A composite aerogel fiber for adaptive thermal management and dynamic display, and a preparation method and application thereof

Abstract

The present invention provides a composite aerogel fiber for adaptive thermal management and dynamic display, and a preparation method and application thereof, which belongs to the field of aerogel fiber preparation. The method comprises the following steps: S1, dispersing the washed and crushed cellulose raw material and thermochromic material in a non-derivatized aqueous phase solvent, and then obtaining a cellulose spinning solution after defoaming and filtering; S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a spinneret for solvent phase separation and replacement aging to obtain a one-dimensional composite cellulose gel fiber; S3, drying the composite cellulose gel fiber obtained in S2 to obtain a composite aerogel fiber. This method can not only omit the step of water replacement of conventional gel fibers, but also the prepared composite aerogel fibers have stronger mechanical properties. At the same time, this method can also adjust the size and uniformity of micropores in the prepared aerogel.

Description

Technical Field

[0001] The invention belongs to the field of aerogel fiber preparation, and in particular relates to a composite aerogel fiber for adaptive thermal management and dynamic display, and a preparation method and application thereof. Background Art

[0002] At present, global warming and the intensification of extreme weather have had a huge impact on sustainable development and social economy. Personal thermal management (PTM) technology for daily environments has been widely studied, but the exploration is still in its initial stage. Most of them are temperature control strategies at the expense of fossil energy, which ultimately requires energy consumption. Therefore, there is an urgent need to develop environmentally friendly and multifunctional PTM materials that can have good feasibility in complex outdoor scenarios and can be used for adaptive thermal management in extreme environments such as aerospace, plateaus and polar regions.

[0003] Aerogels are widely used in safety protection, environment, energy conversion and storage due to their ultra-high porosity, large specific surface area and ultra-low thermal conductivity. Aerogel materials in fiber form may have relatively high strength, higher flexibility and larger specific surface area. Aerogel fiber products with one-dimensional characteristics can be manufactured into multi-dimensional configurations through textile strategies to obtain better wearability for human body. With its flexibility, scalability and ultra-high porosity, it has been proven to be a customizable and universal strategy for the next generation of thermal insulation and personal thermal management. However, in the real world, almost all environmental scenarios are very dynamic and variable, including fluctuations in space, time, day and night seasons, temperature, etc. A single aerogel fiber only has excellent thermal insulation performance and cannot adapt to energy saving and diverse personal temperature regulation needs.

[0004] Cellulose is the most abundant natural polymer on earth. Combined with the excellent properties of aerogels, it has significant biodegradability, renewability and hydrophilicity, making it a promising candidate material for preparing commercial aerogel fibers. At present, some solvents are used in the cellulose dissolution process, such as ionic liquids, N-methylmorpholine-N-oxide (NMMO) and lithium chloride / dimethylacetamide. These methods generally have problems such as high cost, difficult recycling or environmental pollution. Patents CN105970325A and CN105970326B use a low-temperature alkaline urea solvent system (a combination of sodium hydroxide or lithium hydroxide and urea or thiourea) to dissolve cellulose in the preparation of cellulose aerogels, but this method is difficult to dissolve high molecular weight, high crystallinity and high concentration cellulose, and the low-temperature pretreatment process requires energy consumption, which is limited in practical applications.

[0005] In addition, the existing process of preparing aerogel fibers requires gel and solvent replacement steps. The CN105970325 A patent prepares continuous aerogel fibers by wet spinning, but it needs to be immersed in an aging liquid for aging and water washing again. The process is complicated and the size and uniformity of the micropores in the aerogel cannot be adjusted. At the same time, the functionalization and intelligence of aerogel fibers based on cellulose resources integrating porous structures have not been fully developed. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a composite aerogel fiber for adaptive thermal management and dynamic display on the one hand, and provides a method for preparing the composite aerogel fiber on the other hand. In addition, the application of the composite aerogel fiber is also provided. This method can not only omit the step of water replacement of conventional gel fibers, but also prepare composite aerogel fibers with stronger mechanical properties. At the same time, this method can also adjust the size and uniformity of micropores in the prepared aerogel.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention provides a method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display, comprising the following steps:

[0009] S1, dispersing the washed and crushed cellulose raw material and the thermochromic material in a non-derivatized aqueous solvent, and then defoaming and filtering to obtain a cellulose spinning solution;

[0010] S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a spinneret for solvent phase separation and displacement aging to obtain a one-dimensional composite cellulose gel fiber;

[0011] S3, drying the composite cellulose gel fiber obtained in S2 to obtain composite aerogel fiber.

