Coaxial aerogel liquid crystal elastomer fiber with skin-core structure and preparation method and application thereof

Abstract

The present application relates to the technical field of functional materials, and particularly relates to a coaxial aerogel liquid crystal elastomer fiber with a skin-core structure and a preparation method and application thereof. The coaxial aerogel liquid crystal elastomer fiber with a skin-core structure comprises a core layer and a dense skin layer wrapping the core layer, and the core layer has a porous structure; the dense skin layer is made of a skin layer spinning solution comprising a first liquid crystal monomer, a first chain extender and a first crosslinking agent; the core layer is made of a core layer spinning solution comprising a second liquid crystal monomer, a second chain extender and a second crosslinking agent; wherein the concentration of the first liquid crystal monomer in the skin layer spinning solution is greater than the concentration of the second liquid crystal monomer in the core layer spinning solution. The present application effectively combines liquid crystal elastomers and aerogels, and the prepared coaxial aerogel liquid crystal elastomer fiber with a skin-core structure has the characteristics of high toughness, high tensile strength, excellent heat insulation performance, actuation performance and self-adaptive thermal management function, and has potential application value in the fields of intelligent actuation and self-adaptive thermal management.

Description

Technical Field

[0001] This invention relates to the field of functional materials technology, and in particular to a coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, its preparation method, and its application. Background Technology

[0002] Aerogels are widely recognized as one of the most ideal thermal insulation materials due to their high porosity, large specific surface area, and low thermal conductivity. In recent years, aerogel fibers have attracted increasing attention in fields such as smart fabrics and flexible electronic devices by combining the thermal insulation properties of aerogels with the flexibility of fibers. However, most aerogel fibers have limited functionality, relying on static thermal insulation, which restricts their application scenarios. For example, Chinese patent CN116555930A discloses a composite aerogel fiber for adaptive thermal management and dynamic display. By incorporating a thermochromic material into cellulose aerogel fibers, the resulting composite aerogel fiber exhibits good thermal insulation performance and temperature-responsive color-changing function, but it lacks active actuation capability (no actuation performance).

[0003] With the rapid development of flexible electronics, soft robots, and wearable devices, the demand for smart materials that combine thermal insulation and active actuation capabilities (such as actuation performance) is increasing. Liquid crystal elastomers (LCEs), as an emerging smart polymer material, possess a broad application prospect in fields such as artificial intelligence, optoelectronic materials, bioengineering, and soft robotics due to the ordered orientation of liquid crystal units in their molecular structure, enabling bidirectional actuation responses to external stimuli. However, traditional liquid crystal elastomers typically suffer from poor thermal insulation, insufficient toughness, and low actuation stress, which greatly limits their applications.

[0004] Currently, how to organically combine the thermal insulation properties of aerogels with the actuation properties of liquid crystal elastomers remains a pressing technical challenge. Furthermore, there are few reports of fiber materials that can simultaneously achieve high toughness, efficient thermal insulation, actuation properties, and adaptive thermal management. This lack of such materials poses a significant challenge to developing next-generation smart devices that can adapt to extreme environments and possess active adjustment capabilities.

[0005] Therefore, developing a novel fiber material with high toughness, high efficiency in thermal insulation, actuation properties, and adaptive thermal management functions is not only of great 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] This invention provides a coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure. This coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure has high toughness, high tensile strength, excellent thermal insulation performance, actuation performance and adaptive thermal management function, and it also has good weaving properties.

[0007] The present invention also provides a method for preparing coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure. This method can prepare the aforementioned coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure that have high toughness, high tensile strength, excellent thermal insulation performance, actuation performance, adaptive thermal management function and good weaving properties.

[0008] The present invention also provides the application of the above-described coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, or the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure prepared by the above-described method for preparing the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, in the preparation of actuators. Since the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure possesses actuating properties, it can be applied to actuators.

[0009] This invention also provides a fabric comprising the aforementioned coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, or a coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure prepared by the aforementioned method for preparing such fiber. The inventors' research indicates that the aforementioned coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure possesses excellent weavability. The fabric obtained by weaving the aforementioned coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure can adaptively adjust to different temperature environments, thus possessing adaptive thermal management functionality.

