Liquid crystal elastomer linear actuator and method of making the same

Abstract

The application discloses a liquid crystal elastomer linear driver and a preparation method thereof, and belongs to the technical field of flexible robots. The method comprises the following steps: providing a liquid crystal elastomer fiber and a wire; and braiding the liquid crystal elastomer fiber and the wire together to obtain a liquid crystal elastomer linear driver, wherein the liquid crystal elastomer linear driver comprises a knot structure. The application solves the technical problems of a complex preparation process and high cost of a conventional liquid crystal elastomer linear driver.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flexible robots, and particularly relates to a liquid crystal elastomer linear driver and a preparation method thereof. BACKGROUND

[0002] Since being discovered, people have carried out rich research on bidirectional shape memory polymers. Bidirectional shape memory polymers have the characteristics of light weight and reversible deformation at transition temperature, and exhibit various applications in the fields of aerospace, medicine, biology and the like. Among all bidirectional shape memory polymers, liquid crystal elastomers have very stable thermodynamic characteristics, so that they become ideal bidirectional shape memory materials and can be used to prepare liquid crystal elastomer linear drivers with good driving capacity.

[0003] A conventional liquid crystal elastomer linear driver is prepared by embedding a conductive material in the inside of a liquid crystal elastomer, and then providing driving force by making the liquid crystal elastomer shrink and deform due to heat generated by the conductive material in the process of being electrified. However, this method has a complex preparation process and high cost.

[0004] The above content is only used to assist in understanding the technical solutions of the present application, and does not represent the acknowledgement of the above content as prior art. SUMMARY

[0005] The main purpose of the present application is to provide a liquid crystal elastomer linear driver and a preparation method thereof, and aims to solve the technical problems of complex preparation process and high cost of conventional liquid crystal elastomer linear drivers.

[0006] To achieve the above purpose, the present application provides a liquid crystal elastomer linear driver preparation method, which comprises the following steps:

[0007] providing a liquid crystal elastomer fiber and a wire;

[0008] weaving the liquid crystal elastomer fiber and the wire together to obtain a liquid crystal elastomer linear driver, wherein the liquid crystal elastomer linear driver comprises a knot structure.

[0009] Optionally, the knot comprises at least one of a flat knot, a quiver knot, a three-strand braid, a half knot, a single knot, a stop knot, a word knot, a double eight knot, a double single knot, a single waist knot, a double waist knot, a three waist knot, a double flat knot and a double connection knot.

[0010] Optionally, the wire comprises at least one of a metal fiber, a carbon fiber and a metal-nonmetal composite fiber.

[0011] Optionally, the step of weaving the liquid crystal elastomer fiber and the wire together to obtain a liquid crystal elastomer linear driver comprises:

[0012] synthesizing at least two of the liquid crystal elastomer fibers into a strand to obtain a liquid crystal elastomer fiber strand;

[0013] weaving the liquid crystal elastomer fiber strand and the wire together through a knot to obtain the liquid crystal elastomer linear driver.

[0014] Optionally, a surface of the liquid crystal elastomer fiber is coated with a thermally conductive coating, the thermally conductive coating comprising at least one of carbon, graphene and polydopamine, and the liquid crystal elastomer linear driver is applied to underwater driving.

[0015] Optionally, the preparation method of the liquid crystal elastomer fiber comprises, in parts by weight:

[0016] mixing liquid crystal monomers, a photoinitiator, a thiol, an amine initiator and an organic solvent to obtain a mixed solution;

[0017] heating the mixed solution to volatilize the organic solvent in the mixed solution to obtain a liquid crystal elastomer;

[0018] 3D printing the liquid crystal elastomer to obtain an uncured elastomer fiber, and curing the uncured elastomer fiber to obtain the liquid crystal elastomer fiber.

[0019] Optionally, the mixed solution comprises 70 parts of liquid crystal monomers, 1-2 parts of a photoinitiator, 60 parts of a thiol, 1-5 parts of an amine initiator and 70-500 parts of an organic solvent.

[0020] Optionally, the liquid crystal monomers comprise at least one of RM82, RM257, RM006, RM021 and RM010;

[0021] and / or the photoinitiator comprises at least one of 2-hydroxy-4'- (2-hydroxyethoxy) -2-methylpropiophenone, Irgacure 369, (4-methylthienyl) methyl phenyl sulfonium triflate, 2-methyl-1- (4-methylthiophenyl) -2-morpholino-1-propanone and Irgacure 651;

[0022] and / or the thiol comprises at least one of pentaerythritol tetra (3-mercaptopropionate), 2, 2- (1, 2-ethanediyldioxy) bisethylthiol, 3, 6-dioxa-1, 8-octanedithiol, 1, 2-ethanedithiol, 1, 8-octanedithiol, 1, 3-propanedithiol, 1, 10-decanedithiol, 1, 5-pentanedithiol;

[0023] and / or the amine initiator comprises at least one of n-butylamine, dipropylamine, benzylamine, triethylamine and diethylamine.

