Coaxial aerogel liquid crystal elastomer fiber with skin-core structure as well as preparation method and application of coaxial aerogel liquid crystal elastomer fiber

Abstract

The invention relates to the technical field of functional materials, in particular to a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure and a preparation method and application of the coaxial aerogel liquid crystal elastomer fiber. The coaxial aerogel liquid crystal elastomer fiber with the skin-core structure comprises a core layer and a compact skin layer wrapping the core layer, and the core layer is of a porous structure; the compact skin layer is prepared from a skin layer spinning solution comprising a first liquid crystal monomer, a first chain extender and a first cross-linking agent; the core layer is prepared from a core layer spinning solution comprising a second liquid crystal monomer, a second chain extender and a second cross-linking agent; wherein the concentration of the first liquid crystal monomer in the skin layer spinning solution is greater than that of the second liquid crystal monomer in the core layer spinning solution. According to the invention, the liquid crystal elastomer and the aerogel are effectively combined, and the prepared coaxial aerogel liquid crystal elastomer fiber with the skin-core structure has the characteristics of high toughness, high tensile strength, excellent heat insulation performance, actuating performance and self-adaptive heat management function, and has potential application value in the fields of intelligent actuating and self-adaptive heat management.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure, and a preparation method and application thereof. Background Art

[0002] Aerogel is recognized as one of the most ideal thermal insulation materials due to its high porosity, large specific surface area and low thermal conductivity. In recent years, aerogel fibers have attracted more and more attention in the fields of smart fabrics and flexible electronic devices by combining the thermal insulation properties of aerogel with the flexibility of fibers. However, most aerogel fibers have a single function and rely on static thermal insulation, which limits their application scenarios. For example, the Chinese patent technology with publication number CN116555930A discloses a composite aerogel fiber for adaptive thermal management and dynamic display. By compounding thermochromic materials into cellulose aerogel fibers, the prepared composite aerogel fibers have good thermal insulation properties and temperature-responsive color-changing functions, but the composite aerogel fibers lack active actuation capabilities (no actuation performance).

[0003] With the rapid development of flexible electronics, soft robotics, and wearable devices, there is an increasing demand for smart materials that combine thermal insulation properties with active actuation capabilities (such as actuation performance). Liquid crystal elastomers (LCEs), as an emerging smart polymer material, can achieve bidirectional drive responses (with actuation performance) under external stimuli due to the ordered orientation of liquid crystal units in their molecular structure. They have broad application prospects in artificial intelligence, optoelectronic materials, bioengineering, soft robotics, and other fields. However, traditional liquid crystal elastomers usually have problems such as poor thermal insulation performance, insufficient toughness, and low actuation stress, which greatly limits their application.

[0004] Currently, combining the thermal insulation properties of aerogels with the actuation capabilities of liquid crystal elastomers remains a pressing technical challenge. Furthermore, there are few reports of fiber materials that simultaneously achieve high toughness, efficient thermal insulation, actuation, and adaptive thermal management. The lack of such materials poses a significant challenge to the development of next-generation smart devices capable of adapting to extreme environments and exhibiting active regulation capabilities.

[0005] Therefore, developing a new fiber material with high toughness, efficient thermal insulation, actuation performance and adaptive thermal management functions not only has important scientific significance, but will also provide innovative material solutions for cutting-edge fields such as flexible electronics, adaptive thermal management systems and soft robots. Summary of the Invention

[0006] The present invention provides a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure. The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure has high toughness, high tensile strength, excellent thermal insulation performance, actuation performance and adaptive thermal management function, and has good weaving properties.

[0007] The present invention also provides a method for preparing a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure, by which the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure having high toughness, high tensile strength, excellent thermal insulation performance, actuation performance, adaptive thermal management function and good weaving properties can be prepared.

[0008] The present invention also provides the use of the aforementioned coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure, or the coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure produced by the aforementioned method for producing a coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure, in the manufacture of an actuator. Because the coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure exhibits actuation properties, it can be used in an actuator.

[0009] The present invention also provides a fabric comprising the aforementioned coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure, or a coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure produced by the aforementioned method for producing a coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure. The inventors' research has shown that the coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure exhibits excellent braiding properties. The resulting fabric, woven from the coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure, is capable of adaptively adjusting to different temperature environments, exhibiting adaptive thermal management capabilities.

[0010] A first aspect of the present invention provides a coaxial aerogel liquid crystal elastomer fiber having a skin-core structure, comprising a core layer and a dense skin layer wrapping the core layer, wherein the core layer has a porous structure;

[0011] The dense cortex is made of a cortex spinning solution including a first liquid crystal monomer, a first chain extender and a first cross-linking agent; the core layer is made of a core spinning solution including a second liquid crystal monomer, a second chain extender and a second cross-linking agent; wherein the concentration of the first liquid crystal monomer in the cortex spinning solution is greater than the concentration of the second liquid crystal monomer in the core layer spinning solution.

[0012] For the coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure as described above, the concentration of the first liquid crystal monomer in the sheath spinning solution is 300-1000 mg / mL, and the concentration of the second liquid crystal monomer in the core spinning solution is 100-250 mg / mL.

[0013] The coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure as described above, wherein in the sheath spinning solution, the molar ratio of the first liquid crystal monomer, the first chain extender and the first cross-linking agent is (3-4): (1-2): 1;

[0014] And / or, in the core layer spinning solution, the molar ratio of the second liquid crystal monomer, the second chain extender and the second cross-linking agent is (3-4):(1-2):1.

