Liquid crystal elastomer optical fiber and continuous preparation method and application thereof

Abstract

The invention discloses a liquid crystal elastomer optical fiber and a continuous preparation method and application thereof. The liquid crystal elastomer optical fiber comprises a liquid crystal elastomer fiber core and a cladding; the liquid crystal elastomer fiber core comprises a liquid crystal elastomer and a photothermal conversion material. The continuous preparation method is a coaxial extrusion method, and comprises the following steps: respectively loading a fiber core and a cladding liquid crystal elastomer precursor into two stainless steel needle cylinders connected by coaxial needle heads, and finely regulating and controlling parameters such as needle cylinder temperature, extrusion pressure and needle head height to obtain the liquid crystal elastomer optical fiber with the required size, thereby realizing integrated continuous preparation of the liquid crystal elastomer optical fiber. According to the application, a liquid crystal elastomer optical fiber, a silica optical fiber and a stimulation light source are constructed into a light wave induced actuation device, and the functions of stimulation signal generation, transmission and motion execution are completed. The liquid crystal elastomer optical fiber has the advantages of being uniform in diameter, good in core cladding structure, low in optical transmission loss and the like, the preparation process of the liquid crystal elastomer optical fiber is greatly simplified, the cost is reduced, and a way is laid for industrial large-scale production.

Description

Technical Field

[0001] The invention belongs to the technical field of flexible optical fibers, and in particular relates to a batch preparation method of liquid crystal elastomer optical fibers and applications thereof. Background Art

[0002] Smart materials are a new type of functional material that can sense external stimuli and can respond to external stimuli to varying degrees and show activity. Among them, soft smart materials, with their compliant contact characteristics, significant reversible deformation ability and good biocompatibility, have attracted more and more researchers to develop flexible actuators based on soft smart materials, showing broad application potential in artificial muscles, tactile perception, biomedicine and other fields. As a typical representative of soft smart materials, liquid crystal elastomers (LCEs) have diverse stimulus sources, fast response time and programmable driving modes, making them ideal materials for preparing flexible actuators.

[0003] Among them, liquid crystal elastomer fibers are considered to be ideal actuating units in flexible devices due to their high specific surface area, power density and fast response speed, and can achieve complex deformation modes through a combination of multiple processes. Traditional spatial light-actuated liquid crystal elastomer fibers are difficult to function in environments where light cannot directly irradiate. In contrast, the optical waveguide drive mode can integrate the light source inside the fiber to achieve axial propagation of light energy, which can not only overcome the many limitations of spatial light drive, but also ensure efficient use and precise control of light energy.

[0004] However, the existing optical waveguide-driven liquid crystal elastomer fiber devices nowadays rarely have a complete core-package structure of the optical fiber or cannot be continuously prepared in an integrated manner (such as the existing Chinese invention patent application 202310418855.5). Therefore, the development of a method for continuously preparing liquid crystal elastomer optical fibers will provide a feasible way for the efficient preparation of liquid crystal elastomer fiber devices, and greatly broaden its application scenarios and functional scope, providing strong technical support and innovative inspiration for the development of future soft robots, remote control technology and intelligent medical equipment. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a liquid crystal elastomer optical fiber (LCEOFs) and a continuous preparation method and application thereof to obtain a uniform, continuous and low-loss liquid crystal elastomer optical fiber. The use of optical waveguide drive solves the limitations of spatial light drive and is convenient for application in curved pipes, internal cavities or deeply shielded spaces that are difficult for light to reach.

[0006] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0007] A continuous preparation method of a liquid crystal elastomer optical fiber comprises the following steps:

[0008] 1) Dispersing liquid crystal monomers, chain extenders, photoinitiators and catalysts in a certain proportion in a solvent and reacting them fully to form a cladding precursor; on the basis of the above, changing the type and ratio of liquid crystal monomers, and adding photothermal conversion materials to form a core precursor;

[0009] 2) The core and cladding precursors are respectively loaded into two stainless steel syringes connected by a coaxial needle, kept warm and de-bubbled, and then the syringe temperature, extrusion pressure, needle height and other parameters are adjusted to be suitable for extrusion;

[0010] 3) Synchronously extrude the core and cladding precursors, rely on the shear force during the extrusion process and the gravity during the falling process to achieve uniaxial orientation of the liquid crystal primitives to form the initial shape of the optical fiber; use ultraviolet lamps on both sides of the optical fiber to preliminarily solidify it and collect it on a drum;

[0011] 4) After the extrusion is completed, the optical fiber is further photocured using an ultraviolet lamp on the outside of the drum to obtain a permanently cross-linked liquid crystal elastomer optical fiber with a core-cladding structure.

