Bionic spiral yarn driver and preparation method and application thereof

Abstract

The application relates to the technical field of intelligent materials, and discloses a bionic spiral yarn driver and a preparation method and application thereof, a liquid crystal elastomer dry spinning solution is prepared; a bacterial cellulose wet spinning solution is prepared; the obtained liquid crystal elastomer dry spinning solution is subjected to dry spinning, and the bacterial cellulose wet spinning solution is subjected to wet spinning; the liquid crystal elastomer fiber and the bacterial cellulose fiber are twisted, and are treated by using an ultraviolet lamp to obtain the bionic spiral yarn driver. The bionic spiral yarn driver obtained by the application has good mechanical properties, weight lifting performance and sensitive thermal response performance, and can be applied to various micro devices.

Description

Technical Field

[0001] This invention relates to the field of smart materials technology, and in particular to a biomimetic spiral yarn actuator, its preparation method, and its application. Background Technology

[0002] Soft actuators possess excellent flexibility and deformability, enabling them to better adapt to complex and unknown environments. This makes them highly advantageous when interacting with fragile objects or living organisms. As a typical stimulus-responsive material, liquid crystal elastomers (LCEs) have proven to be one of the ideal candidate materials for manufacturing soft actuators due to their rapid response, reversibility, programmable large deformation, and good environmental adaptability. LCEs are network structure compounds formed by connecting liquid crystal motifs and adjacent polymer chains, exhibiting good elasticity in isotropic or liquid crystal phases. LCEs possess both the anisotropy of liquid crystals and the rubber elasticity of polymers. When subjected to external stimuli (heat, light, electricity, magnetism, pH, humidity, etc.), the arrangement of its internal liquid crystal motifs undergoes a reversible change, causing macroscopic deformation of the composite material itself; when the external stimulus is removed, the liquid crystal elastomer can gradually return to its original shape. Furthermore, one-dimensional LCE soft actuators can break free from the limitations of two-dimensional material shapes, performing various complex and flexible actions and constructing more sophisticated micro-devices. Furthermore, due to its high specific surface area, it can promote the transmission of external stimuli to LCEs, shortening the response time. Currently, by controlling the molecular structure of liquid crystal monomers and the cross-linked network structure of macromolecules, the physical and chemical properties, response speed, and motion modes of LCEs have been greatly optimized, thereby broadening their application prospects in soft robotics, optoelectronic materials, bioengineering, telemedicine, and other fields. However, due to the shortcomings of liquid crystal elastomers, such as low mechanical strength, simple actuation behavior, slow actuation rate and response speed, and high manufacturing cost, the promotion of liquid crystal elastomers is still limited, especially in the fields of crawling robots, stimulus-responsive soft grippers, and passive micromotors. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a biomimetic spiral yarn actuator, its preparation method, and its application. The biomimetic spiral yarn actuator obtained by this invention possesses excellent mechanical properties, load-bearing capacity, and sensitive thermal response performance, and can be applied to various micro-devices.

[0004] This invention provides a method for preparing a biomimetic spiral yarn actuator, comprising the following steps:

[0005] Step S1: Preparation of liquid crystal elastomer dry spinning solution: Dissolve liquid crystal monomer, chain extender and crosslinking agent in dichloromethane solvent, mix evenly, add catalyst to the evenly mixed solution, carry out Michael addition reaction, add photoinitiator, heat to dissolve photoinitiator, and obtain liquid crystal elastomer dry spinning solution.

[0006] Step S2: Preparation of bacterial cellulose wet spinning solution: Add the bacterial cellulose dispersion to a solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide, then add sodium hypochlorite, react, adjust the pH value of the solution during the reaction, adjust the pH value of the solution again after the reaction, concentrate, and obtain bacterial cellulose wet spinning solution.

[0007] Step S3: Dry spin the liquid crystal elastomer dry spinning solution obtained in step S1, and wet spin the bacterial cellulose wet spinning solution obtained in step S2.

[0008] Step S4: Twist the liquid crystal elastomer fiber and bacterial cellulose fiber obtained in step S3, and treat them with ultraviolet light to obtain a biomimetic spiral yarn driver.

[0009] Furthermore, the liquid crystal monomer is 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene (RM257).

[0010] Furthermore, the chain extender includes 3,6-dioxa-1,8-octanedithiol (EDDET).

[0011] Furthermore, the crosslinking agent includes pentaerythritol tetrakis(3-mercaptopropionic acid) ester (PETMP).

[0012] Furthermore, the photoinitiator includes 3-methyl-4-phenylbenzophenone.

[0013] Furthermore, the catalyst includes dipropylamine (DPA).

[0014] Furthermore, the specific process of dissolving the liquid crystal elastomer involves heating in a water bath to promote the dissolution of the photoinitiator. During the water bath heating process, stirring can be used to accelerate the dissolution and dispersion of the photoinitiator.

[0015] Furthermore, based on the acrylate groups in the liquid crystal single crystal, the thiol groups in the chain extender, and the thiol groups in the crosslinking agent, the molar ratio of the liquid crystal single crystal to (chain extender + crosslinking agent) is 1.1:1.

[0016] Furthermore, the molar ratio of the chain extender to the crosslinking agent is 3:1.

[0017] Furthermore, the sum of the mass concentrations of the liquid crystal monomer, chain extender, and crosslinking agent in the uniformly mixed solution is 20%-25%.

[0018] Furthermore, in step S1, the mixing environment is carried out at a constant temperature, which is 25℃-35℃.

[0019] Furthermore, those skilled in the art should understand that uniform mixing facilitates sufficient contact between substances, thereby promoting their interaction. Therefore, to ensure uniform mixing, those skilled in the art may stir the mixture for 3-5 hours.

[0020] Furthermore, the addition of the photoinitiator must be done under light-protected conditions.

[0021] Furthermore, the added mass of the photoinitiator is 1%-5% of the mass of the liquid crystal monomer.

[0022] Furthermore, the molar ratio of the liquid crystal monomer to the catalyst is 11:2.