[0015] The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure as described above, wherein the first liquid crystal monomer or the second liquid crystal monomer includes at least one of 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene, 4-cyanophenyl 4-((6-(acryloxy)hexyl)oxy)benzoate and 4-(4'-hexyloxy)benzoyloxybenzoic acid-R-2-octanol ester, 4'-acryldiphenyl cyanide, polysiloxane side chain acryl liquid crystal, and azobenzene acrylate liquid crystal;

[0016] and / or, the first chain extender or the second chain extender comprises at least one of hexanedithiol, octanedithiol, 2,2'-(1,2-ethanediyldioxy)bis(ethanediol), 1,3-propanedithiol, 1,2-propanedithiol, 1,11-undecanedithiol, 4,4'-dimercaptodiphenyl ether, pentaerythritol tetrakis(3-mercaptopropionic acid), 2,3-dimercaptopropanol, and 1,4-benzenedithiol;

[0017] And / or, the cross-linking agent includes at least one of pentaerythritol tetrakis(3-mercaptopropionate), tetramercaptobenzene, tetramercaptoporphyrin, and tetramercaptopolyethylene glycol.

[0018] A second aspect of the present invention provides a method for preparing the coaxial aerogel liquid crystal elastomer fiber having a skin-core structure, comprising the following steps:

[0019] adding a first liquid crystal monomer, a first chain extender, a first cross-linking agent, a first catalyst and a first photoinitiator into a first organic solvent and performing a first stirring process to obtain a skin spinning solution;

[0020] adding a second liquid crystal monomer, a second chain extender, a second cross-linking agent, and a second catalyst into a second organic solvent and performing ultrasonic treatment, then adding an inhibitor and a second photoinitiator and performing a second stirring treatment to obtain a core layer spinning solution;

[0021] Coaxially spinning the skin layer spinning solution and the core layer spinning solution under ultraviolet light to obtain coaxial liquid crystal gel fibers;

[0022] The coaxial liquid crystal gel fiber is dried to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure.

[0023] The method for preparing the coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure as described above, wherein the content of the first catalyst in the sheath spinning solution is 0.5-5wt%, and the content of the first photoinitiator is 1-3wt%;

[0024] And / or, in the core layer spinning solution, the content of the second catalyst is 0.5-5wt%, the content of the inhibitor is 1-3wt%, and the content of the second photoinitiator is 1-3wt%.

[0025] As described above, in the method for preparing a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure, the first catalyst or the second catalyst includes triethylamine or n-propylenediamine; the first photoinitiator or the second photoinitiator includes benzil dimethyl ether or phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide; the inhibitor includes 2,6-di-tert-butyl-p-cresol; and the first organic solvent or the second organic solvent includes acetone, toluene or xylene.

[0026] The method for preparing the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure as described above, wherein the temperature in the first stirring treatment is 20-30° C. and the stirring speed is 100-500 rpm;

[0027] and / or, in the second stirring process, the temperature is 20-30° C. and the speed is 100-500 rpm;

[0028] And / or, the drying process is a supercritical drying process or a freeze drying process;

[0029] In the supercritical drying process, the temperature is 35 to 50° C., the pressure is 1000 to 1300 Pa, and the time is 6 to 24 hours; in the freeze-drying process, the temperature is -50 to -90° C., and the time is 24 to 72 hours.

[0030] The third aspect of the present invention provides the use of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure or the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure prepared by the preparation method of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in the preparation of an actuator.

[0031] The fourth aspect of the present invention provides a fabric comprising the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure or the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure prepared by the preparation method of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure.

[0032] The solution of the present invention has at least the following effects:

[0033] The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure provided by the present invention is prepared by preparing a skin-core structure by ultraviolet light irradiation-induced reactive coaxial spinning of a skin spinning solution including a first liquid crystal monomer, a first chain extender and a first crosslinking agent and a core spinning solution including a second liquid crystal monomer, a second chain extender and a second crosslinking agent, and then performing a drying treatment (supercritical drying treatment or freeze-drying treatment); wherein the concentration of the first liquid crystal monomer in the skin spinning solution is greater than the concentration of the second liquid crystal monomer in the core spinning solution, so that the obtained skin-core structure has a clear dividing line, and the obtained coaxial aerogel liquid crystal elastomer fiber with a skin-core structure has high toughness and obtains dynamic thermal insulation performance; by regulating the concentration of the second liquid crystal monomer in the skin spinning solution, the skin-core structure is obtained. The concentration of a liquid crystal monomer or the concentration of a second liquid crystal monomer in the core layer spinning solution makes the obtained skin-core structure have strong interface compatibility, and the core layer with a porous structure can improve the toughness of the dense skin layer, so that the mechanical properties (such as toughness) of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure are better than the mechanical properties (such as toughness) of the liquid crystal elastomer fiber; the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure not only has the actuation properties of the liquid crystal elastomer, but also has the thermal insulation properties of the aerogel, and has potential application value in the fields of intelligent actuation and adaptive thermal management; and the tensile strength of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure can reach 18.81MPa, and the toughness can reach 16.58MJ / m 3 , and has good weavability, which is of great significance to the development of smart textiles and has huge economic value and application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 The chemical structural formulas of the raw materials (crosslinking agent, chain extender and liquid crystal monomer) required for the preparation process of the present invention, and the coaxial spinning process of the skin spinning solution and the core spinning solution under the irradiation of the ultraviolet curing lamp;

[0036] Figure 2 The SEM images of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1 of the present invention and the liquid crystal elastomer fiber in Comparative Example 1 are shown. Figure 2 a is the SEM image of the liquid crystal elastomer fiber in Comparative Example 1, Figure 2 b is a local enlarged SEM image of the interior of the liquid crystal elastomer fiber in Comparative Example 1. Figure 2c is a local enlarged SEM image of the surface layer of the liquid crystal elastomer fiber in Comparative Example 1, Figure 2 d is the SEM image of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1, Figure 2 e is a local magnified SEM image of the core layer of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1. Figure 2 f is a local magnified SEM image of the skin layer of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1;

[0037] Figure 3 Graphs showing stress-strain curves of the coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Examples 1-5, the liquid crystal elastomer fibers in Comparative Example 1, and the liquid crystal elastomer aerogel fibers in Comparative Example 2;

[0038] Figure 4 This is a physical picture of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 of the present invention, wherein 1 refers to the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure, and 2 refers to a human arm model.