[0024] Optionally, the heating temperature of the mixed solution is 80-100 ℃, and the heating time is 24-72 h.

[0025] And / or the curing time of the uncured elastomer fiber is 5-60 min, and the curing mode is ultraviolet light curing, and the wavelength of the ultraviolet light curing is 365-405 nm.

[0026] And / or the printing temperature of the 3D printing is 25-100 ℃, the printing pressure is 1-100 psi, and the printing speed is 0.1-6 mm / s.

[0027] The application also provides a liquid crystal elastomer linear driver prepared by the above method.

[0028] The application discloses a liquid crystal elastomer linear driver preparation method, which comprises the following steps: providing a liquid crystal elastomer fiber and a wire; and then weaving the liquid crystal elastomer fiber and the wire together through a knot, so that a liquid crystal elastomer linear driver can be quickly prepared; the wire is heated by energizing the liquid crystal elastomer linear driver, and the liquid crystal elastomer fiber is deformed by shrinking under the heat; and the liquid crystal elastomer fiber is further wound around the wire when shrinking, which is beneficial to further heating, so as to improve the driving strain of the liquid crystal elastomer linear driver; and after power-off, the liquid crystal elastomer fiber cools down and restores to the original shape, realizing linear driving; the preparation process of the application is simple, the preparation cost is low, the repeatability is strong, and the application is suitable for industrial mass production; and by controlling the number and weaving mode of the liquid crystal elastomer fiber, the driving performance of the liquid crystal elastomer linear driver can be adjusted, so that the expansibility of the driver is strong. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The flowchart of the liquid crystal elastomer linear driver preparation method involved in the embodiment scheme of the application is shown in the figure;

[0030] Figure 2 The schematic diagram of different knot weaving structures involved in the embodiment scheme of the application is shown in the figure;

[0031] Figure 3 The deformation schematic diagram of the liquid crystal elastomer linear driver involved in the embodiment scheme of the application is shown in the figure;

[0032] Figure 4 The underwater driving schematic diagram of the liquid crystal elastomer linear driver involved in the embodiment 12 of the application is shown in the figure.

[0033] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0034] In order to make the purposes, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. The specific conditions not noted in the embodiments are implemented according to conventional conditions or the conditions suggested by the manufacturers. The reagents or instruments not noted by the manufacturers are conventional products that can be obtained by market purchase.

[0035] In addition, the meaning of "and / or" appearing throughout the present application includes three parallel solutions. Taking "A and / or B" as an example, it includes the A solution, or the B solution, or the solution of A and B being satisfied at the same time. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the premise that a person skilled in the art can realize it. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope claimed by the present application. Based on the embodiments in the present application, all other embodiments obtained by a person skilled in the art without creative labor are within the protection scope of the present application.

[0036] Since the discovery, people have carried out rich research on bidirectional shape memory polymers. Bidirectional shape memory polymers have the characteristics of light weight and reversible deformation at transition temperature, and show various applications in the fields of aerospace, medicine, biology, etc. Among all bidirectional shape memory polymers, liquid crystal elastomers have very stable thermodynamic characteristics, making them ideal bidirectional shape memory materials, which can be used to prepare liquid crystal elastomer linear actuators with good driving ability.

[0037] The conventional liquid crystal elastomer linear actuator is prepared by embedding a conductive material, such as a wire, a liquid metal, etc., into the liquid crystal elastomer, and then using multiple liquid crystal elastomers separated and connected in parallel to prepare the actuator. However, the preparation process of embedding the conductive material into the liquid crystal elastomer is relatively complex and has high cost. Moreover, since the wire itself is not deformable, but the liquid crystal elastomer shrinks under heat, thus in the case that the liquid crystal elastomer deforms but the wire does not deform, the connection between the wire and the liquid crystal elastomer is prone to disconnection, and there is an interface problem. In addition, the separation and parallel connection requires the wires to be placed side by side at a certain distance and then connected, so this method requires a large operation space and the arrangement and distribution are relatively troublesome, and the expansion degree is low. Moreover, the heating speed is low, and the driving performance is poor.