[0023] Furthermore, the concentration of the bacterial cellulose dispersion is 10 g / L.

[0024] Furthermore, the method for preparing the bacterial cellulose dispersion includes: dispersing bacterial cellulose in deionized water.

[0025] Furthermore, the volume ratio of the bacterial cellulose dispersion to the solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide is 10:1.

[0026] Furthermore, the mass concentration of the 2,2,6,6-tetramethylpiperidine oxide in a solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide is 0.016 g / 10 mL.

[0027] Furthermore, the sodium bromide in the solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide has a mass concentration of 0.1 g / 10 mL.

[0028] Furthermore, the method for preparing the solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide includes: dispersing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide in deionized water.

[0029] Furthermore, the volume ratio of sodium hypochlorite to bacterial cellulose dispersion is 3.9:100.

[0030] Furthermore, the reaction time in step S2 is 55 min to 65 min.

[0031] Furthermore, in step S2, the pH value of the solution is adjusted to 10.2-10.4 during the reaction.

[0032] Furthermore, in step S2, the pH of the solution is adjusted again to 6.9-7.1 after the reaction.

[0033] Furthermore, after concentration, the mass concentration of bacterial cellulose in the bacterial cellulose wet spinning solution is 3.6%.

[0034] Furthermore, in the specific process of concentration, in step S2, after adjusting the pH value of the solution after the reaction is terminated, the bacterial cellulose is centrifuged and washed with deionized water, and then the bacterial cellulose is dissolved in deionized water to obtain a bacterial cellulose wet spinning solution with a mass concentration of 3.6%.

[0035] Furthermore, the specific parameters of the dry spinning process include: an extrusion speed of 2.5 mL / min-3.5 mL / min, a receiving roller rotation speed of 4.5 m / min-5.1 m / min, solvent evaporation at 55℃-65℃, and stretching of the liquid crystal elastomer fiber to twice its original length.

[0036] Furthermore, the specific parameters of the wet spinning process include: an extrusion rate of 5.5 mL / min-6.5 mL / min, a receiving roller rotation speed of 7 m / min-9 m / min, stretching the bacterial cellulose fibers to 1.2 times their original length, and drying at 55℃-65℃.

[0037] Furthermore, the ultraviolet lamp treatment specifically includes irradiation for 25-35 minutes under ultraviolet light with a wavelength of 365nm, and the irradiance of the ultraviolet lamp is 14mW / cm². 2 -16mW / cm 2 .

[0038] Furthermore, during the twisting process, the ratio of the number of liquid crystal elastomer fibers to the number of bacterial cellulose fibers is 1:1-4.

[0039] Furthermore, after twisting, the twist angle formed by the liquid crystal elastomer fiber and the bacterial cellulose fiber is 10°-30°.

[0040] Furthermore, during the twisting process, the ratio of the number of liquid crystal elastomer fibers to bacterial cellulose fibers is 1:3, and after twisting, the twist angle formed by the liquid crystal elastomer fibers and bacterial cellulose fibers is 20°.

[0041] In this invention, the bionic spiral yarn actuator combines mechanical strength and thermal drive rate. When the above conditions are met, the bionic spiral yarn actuator can simultaneously possess superior mechanical strength and thermal drive rate.

[0042] Furthermore, after wet spinning of the bacterial cellulose wet spinning solution, the orientation degree of the obtained bacterial cellulose fibers is 32%-34%.

[0043] The present invention also provides a biomimetic spiral yarn actuator obtained by the preparation method of the aforementioned biomimetic spiral yarn actuator.

[0044] Furthermore, the ratio of liquid crystal elastomer fibers to bacterial cellulose fibers in the biomimetic spiral yarn actuator is 1:1-4.

[0045] Furthermore, the twist angle formed by the liquid crystal elastomer fiber and the bacterial cellulose fiber is 10°-30°.

[0046] Furthermore, the orientation degree of the bacterial cellulose fibers is 32%-34%.

[0047] Furthermore, the diameter of the liquid crystal elastomer fiber is 398µm-434µm, and the diameter of the bacterial cellulose fiber is 169µm-183µm.

[0048] The present invention also provides the application of the biomimetic spiral yarn actuator in stimulus-responsive soft grippers and passive micro motors.

[0049] The embodiments of the present invention have the following technical effects:

[0050] 1. In this invention, liquid crystal elastomer fibers and bacterial cellulose fibers are twisted together to form a biomimetic spiral yarn actuator. First, the bacterial cellulose fibers help to improve the mechanical strength of the biomimetic spiral yarn actuator. The high-strength bacterial fibers disperse the stress concentrated on the soft liquid crystal elastomer, thereby improving the breaking strength of the spiral composite yarn. Second, through the twisting technology, the friction and entanglement between the fibers are enhanced, and the gaps and defects in the yarn are effectively reduced, which in turn helps to further improve the mechanical strength of the biomimetic spiral yarn actuator.

[0051] 2. In this invention, to improve the mechanical properties of the biomimetic spiral yarn actuator, liquid crystal elastomer fibers are prepared by dry spinning and bacterial cellulose fibers are prepared by wet spinning. During the preparation process, the orientation of the liquid crystal elastomer fibers and bacterial cellulose fibers is adjusted by stretching them, which is beneficial to improving the mechanical strength of the liquid crystal elastomer fibers and bacterial cellulose fibers. However, if the stretching strength is too high, it will cause the fibers to break. Therefore, in this invention, the length of the liquid crystal elastomer fibers is stretched to twice the original length, and the length of the bacterial cellulose fibers is stretched to 1.2 times the original length.

[0052] 3. In this invention, during the preparation of bacterial cellulose, in order to adjust the orientation of the bacterial cellulose fibers, 2,2,6,6-tetramethylpiperidine oxide is added to the bacterial cellulose wet spinning solution. 2,2,6,6-tetramethylpiperidine oxide can promote the oxidation of the hydroxyl group on the sixth carbon (C6) of the bacterial cellulose molecular chain to a carboxyl group, reduce the hydrogen bonds between molecular chains, and achieve uniform dispersion of bacterial cellulose in water through electrostatic repulsion, thereby obtaining a uniform and stable bacterial cellulose spinning solution, which is beneficial for better adjusting the orientation of bacterial cellulose fibers during wet spinning.