[0039] Figure 5 The actuation effect of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 under thermal stimulation at 100°C is shown in FIG. Figure 5 a is the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 before thermal stimulation. Figure 5 b is the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 after thermal stimulation;

[0040] Figure 6 is a graph showing the change in actuation stress of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 and the liquid crystal elastomer fiber actuator in Comparative Application Example 1 as a function of thermal stimulation frequency, wherein Figure 6 a is a graph showing the change in actuation stress of the coaxial aerogel liquid crystal elastomer fiber actuator with the frequency of thermal stimulation in Application Example 1. Figure 6 b is a graph showing the change in actuation stress of the liquid crystal elastomer fiber actuator with the frequency of thermal stimulation in Comparative Application Example 1;

[0041] Figure 7 The actual pictures of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 are shown in FIG. Figure 7 a is a physical picture of the liquid crystal elastomer fiber fabric in comparative application example 2, Figure 7 b is a physical picture of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2;

[0042] Figure 8The thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at different heating temperatures, wherein: Figure 8 a is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 50°C, Figure 8 b is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 60°C, Figure 8 c is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 70°C, Figure 8 d is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 80°C;

[0043] Figure 9 The temperature difference (ΔT) of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 in different temperature environments. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. If the specific technology or conditions are not specified in the embodiments, they shall be carried out according to the technology or conditions described in the literature in this field or according to the product specifications. The raw materials, reagents or instruments used that do not indicate the manufacturer are all conventional products that can be obtained through commercial purchase.

[0045] It should be noted that the descriptions involving “first”, “second”, etc. in the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence, and therefore cannot be understood as a limitation of the present invention.

[0046] In the present invention, the term "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items. For example, "at least one of a, b, or c" or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be a single or multiple.

[0047] In addition, in the specification and claims, "and / or" means at least one of the connected objects, and the character " / " generally indicates that the previous and subsequent related objects are in an "or" relationship.

[0048] A first aspect of the present invention provides a coaxial aerogel liquid crystal elastomer fiber having a skin-core structure, comprising a core layer and a dense skin layer wrapping the core layer, wherein the core layer has a porous structure;

[0049] The dense cortex is made of a cortex spinning solution including a first liquid crystal monomer, a first chain extender and a first cross-linking agent; the core layer is made of a core spinning solution including a second liquid crystal monomer, a second chain extender and a second cross-linking agent; wherein the concentration of the first liquid crystal monomer in the spinning solution is greater than the concentration of the second liquid crystal monomer in the core layer spinning solution.

[0050] Specifically, the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure provided by the present invention includes a core layer with a porous structure and a dense skin layer wrapping the core layer, the dense skin layer is made of a skin spinning solution including a first liquid crystal monomer, a first chain extender and a first cross-linking agent, and the core layer with a porous structure is made of a core spinning solution including a second liquid crystal monomer, a second chain extender and a second cross-linking agent; wherein the concentration of the first liquid crystal monomer in the skin spinning solution is greater than the concentration of the second liquid crystal monomer in the core spinning solution, so that the obtained skin-core structure has a clear dividing line, and the obtained coaxial aerogel liquid crystal elastomer fiber with a skin-core structure has high toughness and high tensile strength while obtaining dynamic thermal insulation performance, and the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure also has actuation performance, adaptive thermal management function and good weaving properties, and has potential application value in the fields of intelligent actuation, adaptive thermal management and intelligent textiles.

[0051] In a specific embodiment, the concentration of the first liquid crystal monomer in the spinning solution is 300-1000 mg / mL, and the concentration of the second liquid crystal monomer in the core layer spinning solution is 100-250 mg / mL.

[0052] When the concentration of the first liquid crystal monomer in the skin spinning solution and the concentration of the second liquid crystal monomer in the core spinning solution are respectively within the above ranges, the concentration of the first liquid crystal monomer in the skin spinning solution is greater than the concentration of the second liquid crystal monomer in the core spinning solution, which is beneficial to the preparation of coaxial aerogel liquid crystal elastomer fibers with a skin-core structure having high toughness, high tensile strength, excellent thermal insulation performance, actuation performance and adaptive thermal management function, and good weavability.

[0053] In a specific embodiment, in the above-mentioned spinning solution, the molar ratio of the first liquid crystal monomer, the first chain extender and the first cross-linking agent is (3-4): (1-2): 1, for example, the molar ratio of the first liquid crystal monomer, the first chain extender and the first cross-linking agent is 3:1:1, 3:2:1, 4:1:1, 4:2:1, etc.

[0054] When the molar ratio of the first liquid crystal monomer, the first chain extender and the first cross-linking agent in the cortex spinning solution is within the above range, the cortex of the obtained coaxial aerogel liquid crystal elastomer fiber is a dense elastomer (dense cortex), which is beneficial to improving the breaking elongation and breaking stress of the coaxial aerogel liquid crystal elastomer fiber and making it have actuation performance.

[0055] In a specific embodiment, in the above-mentioned core layer spinning solution, the molar ratio of the second liquid crystal monomer, the second chain extender and the second cross-linking agent is (3-4): (1-2): 1, for example, the molar ratio of the second liquid crystal monomer, the second chain extender and the second cross-linking agent is 3:1:1, 3:2:1, 4:1:1, 4:2:1, etc.

[0056] When the molar ratio of the second liquid crystal monomer, the second chain extender and the second cross-linking agent in the core layer spinning solution is within the above range, the core layer of the obtained coaxial aerogel liquid crystal elastomer fiber is an aerogel with a porous structure, which is beneficial to improving the breaking stress and Young's modulus of the coaxial aerogel liquid crystal elastomer fiber and making it have thermal insulation properties.

[0057] In a specific embodiment, the first liquid crystal monomer or the second liquid crystal monomer includes at least one of 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene, 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene, 4-cyanophenyl 4-((6-(acryloyloxy)hexyl)oxy)benzoate and 4-(4'-hexyloxy)benzoyloxybenzoic acid-R-2-octanol ester, 4'-acryloyldiphenyl cyanide, polysiloxane side chain acryl liquid crystal, and azobenzene acrylate liquid crystal.

