Poly-4-methyl-1-pentene aerogel, its preparation method and application
Poly(4-methyl-1-pentene) aerogel was prepared by camphene solvothermal phase separation, which solved the problem of preparing aerogel materials with high solar reflectivity and superhydrophobicity. It achieved low cost, effective passive cooling and self-cleaning properties, and is suitable for large-area production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HUNAN UNIV OF TECH
- Filing Date
- 2026-05-28
- Publication Date
- 2026-06-26
AI Technical Summary
Existing technologies make it difficult to prepare aerogel materials with both high solar reflectivity and superhydrophobicity using simple methods. Furthermore, the preparation process is cumbersome and costly, making it difficult to achieve effective passive cooling and self-cleaning properties.
Using camphene as a solvent, poly-4-methyl-1-pentene aerogels were prepared through a thermally induced phase separation process. By combining conventional drying methods and avoiding solvent displacement and supercritical drying, aerogels with abundant micron-pore structures were prepared.
It achieves high solar reflectivity and low thermal conductivity, possesses excellent self-cleaning and heat insulation properties, is suitable for radiative cooling, has a significant cooling effect, is low in cost, and is suitable for large-scale production.
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Figure CN122277984A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of energy-saving and thermal insulation technology, specifically to a poly4-methyl-1-pentene aerogel, its preparation method, and its passive cooling application. Background Technology
[0002] With accelerated urbanization and frequent extreme heat waves, the demand for cooling has exploded. Statistics show that building cooling energy consumption accounts for approximately 15% of global energy consumption, and even exceeds 50% in tropical and subtropical regions. While traditional active cooling technologies (such as air conditioning systems) are highly efficient, their reliance on electricity not only exacerbates grid load and carbon emissions but also contributes significantly to the urban heat island effect. This energy consumption pattern runs counter to the global goal of "carbon neutrality," urgently necessitating the development of low-energy, pollution-free alternative cooling solutions. Recently, passive daytime radiant cooling (PDRC), as a passive and green cooling solution, has attracted widespread attention and possesses enormous application potential.
[0003] To achieve PDRC (Plastic Photoconductive Reflective) materials, it is necessary to reflect most solar radiation (0.3-2.5 μm) while possessing the ability to emit light through a mid-infrared atmospheric window (LWIR, 8-13 μm). The most crucial aspect is achieving high solar reflectivity in the PDRC material. Furthermore, the impact of non-radiative heat transfer pathways on the cooling effect must be considered, primarily the heat convection and conduction between the cooled object and its surrounding environment. This is typically addressed through insulation measures, such as foam insulation, polyethylene film sealing, and vacuum encapsulation. However, these additional methods are detrimental to the practical application of PDRC materials.
[0004] Currently, the development of materials that simultaneously possess thermal insulation and high solar reflectivity has attracted researchers' interest. The combination of high solar reflectivity and low thermal conductivity can significantly reduce the absorption of solar radiation energy and the effects of non-radiative heat transfer, thus achieving effective cooling to a certain extent. Further achieving sub-ambient (sub-environmental) radiative cooling mechanisms mainly fall into two categories. The first is the mid-infrared transparency mechanism: the material has high solar reflectivity, resulting in less solar radiation absorbed by the object being cooled; it also has low thermal conductivity, reducing heat conduction and convection between the object and the environment; and its mid-infrared transparency allows infrared radiation from the object to pass through, thereby achieving highly efficient sub-environmental cooling. A typical material is ultra-high molecular weight polyethylene aerogel (UHMWPEA), with a thermal conductivity (κ) of 28 mW / m². -1 K -1The first method involves incorporating heat-insulating properties close to air, which, when placed on a heat emitter, can achieve a daytime temperature drop of up to 13 °C. The second method utilizes a heat-insulating radiation mechanism: directly combining heat insulation with the PDRC principle (high solar reflectance and high-infrared emission), which can reduce non-radiative heat transfer while achieving effective cooling. For example, porous polydimethylsiloxane (PDMS) foam (κ~60 mW m) -1 K -1 ).