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

[0011] The dense outer layer is made of an outer layer spinning solution comprising a first liquid crystal monomer, a first chain extender, and a first crosslinking agent; the core layer is made of a core layer spinning solution comprising a second liquid crystal monomer, a second chain extender, and a second crosslinking agent; wherein the concentration of the first liquid crystal monomer in the outer layer spinning solution is greater than the concentration of the second liquid crystal monomer in the core layer spinning solution.

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

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

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

[0015] The coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure as described above, wherein the first liquid crystal monomer or the second liquid crystal monomer comprises 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'-propenyl biphenyl cyanide, polysiloxane side-chain propylene 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-ethylenedioxy)diethylthiol, 1,3-propanedithiol, 1,2-propanedithiol, 1,11-undecanedithiol, 4,4'-dimercaptodiphenyl ether, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, 2,3-dimercaptopropanol, and 1,4-benzenedithiol;

[0017] And / or, the crosslinking agent includes at least one of pentaerythritol tetrakis(3-mercaptopropionic acid), 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 with a core-sheath structure, comprising the following steps:

[0019] The first liquid crystal monomer, the first chain extender, the first crosslinking agent, the first catalyst and the first photoinitiator are added to the first organic solvent and stirred for the first time to obtain the skin spinning solution;

[0020] The second liquid crystal monomer, the second chain extender, the second crosslinking agent and the second catalyst are added to the second organic solvent and subjected to ultrasonic treatment. Then, the inhibitor and the second photoinitiator are added and subjected to the second stirring treatment to obtain the core layer spinning solution.

[0021] The sheath spinning solution and the core spinning solution are coaxially spun under ultraviolet light irradiation 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 core-sheath structure.

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

[0024] And / or, in the core 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%.

[0025] The preparation method of coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure as described above, wherein the first catalyst or the second catalyst comprises triethylamine or n-propylenediamine; the first photoinitiator or the second photoinitiator comprises benzoyl dimethyl ether or phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide; the inhibitor comprises 2,6-di-tert-butyl-p-cresol; and the first organic solvent or the second organic solvent comprises acetone, toluene, or xylene.

[0026] In the preparation method of coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure as described above, 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 35–50℃, the pressure is 1000–1300 Pa, and the time is 6–24 h; in the freeze-drying process, the temperature is -50–-90℃, and the time is 24–72 h.

[0030] A third aspect of the present invention provides the application of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, or the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure prepared by the method thereof, in the preparation of an actuator.

[0031] A fourth aspect of the present invention provides a fabric comprising the coaxial aerogel liquid crystal elastomer fiber having a core-sheath structure, or a coaxial aerogel liquid crystal elastomer fiber having a core-sheath structure prepared by the method for preparing the coaxial aerogel liquid crystal elastomer fiber having a core-sheath structure.

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

[0033] The coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure provided by this invention is prepared by preparing a core-sheath structure through ultraviolet light irradiation-induced reactive coaxial spinning of a sheath 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, followed by drying treatment (supercritical drying or freeze-drying). The concentration of the first liquid crystal monomer in the sheath spinning solution is greater than the concentration of the second liquid crystal monomer in the core spinning solution, resulting in a clear boundary between the core and sheath structures. The resulting coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure possesses high toughness and dynamic thermal insulation properties. This is achieved by controlling the concentration of the first liquid crystal monomer in the sheath spinning solution... The concentration of one liquid crystal monomer or the concentration of the second liquid crystal monomer in the core spinning solution results in strong interfacial compatibility of the obtained core-sheath structure. The porous core structure can enhance the toughness of the dense skin layer, making the mechanical properties (such as toughness) of the obtained coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure superior to those of liquid crystal elastomer fiber. This coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure not only possesses the actuation properties of liquid crystal elastomer but also the thermal insulation properties of aerogel, showing potential application value in the fields of intelligent actuation and adaptive thermal management. Furthermore, the tensile strength of this coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure can reach 18.81 MPa, and the toughness can reach 16.58 MJ / m. 3 It also has good weaving properties, which is of great significance to the development of smart textiles, and has huge economic value and application potential. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