[0058] In a specific embodiment, the first chain extender or the second chain extender includes at least one of hexanedithiol, octanedithiol, 2,2'-(1,2-ethanediyldioxy)diethanethiol, 1,3-propylene glycol, 1,2-propylene glycol, 1,11-undecanedithiol, 4,4'-dimercaptodiphenyl ether, pentaerythritol tetrakis(3-mercaptopropionic acid), 2,3-dimercaptopropanol, and 1,4-benzenedithiol.

[0059] In a specific embodiment, the cross-linking agent includes at least one of pentaerythritol tetrakis(3-mercaptopropionate), tetramercaptobenzene, tetramercaptoporphyrin, and tetramercaptopolyethylene glycol.

[0060] A second aspect of the present invention provides a method for preparing the above-mentioned coaxial aerogel liquid crystal elastomer fiber having a skin-core structure, comprising the following steps:

[0061] adding a first liquid crystal monomer, a first chain extender, a first cross-linking agent, a first catalyst and a first photoinitiator into a first organic solvent and performing a first stirring process to obtain a skin spinning solution;

[0062] adding a second liquid crystal monomer, a second chain extender, a second cross-linking agent, and a second catalyst into a second organic solvent and performing ultrasonic treatment, then adding an inhibitor and a second photoinitiator and performing a second stirring treatment to obtain a core layer spinning solution;

[0063] The skin layer spinning solution and the core layer spinning solution are coaxially spun under ultraviolet light to obtain coaxial liquid crystal gel fibers;

[0064] The coaxial liquid crystal gel fiber is dried to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure.

[0065] The present invention does not particularly limit the specific order of adding the first liquid crystal monomer, the first chain extender, the first cross-linking agent, the first catalyst and the first photoinitiator into the first organic solvent.

[0066] The present invention does not particularly limit the specific order of adding the second liquid crystal monomer, the second chain extender, the second cross-linking agent, and the second catalyst into the second organic solvent.

[0067] The object of preparation of the present invention is a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure. Specifically, a first liquid crystal monomer, a first chain extender, a first cross-linking agent, a first catalyst and a first photoinitiator are first added to a first organic solvent and subjected to a first stirring treatment to obtain a skin spinning solution; then a second liquid crystal monomer, a second chain extender, a second cross-linking agent and a second catalyst are added to a second organic solvent and subjected to ultrasonic treatment, and then an inhibitor and a second photoinitiator are added and subjected to a second stirring treatment to obtain a core spinning solution; then, ultraviolet light is used to induce reactive coaxial spinning, and the skin spinning solution and the core spinning solution are coaxially spun under ultraviolet light to obtain a coaxial liquid crystal gel fiber; finally, the coaxial liquid crystal gel fiber is dried to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure; the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure prepared by this method has the characteristics of high toughness, high tensile strength, and excellent thermal insulation performance, and it also has actuation performance, adaptive thermal management function and good weaving properties.

[0068] In some embodiments, the spinning solution and the core layer spinning solution are coaxially spun under ultraviolet light to obtain coaxial liquid crystal gel fibers by inducing reactive coaxial spinning under ultraviolet light irradiation, specifically comprising: injecting the spinning solution and the core layer spinning solution into acetone through syringe A and syringe B of the coaxial spinning device, respectively, and inducing reactive coaxial spinning through ultraviolet light irradiation to obtain continuous coaxial liquid crystal gel fibers; the coaxial needle diameters of syringe A and syringe B are both 22 / 17G; and the injection speed is 4 to 10 mL / h.

[0069] The principle of preparing the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to the present invention is explained:

[0070] After the skin spinning solution and the core spinning solution undergo "propylene-mercapto click" reaction, free radical polymerization is carried out under ultraviolet light to form coaxial liquid crystal gel fibers. During the drying process, the solvent in the coaxial liquid crystal gel fibers is removed. Due to the difference in cross-linking degree, coaxial aerogel liquid crystal elastomer fibers with a dense skin and a porous core layer are obtained, that is, coaxial aerogel liquid crystal elastomer fibers with a skin-core structure are obtained.

[0071] In a specific embodiment, in the above-mentioned skin layer spinning solution, the content of the first catalyst is 0.5-5 wt%, and the content of the first photoinitiator is 1-3 wt%.

[0072] When the content of the first catalyst and the content of the first photoinitiator in the skin layer spinning solution are respectively within the above ranges, it is beneficial to obtain a dense skin layer.

[0073] In a specific embodiment, in the core layer spinning solution, the content of the second catalyst is 0.5-5 wt %, the content of the inhibitor is 1-3 wt %, and the content of the second photoinitiator is 1-3 wt %.

[0074] When the content of the second catalyst, the content of the inhibitor and the content of the second photoinitiator in the core layer spinning solution are each within the above ranges, it is beneficial to obtain a core layer with a porous structure.

[0075] In one specific embodiment, the first catalyst or the second catalyst comprises triethylamine or n-propylenediamine.

[0076] In a specific embodiment, the first photoinitiator or the second photoinitiator includes dimethylbenzil (DMPA) or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (XBPO).

[0077] In one embodiment, the inhibitor includes 2,6-di-tert-butyl-p-cresol (BHT).

[0078] The purpose of using 2,6-di-tert-butyl-p-cresol as an inhibitor is to prevent the core layer spinning solution system from rapidly gelling.

[0079] In a specific embodiment, the first organic solvent or the second organic solvent includes acetone, toluene or xylene.

[0080] In a specific embodiment, in the first stirring process, the temperature is 20-30° C. and the stirring speed is 100-500 rpm.

[0081] The present invention does not impose any particular limitation on the specific time of the first stirring treatment, and the time can be selected according to actual conditions.

[0082] For example, in the first stirring process, the temperature may be in the range of any one or any two of 20° C., 22° C., 24° C., 26° C., 28° C., and 30° C.;

[0083] The speed may be any one of 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, or a range consisting of any two of them.