[0053] 4. In this invention, in addition to considering the orientation of bacterial cellulose fibers and liquid crystal elastomer fibers, it is also necessary to further consider the ratio of the number of bacterial cellulose fibers and liquid crystal elastomer fibers and the twist angle, so as to balance the relationship between mechanical strength and the crawling speed and distance of the biomimetic spiral yarn driver. Attached Figure Description

[0054] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0055] Figure 1 This is a SEM image of the liquid crystal elastomer fiber provided in Embodiment 3 of the present invention.

[0056] Figure 2 These are polarized light microscope images of multi-domain liquid crystal elastomer fibers and single-domain liquid crystal elastomer fibers provided in Comparative Examples 1 and 2 of this invention, wherein... Figure 2 Figure A shows the test results of the multi-domain liquid crystal elastomer in Comparative Example 1 at 45° on the analyzer. Figure 2 Figure B shows the test results of the multi-domain liquid crystal elastomer in Comparative Example 1 at 90° on the analyzer. Figure 2 C represents the test results of the single-domain liquid crystal elastomer in Comparative Example 2 at 45° on the analyzer. Figure 2 The result of test on the single-domain liquid crystal elastomer of Comparative Example 2 at 90° in the analyzer is shown in Figure D.

[0057] Figure 3 This is a SEM image of the stretched bacterial microcellulose fibers provided in Embodiment 3 of the present invention.

[0058] Figure 4 This is the Fourier transform infrared spectrum of bacterial cellulose before and after oxidation in Example 3 of the present invention, where the red curve is the spectrum after oxidation and the black curve is the spectrum before oxidation.

[0059] Figure 5 These are physical images and SEM images of bacterial cellulose fibers from Example 3 of the present invention, wherein... Figure 5 Image A is a physical image of bacterial cellulose fibers from Example 3. Figure 5 Image B is an SEM image of bacterial cellulose fibers from Example 3.

[0060] Figure 6 This is a two-dimensional small-angle X-ray scattering pattern of Embodiment 3 of the present invention.

[0061] Figure 7 These are physical images of the spiral yarn actuators of Examples 1-4, wherein, Figure 7 Image A is the physical image of Example 1. Figure 7 Image B in the image is a physical image of Example 2. Figure 7 C is the physical image of Example 3. Figure 7 D is a physical image of Example 4.

[0062] Figure 8 These are SEM images of spiral yarn drivers with different twists from Examples 3, 5-6. Figure 8 In the image, A is the SEM image of Example 3. Figure 8 B in the image is the SEM image of Example 5. Figure 8 C in the figure is the SEM image of Example 6.

[0063] Figure 9 This is a model diagram of an excitation-response soft gripper.

[0064] Figure 10 This is a graph showing the change in the length of the spiral yarn actuator of Example 3 over time during the operation of the stimulus-responsive soft gripper.

[0065] Figure 11 This is a model diagram of a passive micro motor.

[0066] Figure 12 This is a graph showing the changes in the rotation angle and angular velocity of the blades of a passive micro motor over time. Figure 12 In the diagram, A represents the change of the rotation angle over time. Figure 12 In the equation, B represents the change of angular velocity over time. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. 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.

[0068] In a first aspect, some embodiments of the present invention provide a method for preparing a biomimetic spiral yarn actuator, comprising the following steps:

[0069] Step S1: Preparation of liquid crystal elastomer dry spinning solution: Dissolve liquid crystal monomer, chain extender and crosslinking agent in dichloromethane solvent, mix evenly, add catalyst to the evenly mixed solution to carry out Michael addition reaction, add photoinitiator, dissolve photoinitiator to obtain liquid crystal elastomer dry spinning solution;

[0070] Step S2: Preparation of bacterial cellulose wet spinning solution: Add the bacterial cellulose dispersion to a solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide, then add sodium hypochlorite, react, adjust the pH value of the solution during the reaction, adjust the pH value of the solution again after the reaction, concentrate, and obtain bacterial cellulose wet spinning solution.

[0071] Step S3: Dry spin the liquid crystal elastomer dry spinning solution obtained in step S1, and wet spin the bacterial cellulose wet spinning solution obtained in step S2.

[0072] Step S4: Twist the liquid crystal elastomer fiber and bacterial cellulose fiber obtained in step S3, and treat them with ultraviolet light to obtain a biomimetic spiral yarn driver.

[0073] In some embodiments, the liquid crystal monomer is 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene.

[0074] In some embodiments, the chain extender includes 3,6-dioxa-1,8-octanedithiol.

[0075] In some embodiments, the crosslinking agent includes pentaerythritol tetrakis(3-mercaptopropionic acid) ester.

[0076] In some embodiments, the photoinitiator includes 3-methyl-4-phenylbenzophenone.

[0077] In some embodiments, the catalyst comprises dipropylamine.

[0078] In some embodiments, the molar ratio of the liquid crystal single crystal to (chain extender + crosslinker) is 1.1:1, based on the acrylate groups in the liquid crystal single crystal, the thiol groups in the chain extender, and the thiol groups in the crosslinker.

[0079] In some embodiments, the molar ratio of the chain extender to the crosslinking agent is 3:1.

[0080] In some embodiments, the sum of the mass concentrations of the liquid crystal monomer, chain extender, and crosslinking agent in the uniformly mixed solution is 20%-25%.

[0081] In some embodiments, in step S1, the mixing environment is such that the mixing is carried out at a constant temperature, which is 25°C-35°C.

[0082] In some embodiments, the addition of the photoinitiator needs to be done under light-protected conditions.

[0083] In some embodiments, the added mass of the photoinitiator is 1%-5% of the mass of the liquid crystal monomer.

[0084] In some embodiments, the molar ratio of the liquid crystal monomer to the catalyst is 11:2.

[0085] In some embodiments, the concentration of the bacterial cellulose dispersion is 10 g / L.