[0036] Figure 2 These are SEM images of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Embodiment 1 of the present invention and the liquid crystal elastomer fiber in Comparative Example 1, wherein... Figure 2 Image a is a SEM image of the liquid crystal elastomer fiber in Comparative Example 1. Figure 2 b is a magnified SEM image of a local area inside the liquid crystal elastomer fiber in Comparative Example 1. Figure 2c is a magnified SEM image of a portion of the surface layer of the liquid crystal elastomer fiber in Comparative Example 1. Figure 2 d is a SEM image of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Example 1. Figure 2 Image e is a magnified SEM image of the core layer of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Example 1. Figure 2 f is a 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 The stress-strain curves are shown for the coaxial aerogel liquid crystal elastomer fibers with core-sheath 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 The image shown is a physical diagram of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 of the present invention, where 1 refers to the coaxial aerogel liquid crystal elastomer fiber with a core-skin structure, and 2 refers to the human arm model.

[0039] Figure 5 To illustrate the actuation effect of the coaxial aerogel liquid crystal elastomer fiber actuator in Example 1 under thermal stimulation at 100°C, wherein... Figure 5 In Example 1, 'a' represents the coaxial aerogel liquid crystal elastomer fiber actuator before thermal stimulation. Figure 5 b represents the coaxial aerogel liquid crystal elastomer fiber actuator in Example 1 after thermal stimulation.

[0040] Figure 6 The graphs show the 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. Figure 6 'a' is a graph showing the change in actuation stress of the coaxial aerogel liquid crystal elastomer fiber actuator with thermal stimulation frequency in Application Example 1. Figure 6 b is a curve showing the change of actuation stress of the liquid crystal elastomer fiber actuator with thermal stimulation frequency in Comparative Application Example 1.

[0041] Figure 7 The images show physical examples 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. Figure 7 Image 'a' is a physical image of the liquid crystal elastomer fiber fabric in Comparative Application Example 2. Figure 7 b is a physical image of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2;

[0042] Figure 8To compare the thermal insulation properties 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' represents 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 represents 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 represents 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 represents 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 is shown in different temperature environments. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this art or in accordance with the product instructions. Raw materials, reagents, or instruments used without specified manufacturers are all conventional products that can be obtained commercially.

[0045] It should be noted that the use of terms such as "first" and "second" in this invention is for distinguishing similar objects and not for describing a specific order or sequence, and therefore should not be construed as a limitation of this invention.

[0046] In this invention, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer 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 both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0047] Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following 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 core-sheath structure, comprising a core layer and a dense sheath layer enclosing the core layer, the core layer having a porous structure;

[0049] The dense skin layer is made of a skin layer spinning solution including a first liquid crystal monomer, a first chain extender and a first crosslinking agent; the core layer is made of a core layer spinning solution including a second liquid crystal monomer, a second chain extender and a second crosslinking 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 core-sheath structure provided by the present invention includes a porous core layer and a dense sheath layer surrounding the core layer. The dense sheath layer is made of a sheath spinning solution including a first liquid crystal monomer, a first chain extender, and a first crosslinking agent. The porous core layer is made of a core spinning solution including a second liquid crystal monomer, a second chain extender, and a second crosslinking agent. The concentration of the first liquid crystal monomer in the sheath spinning solution is greater than the concentration of the second liquid crystal monomer in the core spinning solution, resulting in a clear boundary between the core and sheath structures. The resulting coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure possesses high toughness and high tensile strength while achieving dynamic thermal insulation performance. Furthermore, the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure also exhibits actuation performance, adaptive thermal management function, and good weaving properties, making it potentially valuable in the fields of intelligent actuation, adaptive thermal management, and smart textiles.

[0051] In one 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 spinning solution is 100-250 mg / mL.

[0052] When the concentrations of the first liquid crystal monomer in the sheath spinning solution and the second liquid crystal monomer in the core spinning solution are each within the above-mentioned ranges, making the concentration of the first liquid crystal monomer in the sheath spinning solution greater than the concentration of the second liquid crystal monomer in the core spinning solution is beneficial for preparing coaxial aerogel liquid crystal elastomer fibers with a sheath-core structure that have high toughness, high tensile strength, excellent thermal insulation performance, actuation performance and adaptive thermal management function, and good weaving properties.

[0053] In one specific embodiment, the molar ratio of the first liquid crystal monomer, the first chain extender and the first crosslinking agent in the above spinning solution is (3-4):(1-2):1, for example, the molar ratio of the first liquid crystal monomer, the first chain extender and the first crosslinking 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 crosslinking 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 elongation at break and the breaking stress of the coaxial aerogel liquid crystal elastomer fiber, and also gives it actuation properties.