[0038] In view of this, the application provides a liquid crystal elastomer linear driver preparation method, which comprises the following steps: providing a liquid crystal elastomer fiber and a wire; and weaving the liquid crystal elastomer fiber and the wire together through a knot to quickly prepare a liquid crystal elastomer linear driver. The wire is heated by being electrified, and the liquid crystal elastomer fiber is deformed by being shrunk. The liquid crystal elastomer fiber is further wound around the wire when it is shrunk, which is beneficial to further heating and improves the driving strain of the liquid crystal elastomer linear driver. After power-off, the liquid crystal elastomer fiber cools down and returns to the original shape, realizing linear driving. The preparation process of the application is simple, the preparation cost is low, the repeatability is strong, and the application is suitable for industrial mass production. The conductive material does not need to be embedded in the liquid crystal elastomer, which avoids the interface problem. The number and weaving method of the liquid crystal elastomer fiber can be controlled to adjust the driving performance of the liquid crystal elastomer linear driver, so that the extensibility of the driver is strong.

[0039] The first aspect of the embodiment of the application provides a liquid crystal elastomer linear driver preparation method, which comprises the following steps: Figure 1 The liquid crystal elastomer linear driver preparation method comprises the following steps:

[0040] In step S10, a liquid crystal elastomer fiber and a wire are provided.

[0041] In an embodiment, the wire comprises at least one of a metal fiber, a carbon fiber and a metal-nonmetal composite fiber. The wire generates heat when electrified, and then the liquid crystal elastomer fiber is deformed and shrunk. After power-off and cooling, the liquid crystal elastomer fiber returns to the original state to provide driving force for the liquid crystal elastomer linear driver.

[0042] The metal fiber refers to a fiber-shaped material with a high metal content and a continuous distribution of metal materials, and the transverse size is in the micron level. It can comprise at least one of a metal foil and an organic fiber composite fiber (thread), a metalized fiber and a pure metal fiber.

[0043] The carbon fiber refers to a high-strength and high-modulus fiber with a carbon content of more than 90%.

[0044] The metal-nonmetal composite fiber refers to a composite fiber material of metal and flexible nonmetal. The nonmetal can be an organic nonmetal, such as nylon, polyester fiber, polypropylene fiber, etc., or an inorganic nonmetal material. By compounding the flexible nonmetal material with the metal material, the softness of the wire is increased on the basis of conductivity, so as to avoid hindering the deformation of the liquid crystal elastomer fiber during driving and ensure the driving ability of the liquid crystal elastomer linear driver.

[0045] In step S20, the liquid crystal elastomer fiber and the wire are woven together to obtain a liquid crystal elastomer linear driver, wherein the liquid crystal elastomer linear driver comprises a knot structure.

[0046] The liquid crystal elastomer fiber and the wire are braided together to form a knot structure to make the liquid crystal elastomer linear driver.

[0047] In an implementation, the knot includes at least one of a sheet knot, a clinch knot, a three-strand braid, a half hitch, a single knot, a stop knot, a word knot, a double eight knot, a single hitch, a single sheet bend, a double sheet bend, a three sheet bend, a double sheet knot, and a double clinch knot. The number of the liquid crystal elastomer fiber and the wire can be determined according to the driving requirement and the braiding manner of the knot.

[0048] Preferably, the knot includes at least one of the sheet knot, the clinch knot, and the three-strand braid. The sheet knot, the clinch knot, and the three-strand braid can make the heated wire closer to the liquid crystal elastomer in the process of deformation of the liquid crystal elastomer, so that the wire has a larger effective heating area with the liquid crystal elastomer, which is beneficial to further heating, and thus improves the driving strain of the liquid crystal elastomer linear driver.

[0049] For example, referring to Figure 2 , the liquid crystal elastomer fiber 101 and the wire 102 are braided together by the sheet knot 111, the clinch knot 112, and the three-strand braid 113 to make the liquid crystal elastomer linear driver. The wire is heated by energizing the liquid crystal elastomer linear driver, and the liquid crystal elastomer fiber is heated and shrinks to deform. Because the knot makes the liquid crystal elastomer fiber more tightly wound with the wire when the liquid crystal elastomer fiber shrinks, compared with the segmented fixation 114, the braiding by the knot is beneficial to further heating, and thus improves the driving strain of the liquid crystal elastomer linear driver.