[0012] In a specific embodiment of the present invention, after the cellulose raw material is washed and crushed, it is also dried, the drying temperature is 100-110° C., the time is 6-24 hours, and the mass ratio of the cellulose raw material to the thermochromic material is 5:1-5:3.

[0013] In a specific embodiment of the present invention, the dispersion process includes vigorous stirring at room temperature for 60 to 200 minutes; the defoaming process includes centrifugation at 4000 to 6000 r / min for 10 to 15 minutes to remove bubbles.

[0014] In a specific embodiment of the present invention, the cellulose raw material in S1 is preferably at least one of bamboo pulp, cotton pulp or regenerated viscose.

[0015] In a specific embodiment of the present invention, the non-derivatized aqueous solvent in S1 includes 40-50 wt % of tetrabutylammonium hydroxide and 2.5-3 wt % of urea.

[0016] In a specific embodiment of the present invention, the thermochromic material in S1 is a low-temperature color-developing microcapsule and / or a high-temperature color-developing microcapsule, the particle size of the low-temperature color-developing microcapsule and the high-temperature color-developing microcapsule is 1 to 5 μm, and the low-temperature color-developing microcapsule and the high-temperature color-developing microcapsule are a core-shell structure composed of a resin and a thermochromic dye.

[0017] In a specific embodiment of the present invention, the low-temperature color-developing microcapsules can display color when the ambient temperature is below a threshold value, and are colorless in a high-temperature state. The high-temperature color-developing microcapsules can display color when the ambient temperature is above a threshold value, and are colorless in a low-temperature state. The color can be selected from one of black, blue, yellow, red and green.

[0018] Generally, the threshold values ​​of low-temperature color-developing microcapsules are 5°C, 18°C, 25°C, and 28°C; the threshold values ​​of high-temperature color-developing microcapsules are 31°C, 33°C, 35°C, 40°C, and 45°C.

[0019] In a specific embodiment of the present invention, the coagulation bath described in S2 includes 5-15 wt % of citric acid, 0-5 wt % of trisodium citrate, and 10-50 wt % of tert-butyl alcohol.

[0020] In a specific embodiment of the present invention, the specific step of S2 is: the cellulose spinning solution described in S1 is squeezed into the coagulation bath through a 21-27G needle at a rate of 0.6-2 ml / min, gelled at 20-30°C and aged for 5-24 hours to obtain a one-dimensional composite cellulose gel fiber.

[0021] In a specific embodiment of the present invention, the drying method in S3 is one of supercritical carbon dioxide drying and freeze drying.

[0022] In a specific embodiment of the present invention, the freeze-drying step is: the composite aerogel fiber is frozen at -10 to -20°C for 3 to 10 hours, and then freeze-dried in a freeze dryer at a temperature of -60 to -85°C and a low pressure of 8 to 15 Pa for 24 to 48 hours.

[0023] In a specific embodiment of the present invention, the step of supercritical carbon dioxide drying is: the composite aerogel fiber is dried and extracted for 4 to 6 hours in a supercritical point dryer with a critical temperature of 40 to 50° C. and a critical pressure of 9.0 to 20 MPa.

[0024] The present invention also provides a composite aerogel fiber for adaptive thermal management and dynamic display, which is prepared by the above-mentioned preparation method.