[0055] In one specific embodiment, the molar ratio of the second liquid crystal monomer, the second chain extender, and the second crosslinking agent in the above-mentioned core layer spinning solution is (3-4):(1-2):1, for example, the molar ratio of the second liquid crystal monomer, the second chain extender, and the second crosslinking 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 crosslinking agent in the core 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 improve the fracture stress and Young's modulus of the coaxial aerogel liquid crystal elastomer fiber and gives it thermal insulation properties.

[0057] In one specific embodiment, the first liquid crystal monomer or the second liquid crystal monomer comprises 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'-propenylbiphenyl cyanide, polysiloxane side-chain propylene liquid crystal, and azobenzene acrylate liquid crystal.

[0058] In one specific embodiment, the first chain extender or the second chain extender comprises at least one of hexanedithiol, octanedithiol, 2,2'-(1,2-ethylenedioxy)diethylthiol, 1,3-propanedithiol, 1,2-propanedithiol, 1,11-undecanedithiol, 4,4'-dimercaptodiphenyl ether, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, 2,3-dimercaptopropanol, and 1,4-benzenedithiol.

[0059] In one specific embodiment, the crosslinking agent includes at least one of pentaerythritol tetrakis(3-mercaptopropionic acid), 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 core-sheath structure, comprising the following steps:

[0061] The first liquid crystal monomer, the first chain extender, the first crosslinking agent, the first catalyst and the first photoinitiator are added to the first organic solvent and stirred for the first time to obtain the skin spinning solution;

[0062] The second liquid crystal monomer, the second chain extender, the second crosslinking agent and the second catalyst are added to the second organic solvent and subjected to ultrasonic treatment. Then, the inhibitor and the second photoinitiator are added and subjected to the second stirring treatment to obtain the core layer spinning solution.

[0063] Coaxial spinning of the sheath spinning solution and the core spinning solution under ultraviolet light irradiation was carried out to obtain coaxial liquid crystal gel fiber.

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

[0065] The present invention does not impose any particular limitation on the specific order in which the first liquid crystal monomer, the first chain extender, the first crosslinking agent, the first catalyst and the first photoinitiator are added to the first organic solvent.

[0066] The present invention does not impose any particular limitation on the specific order in which the second liquid crystal monomer, the second chain extender, the second crosslinking agent, and the second catalyst are added to the second organic solvent.

[0067] The present invention prepares coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure. Specifically, a first liquid crystal monomer, a first chain extender, a first crosslinking 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 sheath spinning solution. Then, a second liquid crystal monomer, a second chain extender, a second crosslinking agent, and a second catalyst are added to a second organic solvent and subjected to ultrasonic treatment. An inhibitor and a second photoinitiator are then added and subjected to a second stirring treatment to obtain a core spinning solution. Next, the sheath spinning solution and the core spinning solution are coaxially spun under ultraviolet light irradiation using an ultraviolet light-induced reactive coaxial spinning method to obtain coaxial liquid crystal gel fibers. Finally, the coaxial liquid crystal gel fibers are dried to obtain coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure. The coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure prepared by this method have high toughness, high tensile strength, and excellent thermal insulation properties. Furthermore, they also possess actuation properties, adaptive thermal management functions, and good weaving properties.

[0068] In some embodiments, ultraviolet light irradiation-induced reactive coaxial spinning is used to coaxially spin the above-mentioned spinning solution and the above-mentioned core layer spinning solution under ultraviolet light irradiation to obtain coaxial liquid crystal gel fibers. Specifically, the spinning solution and the core layer spinning solution are injected into acetone through syringe A and syringe B of the coaxial spinning device, respectively, and ultraviolet light irradiation-induced reactive coaxial spinning is performed to obtain continuous coaxial liquid crystal gel fibers; the coaxial needle diameter of syringe A and syringe B is 22 / 17G; the injection speed is 4-10 mL / h.