[0005] Aerogels are porous materials formed when a wet gel is dried, with gas replacing the liquid phase, allowing the gel framework and pore structure to be stably preserved. Aerogels generally possess not only extremely high porosity but also micro-nanoscale frameworks and macropores. This results in extremely low thermal conductivity and excellent thermal insulation properties. Unlike porous foam materials, aerogel preparation typically involves sol-gel and aging drying processes, and requires the framework network to be highly preserved after drying. Therefore, solvent replacement, freeze-drying, or supercritical drying processes are usually required, making the preparation steps complex and time-consuming.
[0006] Researchers such as Yang Yuan proposed constructing porous structures in polymers to effectively scatter sunlight, providing a new approach for the development of PDRC materials. Therefore, aerogels have significant potential for achieving high solar reflectivity; for example, the reported UHMWPEA achieves cooling through a mid-infrared transparency mechanism. Furthermore, PDRC materials are easily contaminated by rainwater, dust, and microorganisms during outdoor applications, leading to performance degradation. Recently, researchers proposed endowing PDRC materials with superhydrophobicity, enabling self-cleaning and improving their long-term outdoor performance. In conclusion, achieving both high solar reflectivity and superhydrophobicity in the preparation of thermally insulating aerogels using simple methods remains a challenge.
[0007] Poly(4-methyl-1-pentene) (PMP) is a semi-crystalline, non-polar polyolefin resin characterized by low surface energy and excellent weather resistance. PMP porous membranes typically consist of a loose porous support layer and a dense skin layer, exhibiting both excellent gas permeability and good mechanical properties. Due to these properties, PMP is widely used in the preparation of hollow fiber membranes, primarily for gas exchange, and is therefore particularly suitable for membrane oxygenators in extracorporeal membrane oxygenation (ECMO) devices. Patent CN114634640 discloses a method for preparing poly(4-methyl-1-pentene) porous films, employing a silica microsphere template method combined with acid etching to achieve porous PMP films with uniform pore size and dispersion. Patent CN11283130 discloses an extrusion casting process using a blended modifier to prepare poly(4-methyl-1-pentene) microporous membranes, enabling applications in battery separators. These pore-forming methods are cumbersome and require acid post-treatment, resulting in high production costs.
[0008] In 2017, researchers including Yang Ronggui proposed doping PMP with glass microspheres for the preparation of PDRC films. PMP has almost no absorption peak in the solar radiation region, which is beneficial for the silver coating layer to reflect sunlight transmitted through the film, reducing the impact of solar radiation on the cooling effect and opening up a new application field for PMP. Previously, researchers had only reported the preparation of PMP aerogels by thermally induced phase separation (TIPS) and supercritical CO2 drying, and studied the effects of different solvents (such as mesitylene, decahydronaphthalene, cyclopentane, and cyclohexane) on the crystal morphology and pore structure of the prepared PMP aerogels, but did not explore their optical properties. Summary of the Invention
[0009] To address the problems existing in the prior art, the purpose of this application is to provide a poly(4-methyl-1-pentene) aerogel and its preparation method. The preparation method described in this invention is simple and mild, requiring no complicated processes or expensive equipment, and can be produced on a large scale. It possesses extremely high solar reflectivity and can be used for radiative cooling to achieve passive cooling. Furthermore, the aerogel prepared by this method exhibits good self-cleaning and thermal insulation properties, enhancing its potential for outdoor applications.
[0010] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a poly(4-methyl-1-pentene) aerogel, which is prepared by thermally induced phase separation using camphene as a solvent and has a rich micron-pore structure.
[0011] The present invention also discloses a method for preparing such aerogel, which involves controlling the cooling rate to induce a thermally induced phase separation process in poly-4-methyl-1-pentene, followed by conventional drying to obtain a white aerogel with good self-supporting properties.
[0012] The preparation steps include: using camphene as a solvent for poly4-methyl-1-pentene, preparing a solution of a certain concentration, heating to a high temperature to dissolve, stirring until homogeneous and transparent, and then slowly cooling the solution below the melting point of camphene to obtain a waxy gel. Finally, the solvent is removed by freeze-drying or atmospheric pressure drying. The preparation process does not require solvent replacement or supercritical drying.