[0084] In a specific embodiment, in the second stirring process, the temperature is 20-30° C. and the stirring speed is 100-500 rpm.

[0085] The present invention does not impose any particular limitation on the specific time of the second stirring treatment, and the time can be selected according to actual conditions.

[0086] For example, in the second stirring process, the temperature may be in the range of any one or any two of 20° C., 22° C., 24° C., 26° C., 28° C., and 30° C.;

[0087] The speed may be any one of 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, or a range consisting of any two of them.

[0088] In a specific embodiment, the drying process is a supercritical drying process or a freeze-drying process.

[0089] Specifically, the coaxial liquid crystal gel fiber can be subjected to supercritical drying treatment to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure; the coaxial liquid crystal gel fiber can also be subjected to freeze drying treatment to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure.

[0090] In a specific embodiment, in the supercritical drying treatment, the temperature is 35-50° C., the pressure is 1000-1300 Pa, and the time is 6-24 hours.

[0091] Specifically, the present invention can subject the coaxial liquid crystal gel fiber to a supercritical drying process to obtain a coaxial aerogel liquid crystal elastomer fiber having a skin-core structure.

[0092] When the temperature, pressure and time parameters are within the above ranges during the supercritical drying process, it is beneficial to maintain the regular porous morphology structure in the coaxial aerogel liquid crystal elastomer fiber without collapse.

[0093] For example, in the supercritical drying process, the temperature may be any one of 35°C, 40°C, 45°C, 50°C, or any two thereof;

[0094] The pressure may be any one of 1000 Pa, 1100 Pa, 1200 Pa, 1300 Pa, or a range consisting of any two of them;

[0095] The time can be any one of 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, or a range consisting of any two of them.

[0096] In a specific embodiment, during the freeze-drying process, the temperature is -50 to -90°C and the time is 24 to 72 hours.

[0097] Specifically, the present invention can freeze-dry the coaxial liquid crystal gel fiber to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure.

[0098] When the temperature and time parameters during the freeze-drying process are each within the above range, it is beneficial to maintain the regular porous morphology structure in the coaxial aerogel liquid crystal elastomer fiber and prevent collapse.

[0099] Illustratively, during the freeze-drying process, the temperature may be in the range of any one of -50°C (minus 50°C), -60°C (minus 60°C), -70°C (minus 70°C), -80°C (minus 80°C), and -90°C (minus 90°C), or any two thereof;

[0100] The time can be any one of 24 hours, 30 hours, 34 hours, 38 hours, 42 hours, 46 hours, 50 hours, 54 hours, 58 hours, 62 hours, 66 hours, and 72 hours, or a range consisting of any two of them.

[0101] A third aspect of the present invention provides the use of the aforementioned coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure, or a coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure produced by the aforementioned method for producing a coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure, in the manufacture of an actuator. Because the coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure exhibits actuation properties, it can be used in an actuator.

[0102] A fourth aspect of the present invention provides a fabric comprising the aforementioned coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure, or a coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure produced by the aforementioned method for producing a coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure. Research by the inventors has shown that the coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure exhibits excellent braidability. The resulting fabric, obtained by braiding the coaxial aerogel liquid crystal elastomer fiber having a sheath-core structure, can adaptively adjust to different temperature environments, exhibiting adaptive thermal management capabilities.

[0103] The present invention is further described below through specific examples.

[0104] Example 1

[0105] Figure 1 The chemical structural formulas of the raw materials (crosslinking agent, chain extender and liquid crystal monomer) required for the preparation process of the present invention, and the coaxial spinning process of the skin spinning solution and the core spinning solution under the irradiation of the ultraviolet curing lamp, such as Figure 1 As shown, this embodiment provides a method for preparing a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure, comprising the following steps:

[0106] (1) 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene (RM257), 2,2'-(1,2-ethylenedioxy)bis(ethylenethiol) (EDDT), and pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) were added to acetone at a molar ratio of 3:1:1, and then triethylamine and benzil dimethyl ether were added. The mixture was stirred at 25°C for 18 hours to obtain a cortex spinning solution. In the cortex spinning solution, the concentration of RM257 was 420 mg / mL, the content of triethylamine was 0.8 wt%, and the content of photoinitiator was 1.5 wt%.

[0107] (2) RM257, EDDT, and PETMP were added to acetone at a molar ratio of 3:1:1, and then triethylamine was added. After ultrasonic treatment for 5 minutes, 2,6-di-tert-butyl-p-cresol (BHT) and benzil dimethyl ether were added, and then stirred at 25°C for 18 hours to obtain a core layer spinning solution; in the core layer spinning solution, the concentration of RM257 was 150 mg / mL, the content of triethylamine was 0.8 wt%, the content of BHT was 1 wt%, and the content of benzil dimethyl ether was 1.5 wt%;

[0108] (3) The cortex spinning solution (1) is used to prepare the cortex of the fiber, and the core spinning solution (2) is used to prepare the core of the fiber; the cortex spinning solution and the core spinning solution are respectively injected into acetone through syringe A and syringe B of the coaxial spinning device by ultraviolet light irradiation-induced reactive coaxial spinning, and coaxial spinning is carried out under ultraviolet light irradiation with a wavelength of 365 nm to obtain continuous coaxial liquid crystal gel fibers; wherein the coaxial needle diameters of syringe A and syringe B are both 22 / 17G, and the injection speed is 8 mL / h;

[0109] (4) The continuous coaxial liquid crystal gel fiber in (3) was subjected to supercritical drying treatment at a temperature of 40°C and a pressure of 1300 Pa for 10 hours to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure.

[0110] Example 2

[0111] The preparation method of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure provided in this embodiment is basically the same as that in Example 1, except that:

[0112] (2) The concentration of RM257 in the core spinning solution is 100 mg / mL.

[0113] Example 3

[0114] The preparation method of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure provided in this embodiment is basically the same as that in Example 1, except that:

[0115] (2) The concentration of RM257 in the core spinning solution is 200 mg / mL.