[0069] The principle of preparing coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure according to the present invention will be explained as follows:

[0070] After the sheath spinning solution and the core spinning solution undergo an "acrylic-thiol click" reaction, they are subjected to free radical polymerization under ultraviolet light irradiation 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 the degree of crosslinking, a coaxial aerogel liquid crystal elastomer fiber with a dense sheath and a porous core layer is obtained, which is a coaxial aerogel liquid crystal elastomer fiber with a sheath-core structure.

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

[0072] When the contents of the first catalyst and the first photoinitiator in the cortex spinning solution are each within the above-mentioned range, it is beneficial to obtain a dense cortex.

[0073] In one specific embodiment, the content of the second catalyst in the core spinning solution 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 contents of the second catalyst, the inhibitor, and the second photoinitiator in the core spinning solution are all within the above-mentioned 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 described above comprises triethylamine or n-propylenediamine.

[0076] In one specific embodiment, the first or second photoinitiator includes benzoyl dimethyl ether (DMPA) or phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (XBPO).

[0077] In one specific embodiment, the inhibitor comprises 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 rapid gelation of the core spinning solution system.

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

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

[0081] The present invention does not impose a specific time limit on the first stirring treatment, and can select it according to the actual situation.

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

[0083] The speed can be any one or a combination of any two of the following: 100rpm, 200rpm, 300rpm, 400rpm, and 500rpm.

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

[0085] The present invention does not impose a specific time limit on the second stirring process, which can be selected according to the actual situation.

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

[0087] The speed can be any one or a combination of any two of the following: 100rpm, 200rpm, 300rpm, 400rpm, and 500rpm.

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

[0089] Specifically, coaxial liquid crystal gel fibers can be subjected to supercritical drying to obtain coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure; alternatively, coaxial liquid crystal gel fibers can be freeze-dried to obtain coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure.

[0090] In one specific embodiment, the supercritical drying process described above is carried out at a temperature of 35–50°C, a pressure of 1000–1300 Pa, and a time of 6–24 h.

[0091] Specifically, the present invention can subject the above-mentioned coaxial liquid crystal gel fiber to supercritical drying treatment to obtain coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure.

[0092] When the parameters of temperature, pressure, and time are within the above-mentioned ranges during supercritical drying, it is beneficial to maintain the regular porous morphology of the coaxial aerogel liquid crystal elastomer fiber and prevent it from collapsing.

[0093] For example, in supercritical drying, the temperature can be any one or a combination of any two of 35°C, 40°C, 45°C, and 50°C.

[0094] The pressure can be any one of 1000Pa, 1100Pa, 1200Pa, 1300Pa or any combination of two.

[0095] The time can be any one or any combination of 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, and 24h.

[0096] In one specific embodiment, the freeze-drying process described above involves a temperature of -50 to -90°C and a time of 24 to 72 hours.

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

[0098] When the temperature and time parameters are within the above-mentioned ranges during freeze-drying, it is beneficial to maintain the regular porous morphology of the coaxial aerogel liquid crystal elastomer fiber and prevent it from collapsing.

[0099] For example, in the freeze-drying process, the temperature can be any one or any combination of two 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).

[0100] The time can be any one or any combination of two of the following: 24h, 30h, 34h, 38h, 42h, 46h, 50h, 54h, 58h, 62h, 66h, and 72h.

[0101] A third aspect of the present invention provides the application of the above-described coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, or the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure prepared by the above-described method for preparing the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, in the manufacture of an actuator. Since this coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure possesses actuating properties, it can be applied to actuators.

[0102] A fourth aspect of the present invention provides a fabric comprising the aforementioned coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure, or a coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure prepared by the aforementioned method for preparing the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure. The inventors have demonstrated that the aforementioned coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure possesses excellent weavability, and the fabric obtained by weaving the aforementioned coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure can adaptively adjust to different temperature environments, thus possessing adaptive thermal management functionality.

[0103] The present invention will be further described below through specific embodiments.