[0050] For example, referring to Figure 3 , the knot structure of the liquid crystal elastomer linear driver is the clinch knot 112. After being energized, the liquid crystal elastomer fiber 101 is heated and shrinks, and then based on the knot-clinch knot 112 and the wire 102, the liquid crystal elastomer fiber 101 is further wound with the wire 102, which is beneficial to further heating, and thus improves the driving strain of the liquid crystal elastomer linear driver. After being de-energized, the liquid crystal elastomer fiber 101 cools and deforms to recover, and thus realizes linear driving.

[0051] In the embodiment, the liquid crystal elastomer linear actuator can be quickly prepared by providing the liquid crystal elastomer fiber and the wire, and then weaving the liquid crystal elastomer fiber and the wire together through a knot structure; the wire is heated and cooled by energizing the liquid crystal elastomer linear actuator, and the liquid crystal elastomer fiber is deformed by shrinking under the heat; and the liquid crystal elastomer fiber is further wound around the wire when shrinking, which is beneficial to further heating and improves the driving strain of the liquid crystal elastomer linear actuator, and the liquid crystal elastomer fiber returns to the original shape after power-off to realize linear driving; the preparation cost of the application is low, the repeatability is strong, and the application is suitable for industrial mass production; and the driving performance of the liquid crystal elastomer linear actuator can be adjusted by controlling the number and weaving method of the liquid crystal elastomer fiber, so that the expansibility of the actuator is strong; the deformation rate can reach 40%, the deformation speed can reach 2% / s, the driving strain can reach 40%, and the driving stress is 0.1-30 MPa. In addition, the reversible deformation of the liquid crystal elastomer fiber can be controlled by low voltage to provide different driving forces; and the wire can be used in a wide range, so that the liquid crystal elastomer linear actuator has different driving characteristics.

[0052] In an implementable embodiment, the step S20 of weaving the liquid crystal elastomer fiber and the wire together to obtain the liquid crystal elastomer linear actuator comprises:

[0053] The step S21 comprises: combining at least two liquid crystal elastomer fibers into a strand to obtain a liquid crystal elastomer fiber strand.

[0054] The step S22 comprises: weaving the liquid crystal elastomer fiber strand and the wire together through a knot to obtain the liquid crystal elastomer linear actuator.

[0055] In actual use, a larger driving force can be required, and the driving force of a single liquid crystal elastomer fiber is weak; therefore, at least two liquid crystal elastomer fibers can be combined into a strand to obtain a liquid crystal elastomer fiber strand according to the driving force requirement, and then the liquid crystal elastomer fiber strand and the wire are woven together through a knot to prepare the liquid crystal elastomer linear actuator. The number of liquid crystal elastomers in the liquid crystal elastomer fiber strand can be set according to the driving force requirement; the surface area of the liquid crystal elastomer fiber strand formed by the plurality of liquid crystal elastomer fibers is larger, and thus the area receiving heat is larger, so that the response speed is faster than that of a single liquid crystal elastomer fiber with the same diameter, and the driving performance is better.

[0056] In an implementable embodiment, the liquid crystal elastomer linear actuator is applied to lifting a heavy object; the liquid crystal elastomer linear actuator is connected with a power supply, for example, the voltage is set to 2-5 V, the liquid crystal elastomer fiber shrinks after being energized, and then the heavy object connected to the tail end of the liquid crystal elastomer linear actuator is lifted.

[0057] In an implementable embodiment, the liquid crystal elastomer linear driver is applied to underwater driving. Illustratively, by connecting the liquid crystal elastomer linear driver with a power supply, setting the voltage to 5-30 v, and powering on to make the liquid crystal elastomer fiber contract and pull the moving component.

[0058] In the present embodiment, the conventional underwater driving is light driving, but the driving force provided by the light driving is limited and difficult to meet the demand of underwater driving. The present application uses electric driving, and by controlling the number and weaving method of the liquid crystal elastomer fiber, the driving performance of the liquid crystal elastomer linear driver can be adjusted, so that the extensibility of the driver is strong. The deformation rate can reach 40 %, and the deformation speed can reach 2 % / s, with excellent driving performance. At the same time, compared with the conventional electric driving which needs to bury conductive materials in the liquid crystal elastomer, the preparation process is more complex and the cost is higher. The liquid crystal elastomer linear driver can be quickly prepared by weaving the liquid crystal elastomer fiber and the wire together through a knot, and the preparation process is simple, the preparation cost is low, the repeatability is strong, and it is suitable for industrial mass production.

[0059] In an implementable embodiment, the surface of the liquid crystal elastomer fiber is coated with a heat-conducting coating, and the heat-conducting coating comprises at least one of carbon, graphene and polydopamine.