[0013] Furthermore, the preferred concentration of poly-4-methyl-1-pentene aerogel is 4%-9%.
[0014] Furthermore, the preferred initial and final temperatures for thermally induced phase separation are 60 °C and 26 °C (room temperature), respectively, with a corresponding cooling rate of ~2.1 °C min. -1 .
[0015] According to the present invention, the thickness of the poly4-methyl-1-pentene aerogel is 1.6-3 mm, preferably 2 mm.
[0016] According to the present invention, the micropore size of the poly4-methyl-1-pentene aerogel is 1-15 μm.
[0017] According to the present invention, the poly4-methyl-1-pentene aerogel exhibits a random bicontinuous structure with a porosity higher than 88%, preferably, the porosity of the aerogel is higher than 94%.
[0018] According to the present invention, the solar reflectance of the poly4-methyl-1-pentene aerogel is higher than 95%.
[0019] According to the present invention, the intrinsic static contact angle of the poly-4-methyl-1-pentene aerogel is greater than 160° and the roll-off angle is less than 5°.
[0020] According to the present invention, the thermal conductivity of the poly-4-methyl-1-pentene aerogel is less than 42 mW / m. -1 K -1 Preferably, the thermal conductivity of the aerogel is less than 38 mW / m. -1 K -1 .
[0021] According to the present invention, outdoor testing of the poly4-methyl-1-pentene aerogel shows that it exhibits good radiative cooling effects under various weather conditions, including hazy and cloudy days. Its average temperature drop on clear nights is ~5 °C, and its average solar irradiance at noon reaches ~700 W / m². -2 The average temperature drop is ~3 °C.
[0022] According to the present invention, the poly4-methyl-1-pentene aerogel prepared by this method is expected to be used directly as a high solar reflectance self-cleaning material, or micron-sized particles, such as silica (SiO2) and polysilsesquioxane (PSQ) micron-sized particles, can be added to it to apply it as a high solar reflectance thermal insulation radiation material in the PDRC field.
[0023] Compared with existing technologies, the advantages of this invention are: compared with other aerogel radiation cooling materials, this invention achieves higher solar scattering efficiency and thermal insulation performance through only one step of thermally induced phase separation and freeze-drying or room temperature drying. Compared with the solvent replacement and supercritical drying processes in the preparation of other polymer aerogels, the poly-4-methyl-1-pentene aerogel in this invention is low in cost, simple to prepare, requires no solvent replacement, and can be dried at ambient pressure, thus having greater cost and performance advantages. Attached Figure Description
[0024] Figure 1 The image shows the lower surface and cross-section of the poly(4-methyl-1-pentene) aerogel (5 wt%) in Example 1.
[0025] Figure 2The reflectance spectrum of poly(4-methyl-1-pentene) aerogel (5 wt%) in Example 1 and the normalized ASTM G173 global solar spectrum are shown.
[0026] Figure 3 The image shows the lower surface and cross-section of the poly(4-methyl-1-pentene) aerogel (9 wt%) in Example 2.
[0027] Figure 4 Photograph of the water droplet contact angle of poly-4-methyl-1-pentene aerogel (9wt%) in Example 2.
[0028] Figure 5 Scanning electron microscope (SEM) images of the lower surface and cross-section of poly(4-methyl-1-pentene) aerogel (5 wt%) with added micron-sized SiO2 in Example 4.
[0029] Figure 6 The image shows the 24-hour cooling effect of poly-4-methyl-1-pentene aerogel (5wt%) with added micron PSQ in Example 5.
[0030] Figure 7 The image shows the lower surface and cross-section of the poly(4-methyl-1-pentene) aerogel (5 wt%) obtained under rapid cooling conditions in Comparative Example 1. Detailed Implementation
[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0032] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods. Example 1
[0033] First, 1 g of poly-4-methyl-1-pentene and 19 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. The solution was then poured into a mold at 60 °C, and finally the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the solvent was completely removed by freeze-drying, resulting in a white poly-4-methyl-1-pentene aerogel.