[0086] In some embodiments, the volume ratio of the bacterial cellulose dispersion to the solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide is 10:1.

[0087] In some embodiments, the mass concentration of the 2,2,6,6-tetramethylpiperidine oxide in a solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide is 0.016 g / 10 mL.

[0088] In some embodiments, the sodium bromide is present in a solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide at a mass concentration of 0.1 g / 10 mL.

[0089] In some embodiments, the volume ratio of sodium hypochlorite to bacterial cellulose dispersion is 3.9:100.

[0090] In some embodiments, the reaction time in step S2 is 55 min to 65 min.

[0091] In some embodiments, in step S2, the pH of the solution is adjusted to 10.2-10.4 after the reaction.

[0092] In some embodiments, in step S2, the pH of the solution is adjusted again to 6.9-7.1 after the reaction.

[0093] In some embodiments, after concentration, the mass concentration of bacterial cellulose in the bacterial cellulose wet spinning solution is 3.6%.

[0094] In some embodiments, the specific parameters of the dry spinning include: an extrusion speed of 2.5 mL / min-3.5 mL / min, a receiving roller rotation speed of 4.5 m / min-5.1 m / min, solvent evaporation at 55℃-65℃, and stretching of the liquid crystal elastomer fiber to twice its original length.

[0095] In some embodiments, the specific parameters of the wet spinning process include: an extrusion rate of 5.5 mL / min-6.5 mL / min, a receiving roller rotation speed of 7 m / min-9 m / min, stretching the bacterial cellulose fibers to 1.2 times their original length, and drying at 55℃-65℃.

[0096] In some embodiments, the ultraviolet lamp treatment specifically includes irradiation for 25-35 minutes under ultraviolet light with a wavelength of 365 nm, wherein the irradiance of the ultraviolet lamp is 14 mW / cm². 2 -16mW / cm 2 .

[0097] In this invention, the helical shape of the twisted liquid crystal elastomer is fixed by irradiation with an ultraviolet lamp.

[0098] In some embodiments, during the twisting process, the ratio of liquid crystal elastomer fibers to bacterial cellulose fibers is 1:1-4.

[0099] In some embodiments, the twist angle formed by the liquid crystal elastomer fiber and the bacterial cellulose fiber after twisting is 10°-30°.

[0100] In some embodiments, after the bacterial cellulose wet spinning solution is wet-spun, the orientation degree of the obtained bacterial cellulose fibers is 32%-34%.

[0101] Secondly, some embodiments of the present invention also provide a biomimetic spiral yarn actuator obtained by the preparation method of the biomimetic spiral yarn actuator.

[0102] In some embodiments, the ratio of liquid crystal elastomer fibers to bacterial cellulose fibers in the biomimetic spiral yarn actuator is 1:1-4.

[0103] In some embodiments, the twist angle formed by the liquid crystal elastomer fibers and bacterial cellulose fibers is 10°-30°.

[0104] In some embodiments, the orientation degree of the bacterial cellulose fibers is 32%-34%.

[0105] In some embodiments, the diameter of the liquid crystal elastomer fiber is 398µm-434µm, and the diameter of the bacterial cellulose fiber is 169µm-183µm.

[0106] Thirdly, some embodiments of the present invention also provide the application of the biomimetic spiral yarn actuator in stimulus-responsive soft grippers and passive micro motors.

[0107] The following description uses specific embodiments and comparative examples to illustrate the point:

[0108] Example 1:

[0109] (1) 19.425 g of liquid crystal monomer (RM257), 3.281 g of chain extender (EDDET), and 2.931 g of crosslinking agent (PETMP) were dissolved in dichloromethane (CH2Cl2) solvent and magnetically stirred at room temperature for 2 h to prepare a homogeneous mixed solution with a mass fraction of 24%. Then, 1.214 g of catalyst DPA was added to the above mixed solution for 15 min to induce a Michael addition reaction and prepare the first-step crosslinking system solution. The molar ratio of acrylate groups in the liquid crystal monomer to thiol groups in EDDET and PETMP was 1.1:1, and the molar ratio of chain extender to crosslinking agent was 3:1. Subsequently, 2.023 g of photoinitiator 3-methyl-4-phenylbenzophenone (HHMP) was dissolved in the first-step crosslinking solution system to prepare a homogeneous dry spinning solution (the photoinitiator dosage was 4% of the liquid crystal monomer).

[0110] (2) D-mannitol (25 g / L), tryptone (3 g / L), and yeast extract (5 g / L) were ultrasonically dissolved in water to prepare a fermentation medium, which was then sterilized in an autoclave at 121°C for 20 minutes. After the medium cooled, the bacterial solution (10 vol%) was inoculated into the fermentation medium in a clean bench and then cultured in a biochemical incubator at 30°C for 7 days. The obtained bacterial cellulose was soaked in 1M NaOH solution (sodium hydroxide solution) at 80°C for 4 hours to remove components from the culture medium, and then rinsed repeatedly with deionized water until neutral. 2,2,6,6-Tetramethylpiperidine oxide (TEMPO) (0.016 g) and sodium bromide (0.1 g) were dissolved in deionized water (10 mL) and then poured into 100 mL of bacterial cellulose dispersion (dry weight of bacterial cellulose was 1 g). Sodium hypochlorite was then added at room temperature to start the reaction. During the 1-hour reaction, the suspension was titrated with 0.5M NaOH solution to maintain its pH at approximately 10.3. After the reaction, the dispersion was adjusted to neutral with 0.5M hydrochloric acid. Subsequently, the obtained bacterial cellulose nanofibers were centrifuged and washed several times, and concentrated to a bacterial cellulose wet spinning solution with a bacterial cellulose mass fraction of 3.6%.

[0111] (3) The LCE dry spinning solution was placed in a syringe and extruded from a nozzle with a diameter of 0.84 mm onto the surface of a PTFE receiving roller at 60°C to evaporate the solvent and solidify the fiber. The extrusion speed of the syringe and the rotation speed of the receiving roller were set to 3 mL / min and 4.8 m / min, respectively. Subsequently, the liquid crystal elastomer (LCE) fiber was stretched to twice its initial length by a roller with a rotation speed of 9.6 m / min.