[0060] By coating a heat-conducting coating on the surface of the liquid crystal elastomer fiber, the liquid crystal elastomer can better absorb the heat emitted by the wire in water, thereby further improving the driving ability of the liquid crystal elastomer linear driver under water.

[0061] In an implementable embodiment, the preparation method of the liquid crystal elastomer fiber comprises, in parts by weight:

[0062] Step S11, mixing liquid crystal monomers, photoinitiator, thiol, amine initiator and organic solvent to obtain a mixed solution.

[0063] Step S12, heating the mixed solution to volatilize the organic solvent in the mixed solution to obtain a liquid crystal elastomer.

[0064] The liquid crystal monomers, photoinitiator, thiol, amine initiator and organic solvent are uniformly mixed at room temperature to obtain a mixed solution. Then the mixed solution is heated to promote the click chemistry reaction of each component. Since the organic solvent provides a reaction environment for the remaining components and does not participate in the composition of the liquid crystal elastomer, the organic solvent part in the mixed solution is volatilized to prepare a low-melting-point precursor, i.e. a liquid crystal elastomer.

[0065] Optionally, the mixed solution comprises 70 parts of liquid crystal monomers, 1-2 parts of photoinitiator, 60 parts of thiol, 1-5 parts of amine initiator and 70-500 parts of organic solvent.

[0066] Optionally, the liquid crystal monomer comprises at least one of RM82, RM257, RM006, RM021 and RM010.

[0067] Optionally, the photoinitiator comprises at least one of 2-hydroxy-4'- (2-hydroxyethoxy) -2-methylpropiophenone, Irgacure 369, (4-methylthiophenyl) methyl phenyl sulfonium triflate, 2-methyl-1- (4-methylthiophenyl) -2-morpholino-1-propanone and Irgacure 651; the photoinitiator can generate free radicals after light irradiation to further initiate polymerization and promote the curing of the liquid crystal elastomer.

[0068] Optionally, the thiol comprises at least one of pentaerythritol tetra (3-mercaptopropionate), 2, 2- (1, 2-ethanediyldioxy) bisethane thiol, 3, 6-dioxa-1, 8-octane dithiol, 1, 2-ethanedithiol, 1, 8-octanedithiol, 1, 3-propanedithiol, 1, 10-decanedithiol and 1, 5-pentanedithiol; the introduction of thiol promotes the cross-linking reaction of the liquid crystal monomer to form a polymer network with a specific shape and structure.

[0069] Optionally, the amine initiator comprises at least one of n-butylamine, dipropylamine, benzylamine, triethylamine and diethylamine; the addition of the initiator initiates the polymerization, cross-linking and curing of the liquid crystal monomer.

[0070] Optionally, the photoinitiator can be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, etc.; the amine initiator can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.; the organic solvent can be 70 parts, 100 parts, 200 parts, 300 parts, 400 parts, 500 parts, etc.; by adjusting the amount of each component, the cross-linked liquid crystal elastomer can have good reversible deformation performance; if it is not within the above range, the liquid crystal elastomer may not be successfully printed or lack reversible deformation ability.

[0071] Optionally, the heating temperature of the mixed solution is 80-100 ℃, for example, 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, etc.; the heating time is 24-72 h, for example, 24 h, 30 h, 40 h, 50 h, 60 h, 70 h, 72 h, etc.

[0072] Optionally, the organic solvent is a solvent with a boiling point less than the maximum value of the heating temperature range, so as to volatilize the organic solvent by heating.

[0073] Step S13, 3D printing the liquid crystal elastomer to obtain an uncured elastomer fiber, and curing the uncured elastomer fiber to obtain the liquid crystal elastomer fiber.

[0074] The liquid crystal elastomer is 3D-printed as a printing ink to print different sizes of uncured elastomer fibers according to requirements, and the uncured elastomer fibers are cured to obtain the liquid crystal elastomer fibers.

[0075] Optionally, the curing time of the uncured elastomer fibers is 5-60 min, for example, 5 min, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, etc.; the curing mode is ultraviolet light curing, and the wavelength of the ultraviolet light curing is 365-405 nm, for example, 365 nm, 370 nm, 380 nm, 390 nm, 400 nm, 405 nm, etc.

