Multifunctional flexible composite aerogel with electro-thermal deicing, anti-icing and microwave absorption and preparation method thereof

Abstract

This invention discloses a multifunctional flexible composite aerogel with electrothermal de-icing, anti-icing, and microwave absorption properties, and its preparation method. The method uses deionized water as the solvent for the silicon source precursor and a nickel-copper polyurethane conductive sponge as the reinforcing phase. Vacuum impregnation allows silica aerogel to be uniformly and tightly bonded to the framework of the nickel-copper polyurethane conductive sponge. Due to the large number of methyl groups on the surface of the silicon source precursor, the composite aerogel exhibits excellent superhydrophobicity. Simultaneously, the excellent flexibility of both the silica aerogel and the nickel-copper polyurethane conductive sponge ensures that the flexible composite aerogel retains excellent flexibility and structural stability. Furthermore, this composite aerogel possesses multiple key properties, including electrothermal de-icing, anti-icing, and microwave absorption. This invention solves the problems of high energy consumption and short icing delay time in existing anti-icing materials.

Description

Technical Field

[0001] This invention belongs to the field of electro-thermal de-icing, anti-icing and microwave absorption technology, specifically relating to a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption and its preparation method. Background Technology

[0002] With the rapid development of microwave technology, stealth is playing an increasingly important role in protecting equipment, making the development of multifunctional microwave absorbing materials increasingly crucial. In some cases, equipment needs to operate in extremely cold and humid environments, requiring microwave absorbing materials to possess not only excellent microwave absorption performance but also superior de-icing and anti-icing properties.

[0003] Current research includes, for example, Chinese invention patent publication CN117587625A, which discloses a method for creating a lightweight, superhydrophobic, and self-cleaning rGO / LDH / PPy composite microwave absorbing fabric. This method involves constructing a multidimensional heterogeneous structure of rGO / LDH / PPy layers on aramid nonwoven fabric using hydrothermal methods and in-situ growth, followed by modification with a low surface energy material layer to form the superhydrophobic microwave absorbing fabric. This fabric combines excellent electromagnetic wave absorption performance with superhydrophobicity, and also exhibits good flexibility, thermal insulation, and flame retardant properties. However, the composite microwave absorbing fabric obtained by this method has a complex manufacturing process, high cost, and low mechanical strength.

[0004] Chinese invention patent publication number CN109627905A discloses a multifunctional coating with self-cleaning, anti-icing, and microwave absorption properties and its preparation method. The method mainly involves first synthesizing a low surface energy nanoparticle oily dispersion and a Fe3O4 / rGO / PANI / resin composite coating, and then spraying the Fe3O4 / rGO / PANI / resin composite coating and the low surface energy nanoparticle oily dispersion onto a substrate to obtain a self-cleaning and anti-icing microwave absorbing coating. It has excellent absorption performance, self-cleaning and anti-icing properties, and can be prepared in a large-area controllable manner. Under strong mechanical stress, the outer nanoparticles of the multifunctional coating obtained by this method will be lost, resulting in the loss of hydrophobicity and a decrease in anti-icing ability.

[0005] To enable reliable application of materials in extreme environments, the development of multifunctional integrated microwave absorbing materials is urgently needed. Summary of the Invention

[0006] To address the problems of complex manufacturing processes, high costs, and poor mechanical stability in existing multifunctional integrated microwave absorbing materials, this invention provides a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption capabilities, as well as its preparation method. This invention fully utilizes the key properties of aerogels, broadening their applications in anti-icing and microwave absorption, and solving the problems of high energy consumption and short delayed icing time in existing anti-icing materials.

[0007] The technical solution of the present invention is as follows:

[0008] This invention proposes a method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption functions under normal pressure. The basic steps are as follows: first, silica sol is completely filled into a conductive sponge by vacuum impregnation; the gel structure is stabilized by gelation, aging and displacement; and the multifunctional flexible composite aerogel is obtained by drying under normal pressure.