[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 in this invention, and the coaxial spinning process of the skin spinning solution and core spinning solution under UV curing lamp irradiation, are shown below. Figure 1 As shown, this embodiment provides a method for preparing coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure, including the following steps:

[0106] (1) 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene (RM257), 2,2'-(1,2-ethylenedioxydioxo)bis(ethylenedithio)ethanol (EDDT), and pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP) were added to acetone in a molar ratio of 3:1:1. Then triethylamine and benzoyl dimethyl ether were added, and the mixture was stirred at 25°C for 18 h to obtain a skin spinning solution. In the skin 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 in a molar ratio of 3:1:1, followed by the addition of triethylamine. After ultrasonic treatment for 5 min, 2,6-di-tert-butyl-p-cresol (BHT) and benzoyl dimethyl ether were added. The mixture was then stirred at 25°C for 18 h to obtain the core spinning solution. The core spinning solution contained RM257 at a concentration of 150 mg / mL, triethylamine at a content of 0.8 wt%, BHT at a content of 1 wt%, and benzoyl dimethyl ether at a content of 1.5 wt%.

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

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

[0110] Example 2

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

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

[0113] Example 3

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

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

[0116] Example 4

[0117] The preparation method of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath 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℃ for 36h to obtain coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure.

[0119] Example 5

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

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

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

[0123] Comparative Example 1

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

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

[0126] (2) The spinning solution in (1) was used to prepare liquid crystal elastomer fibers. The spinning solution was spun under ultraviolet light irradiation at a wavelength of 365nm using 17G uniaxial spinning to obtain continuous liquid crystal gel fibers.

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

[0128] Comparative Example 2

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

[0130] (1) RM257, EDDT, and PETMP were added to acetone in a molar ratio of 3:1:1, followed by the addition of triethylamine. After ultrasonic treatment for 5 min, BHT inhibitor and benzoyl dimethyl ether were added, and the mixture was stirred at 25 °C for 18 h to obtain the spinning solution. The spinning solution contained RM257 at a concentration of 150 mg / mL, triethylamine at a content of 0.8 wt%, BHT at a content of 1 wt%, and benzoyl dimethyl ether at a content of 1.5 wt%.

[0131] (2) The spinning solution in (1) was used to prepare liquid crystal elastomer aerogel fibers. The spinning solution was spun under ultraviolet light irradiation at a wavelength of 365nm using 17G uniaxial spinning to obtain continuous liquid crystal gel fibers.

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

[0133] Application Example 1

[0134] Figure 4This is a physical diagram of the coaxial aerogel liquid crystal elastomer fiber actuator in Application Example 1 of the present invention, as shown below. Figure 4 As shown, an 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 core-skin structure prepared in Example 1 was fixed onto a human arm model to obtain a coaxial aerogel liquid crystal elastomer fiber actuator.

[0136] Comparative Application Example 1

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

[0138] The liquid crystal elastomer fibers prepared in Comparative Example 1 were fixed onto 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 image of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 of the present invention, as shown below. Figure 7 As shown in b, an 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 core-sheath structure prepared in Example 1 was woven in a plain weave pattern to obtain a coaxial aerogel liquid crystal elastomer fiber fabric.

[0142] Comparative Application Example 2

[0143] Figure 7 Image 'a' is a physical image of the coaxial aerogel liquid crystal elastomer fiber fabric in Comparative Application Example 2 of this invention, as shown below. Figure 7 As shown in Figure a, an 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 pattern to obtain a liquid crystal elastomer fiber fabric.

[0145] Performance testing

[0146] 1. Scanning electron microscopy (SEM) tests were performed on the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Example 1 of the present invention and the liquid crystal elastomer fiber in Comparative Example 1, respectively. The test results are as follows: Figure 2 As shown; Figure 2 The images shown are SEM images of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Embodiment 1 of the present invention and the liquid crystal elastomer fiber in Comparative Example 1. Figure 2Image a is a SEM image of the liquid crystal elastomer fiber in Comparative Example 1. Figure 2 b is a magnified SEM image of a local area inside the liquid crystal elastomer fiber in Comparative Example 1. Figure 2 c is a magnified SEM image of a portion of the surface layer of the liquid crystal elastomer fiber in Comparative Example 1. Figure 2 d is a SEM image of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Example 1. Figure 2 Image e is a magnified SEM image of the core layer of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Example 1. Figure 2 f is a magnified SEM image of the skin layer of the coaxial aerogel liquid crystal elastomer fiber with a skin-core structure in Example 1.

[0147] Depend on Figure 2 As can be seen from AC, the liquid crystal elastomer fiber in Comparative Example 1 is in a dense state both inside and on the surface.