[0076] Optionally, the printing temperature of the 3D printing is 25-100 ℃, for example, 25 ℃, 30 ℃, 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, 100 ℃, etc.; the printing pressure is 1-100 psi, for example, 1 psi, 20 psi, 40 psi, 60 psi, 80 psi, 100 psi, etc.; the printing speed is 0.1-6 mm / s, for example, 0.1 mm / s, 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, 5 mm / s, 6 mm / s, etc. By adjusting the parameters of the 3D printing, liquid crystal elastomer fibers of different sizes can be prepared.

[0077] In this embodiment, the preparation method of the liquid crystal elastomer fiber is simple. The components are uniformly mixed and the solvent is volatilized to obtain a printable low-melting-point precursor (liquid crystal elastomer) based on a click chemistry reaction. Then, the liquid crystal elastomer is used as a printing ink to print uncured elastomer fibers of different sizes by 3D printing, and then the uncured elastomer fibers are cured to obtain the liquid crystal elastomer fiber. By changing the components and proportions of the liquid crystal elastomer, various liquid crystal elastomer materials can be prepared. The preparation method is simple, and the application range is wide. The deformation temperature of the obtained liquid crystal elastomer fiber is 40-250 ℃.

[0078] To enable the above-mentioned details and operations of the embodiments of the present application to be clearly understood by those skilled in the art, and to enable the significant performance of the preparation method of the liquid crystal elastomer linear drive of the embodiments of the present application to be embodied, the above-mentioned technical solutions are illustrated by multiple embodiments as follows.

[0079] Embodiment 1

[0080] 70 parts of RM257 monomer, 2 parts of dipropylamine, 1.5 parts of Irgacure 651, 60 parts of 2,2-(1,2-ethylenediylbisoxo)bisethyl mercaptan, and 300 parts of dichloromethane are uniformly mixed at room temperature to obtain a mixture.

[0081] The mixture was heated to 80 ℃ and kept for 24 h to make the solvent fully evaporate, to obtain the liquid crystal elastomer.

[0082] The liquid crystal elastomer was transferred into a 3D printer cartridge, and the un-solidified elastomer fiber was printed out with a printing pressure of 60 psi, a speed of 2 mm / s, and a needle diameter of 0.8 mm; and cured by using 365 nm ultraviolet light to obtain the liquid crystal elastomer fiber.

[0083] Reference Figure 2 Eight liquid crystal elastomer fibers were combined into a strand to obtain the liquid crystal elastomer fiber strand, which was then woven into the form of a flat knot 111 with stainless steel fibers to prepare the liquid crystal elastomer linear actuator.

[0084] The liquid crystal elastomer linear actuator was connected to a constant current power supply, the voltage was set to 2.5 V, and the liquid crystal elastomer was contracted by electrifying, and a 10 g weight connected to the tail end was lifted up.

[0085] The prepared liquid crystal elastomer linear actuator had a deformation temperature of 60 ℃ and a diameter of 2 mm; the liquid crystal elastomer linear actuator was tested, and a voltage of 3.5 V was used to heat the liquid crystal elastomer linear actuator until it was deformed by contraction above 100 ℃, and then cooled to room temperature to restore its original shape; the results showed that by applying a certain temperature, the liquid crystal elastomer fiber could achieve a deformation rate of 45 %, the driving stress of the liquid crystal elastomer linear actuator was 27 MPa, the deformation speed was 3 % / s, the driving strain was 53 %, and it could be applied to lifting heavy objects.

[0086] Example 2

[0087] The experimental steps and raw material ratios were the same as those of Example 1, except that the amine initiator was 1 part of dipropylamine.

[0088] After testing, in this embodiment, the deformation temperature of the liquid crystal elastomer fiber was 80-110 ℃, the deformation rate was 40-50 %, the deformation speed of the linear actuator was 2.3 % / s, and the driving strain was 40 %.

[0089] Example 3

[0090] The experimental steps and raw material ratios were the same as those of Example 1, except that the amine initiator was 3 parts of dipropylamine.

[0091] After testing, in this embodiment, the deformation temperature of the liquid crystal elastomer fiber was 75-80 ℃, the deformation rate was 45-55 %, the deformation speed of the linear actuator was 3.1 % / s, and the driving strain was 45 %.

[0092] Example 4

[0093] The experimental procedure and the raw material ratio are the same as those in Example 1, except that the amine initiator is 4 parts of dipropylamine.

[0094] After testing, in this example, the deformation temperature of the liquid crystal elastomer fiber is 70-80 °C, the deformation rate is 45-55%, the deformation speed of the liquid crystal elastomer linear driver is 3% / s, and the driving strain is 46%.