[0009] This invention discloses a method for preparing a multifunctional flexible composite aerogel with electrothermal de-icing, anti-icing, and microwave absorption properties. The method uses deionized water as the solvent for the silicon source precursor and a nickel-copper polyurethane conductive sponge as the reinforcing phase. Vacuum impregnation allows silica aerogel to be uniformly and tightly bonded to the framework of the nickel-copper polyurethane conductive sponge. Due to the large number of methyl groups on the surface of the silicon source precursor, the composite aerogel exhibits excellent superhydrophobicity. Simultaneously, the excellent flexibility of both the silica aerogel and the nickel-copper polyurethane conductive sponge ensures that the flexible composite aerogel retains excellent flexibility and structural stability. Furthermore, due to the inherent properties of the materials, this composite aerogel also possesses multiple key properties such as electrothermal de-icing, anti-icing, and microwave absorption.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0012] (1) The surfactant and deionized water were mixed in proportion and reacted fully. Then, the silicon source precursor was added to completely hydrolyze it to obtain silica sol. The reaction was carried out at a constant temperature of 35°C.

[0013] The molar ratio of the surfactant, deionized water, and silicon source precursor is (0.0002-0.0008):(2-2.8):(0.12-0.21).

[0014] The surfactant is hexadecyltrimethylammonium bromide (CTAB) or hexadecyltrimethylammonium chloride (MSDS);

[0015] The silicon source precursor is methyltrimethoxysilane (MTMS) or methyltriethoxysilane (MTES);

[0016] (2) Add ammonia water to the silica sol obtained in step (1) to make the pH of the sol > 7. Then, completely immerse the sol in the conductive sponge in a vacuum environment and gel and age it in an environment of 35°C for 12-24 hours to obtain a silica composite wet gel reinforced with conductive sponge.

[0017] The conductive sponge is one of nickel-copper polyurethane conductive sponge, porous magnetic metal foam, or carbon nanotube conductive polyurethane sponge.

[0018] (3) The conductive sponge-reinforced silica composite wet gel obtained in step (2) is subjected to solvent replacement. The replacement solvent is n-hexane or anhydrous ethanol. The replacement time is 1-2 days and the replacement temperature is 60℃-80℃.

[0019] (4) The conductive sponge-reinforced silica composite wet gel obtained in step (3) is dried under normal pressure at a temperature of 80℃~90℃ for 1d~2d to obtain a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption. The typical properties of the prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption are as follows:

[0020] ① The aforementioned multifunctional flexible composite aerogel possesses excellent mechanical properties, exhibits good blockiness after drying, shows no cracking, and has a density of 0.11 g / cm³. 3 -0.28g / cm 3 It can recover its original shape after being compressed and bent 1000 times;

[0021] ②The multifunctional flexible composite aerogel has superhydrophobic properties as a whole, and the contact angle is maintained at 150°-155°;

[0022] ③The multifunctional flexible composite aerogel described above has electro-thermal de-icing and anti-icing properties in cold and humid environments. It has excellent electro-thermal conversion effect and excellent thermal insulation performance, and can quickly melt frozen water droplets. In an environment of -20℃, it can delay the icing time by 1500s.

[0023] ④ The multifunctional flexible composite aerogel described above has excellent electromagnetic wave absorption characteristics. Its three-dimensional structure creates dual-interface polarization, which enables the flexible composite aerogel to achieve a minimum reflection loss of -19.07dB and an absorption bandwidth of 8.24GHz with a thickness of 2.2mm.

[0024] Furthermore, the surfactant described in step (1) is preferably hexadecyltrimethylammonium bromide (CTAB).

[0025] Furthermore, the silicon source precursor mentioned in step (1) is preferably methyltrimethoxysilane (MTMS).

[0026] Furthermore, the gelation and aging process described in step (2) is preferably carried out over a period of 12 hours.

[0027] Furthermore, the conductive sponge mentioned in step (2) is preferably a nickel-copper polyurethane conductive sponge.