[0116] Example 4

[0117] The preparation method of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure provided in this embodiment is basically the same as that in Example 1, except that:

[0118] (4) The continuous coaxial liquid crystal gel fibers in (3) were freeze-dried in a freeze dryer at a temperature of -75°C for 36 hours to obtain coaxial aerogel liquid crystal elastomer fibers with a skin-core structure.

[0119] Example 5

[0120] The preparation method of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure provided in this embodiment is basically the same as that in Example 1, except that:

[0121] (1) RM257, EDDT, and PETMP were added to acetone at a molar ratio of 4:2:1.

[0122] (2) RM257, EDDT, and PETMP were added to acetone at a molar ratio of 4:2:1.

[0123] Comparative Example 1

[0124] This comparative example provides a method for preparing liquid crystal elastomer fibers, comprising the following steps:

[0125] (1) RM257, EDDT, and PETMP were added to acetone at a molar ratio of 3:1:1, and then triethylamine and benzil dimethyl ether were added, followed by stirring at 25°C for 18 hours to obtain a spinning solution; in the spinning solution, the concentration of RM257 was 420 mg / mL, the content of triethylamine was 0.8 wt%, and the content of the photoinitiator was 1.5 wt%;

[0126] (2) using the spinning solution in (1) to prepare liquid crystal elastomer fibers; using a 17G uniaxial spinning method, spinning the spinning solution under ultraviolet light with a wavelength of 365 nm to obtain continuous liquid crystal gel fibers;

[0127] (3) The continuous liquid crystal gel fibers in (2) were subjected to supercritical drying treatment at a temperature of 40° C. and a pressure of 1300 Pa for 10 h to obtain liquid crystal elastomer fibers.

[0128] Comparative Example 2

[0129] This comparative example provides a method for preparing liquid crystal elastomer aerogel fibers, comprising the following steps:

[0130] (1) RM257, EDDT, and PETMP were added to acetone at a molar ratio of 3:1:1, and then triethylamine was added. After ultrasonic treatment for 5 minutes, a BHT inhibitor and benzil dimethyl ether were added, and then stirred at 25°C for 18 hours to obtain a spinning solution; in the spinning solution, the concentration of RM257 was 150 mg / mL, the content of triethylamine was 0.8 wt%, the content of BHT was 1 wt%, and the content of benzil dimethyl ether was 1.5 wt%;

[0131] (2) using the spinning solution in (1) to prepare liquid crystal elastomer aerogel fibers; using a 17G uniaxial spinning method, spinning the spinning solution under ultraviolet light with a wavelength of 365 nm to obtain continuous liquid crystal gel fibers;

[0132] (3) The continuous liquid crystal gel fibers in (2) were subjected to supercritical drying treatment at a temperature of 40° C. and a pressure of 1300 Pa for 10 h to obtain liquid crystal elastomer aerogel fibers.

[0133] Application Example 1

[0134] Figure 4This is a physical picture of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 of the present invention, as shown in FIG. Figure 4 As shown, the application example provides a method for preparing a coaxial aerogel liquid crystal elastomer fiber actuator, comprising the following steps:

[0135] The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure prepared in Example 1 was fixed on a human arm model to obtain a coaxial aerogel liquid crystal elastomer fiber actuator.

[0136] Comparative Application Example 1

[0137] The application example provides a method for preparing a liquid crystal elastomer fiber actuator, comprising the following steps:

[0138] The liquid crystal elastomer fiber prepared in Comparative Example 1 was fixed on a human arm model to obtain a coaxial aerogel liquid crystal elastomer fiber actuator.

[0139] Application Example 2

[0140] Figure 7 b is a physical picture of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 of the present invention, as shown in FIG. Figure 7 As shown in b, the application example provides a method for preparing a coaxial aerogel liquid crystal elastomer fiber fabric, comprising the following steps:

[0141] The coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure prepared in Example 1 was woven in a plain weave manner to obtain a coaxial aerogel liquid crystal elastomer fiber fabric.

[0142] Comparative Application Example 2

[0143] Figure 7 a is a physical picture of the coaxial aerogel liquid crystal elastomer fiber fabric in comparative application example 2 of the present invention, as shown in FIG. Figure 7 As shown in a, the application example provides a method for preparing a liquid crystal elastomer fiber fabric, comprising the following steps:

[0144] The liquid crystal elastomer fibers prepared in Comparative Example 1 were woven in a plain weave manner to obtain a liquid crystal elastomer fiber fabric.

[0145] Performance Testing

[0146] 1. Scanning electron microscope (SEM) tests were performed on the coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Example 1 of the present invention and the liquid crystal elastomer fibers in Comparative Example 1. The test results are as follows: Figure 2 As shown; Figure 2 The SEM images of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1 of the present invention and the liquid crystal elastomer fiber in Comparative Example 1 are shown. Figure 2a is the SEM image of the liquid crystal elastomer fiber in Comparative Example 1, Figure 2 b is a local enlarged SEM image of the interior of the liquid crystal elastomer fiber in Comparative Example 1. Figure 2 c is a local enlarged SEM image of the surface layer of the liquid crystal elastomer fiber in Comparative Example 1, Figure 2 d is the SEM image of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1, Figure 2 e is a local magnified SEM image of the core layer of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1. Figure 2 FIG. 5 is a locally enlarged SEM image of the skin layer of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1. FIG.

[0147] Depend on Figure 2 It can be seen from ac that the interior and surface of the liquid crystal elastomer fiber in Comparative Example 1 are both dense.

[0148] Depend on Figure 2 It can be seen from the df that the core layer of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1 has a porous structure, and the skin layer is in a dense state.

[0149] 2. The coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Examples 1-5, the liquid crystal elastomer fibers in Comparative Example 1, and the liquid crystal elastomer aerogel fibers in Comparative Example 2 were tested for stress-strain curves. The stress-strain curves are shown in FIG. Figure 3 As shown, the elongation at break (%), Young's modulus (MPa), stress at break (MPa), tensile strength (MPa) and toughness (MJ / m 3 ), and the results are summarized in Tables 1 and 2; Figure 3 Graphs showing stress-strain curves of the coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Examples 1-5, the liquid crystal elastomer fibers in Comparative Example 1, and the liquid crystal elastomer aerogel fibers in Comparative Example 2.