[0034] like Figure 1 As shown, the obtained poly-4-methyl-1-pentene aerogel has a rich microporous structure and an apparent density of 53.7 mg / cm³. -3 The porosity reaches 93.6%. For example... Figure 2 Its average reflectance in the solar spectral region is 96% (~2 mm thickness), and its thermal conductivity is low (κ ~ 38 mW / m²). -1 K -1 It possesses excellent thermal insulation and radiative cooling potential. Outdoor tests show that PMP aerogel can achieve a cooling effect of ~5 °C at night and ~3 °C at noon. Due to its intrinsically low surface energy and porous surface structure, this aerogel exhibits superhydrophobicity, with a static contact angle of 165° and a roll-off angle of 1° for water droplets. Example 2
[0035] First, 1.8 g of poly-4-methyl-1-pentene and 18.2 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. The solution was then poured into a mold at 60 °C, and finally the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the solvent was completely removed by freeze-drying overnight or drying at normal pressure, resulting in a white poly-4-methyl-1-pentene aerogel.
[0036] like Figure 3 As shown, the obtained poly-4-methyl-1-pentene aerogel has an apparent density of 96.5 mg / cm³. -3 It has a porosity of 88.4%, exhibiting abundant micron-sized pores with dimensions below 10 μm. Its average reflectance in the solar spectral region is 96% (with a thickness of ~2 mm), and its thermal conductivity is ~44 mW / m². -1 K -1 It possesses excellent thermal insulation and radiative cooling potential. Outdoor tests show that PMP aerogel can achieve a cooling effect of ~6 °C at night and ~2 °C at noon. Due to its intrinsically low surface energy and porous surface structure, this aerogel exhibits superhydrophobicity, such as... Figure 4 The static contact angle of the water droplets on the surface is 161°, and the roll-off angle is 4°. Example 3
[0037] First, 1 g of poly-4-methyl-1-pentene and 19 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. The solution was then poured into a mold at 60 °C, and finally the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the gel was dried under pressure to completely remove the solvent, resulting in a white poly-4-methyl-1-pentene aerogel.
[0038] The resulting poly-4-methyl-1-pentene aerogel possesses an abundant microporous structure and an apparent density of 55.6 mg / cm³. -3The porosity reaches 92.1%. The PMP aerogel has an average reflectance of 96% in the solar spectral region (with a thickness of ~2 mm) and a low thermal conductivity (κ ~ 39 mW / m²). -1 K -1 It possesses excellent thermal insulation and radiative cooling potential. Outdoor tests show that PMP aerogel can achieve a cooling effect of ~5 °C at night and ~3 °C at noon. Due to its intrinsically low surface energy and porous surface structure, this aerogel exhibits superhydrophobicity, with a static contact angle of 163° and a roll-off angle of 2° for water droplets. Example 4
[0039] First, 1 g of poly(4-methyl-1-pentene) and 19 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. Then, 0.7 g of SiO2 micron-sized particles were added and stirred for 10 min to disperse the mixture. The solution was then cast into a mold at 60 °C, and finally, the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the gel could be freeze-dried to completely remove the solvent, resulting in a white poly(4-methyl-1-pentene) composite aerogel.
[0040] like Figure 5 As shown, the resulting poly-4-methyl-1-pentene aerogel with micron-sized particles exhibits a particle size of ~5 μm for the added SiO2 microspheres. Comparison of SEM images of the lower surface and cross-section before and after the addition of the micron-sized microspheres reveals (…). Figure 1 and Figure 5 The addition of SiO2 did not disrupt the original phase-separated bicontinuous structure, and the pore size remained essentially unchanged. Furthermore, the solar reflectance of the poly(4-methyl-1-pentene) aerogel remained essentially unchanged before and after the addition of micron-sized particles, still reaching 96%. Outdoor tests showed that the PMP aerogel could achieve a cooling effect of ~6 °C at night and ~3 °C at noon. The poly(4-methyl-1-pentene) aerogel with added micron-sized particles maintained its superhydrophobicity, with a static contact angle of 162° and a roll-off angle of 4° for water droplets. The thermal conductivity of the poly(4-methyl-1-pentene) aerogel sample with added micron-sized particles increased slightly, reaching ~42 mW / m². -1 K -1 . Example 5
[0041] First, 1 g of poly(4-methyl-1-pentene) and 19 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. Then, 0.7 g of polysilsesquioxane (PSQ) micron-sized particles were added and stirred for 10 min to disperse. The solution was then cast into a mold at 60 °C, and finally, the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the gel could be freeze-dried to completely remove the solvent, resulting in a white poly(4-methyl-1-pentene) composite aerogel.