[0028] Furthermore, in step (3), the solvent replacement is preferably n-hexane, the replacement time is 1 day, and the replacement temperature is 60°C.

[0029] This invention also relates to a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties. It is prepared using the aforementioned method for a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties. The typical properties of the prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties are as follows:

[0030] ① The aforementioned multifunctional flexible composite aerogel possesses excellent mechanical properties, exhibits good blockiness after drying, shows no cracking, and has a density of 0.11 g / cm³. 3 -0.28g / cm 3 It can recover its original shape after being compressed and bent 1000 times;

[0031] ②The multifunctional flexible composite aerogel has superhydrophobic properties as a whole, and the contact angle is maintained at 150°-155°;

[0032] ③The multifunctional flexible composite aerogel described above has electro-thermal de-icing and anti-icing properties in cold and humid environments. It has excellent electro-thermal conversion effect and excellent thermal insulation performance, and can quickly melt frozen water droplets. In an environment of -20℃, it can delay the icing time by 1500s.

[0033] ④ The multifunctional flexible composite aerogel described above has excellent electromagnetic wave absorption characteristics. Its three-dimensional structure creates dual-interface polarization, which enables the flexible composite aerogel to achieve a minimum reflection loss of -19.07dB and an absorption bandwidth of 8.24GHz with a thickness of 2.2mm.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] 1. This invention discloses a method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties. It provides a method to enhance the mechanical properties of the aerogel by utilizing the synergistic protective effect of the three-dimensional network structure of a nickel-copper polyurethane conductive sponge and a silica flexible aerogel. The method includes steps such as vacuum impregnation, aging, displacement, and drying. Selecting appropriate aging and displacement times and temperatures, as well as the type of solvent used for displacement, can reduce damage to the silica aerogel structure and pores during drying, allowing the silica aerogel and nickel-copper polyurethane conductive sponge to bond tightly into a whole, thus strengthening the structure and resulting in good flexibility and mechanical properties. Furthermore, this multifunctional flexible composite aerogel also possesses electro-thermal de-icing, anti-icing, and microwave absorption properties.

[0036] 2. The multifunctional flexible composite aerogel described in this invention, which has electro-thermal de-icing, anti-icing and microwave absorption functions, can be used as a material that integrates de-icing, anti-icing and microwave absorption in extremely cold and humid environments. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0038] Figure 1 These are field emission scanning electron microscope images of the nickel-copper polyurethane conductive sponge, silica aerogel, and flexible composite aerogel prepared in Example 3 of the present invention.

[0039] Figure 2 These are macroscopic photographs of the bending state and superhydrophobic properties of the flexible composite aerogel prepared in Example 3 of this invention;

[0040] Figure 3 This is a photograph of the flexible composite aerogel prepared in Example 3 of this invention at a large angle of 72°.

[0041] Figure 4 These are macroscopic images of the compression-rebound of the flexible composite aerogel prepared in Example 3 of this invention;

[0042] Figure 5 These are macroscopic photographs of the de-icing and electro-thermal effects of the flexible composite aerogel prepared in Example 3 of this invention;

[0043] Figure 6 This is a macroscopic photograph of the delayed icing of the flexible composite aerogel prepared in Example 3 of this invention;

[0044] Figure 7 These are microwave absorption performance diagrams of the flexible composite aerogel prepared in Example 3 of this invention at different thicknesses;

[0045] Figure 8 This is a graph showing the shrinkage rate of the pure aerogel of Comparative Example 1 of the present invention at different aging temperatures.

[0046] Figure 9 This is a shrinkage graph of the aerogel prepared in Comparative Example 2 of the present invention after drying at a displacement temperature of 50°C to 90°C. Detailed Implementation

[0047] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1:

[0049] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0050] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0002:2.2:0.15.

[0051] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0052] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0053] (4) The silica composite wet gel obtained in step (3) was solvent-displaced with hexane at 60°C for 1 day.

