ Epoxy 68.7％ 85.1％

[0098] Different adhesives have different effects on the radiation cooling performance of mycelium. As shown in Table 5, PVA adhesive has the best effect on the radiation cooling performance of mycelium.

[0099] Example 7

[0100] Effect of different adhesive concentrations on the radiation cooling performance of materials when loaded with PTFE layer

[0101] Referring to Example 1, only the adhesive concentration in step (4) is different, and the adhesive concentration is replaced with 1%, 3%, and 8%, respectively, and other conditions are the same, different radiation cooling mycelium materials can be prepared.

[0102] The solar reflectivity and infrared emissivity of mycelium with different adhesive concentrations were tested, and the results are shown in Table 6.

[0103] Table 6: Effect of different adhesive concentrations on the radiation cooling performance of materials

[0104]

[0105]

[0106] Different adhesive concentrations have different effects on the radiation cooling performance of mycelium. If the adhesive concentration is too low, the material is not fully covered by PTFE, and the uniformity is poor. If the adhesive concentration is too high, the PTFE layer is too thick, and the light transmittance decreases. As shown in Table 6, 5% adhesive has the best effect on the radiation cooling performance of mycelium.

[0107] Example 8

[0108] Effect of different magnetic stirring times of the prepared solution on the radiation cooling performance of materials when loaded with PTFE layer

[0109] Referring to Example 1, only the magnetic stirring time of the prepared solution in step (4) is different, and the magnetic stirring time is replaced with 5 min and 30 min, respectively, and other conditions are the same, different radiation cooling mycelium materials can be prepared.

[0110] The solar reflectivity and infrared emissivity of mycelium with different magnetic stirring times were tested, and the results are shown in Table 7.

[0111] Table 7: Effect of different magnetic stirring times on the radiation cooling performance of materials

[0112] Magnetic stirring time Solar reflectance Infrared emittance 15 min (Example 1) 89.3％ 96.4％ 5 min 74.5％ 85.3％ 30 min 83.5％ 91.2％

[0113] Different magnetic stirring times have different effects on the radiation cooling performance of mycelium. If the time is too short, the PTFE particles are not evenly dispersed, and if the time is too long, the PTFE particles are easily broken, and the solution stability is low. As shown in Table 7, magnetic stirring for 15 min has the best effect on the radiation cooling performance of mycelium.

[0114] Example 9

[0115] Influence of different magnetic stirring speeds of the prepared solution on the radiation refrigeration performance of the material when loading the PTFE layer

[0116] Referring to Example 1, only the magnetic stirring speed of the prepared solution in step (4) is different, and the magnetic stirring speed is replaced by 100 rpm and 400 rpm respectively, and other conditions are the same, different radiation refrigeration mycelium materials can be prepared.

[0117] The solar reflectance and infrared emissivity of the mycelium with different magnetic stirring speeds are tested, and the results are shown in Table 8.

[0118] Table 8: Influence of different magnetic stirring speeds on the radiation refrigeration performance of the material

[0119] Magnetic stirring speed Solar reflectance Infrared emittance 300 rpm (Example 1) 89.3％ 96.4％ 100 rpm 77.8％ 92.1％ 400 rpm 76.6％ 88.3％

[0120] The influence of different magnetic stirring speeds on the radiation refrigeration performance of the mycelium is different, the PTFE particles are not uniformly dispersed when the stirring speed is too small, and the PTFE particles are easily broken when the stirring speed is too large, the solution is foamed, and it can be known from Table 8 that the magnetic stirring speed of 300 rpm has the best effect on the radiation refrigeration performance of the mycelium.

[0121] Example 10

[0122] Influence of different solidification times on the radiation refrigeration performance of the material when loading the PTFE layer

[0123] Referring to Example 1, only the solidification time in step (4) is different, and the solidification time is replaced by 0.5 h and 2 h respectively, and other conditions are the same, different radiation refrigeration mycelium materials can be prepared.

[0124] The solar reflectance and infrared emissivity of the mycelium with different solidification times are tested, and the results are shown in Table 9.

[0125] Table 9: Influence of different solidification times on the radiation refrigeration performance of the material

[0126] Curing time Solar reflectance Infrared emittance 1 h (Example 1) 89.3％ 96.4％ 0.5h 74.5％ 86.2％ 2h 81.4％ 92.3％

[0127] The influence of different solidification temperatures on the radiation refrigeration performance of the mycelium is different, the adhesion of PTFE is low and the film forming quality is poor when the solidification time is too short, and the PTFE layer is slightly shrunk and the film forming quality is poor when the solidification time is too long, and it can be known from Table 9 that the solidification time of 1 h has the best effect on the radiation refrigeration performance of the mycelium.