[0042] The resulting poly-4-methyl-1-pentene composite aerogel, blended with PSQ microparticles, had a PSQ particle size of ~2 μm. The addition of the PSQ microparticles did not disrupt the original phase-separated bicontinuous structure, and the pore size remained essentially unchanged. Figure 6 As shown in the 24-hour cooling effect diagram, outdoor tests indicate that PMP aerogel can achieve a cooling effect of ~5 °C at night and ~3 °C at noon. Furthermore, the solar reflectance of the poly-4-methyl-1-pentene aerogel remains essentially unchanged before and after the addition of microspheres, still reaching a high level of 96%; the poly-4-methyl-1-pentene aerogel with added microspheres retains its superhydrophobicity, with a static contact angle of 165° and a roll-off angle of 2° for water droplets; the thermal conductivity of the poly-4-methyl-1-pentene aerogel sample with added PSQ microspheres still increases slightly to ~42 mW / m². -1 K -1 . Comparative Example 1
[0043] This comparative example aims to investigate the effect of cooling rate on the structure of poly(4-methyl-1-pentene) aerogel. First, 1 g of poly(4-methyl-1-pentene) and 19 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. The solution was then cast into a mold at 120 °C, and finally, the mold was directly transferred to an ice-water bath. This rapid cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the solvent was completely removed by freeze-drying overnight or drying at normal pressure, resulting in a white poly(4-methyl-1-pentene) aerogel.
[0044] like Figure 7 As shown, the obtained poly(4-methyl-1-pentene) aerogel possesses a rich microporous structure, all exhibiting oriented, regular channels, indicating that camphene can still achieve a dendritic crystalline morphology even under rapid cooling. Its average reflectance in the solar spectral region is 94% (~2 mm thickness), which is unfavorable for improving random backscattering. Therefore, the preparation of poly(4-methyl-1-pentene) aerogel under controlled slow cooling rates reduces material consumption while achieving high solar reflectance. Comparative Example 2
[0045] This comparative example aims to investigate the effect of thermally induced phase separation solvent on the structure of poly(4-methyl-1-pentene) aerogel. First, 1 g of poly(4-methyl-1-pentene) was mixed with 19 g of cyclohexane and stirred at 60 °C until the solution was homogeneous and transparent. The solution was then cast into a mold at 60 °C, and finally the mold was moved to room temperature to obtain a white gel. Then, the cyclohexane was replaced with ethanol by solvent displacement, three times a day for three days. Finally, the solvent was completely removed by freeze-drying overnight, yielding a white poly(4-methyl-1-pentene) film.