[0112] Simultaneously, the bacterial cellulose wet spinning solution was transferred to a syringe and extruded into an acetone coagulation bath through a nozzle with an inner diameter of 1.07 mm. The formed bacterial cellulose was collected and wound onto a roller. The extrusion speed and the rotational speed of the receiving roller were set to 6 mL / min and 8 m / min, respectively. The fibers were then stretched to 1.2 times their original length using a roller rotating at 9.6 m / min. The prepared bacterial cellulose fibers were subsequently dried at 60 °C.

[0113] (4) An LCE / bacterial cellulose spiral yarn driver with a 1:1 ratio of LCE fiber to bacterial cellulose fiber and a twist angle of 20° was prepared by a rotary twisting device. A 365 nm ultraviolet lamp (15 mW / cm²) was used for the process. 2 Irradiate the LCE / bacterial cellulose spiral yarn for 30 minutes to induce a second cross-linking reaction in the LCE fibers, thereby fixing the alignment of the liquid crystal units and molecular chains.

[0114] Example 2:

[0115] (1) Same as Example 1;

[0116] (2) Same as Example 1;

[0117] (3) Same as Example 1;

[0118] (4) An LCE / bacterial cellulose spiral yarn driver with a 1:2 ratio of LCE fiber to bacterial cellulose fiber and a twist angle of 20° was prepared by a rotary twisting device. A 365nm ultraviolet lamp (15mW / cm²) was used. 2 Irradiate the LCE / bacterial cellulose spiral yarn for 30 minutes to induce a second cross-linking reaction in the LCE fibers, thereby fixing the alignment of the liquid crystal units and molecular chains.

[0119] Example 3:

[0120] (1) Same as Example 1;

[0121] (2) Same as Example 1;

[0122] (3) Same as Example 1;

[0123] (4) An LCE / bacterial cellulose spiral yarn driver with a 1:3 ratio of LCE fiber to bacterial cellulose fiber and a twist angle of 20° was prepared by a rotary twisting device. A 365nm ultraviolet lamp (15mW / cm²) was used for the process. 2 Irradiate the LCE / bacterial cellulose spiral yarn for 30 minutes to induce a second cross-linking reaction in the LCE fibers, thereby fixing the alignment of the liquid crystal units and molecular chains.

[0124] Example 4:

[0125] (1) Same as Example 1;

[0126] (2) Same as Example 1;

[0127] (3) Same as Example 1;

[0128] (4) An LCE / bacterial cellulose spiral yarn driver with a LCE fiber to bacterial cellulose fiber ratio of 1:4 and a twist angle of 20° was prepared by a rotary twisting device. A 365nm ultraviolet lamp (15mW / cm²) was used for the process. 2 Irradiate the LCE / bacterial cellulose spiral yarn for 30 minutes to induce a second cross-linking reaction in the LCE fibers, thereby fixing the alignment of the liquid crystal units and molecular chains.

[0129] Example 5:

[0130] (1) Same as Example 1;

[0131] (2) Same as Example 1;

[0132] (3) Same as Example 1;

[0133] (4) An LCE / bacterial cellulose spiral yarn driver with a 1:3 ratio of LCE fiber to bacterial cellulose fiber and a twist angle of 10° was prepared using a rotary twisting device. A 365nm ultraviolet lamp (15mW / cm²) was used for the process. 2 Irradiate the LCE / bacterial cellulose spiral yarn for 30 minutes to induce a second cross-linking reaction in the LCE fibers, thereby fixing the alignment of the liquid crystal units and molecular chains.

[0134] Example 6

[0135] (1) Same as Example 1;

[0136] (2) Same as Example 1;

[0137] (3) Same as Example 1;

[0138] (4) An LCE / bacterial cellulose spiral yarn driver with a LCE fiber to bacterial cellulose fiber ratio of 1:3 and a twist angle of 30° was prepared by a rotary twisting device. A 365nm ultraviolet lamp (15mW / cm²) was used. 2 Irradiate the LCE / bacterial cellulose spiral yarn for 30 minutes to induce a second cross-linking reaction in the LCE fibers, thereby fixing the alignment of the liquid crystal units and molecular chains.

[0139] Comparative Example 1:

[0140] (1) Dissolve 19.425g of liquid crystal monomer (RM257), 3.281g of chain extender (EDDET) and 2.931g of crosslinking agent (PETMP) in dichloromethane solvent and stir magnetically for 2h at room temperature to prepare a homogeneous mixed solution with a mass fraction of 24%; then add 1.214g of catalyst DPA to the above mixed solution for 15min to allow the system to undergo Michael addition reaction to prepare the first crosslinking system solution; wherein the molar ratio of acrylate groups in liquid crystal monomer to thiol groups in EDDET and PETMP is 1.1:1; the molar ratio of chain extender to crosslinking agent is 3:1. Then, dissolve 2.023g of photoinitiator 3-methyl-4,phenylbenzophenone (HHMP) in the first crosslinking solution system to prepare a homogeneous dry spinning solution (photoinitiator dose accounts for 4% of the liquid crystal monomer).

[0141] (2) The LCE dry spinning solution was placed in a syringe and extruded from a nozzle with a diameter of 0.84 mm onto the surface of the PTFE receiving roller at 60°C to evaporate the solvent and solidify the fiber. The extrusion speed of the syringe and the rotation speed of the receiving roller were set to 3 mL / min and 4.8 m / min, respectively. No drafting was performed; instead, a 365 nm ultraviolet lamp (15 mW / cm²) was used directly. 2 Irradiate the stretched LCE fibers for 30 minutes to allow the liquid crystal elastomer fibers to undergo a second crosslinking reaction, thereby fixing the alignment direction of the liquid crystal units and molecular chains of the LCE fibers and obtaining a multi-domain LCE fiber soft actuator.