[0025] The present invention also provides an application of a composite aerogel fiber for adaptive thermal management and dynamic display in anti-counterfeiting textiles, temperature indicating fabrics, temperature-sensitive color-changing clothing or cold-proof protective clothing.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The existing method for preparing aerogels requires gelation, water washing, replacement aging and other steps for the fiber spinning solution, which is not only complicated but also unable to adjust the size and uniformity of the micropores in the aerogel. The technical solution of the present application can adopt a one-step method for the gelation and aging of the fiber spinning solution, and tert-butyl alcohol is used as a component in the coagulation bath, which can not only omit the step of water replacement of conventional gel fibers, but also reorganize and regenerate cellulose hydrogen bonds by delaying the mutual diffusion between the coagulant and the solvent, thereby effectively improving the mechanical properties. In addition, tert-butyl alcohol has a high freezing point and low surface tension, which can serve as a guide for ice crystal growth, change the crystal morphology of the wet gel, and thus effectively adjust the pore structure of the macroscopic fiber. Therefore, by adjusting the proportion of tert-butyl alcohol in the coagulation bath, the size and distribution of microscopic pores in the fiber and the fiber diameter can be synergistically adjusted.

[0028] 2. The method of the present invention compounds thermochromic materials into aerogel fibers. The prepared composite aerogel fibers not only have good thermal insulation, but also have temperature-responsive color-changing function, and have potential application value in the fields of adaptive thermal management and dynamic display.

[0029] 3. The raw materials of the present invention are widely available, cellulose can be dissolved at room temperature, the preparation process is green and pollution-free, the operation is simple, and the spinnability is good, which solves the problem of poor mechanical properties of cellulose aerogel fibers. At the same time, the composite cellulose aerogel fibers prepared by the present invention have a strength of 200 to 300 m 2 / g specific surface area and 80.3-90% porosity, as well as low density characteristics, while having a fiber tensile property of 15-30Mpa and good weaving properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The scanning electron microscope images of the cross-sections of the cellulose aerogel fibers prepared in Example 1 and Comparative Example 1 at magnifications of 500 and 30,000 times;

[0031] Figure 2 The actual picture of the color change of the fabric woven with the composite aerogel fibers prepared in Example 1 at different temperatures;

[0032] Figure 3A comparison chart of the adaptive thermal management function of the fabric woven with composite aerogel fibers prepared in Example 1 and Comparative Example 1;

[0033] Figure 4 This is a physical picture of a fabric woven from composite aerogel fibers prepared in Example 3;

[0034] Figure 5 The composite aerogel fibers prepared in Example 1, Example 3 and Example 4 have a dynamic display function of a QR code displayed by embroidery. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] Unless otherwise specified, the methods described in the examples are all conventional experimental methods. The solvents and materials used can be obtained from commercial sources.

[0037] Example 1

[0038] This embodiment provides a method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display, which specifically includes the following steps:

[0039] S1. After washing and crushing the bamboo pulp, dry it at 105°C for 12h, then immerse 1.45g of bamboo pulp and 0.6g of thermochromic microcapsules that turn black at a low temperature of 18°C ​​in 20ml of a solvent containing 40wt% tetrabutylammonium hydroxide and 3wt% urea, stir vigorously at room temperature for 120min, then centrifuge at 6000r / min for 15min to remove bubbles, and obtain a cellulose spinning solution after filtration;

[0040] S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a 21G needle at a rate of 1.6 ml / min, gelling and aging at 25°C for 12 hours to obtain a one-dimensional composite cellulose gel fiber, wherein the coagulation bath is an aqueous solution containing 15wt% of citric acid, 5wt% of trisodium citrate and 25wt% of tert-butanol;

[0041] S3. Freeze the composite cellulose gel fiber obtained in S2 in a -20°C refrigerator for 5 h, and then freeze-dry it in a freeze dryer at a temperature of -60°C and a low pressure of 10 Pa for 24 h to obtain a composite aerogel fiber.

[0042] The specific surface area of ​​the composite cellulose gel fiber prepared in this example is 270 m 2 / g, porosity is 86.7%, density is 0.2g / cm 3It has the characteristics of lightness and porosity, with a breaking strength of 20MPa, an elongation of 19.5%, and a thermal conductivity of 0.055W / (m·K). It has good mechanical properties and thermal insulation effects.

[0043] Comparative Example 1

[0044] The method is basically the same as Example 1, except that the thermochromic microcapsules that turn black at a low temperature of 18°C ​​are not added.