[0150] Table 1 Elongation at break, Young's modulus, and stress at break of each embodiment and each comparative example

[0151] project Elongation at break (%) Young's modulus (MPa) Fracture stress (MPa) Example 1 88.13 94.53 16.86 Example 2 55.41 89.62 9.62 Example 3 69.02 54.76 6.65 Example 4 73.91 86.99 10.15 Example 5 113.25 109.45 18.81 Comparative Example 1 94.06 6.04 5.59 Comparative Example 2 16.28 28.60 0.98

[0152] Table 2 Tensile strength and toughness of each embodiment and each comparative example

[0153] project Tensile strength (MPa) <![CDATA[Toughness (MJ / m 3 )]]> Example 1 16.86 8.01 Example 2 9.62 4.56 Example 3 6.65 4.03 Example 4 10.15 6.33 Example 5 18.81 16.58 Comparative Example 1 5.59 2.84 Comparative Example 2 0.98 1.22

[0154] Depend on Figure 3As shown in Table 1, compared with Comparative Example 1, Examples 1-5 demonstrate that the introduction of a porous core layer structure can increase the breaking stress and Young's modulus of the liquid crystal elastomer fibers; compared with Comparative Example 2, Examples 1-5 demonstrate that the dense structure of the skin layer can increase the breaking elongation and breaking stress of the liquid crystal aerogel fibers. These results demonstrate that the coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Examples 1-5 of the present invention have the advantages of high breaking elongation, breaking stress, and Young's modulus.

[0155] Depend on Figure 3 As shown in Table 2, the coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Examples 1-5 of the present invention have the advantages of high toughness and high tensile strength. The toughness and tensile strength of the coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Examples 1-5 are higher than those of the liquid crystal elastomer fibers in Comparative Example 1 and the liquid crystal elastomer aerogel fibers in Comparative Example 2, indicating that the introduction of a porous core structure can significantly improve the toughness and tensile strength of the liquid crystal elastomer fibers. These results demonstrate that the coaxial aerogel liquid crystal elastomer fibers with a skin-core structure in Examples 1-5 of the present invention have the advantages of excellent mechanical properties.

[0156] 3. Actuation performance test of coaxial aerogel liquid crystal elastomer fibers

[0157] The coaxial aerogel liquid crystal elastomer fiber actuator in Example 1 and the liquid crystal elastomer fiber actuator in Comparative Application Example 1 were used as test samples for actuation performance testing: thermal stimulation from a heat gun was used to enable the test samples to achieve arm flexion actuation on a human arm model; Figure 5 The actuation effect of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 under thermal stimulation at 100°C is shown in FIG. Figure 5 a is the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 before thermal stimulation. Figure 5 b is the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 after thermal stimulation; Figure 6 is a graph showing the change in actuation stress of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 and the liquid crystal elastomer fiber actuator in Comparative Application Example 1 as a function of thermal stimulation frequency, wherein Figure 6 a is a graph showing the change in actuation stress of the coaxial aerogel liquid crystal elastomer fiber actuator with the frequency of thermal stimulation in Application Example 1. Figure 6 b is a graph showing the change in actuation stress of the liquid crystal elastomer fiber actuator with the frequency of thermal stimulation in comparative application example 1.

[0158] Depend on Figure 5 It can be seen that the coaxial aerogel liquid crystal elastomer fiber actuator before thermal stimulation presents an anisotropic state ( Figure 5a), that is, the liquid crystal units are arranged in an orderly manner. After applying thermal stimulation, the coaxial aerogel liquid crystal elastomer fiber actuator presents an isotropic state ( Figure 5 b), that is, the liquid crystal units are arranged in a disordered manner. The transformation from ordered arrangement to disordered arrangement will enable the coaxial aerogel liquid crystal elastomer fiber actuator to achieve axial contraction actuation. The deformation effect can be seen in Figure 5 .

[0159] Depend on Figure 6 It can be seen that under thermal stimulation, the actuation stresses of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 and the liquid crystal elastomer fiber actuator in Comparative Application Example 1 are both around 0.2 MPa, indicating that the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1 and the liquid crystal elastomer fiber in Comparative Example 1 both have actuation properties.

[0160] 4. Thermal insulation performance test of coaxial aerogel liquid crystal elastomer fiber

[0161] ① Figure 7 The actual pictures of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 are shown in FIG. Figure 7 a is a physical picture of the liquid crystal elastomer fiber fabric in comparative application example 2, Figure 7 b is a real picture of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2.

[0162] Depend on Figure 7 It can be seen from ab that the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure prepared in Example 1 and the liquid crystal elastomer fiber prepared in Comparative Example 1 can be woven into fabrics, and the fiber structure remains intact and regular, and no damage is found in the fibers, which have good weavability.

[0163] ② Figure 8 The thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at different heating temperatures, wherein: Figure 8 a is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 50°C, Figure 8 b is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 60°C, Figure 8 c is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 70°C, Figure 8 d is the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 at 80°C.

[0164] Depend on Figure 8 It can be seen from a that the heat transfer temperature of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is 40°C, and the heat transfer temperature of the liquid crystal elastomer fiber fabric in Comparative Application Example 2 is 43°C, and the insulation temperature difference is 3°C.

[0165] Depend on Figure 8 From b, it can be seen that the heat transfer temperature of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is 48°C, while the heat transfer temperature of the liquid crystal elastomer fiber fabric in Comparative Application Example 2 is 52°C, and the insulation temperature difference is 4°C.

[0166] Depend on Figure 8 It can be seen from c that the heat transfer temperature of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is 55°C, and the heat transfer temperature of the liquid crystal elastomer fiber fabric in Comparative Application Example 2 is 60°C, and the insulation temperature difference is 5°C.