[0142] Comparative Example 2

[0143] (1) Same as Comparative Example 1;

[0144] (2) The LCE dry spinning solution was placed in a syringe and extruded from a nozzle with a diameter of 0.84 mm onto the surface of a PTFE receiving roller at 60°C to evaporate the solvent and solidify the fiber. The extrusion speed of the syringe and the rotation speed of the receiving roller were set to 3 mL / min and 4.8 m / min, respectively. Subsequently, the LCE fiber was stretched to twice its initial length by a roller with a rotation speed of 9.6 m / min, and the stretched fiber was collected on the surface of a second PTFE rotating cylinder. During the stretching process, the macromolecular chains or liquid crystal units of the fiber were aligned along the fiber axis and highly oriented, and the fiber morphology gradually became transparent. At the same time, a 365 nm ultraviolet lamp (15 mW / cm²) was used to heat the fiber. 2 Irradiate the stretched LCE fibers for 30 minutes to allow the liquid crystal elastomer fibers to undergo a second crosslinking reaction, thereby fixing the alignment direction of the liquid crystal units and molecular chains of the LCE fibers and obtaining a single-domain LCE fiber soft actuator.

[0145] Comparative Example 3:

[0146] (1) D-mannitol (25 g / L), tryptone (3 g / L), and yeast extract (5 g / L) were ultrasonically dissolved in water to prepare a fermentation medium, which was then sterilized in an autoclave at 121°C for 20 minutes. After the medium cooled, the bacterial solution (10 vol%) was inoculated into the fermentation medium in a clean bench and then cultured in a biochemical incubator at 30°C for 7 days. The obtained bacterial cellulose was soaked in 1M NaOH solution at 80°C for 4 hours to remove components from the culture medium, and then rinsed repeatedly with deionized water until neutral. TEMPO (0.016 g) and NaBr (0.1 g) were dissolved in deionized water (10 mL) and then poured into 100 mL of bacterial cellulose dispersion (dry weight of bacterial cellulose was 1 g). Sodium hypochlorite was then added at room temperature to start the reaction. During the one-hour reaction, the suspension was titrated with 0.5M NaOH solution to maintain its pH at around 10.3. After the reaction was completed, the dispersion was adjusted to neutral with 0.5M hydrochloric acid. Subsequently, the obtained bacterial cellulose was centrifuged and washed several times, and concentrated to a bacterial cellulose mass fraction of 3.6% to prepare a bacterial cellulose wet spinning solution.

[0147] (2) The bacterial cellulose wet spinning solution was transferred to a syringe and extruded into an acetone coagulation bath through a nozzle with an inner diameter of 1.07 mm. The formed bacterial cellulose was collected and wound onto a roller. The extrusion speed and the rotation speed of the receiving roller were set to 6 mL / min and 8 m / min, respectively. The prepared bacterial cellulose fibers were then dried at 60 °C.

[0148] Comparative Example 4

[0149] (1) Same as example 3

[0150] (2) The bacterial cellulose wet spinning solution was transferred to a syringe and extruded into an acetone coagulation bath through a nozzle with an inner diameter of 1.07 mm. The formed bacterial cellulose was collected and wound onto a roller. The extrusion speed and the rotation speed of the receiving roller were set to 6 mL / min and 8 m / min, respectively. The fibers were stretched to 1.2 times their original length through a roller with a rotation speed of 9.6 m / min. The prepared bacterial cellulose fibers were then dried at 60 °C.

[0151] Comparative Example 5:

[0152] The preparation method was the same as in Example 1, except that the length of the liquid crystal elastomer fiber was stretched to 1.5 times the original length, and the other experimental conditions were the same as in Example 1.

[0153] Test method: The test samples (50mm in length) of the examples and comparative examples were prepared according to the requirements of fiber strength testing, and the fiber strength was tested using a tensile strength measuring instrument (model: PT-990T).

[0154] Results and Analysis:

[0155] Table 1. Test results of the embodiments and comparative examples in this invention.

[0156]

[0157] First, a biomimetic spiral yarn actuator was successfully prepared using the method of this invention. This biomimetic spiral yarn actuator is formed by twisting liquid crystal elastomer fibers and bacterial cellulose fibers. The bacterial cellulose fibers enhance the mechanical strength and load-bearing capacity of the biomimetic spiral yarn actuator. Firstly, the high-strength bacterial fibers disperse the stress concentrated on the soft liquid crystal elastomer, improving the breaking strength of the spiral composite yarn. Secondly, by combining the liquid crystal elastomer fibers and bacterial cellulose fibers through twisting, the friction and entanglement between the liquid crystal elastomer fibers and bacterial cellulose fibers are enhanced, and the gaps and defects between them are effectively reduced, further improving the mechanical strength of the biomimetic spiral yarn actuator. Finally, the biomimetic spiral arrangement can absorb energy during deformation, thereby enhancing the toughness of the liquid crystal elastomer fibers, preventing sudden breakage during operation, and enhancing their ability to withstand impacts or sudden loads. As can be verified from Table 1, the mechanical strength of the biomimetic spiral yarn actuators obtained by twisting liquid crystal elastomer fibers and bacterial cellulose fibers in Examples 1-6 of this invention is significantly better than that in Comparative Examples 1-2.