[0054] (5) The silica composite wet gel obtained in step (4) is dried at 80°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0055] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking properties after drying, without cracking, and has a density of 0.15 g / cm³. 3-0.20g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 155°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0056] Example 2:

[0057] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0058] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0005:2.2:0.15.

[0059] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0060] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0061] (4) The silica composite wet gel obtained in step (3) was solvent-displaced with hexane at 60°C for 1 day.

[0062] (5) The silica composite wet gel obtained in step (4) is dried at 80°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0063] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good blockiness and no cracking after drying, with a density of 0.14 g / cm³. 3 -0.22g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 155°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0064] Example 3:

[0065] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0066] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0008:2.2:0.15.

[0067] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0068] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0069] (4) The silica composite wet gel obtained in step (3) was solvent-displaced with hexane at 60°C for 1 day.

[0070] (5) The silica composite wet gel obtained in step (4) is dried at 80°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0071] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking properties after drying, without cracking, and has a density of 0.13 g / cm³. 3 -0.27g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel has superhydrophobic properties and the contact angle is maintained above 153°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0072] pass Figure 1 It can be seen that the prepared nickel-copper polyurethane conductive sponge, silica aerogel and flexible composite aerogel provide structural guarantee for the stable application of nickel-copper polyurethane conductive sponge, silica aerogel and flexible composite aerogel due to the tight filling of silica aerogel.

[0073] pass Figure 2 , Figure 3 and Figure 4It is known that flexible composite aerogels possess excellent mechanical properties and superhydrophobicity, as well as excellent cutability.

[0074] pass Figure 5 It is known that flexible composite aerogels have excellent electro-thermal conversion effects and can quickly melt frozen water droplets;

[0075] pass Figure 6 It is known that flexible composite aerogel has excellent anti-icing properties. Due to the excellent thermal insulation properties of silica aerogel, the icing delay time can reach 1500s in an environment of -20℃.

[0076] pass Figure 7 It is known that flexible composite aerogel has excellent electromagnetic wave absorption characteristics. Therefore, the three-dimensional structure constructs a dual-interface polarization, which enables the flexible composite aerogel to achieve a minimum reflection loss of -19.07dB and an absorption bandwidth of 8.24GHz with a thickness of 2.2mm.

[0077] pass Figures 1 to 7 It can be seen that this flexible composite aerogel provides an effective approach for designing functional materials that integrate ice melting, anti-icing, and wave absorption in extreme environments, and has broad development prospects in aerospace, marine bases, and radar stealth.

[0078] Example 4:

[0079] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0080] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0002:2.2:0.15.

[0081] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0082] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0083] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day.

[0084] (5) The silica composite wet gel obtained in step (4) is dried at 80°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0085] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good blockiness and no cracking after drying, with a density of 0.11 g / cm³. 3 -0.24g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 153°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0086] Example 5:

[0087] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0088] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0005:2.2:0.15.

[0089] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0090] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0091] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day.

[0092] (5) The silica composite wet gel obtained in step (4) is dried at 80°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0093] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking properties after drying, without cracking, and has a density of 0.15 g / cm³. 3 -0.27g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 155°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0094] Example 6:

[0095] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0096] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0008:2.2:0.15.

[0097] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0098] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0099] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day.

[0100] (5) The silica composite wet gel obtained in step (4) is dried at 80°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0101] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking properties after drying, without cracking, and has a density of 0.13 g / cm³. 3 -0.25g / cm 3It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 153°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0102] Example 7:

[0103] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0104] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0002:2.2:0.15.

[0105] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0106] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0107] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day.

[0108] (5) The silica composite wet gel obtained in step (4) is dried at 90°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0109] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good blockiness and no cracking after drying, with a density of 0.14 g / cm³. 3 -0.27g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 152°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0110] Example 8:

[0111] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0112] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0005:2.2:0.15.

[0113] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0114] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0115] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day.