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

[0149] 2. Stress-strain curve tests were performed on the coaxial aerogel liquid crystal elastomer fibers with core-sheath 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, respectively. The stress-strain curves are shown below. Figure 3 As shown, the elongation at break (%), Young's modulus (MPa), fracture stress (MPa), tensile strength (MPa), and toughness (MJ / m) were obtained from the stress-strain curve. 3 The results are summarized in Tables 1 and 2. Figure 3 The stress-strain curves are shown for the coaxial aerogel liquid crystal elastomer fibers with core-sheath 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 fracture stress of each embodiment and 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 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 structure can improve the fracture stress and Young's modulus of the liquid crystal elastomer fibers; compared with Comparative Example 2, Examples 1-5 demonstrate that a dense skin structure can improve the elongation at break and fracture stress of the liquid crystal aerogel fibers. These results indicate that the coaxial aerogel liquid crystal elastomer fibers with a core-skin structure in Examples 1-5 of the present invention possess the advantages of high elongation at break, high fracture stress, and high Young's modulus.

[0155] Depend on Figure 3 As shown in Table 2, the coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure in Examples 1-5 of this invention possess the advantages of high toughness and high tensile strength. The toughness and tensile strength of the coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure in Examples 1-5 are higher than those of the liquid crystal elastomer fibers in Comparative Example 1 and 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 core-sheath structure in Examples 1-5 of this invention have 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 Case 1 and the liquid crystal elastomer fiber actuator in Comparative Application Case 1 were used as test samples for actuation performance testing: the test samples achieved arm flexion actuation on the human arm model by thermal stimulation with a hot air gun. Figure 5 To illustrate the actuation effect of the coaxial aerogel liquid crystal elastomer fiber actuator in Example 1 under thermal stimulation at 100°C, wherein... Figure 5 In Example 1, 'a' represents the coaxial aerogel liquid crystal elastomer fiber actuator before thermal stimulation. Figure 5 b represents the coaxial aerogel liquid crystal elastomer fiber actuator in Example 1 after thermal stimulation. Figure 6 The graphs show the 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. Figure 6 'a' is a graph showing the change in actuation stress of the coaxial aerogel liquid crystal elastomer fiber actuator with thermal stimulation frequency in Application Example 1. Figure 6 b is a curve showing the change of actuation stress of the liquid crystal elastomer fiber actuator with thermal stimulation frequency 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 exhibits an anisotropic state. Figure 5(a) That is, the liquid crystal cells are arranged in an orderly manner. After applying thermal stimulation, the coaxial aerogel liquid crystal elastomer fiber actuator exhibits an isotropic state. Figure 5 (b) This refers to the liquid crystal cells being arranged in a disordered manner. The shift from an ordered to a disordered arrangement will cause the coaxial aerogel liquid crystal elastomer fiber actuator to achieve axial contraction actuation; for the deformation effect, please refer to [link to documentation]. Figure 5 .

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

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

[0161] ① Figure 7 The images show physical examples 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. Figure 7 Image 'a' is a physical image of the liquid crystal elastomer fiber fabric in Comparative Application Example 2. Figure 7 b is a physical image of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2.

[0162] Depend on Figure 7 As can be seen from ab, the coaxial aerogel liquid crystal elastomer fiber with a core-sheath 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, with no damage found in the fibers, exhibiting good weavability.

[0163] ② Figure 8 To compare the thermal insulation properties 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' represents 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 represents 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 represents 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 represents 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 As can be seen from a, the heat transfer temperature of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is 40°C, while the heat transfer temperature of the liquid crystal elastomer fiber fabric in Comparative Application Example 2 is 43°C, with a difference of 3°C in the heat insulation temperature.

[0165] Depend on Figure 8 As can be seen from b, 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 Application Example 2 is 52°C, with a difference of 4°C in the heat insulation temperature.

[0166] Depend on Figure 8 As can be seen from c, the heat transfer temperature of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is 55°C, while the heat transfer temperature of the liquid crystal elastomer fiber fabric in this comparative Application Example 2 is 60°C, with a difference of 5°C in the heat insulation temperature.

[0167] Depend on Figure 8 As can be seen from d, the heat transfer temperature of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is 63°C, while the heat transfer temperature of the liquid crystal elastomer fiber fabric in this comparative Application Example 2 is 68°C, with a difference of 5°C in the heat insulation temperature.