[0095] Example 5

[0096] The experimental procedure and the raw material ratio are the same as those in Example 1, except that the amine initiator is 5 parts of dipropylamine.

[0097] After testing, in this example, the deformation temperature of the liquid crystal elastomer fiber is 66-80 °C, the deformation rate is 48-55%, the deformation speed of the liquid crystal elastomer linear driver is 3% / s, and the driving strain is 43%.

[0098] Example 6

[0099] The experimental procedure and the raw material ratio are the same as those in Example 1, except that the knot is a swallow 112, and the reference is Figure 2 .

[0100] After testing, in this example, the deformation speed of the liquid crystal elastomer linear driver is 2.4% / s, and the driving strain is 40%.

[0101] Example 7

[0102] The experimental procedure and the raw material ratio are the same as those in Example 1, except that the knot is a three-strand 113, and the reference is Figure 2 .

[0103] After testing, in this example, the deformation speed of the liquid crystal elastomer linear driver is 2.0% / s, and the driving strain is 40%.

[0104] Example 8

[0105] The experimental procedure and the raw material ratio are the same as those in Example 1, except that the liquid crystal elastomer fiber strands use 4 liquid crystal elastomer fibers.

[0106] After testing, in this example, the deformation speed of the liquid crystal elastomer linear driver is 3-5% / s, and the driving strain is 30%.

[0107] Example 9

[0108] The experimental procedure and the raw material ratio are the same as those in Example 1, except that the liquid crystal elastomer fiber strands use 12 liquid crystal elastomer fibers.

[0109] The test shows that in this embodiment, the deformation speed of the liquid crystal elastomer linear driver is 2-2.5 % / s, and the driving strain is 50 %.

[0110] Example 10

[0111] The experimental steps and the raw material ratio are the same as those in Example 1, except that the liquid crystal elastomer fiber used in the liquid crystal elastomer fiber strand is 16.

[0112] The test shows that in this embodiment, the deformation speed of the liquid crystal elastomer linear driver is 1-3 % / s, and the driving strain is 45 %.

[0113] Example 11

[0114] The experimental steps and the raw material ratio are the same as those in Example 1, except that the wire is a nichrome wire, and the applied voltage is 6 V.

[0115] The test shows that in this embodiment, the deformation speed of the liquid crystal elastomer linear driver is 1-3 % / s, and the driving strain is 50 %.

[0116] Example 12

[0117] The experimental steps and the raw material ratio are the same as those in Example 1, except that the liquid crystal elastomer fiber used in the liquid crystal elastomer fiber strand is 16, and a carbon coating is coated on the surface of the liquid crystal elastomer fiber.

[0118] Under the driving pressure of 15 V, underwater driving is performed, referring to Figure 4 The liquid crystal elastomer is contracted by power supply, and the swimming component in the form of fish tail is pulled.

[0119] According to Example 12, the liquid crystal elastomer linear driver prepared in this embodiment can be applied to underwater driving.

[0120] Comparative Example 1

[0121] The experimental steps and the raw material ratio are the same as those in Example 1, except that the liquid crystal elastomer linear driver is prepared by using the segmented fixing 114 mode instead of the knot weaving, referring to Figure 2 .

[0122] The test shows that in this embodiment, the deformation speed of the liquid crystal elastomer linear driver is 0.5-3 % / s, and the driving strain is 23 %.

[0123] Comparative Example 2

[0124] The experimental steps and the raw material ratio are the same as those in Example 1, except that the liquid crystal elastomer linear driver is prepared by embedding the liquid metal into the liquid crystal elastomer.

[0125] Through tests, in the embodiment, the liquid crystal elastomer linear driver has a deformation speed of 0.5-2 % / s and a driving strain of 50 %.

[0126] Comparative Example 3

[0127] The experimental steps and the proportion of raw materials are the same as those in Example 1, except that the stainless steel fibers are embedded in the liquid crystal elastomer to prepare the liquid crystal elastomer linear driver.

[0128] Through tests, in the embodiment, the liquid crystal elastomer linear driver has a deformation speed of 1-2 % / s and a driving strain of 40 %.

[0129] According to the above Examples 1-12 and Comparative Examples 1-3, the method for preparing the liquid crystal elastomer linear driver has simple preparation process, strong repeatability, and can be applied to lifting heavy objects; and the driving performance of the liquid crystal elastomer linear driver can be adjusted by controlling the number and weaving method of the liquid crystal elastomer fibers, so that the extensibility of the driver is strong, and the deformation speed can reach 2 % / s; by controlling the knot structure and / or the number of fibers in the liquid crystal elastomer fiber strand, the driving strain of the prepared liquid crystal elastomer linear driver can be comparable to or better than that of Comparative Examples 2 and 3, and has better driving performance; in addition, according to Example 12, the liquid crystal elastomer linear driver can be applied to underwater driving, and has strong extensibility.