[0128] Comparative Example 1

[0129] The radiation refrigeration mycelium material loaded with a silica layer and a PTFE layer has a flat surface.

[0130] The elephant leather mold in step (1) in Example 1 was replaced with a flat silica gel mold, and the rest was consistent with Example 1.

[0131] Example 1 and Comparative Example 1 were tested for solar emittance, infrared emittance, and net radiative cooling power, and the test results are shown in Table 10.

[0132] Table 10

[0133]

[0134] The biomimetic elephant leather structure makes the mycelium surface undulate, increases the roughness, enhances the strong light scattering of the mycelium material surface, and significantly improves the solar reflectivity and net radiative cooling power.

[0135] Comparative Example 2: Biomimetic elephant leather radiative cooling mycelium material without a PTFE layer

[0136] Step (4) in Example 1 was omitted, and the rest was consistent with Example 1.

[0137] Comparative Example 3: Biomimetic elephant leather radiative cooling mycelium material without a silica layer

[0138] Step (3) in Example 1 was omitted, and the rest was consistent with Example 1.

[0139] The biomimetic elephant leather radiative cooling mycelium materials prepared in Example 1 and Comparative Examples 2 and 3 were tested for solar emittance, infrared emittance, net radiative cooling power, and hydrophobicity, and the test results are shown in Table 11.

[0140] Hydrophobicity test: The water contact angle was measured using a contact angle meter.

[0141] Table 11

[0142]

[0143] Solar reflectivity and infrared emittance are important indicators for measuring the radiative cooling performance of materials. The biomimetic elephant leather mycelium material without a PTFE layer has acceptable infrared emittance, but lower solar reflectivity and net radiative power. Meanwhile, the material has a small water contact angle and poor hydrophobicity, and poor stability in the environment. The biomimetic elephant leather mycelium material without a silica layer has good hydrophobicity, but lower solar reflectivity, infrared emittance, and net radiative cooling power, and poor overall radiative cooling performance.

[0144] Comparative Example 4: Radiative cooling material with a cotton fabric base, a silica layer, and a PTFE layer

[0145] (1) Preparation of biomimetic elephant leather cotton fabric substrate: cotton fabric was immersed in 0.5M NaOH solution, and reacted in a water bath heating environment at 80°C for 30 min. After the reaction, it was washed to neutral and dried to constant weight in an oven at 60°C. The treated cotton fabric was immersed in a 5% gelatin solution, soaked at 30°C for 15 min, and then the solution retention rate was about 80% by mangle. It was first placed in an oven at 80°C for 10 min, and then in an oven at 120°C for heat treatment for 5 min. It was then rinsed with deionized water at 40°C for 3 times, and placed in an oven at 60°C for drying to constant weight. The treated cotton fabric was laid flat in an elephant leather mold, and hot-pressed at a temperature of 150°C and a pressure of 2 MPa for 3 min to obtain a biomimetic elephant leather cotton fabric substrate.

[0146] (2) The radiation refrigeration material was prepared according to steps (3)-(4) in Example 1.

[0147] The cotton fabric-based radiation refrigeration material prepared in Example 1 and Comparative Example 4 was tested for solar emissivity, infrared emissivity, net radiation cooling power, and thermal conductivity. The test results are shown in Table 12.

[0148] Table 12

[0149]

[0150]

[0151] The cotton fabric-based material has a certain relatively high infrared emissivity, but the net radiation cooling power is significantly lower than that of the mycelium-based material of the present application, and the thermal conductivity is also significantly increased, and the overall radiation refrigeration effect is poor.

[0152] Comparative Examples 5-6

[0153] Replacing the substrate mycelium with polydimethylsiloxane (PDMS) or nanocellulose (CNF)

[0154] (1) Preparation of biomimetic elephant leather substrate:

[0155] In Comparative Example 5, the stainless steel elephant leather mold was heated to 120°C, and the uncured PDMS film was placed between the mold, and was pressurized to 5 MPa. After cooling to 60°C under pressure, the mold was demolded.

[0156] In Comparative Example 6, nanocellulose was soaked in a 4% NaOH solution, and was immersed in a water bath heated at 80°C for 2 hours. After filtration, it was washed to neutral with deionized water, and was dried to constant weight in an oven at 60°C. 2g of cellulose was slowly added to 98g of deionized water, and was stirred at a temperature of 80°C and a rotation speed of 500 rpm for 2h. The cellulose slurry was injected into an elephant leather mold, and was hot-pressed at 100°C and 5 MPa for 10 min. After freeze-drying at -50°C for 24h, the mold was demolded.