[0168] The above results indicate 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. Clearly, the thermal insulation performance of the coaxial aerogel liquid crystal elastomer fiber fabric in Application Example 2 is superior to that of the liquid crystal elastomer fiber fabric in Comparative Application Example 2, demonstrating that the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure in Example 1 possesses superior thermal insulation performance.

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

[0170] Test method: The coaxial aerogel liquid crystal elastomer fiber fabric in test case 2 was subjected to thermal equilibrium treatment on heating platforms at 40℃, 50℃, 60℃, 70℃ and 80℃ respectively, and the entire process of thermal equilibrium temperature 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 is shown in different temperature environments.

[0172] Depend on Figure 9 It can be seen that in Application Example 2, the temperature difference of the coaxial aerogel liquid crystal elastomer fiber fabric gradually increases with the increase of the ambient temperature. This may be 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 core-sheath structure in Example 1 has an adaptive thermal management function.

[0173] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 core-sheath structure, characterized in that, It includes a core layer and a dense skin layer that encloses the core layer, the core layer having a porous structure; The dense outer layer is made of an outer layer spinning solution comprising a first liquid crystal monomer, a first chain extender, and a first crosslinking agent; the core layer is made of a core layer spinning solution comprising a second liquid crystal monomer, a second chain extender, and a second crosslinking agent; the outer layer spinning solution and the core layer spinning solution are prepared by ultraviolet light irradiation-induced reactive coaxial spinning to form a core-shell structure, and then dried to obtain the coaxial aerogel liquid crystal elastomer fiber with the core-shell structure; Wherein, the concentration of the first liquid crystal monomer in the sheath spinning solution is greater than the concentration of the second liquid crystal monomer in the core spinning solution; 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. In the sheath spinning solution, the molar ratio of the first liquid crystal monomer, the first chain extender, and the first crosslinking agent is (3-4):(1-2):1; in the core spinning solution, the molar ratio of the second liquid crystal monomer, the second chain extender, and the second crosslinking agent is (3-4):(1-2):

1. 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, 4'-propenyl biphenyl cyanide, polysiloxane side-chain propylene liquid crystal, and azobenzene acrylate liquid crystal; The first chain extender or the second chain extender includes at least one of hexanedithiol, octanedithiol, 2,2'-(1,2-ethylenedioxy)bis(ethyl)thiol, 1,3-propanedithiol, 1,2-propanedithiol, 1,11-undecanedithiol, 4,4'-dimercaptodiphenyl ether, pentaerythritol tetrakis(3-mercaptopropionic acid) ester, 2,3-dimercaptopropanol, and 1,4-benzenedithiol; The crosslinking agent includes at least one of pentaerythritol tetrakis(3-mercaptopropionic acid), tetramercaptobenzene, tetramercaptoporphyrin, and tetramercaptopolyethylene glycol.

2. A method for preparing coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure as described in claim 1, characterized in that, Includes the following steps: The first liquid crystal monomer, the first chain extender, the first crosslinking agent, the first catalyst and the first photoinitiator are added to the first organic solvent and stirred for the first time to obtain the skin spinning solution; The second liquid crystal monomer, the second chain extender, the second crosslinking agent and the second catalyst are added to the second organic solvent and subjected to ultrasonic treatment. Then, the inhibitor and the second photoinitiator are added and subjected to the second stirring treatment to obtain the core layer spinning solution. The sheath spinning solution and the core spinning solution are coaxially spun under ultraviolet light irradiation 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 core-sheath structure.

3. The method for preparing coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure according to claim 2, characterized in that, In the skin 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 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%.

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

5. The method for preparing coaxial aerogel liquid crystal elastomer fibers with a core-sheath structure according to claim 2, 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 35–50 °C, the pressure is 1000–1300 Pa, and the time is 6–24 h; in the freeze-drying process, the temperature is -50–-90 °C, and the time is 24–72 h.

6. The application of a coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure as described in claim 1, or a coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure prepared by the preparation method of any one of claims 2 to 5, in the preparation of an actuator.

7. A fabric, characterized in that, This includes the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure as described in claim 1, or the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure prepared by the preparation method of the coaxial aerogel liquid crystal elastomer fiber with a core-sheath structure as described in any one of claims 2 to 5.

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