[0045] The scanning electron microscope images of the cross sections of the aerogel fibers prepared in Example 1 and Comparative Example 1 are shown in Figure 1 As shown, Figure 1 Figures (a) and (b) are scanning electron microscope images of the cross-section of the aerogel fiber prepared in Comparative Example 1 magnified 500 times and 30,000 times, respectively. Figure 1 Figures (c) and (d) are scanning electron microscope images of the cross-section of the aerogel fiber prepared in Example 1 magnified 500 times and 30,000 times, respectively. Figure 1 It can be seen that the diameter of the aerogel fibers prepared in Example 1 and Comparative Example 1 is about 500 μm, both have a circular cross-section and a nanoscale skeleton structure, and have a highly porous three-dimensional network inside. The cross-sectional macroscopic morphology of the composite fiber of the mixed microcapsule is very similar to that of the pure cellulose aerogel fiber (Figures b and d). The thermochromic microcapsules contained in the composite aerogel fiber maintain a spherical structure without being dissolved and destroyed, and they are well dispersed and firmly embedded in the loose porous aerogel phase.

[0046] The actual picture of the fabric woven from composite aerogel fibers prepared in Example 1 is shown in Figure 2 When the temperature is below 18℃, the textile fabric appears black, and when the temperature is above 18℃, the textile fabric appears white.

[0047] The adaptive thermal management function of the fabric woven with aerogel fibers of Example 1 and Comparative Example 1 is shown in Figure 3 ,Depend on Figure 3 It can be seen that when the cold platform is -45℃, both the single cellulose aerogel fiber fabric and the aerogel fiber fabric with added thermochromic microcapsules have good thermal insulation effect, and the surface temperature of the aerogel fiber fabric is -12℃. After illumination, the surface temperature of the aerogel fiber fabric with added thermochromic microcapsules is 6℃ higher than that of the single cellulose aerogel fiber fabric. It can adaptively increase the surface temperature of the fabric in a low temperature environment, showing the function of thermal insulation and adaptive thermal management. It can be widely used in outdoor environments with low temperature but strong sunlight, such as plateaus, polar regions, and outer space.

[0048] Example 2

[0049] This embodiment provides a method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display, which specifically includes the following steps:

[0050] S1. After cleaning and crushing the cotton pulp, dry it at 100°C for 24h, then immerse 1.5g of cotton pulp, 0.15g of two thermochromic microcapsules that turn black at low temperature of 18°C ​​and 0.15g of two thermochromic microcapsules that turn black at high temperature of 28°C in 20ml of a solvent containing 40wt% tetrabutylammonium hydroxide and 2.5wt% urea, stir vigorously at room temperature for 200min, then centrifuge at 6000r / min for 15min to remove bubbles, and obtain a cellulose spinning solution after filtration;

[0051] S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a 25G needle at a rate of 0.6 ml / min, gelling and aging at 25°C for 5 hours to obtain a one-dimensional composite cellulose gel fiber, wherein the coagulation bath is an aqueous solution containing 5wt% of citric acid, 2.5wt% of trisodium citrate and 10wt% of tert-butanol;

[0052] S3. Freeze the composite cellulose gel fiber obtained in S2 in a -10°C refrigerator for 10 h, and then freeze-dry it in a freeze dryer at a temperature of -85°C and a low pressure of 8 Pa for 48 h to obtain a composite aerogel fiber.

[0053] The specific surface area of ​​the composite cellulose gel fiber prepared in this example is 220 m 2 / g, porosity is 84%, density is 0.24g / cm 3 It is lightweight and porous, with a breaking strength of 22MPa, an elongation of 25%, and a thermal conductivity of 0.06W / (m·K). It has good mechanical properties and thermal insulation properties.