[0157] (2) Refer to the steps (3)-(4) of the example, the radiation refrigeration material is prepared.

[0158] The solar emissivity, infrared emissivity, net radiation cooling power, and thermal conductivity of the radiation refrigeration material based on cotton spinning prepared in the above example 1 and comparative example 5 are tested. The test results are shown in Table 13.

[0159] Table 13

[0160]

[0161] The comparative test shows that the comprehensive radiation refrigeration performance is not as good as that of the mycelium-based material, when using the more conventional radiation refrigeration materials, polydimethylsiloxane (PDMS) or nanocellulose (CNF) as the base.

[0162] The above provided examples are not intended to limit the scope covered by the present application, and the described steps are not intended to limit the execution order. The obvious improvements made by those skilled in the art to the present application in combination with the existing common knowledge also fall within the protection scope defined by the claims of the present application.

Claims

1. A method of producing a radiative cooling mycelium material, characterized in that, The method comprises the following steps: (1) Preparation of the elephant skin mycelium substrate: inoculate the strain into the fungus bag containing the culture medium for a period of time until the mycelium covers the fungus bag; then, spread the fungus bag loosely in the elephant skin mold and continue to culture for a period of time, demold, and obtain the elephant skin mycelium substrate; (2) Pretreatment of the elephant skin mycelium substrate: soak the elephant skin mycelium substrate obtained in step (1) in the ethanol aqueous solution containing silane coupling agent, and then dry; (3) Load the silica layer: mix tetraethyl orthosilicate, anhydrous ethanol, deionized water, and catalyst to obtain a mixed solution; soak the pretreated elephant skin mycelium substrate in the mixed solution, dry after soaking, and obtain the mycelium loaded with silica; (4) Load the polytetrafluoroethylene layer: respectively disperse the adhesive and polytetrafluoroethylene in water to obtain an adhesive solution and a polytetrafluoroethylene dispersion; slowly drop the adhesive solution into the polytetrafluoroethylene dispersion, stir, and obtain a mixed dispersion; soak the mycelium loaded with silica obtained in step (3) in the mixed dispersion, dry and solidify after soaking, and obtain the radiation cooling mycelium material loaded with silica and PTFE.

2. The production method according to claim 1, characterized by, In step (1), the fungus bag containing the culture medium is prepared by the following method: mix cottonseed hulls, corn cobs, bran, soybean meal, and flour, then add an aqueous solution containing potassium dihydrogen phosphate, soluble starch, glucose, calcium carbonate, and peptone, stir uniformly, and form the culture medium; then, load the culture medium into a polypropylene fungus bag, sterilize, and obtain the fungus bag.

3. The preparation method according to claim 1, characterized in that, In step (1), the inoculation method is as follows: inoculate the strain on a wooden stick, and then insert the wooden stick into the fungus bag; the inoculation amount of the strain is 5%-10% of the weight of the fungus bag; the strain is a fungal strain.

4. The method of claim 1, wherein, In step (2), the concentration of ethanol in the ethanol aqueous solution is 30vol%-50vol%; the concentration of silane coupling agent in the ethanol aqueous solution containing silane coupling agent is 2wt%-5wt%.

5. The preparation method according to claim 1, characterized in that, In step (3), the catalyst is selected from any one or a combination of the following: ammonia, tetramethylammonium hydroxide, triethylamine, ammonium carbonate, acetic acid, hydrochloric acid, nitric acid, and silicic acid esterase.

6. The production method according to claim 5, wherein In step (3), the catalyst is ammonia, and the volume ratio of TEOS, anhydrous ethanol, deionized water, and ammonia is 1:4:4:0.

1.

7. The preparation method according to claim 1, characterized in that, In step (4), the adhesive includes but is not limited to any one or a combination of the following: polyvinyl alcohol, water-based polyurethane, chitosan, sodium alginate, lignin sulfonate, silane coupling agent, and polyethylene glycol.

8. The method of any one of claims 1-7, wherein, In step (4), the concentration of the adhesive solution is 2wt%-10wt%; the concentration of the PTFE dispersion is 20wt%-30wt; and the volume ratio of the adhesive solution to the PTFE dispersion is 5-10:

1.

9. A radiation cooling mycelium material prepared by the method of any one of claims 1-8.

10. The radiation cooling mycelium material of claim 9 for use in the fields of building energy saving, electronic device heat dissipation, or outdoor protection.

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