[0116] (5) The silica composite wet gel obtained in step (4) is dried at 90°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0117] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking properties after drying, without cracking, and has a density of 0.13 g / cm³. 3 -0.21g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 150°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0118] Example 9:

[0119] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0120] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0008:2.4:0.12.

[0121] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0122] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0123] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day.

[0124] (5) The silica composite wet gel obtained in step (4) is dried at 90°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0125] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking after drying, without cracking, and has a density of 0.12 g / cm³. 3 -0.28g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 155°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0126] Example 10:

[0127] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0128] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0002:2.8:0.15.

[0129] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the nickel-copper polyurethane conductive sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0130] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 12 hours;

[0131] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day; then solvent-replaced at 80°C for 1 day.

[0132] (5) The silica composite wet gel obtained in step (4) is dried at 90°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0133] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good blockiness and no cracking after drying, with a density of 0.14 g / cm³. 3 -0.24g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 154°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0134] Example 11:

[0135] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0136] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium bromide and the silicon source precursor was methyltrimethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0005:2.5:0.18.

[0137] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the carbon nanotube conductive polyurethane sponge in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0138] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 16 hours;

[0139] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 60°C for 1 day; then solvent-replaced at 80°C for 1 day.

[0140] (5) The silica composite wet gel obtained in step (4) is dried at 90°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0141] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking properties after drying, without cracking, and has a density of 0.13 g / cm³. 3 -0.28g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 151°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0142] Example 12:

[0143] A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption functions includes the following steps:

[0144] (1) The surfactant and deionized water were mixed evenly by mechanical stirring and reacted fully. Then, a silicon source precursor was added for hydrolysis to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The surfactant was hexadecyltrimethylammonium chloride and the silicon source precursor was methyltriethoxysilane. The molar ratio of surfactant:deionized water:silicon source precursor was 0.0008:2.0:0.21.

[0145] (2) Add diluted ammonia to the sol obtained in step (1) to make the pH of the sol > 7. Then, completely impregnate the sol into the porous magnetic metal foam in a vacuum environment. After impregnation, let it stand to obtain silica composite wet gel. The amount of ammonia added is guaranteed to be in molar ratio of ammonia:silicon source precursor = 0.002:0.12.

[0146] (3) The silica composite wet gel obtained in step (2) is aged in a constant temperature environment of 35°C for 24 hours;

[0147] (4) The silica composite wet gel obtained in step (3) was solvent-replaced with anhydrous ethanol at 80°C for 2 days; then solvent-replaced at 90°C for 2 days.

[0148] (5) The silica composite wet gel obtained in step (4) is dried at 90°C under normal pressure to obtain a multifunctional flexible composite aerogel.

[0149] The prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties exhibits good bulking properties after drying, without cracking, and has a density of 0.13 g / cm³. 3 -0.22g / cm 3 It can recover its original shape after 1000 compressions and bending deformations; the flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption has superhydrophobic properties and the contact angle is maintained above 152°; it has electro-thermal de-icing and anti-icing properties in cold and humid environments, as well as excellent wave absorption properties.

[0150] Comparative Example 1:

[0151] Comparative Example 1 was designed to explore the effect of aging temperature on the morphological changes of aerogel after drying. The difference between Comparative Example 1 and Example 3 is that a displacement process was added in step (3). Comparative Example 1 was dried directly at 90°C after aging at room temperature and 35°C for 12 hours. The rest was the same as Example 3.

[0152] like Figure 8 As shown, the shrinkage rate of pure aerogels varies under different aging temperatures. The shrinkage rate of pure aerogels affects the structural stability, electrothermal de-icing and anti-icing properties, and absorption characteristics of composite aerogels. Therefore, ensuring zero shrinkage of the prepared pure aerogels is crucial for achieving more reliable structures and properties in the composite aerogels. It can be seen that aerogels prepared without a displacement process exhibit extremely high shrinkage rates: 9.4% after drying at room temperature and 8.0% after drying at 35°C.