[0054] Example 3

[0055] This embodiment provides a method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display, which specifically includes the following steps:

[0056] S1. After washing and crushing the bamboo pulp, dry it at 110°C for 6h, then immerse 1.45g of bamboo pulp, 0.3g of two thermochromic microcapsules that show blue at low temperature of 18°C ​​and 0.3g of two thermochromic microcapsules that show red at high temperature of 35°C in 20ml of a solvent containing 50wt% of tetrabutylammonium hydroxide and 2.5wt% of urea, stir vigorously at room temperature for 60min, then centrifuge at 6000r / min for 15min to remove bubbles, and obtain a cellulose spinning solution after filtration;

[0057] S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a 27G needle at a rate of 2 ml / min, gelling and aging at 25°C for 5 hours to obtain a one-dimensional composite cellulose gel fiber, wherein the coagulation bath is an aqueous solution containing 15wt% of citric acid and 50wt% of tert-butyl alcohol;

[0058] S3. Freeze the composite cellulose gel fiber obtained in S2 in a -20°C refrigerator for 3 h, and then freeze-dry it in a freeze dryer at a temperature of -85°C and a low pressure of 15 Pa for 24 h to obtain a composite aerogel fiber.

[0059] (1) The actual picture of the fabric woven with composite aerogel fibers prepared in this example is shown in Figure 4 ,Depend on Figure 4 It can be seen that when the temperature is below 18°C, the textile fabric appears blue, when the temperature is between 18°C ​​and 35°C, the textile fabric appears white, and when the temperature is above 35°C, the textile fabric appears pink.

[0060] The specific surface area of ​​the composite cellulose gel fiber prepared in this example is 208 m 2 / g, porosity is 83.3%, density is 0.255g / cm 3 It is lightweight and porous, with a breaking strength of 23MPa, an elongation of 26%, and a thermal conductivity of 0.07W / (m·K). It has good mechanical properties and thermal insulation properties.

[0061] Example 4

[0062] This embodiment provides a method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display, which specifically includes the following steps:

[0063] S1. After washing and crushing the regenerated viscose, dry it at 105°C for 12h, then immerse 1.5g of the regenerated viscose and 0.9g of thermochromic microcapsules that turn red at 35 degrees Celsius in 20ml of a solvent containing 40wt% tetrabutylammonium hydroxide and 3wt% urea, stir vigorously at room temperature for 120min, then centrifuge at 6000r / min for 15min to remove bubbles, and obtain a cellulose spinning solution after filtration;

[0064] S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a 25G needle at a rate of 1.2 ml / min, gelling and aging at 25°C for 12 hours to obtain a one-dimensional composite cellulose gel fiber, wherein the coagulation bath is an aqueous solution containing 15wt% of citric acid, 5wt% of trisodium citrate and 40wt% of tert-butanol;

[0065] S3. Dry and extract the composite cellulose gel fiber obtained in S2 in a supercritical point dryer with a critical temperature of 45° C. and a critical pressure of 15 MPa for 5 h to obtain a composite aerogel fiber.

[0066] The specific surface area of ​​the composite cellulose gel fiber prepared in this example is 205 m 2 / g, porosity is 82%, density is 0.27g / cm 3It is lightweight and porous, with a breaking strength of 20.3MPa, an elongation of 20.4%, and a thermal conductivity of 0.08W / (m·K). It has good mechanical properties and thermal insulation properties.

[0067] The composite aerogel fibers prepared in Example 1, Example 4 and Example 3 have a dynamic display function of a QR code displayed by embroidery. Figure 5 Different patterns are displayed in different temperature ranges: at a temperature of 18-35°C, the textile appears white and the QR code is invalid. When the ambient temperature is below 18°C, a QR code can be read message I appears, and when the temperature exceeds 35°C, another QR code can be read message II is displayed.

[0068] The composite aerogel fibers prepared in the present application can be used to prepare functional fabrics such as temperature indication, information transmission and anti-counterfeiting.

[0069] Comparative Example 2

[0070] This comparative example provides a method for preparing a composite cellulose aerogel fiber, which specifically comprises the following steps:

[0071] S1. After washing and crushing the bamboo pulp, dry it at 105°C for 12h, then immerse 1.45g of bamboo pulp and 0.6g of thermochromic microcapsules that turn black at a low temperature of 18°C ​​in 20ml of a solvent containing 40wt% tetrabutylammonium hydroxide and 3wt% urea, stir vigorously at room temperature for 120min, then centrifuge at 6000r / min for 15min to remove bubbles, and obtain a cellulose spinning solution after filtration;

[0072] S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a 21G needle at a rate of 1.6 ml / min, and collecting the gelled fibers after gelling at 25°C for 15 minutes, wherein the coagulation bath contains 15 wt% citric acid and 5 wt% trisodium citrate;

[0073] S3, after the collected gel fibers are immersed in water to remove the residual solvent, the hydrogel fibers are immersed in a 25wt% tert-butyl alcohol solution for aging for 12 hours to obtain a one-dimensional composite cellulose gel fiber;

[0074] S4. Freeze the composite cellulose gel fiber obtained in S3 in a -20°C refrigerator for 5 h, and then freeze-dry it in a freeze dryer at a temperature of -60°C and a low pressure of 10 Pa for 24 h to obtain a composite aerogel fiber.