[0046] The resulting thin film has a small number of pores with small diameters, exhibiting a bicontinuous pore structure in cross-section, and showing obvious pore shrinkage. The shrinkage of the resulting porous membrane is due to the presence of cyclohexane as a solvent; during freeze-drying, some of the cyclohexane easily melts into a liquid state (cyclohexane is a non-friendly freeze-drying solvent). Therefore, when the liquid cyclohexane is vacuum-dried, there is a significant capillary force, causing the pore structure to collapse and shrink. Some researchers have used cyclohexane as a solvent to prepare intact, non-shrink poly-4-methyl-1-pentene aerogels because this is achieved using supercritical drying equipment. Comparative Example 3
[0047] This comparative example aims to investigate the effect of a lower poly(4-methyl-1-pentene) concentration on the structure of the resulting aerogel. First, 0.6 g of poly(4-methyl-1-pentene) and 19.4 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. The solution was then cast into a mold at 60 °C, and finally the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the solvent was completely removed by freeze-drying overnight or drying at atmospheric pressure. The resulting poly(4-methyl-1-pentene) aerogel exhibited a rich micron-sized macroporous structure and an apparent density of 33.3 mg / cm³. -3 With a porosity of 96%, the aerogel is difficult to self-support due to its low concentration. Its average reflectance in the solar spectral region is 93% (~2 mm thickness), indicating insufficient radiative cooling potential. Comparative Example 4
[0048] This comparative example aims to investigate the effect of a higher poly(4-methyl-1-pentene) concentration on the structure of the resulting aerogel. First, 4 g of poly(4-methyl-1-pentene) and 16 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. The solution was then cast into a mold at 60 °C, and finally the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the solvent was completely removed by freeze-drying overnight or drying at normal pressure, resulting in a relatively dense poly(4-methyl-1-pentene) aerogel, which could not be obtained. Comparative Example 5
[0049] This comparative example aims to investigate the effect of the thickness of poly(4-methyl-1-pentene) aerogel on its optical properties. First, 1 g of poly(4-methyl-1-pentene) and 19 g of camphene were mixed and stirred at 120 °C until the solution was homogeneous and transparent. The solution was then cast into a mold at 60 °C, and finally the mold was moved to room temperature. This slow cooling rate control method yielded a waxy gel. Since camphene readily sublimates, the solvent was completely removed by freeze-drying overnight or drying at normal pressure. By controlling the amount of solution in the mold, white poly(4-methyl-1-pentene) aerogels of different thicknesses could be obtained. The obtained 0.8 mm thick poly(4-methyl-1-pentene) aerogel had an average reflectance of 92% in the solar spectral region. Therefore, the material absorbs a high amount of external heat, making it difficult to achieve positive power radiative cooling.
Claims
1. A poly-4-methyl-1-pentene aerogel, characterized in that, It is prepared by thermally induced phase separation using camphene as a solvent and has a rich micron-pore structure.
2. The method for preparing poly-4-methyl-1-pentene aerogel according to claim 1, characterized in that, The method involves controlling the cooling rate to induce a thermally induced phase separation process in poly-4-methyl-1-pentene, followed by conventional drying to obtain a white aerogel with good self-supporting properties.
3. The method for preparing poly-4-methyl-1-pentene aerogel according to claim 2, characterized in that, The preparation steps include: using camphene as a solvent for poly4-methyl-1-pentene, preparing a solution of a certain concentration, heating to a high temperature to dissolve, stirring until homogeneous and transparent, and then slowly cooling the solution below the melting point of camphene to obtain a waxy gel. Finally, the solvent is removed by freeze-drying or atmospheric pressure drying. The preparation process does not require solvent replacement or supercritical drying.
4. The method for preparing poly-4-methyl-1-pentene aerogel according to claim 3, characterized in that, The preferred concentration of poly(4-methyl-1-pentene) aerogel is 4%-9%.
5. The method for preparing poly-4-methyl-1-pentene aerogel according to claim 3, characterized in that, The initial and final temperatures of the thermally induced phase separation were 60 °C and 26 °C (room temperature), respectively, with a corresponding cooling rate of ~2.1 °C min. -1 .
6. The poly-4-methyl-1-pentene aerogel according to claim 1, characterized in that, The aerogel has a thickness of 1.6-3 mm and a micron-sized pore size of 1-15 μm.
7. The poly-4-methyl-1-pentene aerogel according to claim 6, characterized in that, The aerogel exhibits a random bicontinuous structure with a porosity higher than 88%.
8. The poly-4-methyl-1-pentene aerogel according to claim 7, characterized in that, The aerogel has a solar reflectance of over 95%.
9. The poly-4-methyl-1-pentene aerogel according to claim 8, characterized in that, The aerogel has an intrinsic static water droplet contact angle greater than 160° and a roll-off angle less than 5°.
10. The poly-4-methyl-1-pentene aerogel according to claims 6-9 is expected to be used directly as a high-solar-reflection self-cleaning material, or it can be used in the field of radiative cooling by adding micron-sized particles as a high-solar-reflection thermal insulation and radiation material.