[0158] In this invention, liquid crystal elastomer fibers are prepared by dry spinning, and bacterial cellulose fibers are prepared by wet spinning. During the preparation process, the length of the liquid crystal elastomer fibers is stretched to twice their original length to adjust their orientation. Comparison of Comparative Examples 1 and 2 shows that the mechanical properties of the liquid crystal elastomer fibers are improved after adjusting their orientation. The orientation of the bacterial cellulose fibers is adjusted by wet spinning. First, 2,2,6,6-tetramethylpiperidine oxide is added to the bacterial cellulose spinning solution to oxidize the bacterial fibers. This oxidizes the hydroxyl group on the sixth carbon (C6) of the bacterial cellulose molecular chain to a carboxyl group, reducing hydrogen bonds between molecular chains. Electrostatic repulsion also achieves uniform dispersion of the bacterial cellulose in water, resulting in a uniform and stable bacterial cellulose spinning solution. This lays the foundation for adjusting the orientation of the bacterial cellulose fibers. When the length of the bacterial cellulose fibers is stretched to 1.2 times their original length, the orientation of the bacterial cellulose fibers can reach 33%-34%, further improving the mechanical strength of the bacterial cellulose fibers. This can also be verified by comparison of Comparative Examples 3 and 4. Figure 3 It can be seen that the stretched bacterial cellulose fibers possess a high-strength 3D interconnected network structure and good mechanical strength. Furthermore... Figure 4 Fourier transform infrared spectroscopy verification showed that bacterial cellulose, after TEMPO-mediated oxidation, oxidized at 1735 cm⁻¹ -1 A distinct peak is observed at this point, corresponding to the C=O stretching vibration of the carboxyl group, which also proves that TEMPO-mediated oxidation oxidizes the hydroxyl group on the sixth carbon (C6) of the bacterial cellulose molecular chain to a carboxyl group. Figure 6 The two-dimensional X-ray scattering experiment results show that the bacterial fibers exhibit good orientation under the combined action of flow shear force and stretching force during wet spinning, resulting in an orientation degree of 33.59% for the bacterial cellulose fibers in Example 3. In summary, in the method of this invention, tensile strength can improve the orientation degree of both liquid crystal elastomer fibers and bacterial cellulose fibers, enabling them to achieve better coordination and thus jointly enhance the mechanical strength of the biomimetic spiral yarn actuator. As observed in Example 1 and Comparative Example 5, when the length of the liquid crystal elastomer fiber is stretched to twice its original length and the length of the bacterial cellulose fiber is stretched to 1.2 times its original length, the mechanical strength of the biomimetic spiral yarn actuator can be significantly improved.

[0159] After adjusting the orientation of liquid crystal elastomer fibers and bacterial cellulose fibers, the mechanical strength of the biomimetic spiral yarn actuator was further studied by combining liquid crystal elastomer fibers and bacterial cellulose fibers. Figure 7 Examples 1-4 show that spiral yarn actuators with different component ratios were prepared using twisting technology. Figure 8The figures show that in Examples 3 and 5-6, spiral yarn actuators with different twist angles were prepared by adjusting the rotation speed of the twisting device. First, the strength of the biomimetic spiral yarn actuators in Examples 1-4 was studied, and it was found that the mechanical strength of the biomimetic spiral yarn actuators increased with the increase of the number of bacterial cellulose fibers. Further comparison of Examples 3 and 5-6 revealed that the mechanical strength of the biomimetic spiral yarn actuators also increased with the increase of the twist angle of the liquid crystal elastomer fibers and bacterial cellulose fibers. Table 1 also discloses the thermally driven elongation rate of the biomimetic spiral yarn actuators in Examples 1-6. The thermally driven elongation rate of the biomimetic spiral yarn actuators decreased with the increase of the number of bacterial cellulose fibers and the increase of the twist angle. Although increasing the number of bacterial fibers and increasing the twist angle can promote close contact between the liquid crystal elastomer fibers and bacterial cellulose fibers, thereby improving the mechanical strength of the biomimetic spiral yarn actuators, the close contact also restricts the space for thermal shrinkage of the liquid crystal elastomer fibers, ultimately resulting in a decrease in the crawling speed and distance of the biomimetic spiral yarn actuators. Further optimization yields a bacterial cellulose fiber to liquid crystal elastomer fiber ratio of 3:1 and a twist angle of 20°.

[0160] In this invention, the diameter of the liquid crystal elastomer fiber is 398µm-434µm, and the diameter of the bacterial cellulose fiber is 169µm-183µm. Figure 1 The diameter of the liquid crystal elastomer fiber in Example 3 is 416µm. Figure 5 In Example 3, the diameter of the bacterial cellulose fibers is 176 µm. As the number of bacterial cellulose fibers increases, the total diameter of the bacterial cellulose fibers becomes closer to the diameter of the liquid crystal elastomer fibers, resulting in a tighter entanglement between the bacterial cellulose fibers and the liquid crystal elastomer fibers. Therefore, the ratio of the number of bacterial cellulose fibers to the number of liquid crystal elastomer fibers is 3:1.

[0161] Figure 2 The polarization optical microscopy images show that, due to the random distribution of isotropic phase domains, the brightness of the multi-domain LCE fiber prepared in Comparative Example 1 is not different when viewed from different angles relative to the analyzer. Therefore, the liquid crystal elastomer in Comparative Example 1 does not have orientation. Figure 2 (A) shows the test results on the left when the analyzer is at 45°, and the test results on the right when the analyzer is at 90°. However, in Comparative Example 2 ( Figure 2 (B) The left side of the test results are at 45° of the analyzer, and the right side is at 90° of the analyzer. After stretching, the single-domain LCE fiber of the liquid crystal elastomer has the highest brightness at 45° relative to the analyzer and the lowest brightness at 90°. This shows that stretching the liquid crystal elastomer fiber to twice its original size in this invention can make the liquid crystal elastomer fiber have a good degree of orientation.

[0162] The biomimetic spiral yarn actuator prepared in Example 3 was applied to a stimulus-responsive soft gripper. Specifically, a polyethylene terephthalate (PET) film was bent, the spiral yarn actuator prepared in Example 3 was installed in the middle, and two polyimide tapes were attached to both sides of the PET film to create a stimulus-responsive soft gripper. Figure 9 As shown, the working process of the stimulus-response soft gripper was recorded using a Canon camera, and the change in the length of the spiral yarn actuator over time was analyzed. The results are as follows. Figure 10 As shown in the figure. The results indicate that the spiral yarn actuator has a sensitive thermal response and can complete the gripping, transfer, and release of heavy objects within 9 seconds.