[0075] The specific surface area of ​​the composite cellulose gel fiber prepared in this comparative example is 180 m 2 / g, porosity is 82%, density is 0.27g / cm 3, breaking strength is 12MPa, elongation is 11.5%, and thermal conductivity is 0.08W / (m·K).

[0076] The main parameters in the preparation process of the examples and comparative examples of the present application and the properties of the prepared composite cellulose gel fibers are shown in the following table:

[0077] Table 1. Main parameters in the preparation process of the examples and comparative examples and properties of the prepared composite cellulose gel fibers

[0078]

[0079] It can be seen from the above table that adding tert-butyl alcohol to the coagulation bath and combining gelation and aging into one step not only has no adverse effect on the performance of the composite cellulose gel fiber, but on the contrary improves its specific surface area, porosity and mechanical strength.

[0080] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing composite aerogel fibers for adaptive thermal management and dynamic display, characterized in that: The steps include: S1, dispersing the washed and crushed cellulose raw material and the thermochromic material in a non-derivatized aqueous solvent, and then defoaming and filtering to obtain a cellulose spinning solution; S2, extruding the cellulose spinning solution described in S1 into a coagulation bath through a spinneret for solvent phase separation and displacement aging to obtain a one-dimensional composite cellulose gel fiber; S3, drying the composite cellulose gel fiber obtained in S2 to obtain a composite aerogel fiber; The non-derivatized aqueous phase solvent in S1 includes 40-50 wt% tetrabutylammonium hydroxide and 2.5-3 wt% urea; The coagulation bath described in S2 includes 5-15 wt% citric acid, 0-5 wt% trisodium citrate, and 10-50 wt% tert-butyl alcohol.

2. The method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display according to claim 1, characterized in that: After the cellulose raw material is washed and crushed, it is dried at a temperature of 100 to 110° C. for 6 to 24 hours. The mass ratio of the cellulose raw material to the thermochromic material is 5:1 to 5:

3.

3. The method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display according to claim 1, characterized in that: The thermochromic material described in S1 is a low-temperature color-developing microcapsule and / or a high-temperature color-developing microcapsule, the particle size of the low-temperature color-developing microcapsule and the high-temperature color-developing microcapsule is 1 to 5 μm, and the low-temperature color-developing microcapsule and the high-temperature color-developing microcapsule have a core-shell structure composed of a resin and a thermochromic dye.

4. The method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display according to claim 3, characterized in that: The low-temperature color-developing microcapsule can display color when the ambient temperature is below a threshold value, and is colorless at a high temperature. The high-temperature color-developing microcapsule can display color when the ambient temperature is above a threshold value, and is colorless at a low temperature. The color can be selected from one of black, blue, yellow, red and green.

5. The method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display according to claim 1, characterized in that: The specific steps of S2 are: extruding the cellulose spinning solution described in S1 into the coagulation bath through a 21-27 G needle at a rate of 0.6-2 ml / min, gelling and aging at 20-30°C for 5-24 hours to obtain a one-dimensional composite cellulose gel fiber.

6. The method for preparing a composite aerogel fiber for adaptive thermal management and dynamic display according to claim 1, characterized in that: The drying method described in S3 is one of supercritical carbon dioxide drying and freeze drying.

7. A composite aerogel fiber for adaptive thermal management and dynamic display, characterized in that: The preparation method is described in any one of claims 1 to 6.

8. Use of the composite aerogel fiber for adaptive thermal management and dynamic display as described in claim 7 in anti-counterfeiting textiles, temperature indicating fabrics, temperature-sensitive color-changing clothing or cold-proof protective clothing.

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