[0153] The results show that applying a constant temperature during the aging process can promote the shrinkage rate of pure aerogel. This is mainly because a constant temperature facilitates the reinforcement of the skeleton during the aging process, thereby preventing the influence of large surface tension generated by water evaporation during drying on the skeleton network. In contrast, aging at ambient temperature has inconsistent temperature changes and has a limited reinforcement effect on the skeleton. Therefore, the shrinkage rate after drying is greater than that of pure aerogel aged at 35℃.

[0154] Comparative Example 2:

[0155] The difference between Comparative Example 2 and Example 3 is that the displacement temperature in step (4) is 50°C and 90°C respectively. The rest is the same as in Example 3. The displacement temperature in Example 3 is changed to 70°C, which confirms that the displacement temperature can be between 60°C and 80°C.

[0156] like Figure 9 As shown, the aerogels prepared at displacement temperatures of 50°C and 90°C showed shrinkage rates of 6.5% and 7.2% after drying, respectively, while the aerogels dried at 70°C showed a shrinkage rate of 0%.

[0157] The results show that the displacement temperature is crucial to the shrinkage rate of pure aerogels. Displacement at 50℃ still results in shrinkage, which is still an improvement compared to no displacement. However, the shrinkage rate cannot be completely eliminated because the temperature of 50℃ is insufficient to completely displace the moisture in the pores of the pure aerogel, resulting in significant surface tension during drying and causing shrinkage. Displacement at 90℃ also results in shrinkage, mainly because the solvent at 90℃ reaches a slight boiling point, accelerating the displacement of moisture from the pores of the pure aerogel. However, this process can cause structural damage to the pure aerogel framework, leading to shrinkage after drying. Maintaining a displacement temperature within the range of 60℃-80℃ ensures sufficient displacement without affecting the framework of the pure aerogel, thus achieving near-zero shrinkage and enabling the successful preparation of flexible composite aerogels.

[0158] Results and Discussion:

[0159] The comparison between Example 3 and Comparative Examples 1 and 2 demonstrates that the aging temperature and displacement temperature in steps (3) and (4) are crucial, significantly affecting the shrinkage rate of the pure aerogel and consequently the structural and performance stability of the composite aerogel. This unique aging and displacement method solves the shrinkage problem of the aerogel, which is significantly different from other inventions, enabling the flexible composite aerogel to maintain its structural stability while possessing excellent electrothermal de-icing, anti-icing, and microwave absorption properties.

[0160] This invention discloses a method for preparing a multifunctional flexible composite aerogel with electrothermal de-icing, anti-icing, and microwave absorption capabilities. This method utilizes a synergistic reinforcement strategy between a flexible conductive sponge and a flexible silica aerogel, resulting in a multifunctional flexible composite aerogel with excellent structural stability, flexibility, cutability, and mechanical properties. The silica aerogel surface is rich in methyl groups, giving the flexible composite aerogel excellent superhydrophobic properties. Combined with the electrothermal effect of the conductive sponge and the thermal insulation properties of the aerogel, the flexible composite aerogel possesses de-icing and anti-icing characteristics. Furthermore, the interfacial polarization between the aerogel and the conductive sponge framework gives the flexible composite aerogel excellent microwave absorption properties. The technical solution proposed in this invention fully integrates the advantages of both materials, achieving convenient processing and low cost while possessing excellent mechanical properties, ensuring stable de-icing, anti-icing, and microwave absorption.