[0167] Depend on Figure 8 It can be seen from d that the heat transfer temperature of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is 63°C, and the heat transfer temperature of the liquid crystal elastomer fiber fabric in Comparative Application Example 2 is 68°C, and the insulation temperature difference is 5°C.

[0168] The above results show that at different heating temperatures, the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 and the liquid crystal elastomer fiber fabric in Comparative Application Example 2 exhibit significantly different thermal insulation properties. Obviously, the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is better than that of the liquid crystal elastomer fiber fabric in Comparative Application Example 2, which shows that the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1 has superior thermal insulation performance.

[0169] 5. Adaptive thermal management function of coaxial aerogel liquid crystal elastomer fiber

[0170] Test method: The coaxial aerogel liquid crystal elastomer fiber fabric in Example 2 was subjected to thermal equilibrium treatment on a heating table at 40°C, 50°C, 60°C, 70°C, and 80°C, respectively. The entire thermal equilibrium temperature process was monitored by an infrared thermal imaging camera.

[0171] Figure 9 The temperature difference (ΔT) of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 in different temperature environments.

[0172] Depend on Figure 9 As can be seen, the temperature difference of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 gradually increases with increasing ambient temperature. This is likely due to the shrinkage of the porous structure in the coaxial aerogel liquid crystal elastomer fiber fabric caused by the temperature stimulus. This demonstrates that the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1 has adaptive thermal management capabilities.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A coaxial aerogel liquid crystal elastomer fiber with a skin-core structure, characterized in that: It comprises a core layer and a dense skin layer wrapping the core layer, wherein the core layer has a porous structure; The dense cortex is made of a cortex spinning solution including a first liquid crystal monomer, a first chain extender and a first cross-linking agent; the core layer is made of a core spinning solution including a second liquid crystal monomer, a second chain extender and a second cross-linking agent; wherein the concentration of the first liquid crystal monomer in the cortex spinning solution is greater than the concentration of the second liquid crystal monomer in the core layer spinning solution.

2. The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to claim 1, characterized in that: The concentration of the first liquid crystal monomer in the skin layer spinning solution is 300-1000 mg / mL, and the concentration of the second liquid crystal monomer in the core layer spinning solution is 100-250 mg / mL.

3. The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to claim 1, characterized in that: In the skin spinning solution, the molar ratio of the first liquid crystal monomer, the first chain extender and the first cross-linking agent is (3-4): (1-2): 1; And / or, in the core layer spinning solution, the molar ratio of the second liquid crystal monomer, the second chain extender and the second cross-linking agent is (3-4):(1-2):

1.

4. The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to claim 1, characterized in that: The first liquid crystal monomer or the second liquid crystal monomer includes at least one of 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene, 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene, 4-cyanophenyl 4-((6-(acryloyloxy)hexyl)oxy)benzoate and 4-(4'-hexyloxy)benzoyloxybenzoic acid-R-2-octanol ester, 4'-acryloyldiphenyl cyanide, polysiloxane side chain acryl liquid crystal, and azobenzene acrylate liquid crystal; and / or, the first chain extender or the second chain extender comprises at least one of hexanedithiol, octanedithiol, 2,2'-(1,2-ethanediyldioxy)bis(ethanediol), 1,3-propanedithiol, 1,2-propanedithiol, 1,11-undecanedithiol, 4,4'-dimercaptodiphenyl ether, pentaerythritol tetrakis(3-mercaptopropionic acid), 2,3-dimercaptopropanol, and 1,4-benzenedithiol; And / or, the cross-linking agent includes at least one of pentaerythritol tetrakis(3-mercaptopropionate), tetramercaptobenzene, tetramercaptoporphyrin, and tetramercaptopolyethylene glycol.

5. A method for preparing the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to any one of claims 1 to 4, characterized in that: The following steps are involved: adding a first liquid crystal monomer, a first chain extender, a first cross-linking agent, a first catalyst and a first photoinitiator into a first organic solvent and performing a first stirring process to obtain a skin spinning solution; adding a second liquid crystal monomer, a second chain extender, a second cross-linking agent, and a second catalyst into a second organic solvent and performing ultrasonic treatment, then adding an inhibitor and a second photoinitiator and performing a second stirring treatment to obtain a core layer spinning solution; Coaxially spinning the skin layer spinning solution and the core layer spinning solution under ultraviolet light to obtain coaxial liquid crystal gel fibers; The coaxial liquid crystal gel fiber is dried to obtain a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure.

6. The method for preparing the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to claim 5, characterized in that: In the cortical spinning solution, the content of the first catalyst is 0.5-5 wt%, and the content of the first photoinitiator is 1-3 wt%; And / or, in the core layer spinning solution, the content of the second catalyst is 0.5-5wt%, the content of the inhibitor is 1-3wt%, and the content of the second photoinitiator is 1-3wt%.

7. The method for preparing the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to claim 5, characterized in that: The first catalyst or the second catalyst includes triethylamine or n-propylenediamine; the first photoinitiator or the second photoinitiator includes benzil dimethyl ether or phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide; the inhibitor includes 2,6-di-tert-butyl-p-cresol; the first organic solvent or the second organic solvent includes acetone, toluene or xylene.

8. The method for preparing the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure according to claim 5, characterized in that: In the first stirring process, the temperature is 20-30°C and the speed is 100-500 rpm; and / or, in the second stirring process, the temperature is 20-30° C. and the speed is 100-500 rpm; And / or, the drying process is a supercritical drying process or a freeze drying process; In the supercritical drying process, the temperature is 35 to 50° C., the pressure is 1000 to 1300 Pa, and the time is 6 to 24 hours; in the freeze-drying process, the temperature is -50 to -90° C., and the time is 24 to 72 hours.

9. Use of a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure as claimed in any one of claims 1 to 4 or a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure prepared by the method for preparing a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure as claimed in any one of claims 5 to 8 in the preparation of an actuator.

10. A fabric, characterized in that: The invention relates to a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure as claimed in any one of claims 1 to 4, or a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure prepared by the preparation method of a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure as claimed in any one of claims 5 to 8.

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