[0130] The above are only preferred embodiments of the present application, and do not limit the patent scope of the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the patent protection scope of the present application.

Claims

1. A method for fabricating a liquid crystal elastomer linear actuator, characterized in that, The method for fabricating the liquid crystal elastomer linear actuator includes the following steps: We provide liquid crystal elastomer fibers and wires; The liquid crystal elastomer fibers and the wires are woven together to form a knot structure, thereby obtaining a liquid crystal elastomer linear actuator.

2. The method for fabricating a liquid crystal elastomer linear actuator as described in claim 1, characterized in that, The knots include at least one of the following: square knot, lark's head knot, three-strand braid, half knot, single knot, stop knot, figure-eight knot, double single knot, single overlock knot, double overlock knot, triple overlock knot, double square knot, and double connecting knot.

3. The method for fabricating a liquid crystal elastomer linear actuator as described in claim 1, characterized in that, The conductor includes at least one of the following: metal fiber, carbon fiber, and metal-nonmetal composite fiber.

4. The method for fabricating a liquid crystal elastomer linear actuator as described in claim 1, characterized in that, The step of weaving the liquid crystal elastomer fibers and the wires together to obtain a liquid crystal elastomer linear actuator includes: At least two of the liquid crystal elastomer fibers are combined into one strand to obtain a liquid crystal elastomer fiber strand; The liquid crystal elastomer fiber strands and the wires are woven together to obtain the liquid crystal elastomer linear actuator.

5. The method for fabricating a liquid crystal elastomer linear actuator as described in claim 1, characterized in that, The surface of the liquid crystal elastomer fiber is coated with a thermally conductive coating, which includes at least one of carbon, graphene, and polydopamine. The liquid crystal elastomer linear actuator is used for underwater actuation.

6. The method for fabricating a liquid crystal elastomer linear actuator according to any one of claims 1-5, characterized in that, The method for preparing the liquid crystal elastomer fiber, by weight parts, includes: A mixture is prepared by mixing liquid crystal monomers, photoinitiators, thiols, amine initiators, and organic solvents. The mixture is heated to evaporate the organic solvent in the mixture, thereby obtaining a liquid crystal elastomer; The liquid crystal elastomer is 3D printed to obtain uncured elastomer fibers, and the uncured elastomer fibers are cured to obtain the liquid crystal elastomer fibers.

7. The method for fabricating a liquid crystal elastomer linear actuator as described in claim 6, characterized in that, The mixture comprises, by weight, 70 parts liquid crystal monomer, 1-2 parts photoinitiator, 60 parts thiol, 1-5 parts amine initiator and 70-500 parts organic solvent.

8. The method for fabricating a liquid crystal elastomer linear actuator as described in claim 6, characterized in that, The liquid crystal monomer includes at least one of RM82, RM257, RM006, RM021 and RM010; And / or the photoinitiator comprises at least one of: 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, Irgacure369, (4-methylthiophene)methylphenylsulfonium trifluoromethanesulfonic acid, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, and Irgacure651; And / or the thiols include at least one of the following: pentaerythritol tetra(3-mercaptopropionic acid) ester, 2,2-(1,2-ethylenedioxy)bis(ethanediol), 3,6-dioxa-1,8-octanedithiol, 1,2-ethylenedithiol, 1,8-octanedithiol, 1,3-propanedithiol, 1,10-decanedithiol, and 1,5-pentanedithiol; And / or the amine initiator includes at least one of n-butylamine, dipropylamine, benzylamine, triethylamine and diethylamine.

9. The method for fabricating a liquid crystal elastomer linear actuator as described in claim 6, characterized in that, The heating temperature of the mixture is 80-100 ℃, and the heating time is 24-72 h; And / or the curing time of the uncured elastomer fiber is 5-60 min, and the curing method is ultraviolet light curing, wherein the wavelength of the ultraviolet light curing is 365-405 nm; And / or the 3D printing temperature is 25-100 ℃, the printing pressure is 1-100 psi, and the printing speed is 0.1-6 mm / s.

10. A liquid crystal elastomer linear actuator, characterized in that, The liquid crystal elastomer linear actuator is prepared by the method described in any one of claims 1-9.

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