[0161] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties, characterized in that: Includes the following steps: (1) The surfactant and deionized water were mixed in proportion and reacted fully. Then, the silicon source precursor was added to completely hydrolyze it to obtain silica sol. The reaction was carried out at a constant temperature of 35°C. The molar ratio of the surfactant, deionized water, and silicon source precursor is (0.0002-0.0008):(2-2.8):(0.12-0.21). The surfactant is hexadecyltrimethylammonium bromide or hexadecyltrimethylammonium chloride; The silicon source precursor is methyltrimethoxysilane or methyltriethoxysilane; (2) Add ammonia water to the silica sol obtained in step (1) to make the pH of the sol > 7. Then, completely immerse the sol in the conductive sponge in a vacuum environment and gel and age it in an environment of 35°C for 12-24 hours to obtain a silica composite wet gel reinforced with conductive sponge. The conductive sponge is one of nickel-copper polyurethane conductive sponge, porous magnetic metal foam, or carbon nanotube conductive polyurethane sponge. (3) The conductive sponge-reinforced silica composite wet gel obtained in step (2) is subjected to solvent replacement. The replacement solvent is n-hexane or anhydrous ethanol. The replacement time is 1-2 days and the replacement temperature is 60℃-80℃. (4) The conductive sponge-reinforced silica composite wet gel obtained in step (3) is dried under normal pressure at a temperature of 80℃~90℃ for 1d~2d to obtain a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption. The typical properties of the prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing and microwave absorption are as follows: ① The aforementioned multifunctional flexible composite aerogel possesses excellent mechanical properties, exhibits good blockiness after drying, shows no cracking, and has a density of 0.11 g / cm³. 3 -0.28g / cm 3 It can recover its original shape after being compressed and bent 1000 times; ②The multifunctional flexible composite aerogel has superhydrophobic properties as a whole, and the contact angle is maintained at 150°-155°; ③The multifunctional flexible composite aerogel described above has electro-thermal de-icing and anti-icing properties in cold and humid environments. It has excellent electro-thermal conversion effect and excellent thermal insulation performance, and can quickly melt frozen water droplets. In an environment of -20℃, it can delay the icing time by 1500s. ④ The multifunctional flexible composite aerogel described above has excellent electromagnetic wave absorption characteristics. Its three-dimensional structure creates dual-interface polarization, which enables the flexible composite aerogel to achieve a minimum reflection loss of -19.07dB and an absorption bandwidth of 8.24GHz with a thickness of 2.2mm.

2. The method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption as described in claim 1, characterized in that: The surfactant mentioned in step (1) is hexadecyltrimethylammonium bromide.

3. The method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption as described in claim 1, characterized in that: The silicon source precursor mentioned in step (1) is methyltrimethoxysilane.

4. The method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption as described in claim 1, characterized in that: The gelation and aging process described in step (2) takes 12 hours.

5. The method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption as described in claim 1, characterized in that: The conductive sponge mentioned in step (2) is a nickel-copper polyurethane conductive sponge.

6. The method for preparing a multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption as described in claim 1, characterized in that: The solvent replacement in step (3) is n-hexane, the replacement time is 1 day, and the replacement temperature is 60°C.

7. A multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties, characterized in that: The multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties is prepared using the method described in any one of claims 1-6. Typical properties of the prepared multifunctional flexible composite aerogel with electro-thermal de-icing, anti-icing, and microwave absorption properties are as follows: ① The aforementioned multifunctional flexible composite aerogel possesses excellent mechanical properties, exhibits good blockiness after drying, shows no cracking, and has a density of 0.11 g / cm³. 3 -0.28g / cm 3 It can recover its original shape after being compressed and bent 1000 times; ②The multifunctional flexible composite aerogel has superhydrophobic properties as a whole, and the contact angle is maintained at 150°-155°; ③The multifunctional flexible composite aerogel described above has electro-thermal de-icing and anti-icing properties in cold and humid environments. It has excellent electro-thermal conversion effect and excellent thermal insulation performance, and can quickly melt frozen water droplets. In an environment of -20℃, it can delay the icing time by 1500s. ④ The multifunctional flexible composite aerogel described above has excellent electromagnetic wave absorption characteristics. Its three-dimensional structure creates dual-interface polarization, which enables the flexible composite aerogel to achieve a minimum reflection loss of -19.07dB and an absorption bandwidth of 8.24GHz with a thickness of 2.2mm.

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