[0163] The biomimetic spiral yarn actuator prepared in Example 3 was applied to a passive micromotor. Specifically, blades composed of PET film and polyvinyl chloride tape were installed at the bottom of the spiral yarn actuator prepared in Example 3 to prepare a passive micromotor, as shown in the schematic diagram below. Figure 11 As shown, the working process of a passive micromotor was recorded using a Canon camera, and the changes in rotation angle and angular velocity over time were analyzed. The results are as follows. Figure 12 As shown in the figure. The results indicate that when the passive micromotor is subjected to thermal stimulation, it immediately exhibits a unique untwisting rotational motion, with the blades completing one rotation within 1.24 s. After the thermal stimulation is removed, the passive micromotor rotates in the opposite direction, and the helical yarn driver restores its twist. The maximum rotational angular velocity of the passive micromotor can reach 7.65 rad / s.

[0164] In summary, the method of this invention has successfully prepared a biomimetic spiral yarn actuator with good mechanical strength and weight-lifting performance.

[0165] It should be noted that the terminology used in this invention is for describing specific embodiments only and is not intended to limit the scope of this application. As shown in this specification, unless the context clearly indicates otherwise, words such as "a," "an," "an," and / or "the" do not specifically refer to the singular and may include the plural. The terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element.

[0166] It should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," "linked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0167] 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 technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a biomimetic spiral yarn actuator, characterized in that, Includes the following steps: Step S1: Preparation of liquid crystal elastomer dry spinning solution: Dissolve liquid crystal monomer, chain extender and crosslinking agent in dichloromethane solvent, mix evenly, add catalyst to the evenly mixed solution, carry out Michael addition reaction, add photoinitiator, heat to dissolve photoinitiator, and obtain liquid crystal elastomer dry spinning solution. Step S2: Preparation of bacterial cellulose wet spinning solution: Add the bacterial cellulose dispersion to a solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide, then add sodium hypochlorite, react, adjust the pH value of the solution during the reaction, adjust the pH value of the solution again after the reaction, concentrate the solution to obtain bacterial cellulose wet spinning solution. Step S3: Dry spin the liquid crystal elastomer dry spinning solution obtained in step S1, and wet spin the bacterial cellulose wet spinning solution obtained in step S2. Step S4: Twist the liquid crystal elastomer fiber and bacterial cellulose fiber obtained in step S3, and treat them with ultraviolet light to obtain a biomimetic spiral yarn driver.

2. The preparation method according to claim 1, characterized in that, The liquid crystal monomer is 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene; The chain extender includes 3,6-dioxa-1,8-octanedithiol; The crosslinking agent includes pentaerythritol tetrakis(3-mercaptopropionic acid); The photoinitiator includes 3-methyl-4-phenylbenzophenone; The catalyst includes dipropylamine.

3. The preparation method according to claim 1, characterized in that, Based on the acrylate groups in the liquid crystal single crystal, the thiol groups in the chain extender, and the thiol groups in the crosslinking agent, the molar ratio of the liquid crystal single crystal to (chain extender + crosslinking agent) is 1.1:

1. The molar ratio of the chain extender to the crosslinking agent is 3:1; The sum of the mass concentrations of the liquid crystal monomer, chain extender, and crosslinking agent in the uniformly mixed solution is 20%-25%. The molar ratio of the liquid crystal monomer to the catalyst is 11:

2.

4. The preparation method according to claim 1, characterized in that, The addition of the photoinitiator must be done under light-protected conditions; The added mass of the photoinitiator is 1%-5% of the mass of the liquid crystal monomer.

5. The preparation method according to claim 1, characterized in that, The volume ratio of the bacterial cellulose dispersion to the solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide is 10:

1. The mass concentration of the 2,2,6,6-tetramethylpiperidine oxide in a solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide is 0.016 g / 10 mL. The sodium bromide in the solution containing 2,2,6,6-tetramethylpiperidine oxide and sodium bromide has a mass concentration of 0.1 g / 10 mL. The volume ratio of sodium hypochlorite to bacterial cellulose dispersion is 3.9:100; After concentration, the mass concentration of bacterial cellulose in the bacterial cellulose wet spinning solution is 3.6%.

6. The preparation method according to claim 1, characterized in that, The reaction time in step S2 is 55 min-65 min; In step S2, the pH of the solution is adjusted to 10.2-10.4 during the reaction; In step S2, the pH of the solution is adjusted again to 6.9-7.1 after the reaction.

7. The preparation method according to claim 1, characterized in that, The specific parameters of the dry spinning method include: an extrusion speed of 2.5 mL / min-3.5 mL / min, a receiving roller rotation speed of 4.5 m / min-5.1 m / min, solvent evaporation at 55℃-65℃, and stretching of the liquid crystal elastomer fiber to twice its original length. The specific parameters of the wet spinning process include: an extrusion rate of 5.5 mL / min-6.5 mL / min, a receiving roller rotation speed of 7 m / min-9 m / min, stretching the bacterial cellulose fibers to 1.2 times their original length, and drying at 55℃-65℃.

8. The preparation method according to claim 1, characterized in that, The specific treatment performed by the ultraviolet lamp includes irradiation for 25-35 minutes under ultraviolet light with a wavelength of 365 nm, and the irradiance of the ultraviolet lamp is 14 mW / cm². 2 -16mW / cm 2 ; During the twisting process, the ratio of the number of liquid crystal elastomer fibers to the number of bacterial cellulose fibers is 1:1-4; After twisting, the twist angle formed by the liquid crystal elastomer fiber and the bacterial cellulose fiber is 10°-30°; After wet spinning, the bacterial cellulose fiber obtained from the bacterial cellulose wet spinning solution has an orientation degree of 32%-34%.

9. The biomimetic spiral yarn actuator obtained by the preparation method according to any one of claims 1-8, characterized in that, The ratio of liquid crystal elastomer fibers to bacterial cellulose fibers in the biomimetic spiral yarn actuator is 1:1-4. The twist angle formed by the liquid crystal elastomer fiber and the bacterial cellulose fiber is 10°-30°; The orientation degree of the bacterial cellulose fibers is 32%-34%; The diameter of the liquid crystal elastomer fiber is 398µm-434µm, and the diameter of the bacterial cellulose fiber is 169µm-183µm.

10. The application of the biomimetic spiral yarn actuator of claim 9 in stimulus-responsive soft grippers and passive micro motors.

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