[0012] Preferably, the liquid crystal monomer in step 1) is an acrylic liquid crystal monomer;

[0013] Further preferably, in step 1), the liquid crystal monomer in the cladding precursor is 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene (RM257), and the liquid crystal monomer in the core precursor is 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene (RM82) and 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene (RM257), and the molar ratio of the two liquid crystal monomers RM82 and RM257 is 1:0.5-3.

[0014] Preferably, the chain extender in step 1) is a dithiol compound.

[0015] Preferably, the photoinitiator in step 1) is at least one of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (photoinitiator 2959) and benzil dimethyl ether (photoinitiator 651).

[0016] Preferably, the catalyst in step 1) is at least one of di-n-butylamine, triethylamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0017] Preferably, the solvent in step 1) is at least one of dichloromethane, acetone, toluene, dichloroethane, chloroform and tetrahydrofuran.

[0018] Preferably, the photothermal conversion material in the core precursor of step 1) is at least one of carbon nanomaterials, carbon black, MXene, organic dyes, bismuth (III) compounds, polydopamine, and metal nanoparticle materials.

[0019] Preferably, in step 1), the molar ratio of the liquid crystal monomer to the chain extender is 0.5 to 2:1.

[0020] Preferably, the mass of the photoinitiator in step 1) accounts for 0.1% to 5% of the total mass of the liquid crystal monomer and the chain extender.

[0021] Preferably, the mass of the catalyst in step 1) accounts for 0.1% to 5% of the total mass of the liquid crystal monomer and the chain extender.

[0022] Preferably, the molar ratio of the solvent to the liquid crystal monomer in step 1) is 50 to 300:1

[0023] Preferably, the mass of the photothermal conversion material in the core precursor in step 1) accounts for 0.01% to 5% of the total mass of the liquid crystal monomer and the chain extender.

[0024] Preferably, the reaction temperature in step 1) is 15°C to 35°C, and the reaction time is 1h to 24h.

[0025] Preferably, in step 2), the inner diameter of the coaxial needle is 0.15 mm to 1.15 mm, and the outer diameter is 0.4 mm to 2 mm.

[0026] Preferably, the insulation temperature in step 2) is 80° C. to 100° C., and the insulation time is 5 min to 60 min.

[0027] Preferably, the degassing pressure in step 2) is -60 psi to -100 psi, and the time is 1 min to 120 min.

[0028] Preferably, in step 2), the syringe temperature is 40°C to 70°C.

[0029] Preferably, the extrusion pressure in step 2) is 20 psi to 200 psi.

[0030] Preferably, the needle height in step 2) is 1 cm to 60 cm;

[0031] Preferably, in step 2), the ultraviolet lamp is placed at a height of 0.5 cm to 59.5 cm.

[0032] Preferably, in step 3), the diameter of the roller is 2 cm to 20 cm, and the rotation speed is 0.5 r / min to 50 r / min.

[0033] Preferably, the ultraviolet light source in step 4) is an LED ultraviolet lamp, an ultraviolet mercury lamp, a xenon ultraviolet lamp, an ultraviolet metal halide lamp or an ultraviolet deuterium lamp, etc., with an output wavelength of 200-400nm and an irradiation energy density of 1000mJ / cm 2 ~25000mJ / cm 2 .

[0034] Preferably, the UV curing time in step 4) is 1 min to 60 min;

[0035] Preferably, in step 4), the core refractive index of the liquid crystal elastomer optical fiber is greater than the cladding refractive index.

[0036] Preferably, in step 4), the core diameter of the liquid crystal elastomer optical fiber is 50 μm to 1000 μm, and the cladding thickness is 50 μm to 1500 μm.

[0037] Preferably, the continuous preparation device of the liquid crystal elastomer optical fiber comprises: a stainless steel syringe, a heating sleeve, a coaxial needle, an air pump and an air inlet pipe, an ultraviolet lamp, and a collecting roller.

[0038] The application actuation unit based on liquid crystal elastomer fiber of the present invention comprises a liquid crystal elastomer fiber 1, a quartz fiber 2, and a stimulation light source 3; the liquid crystal elastomer fiber 1 is coupled with the quartz fiber 2 and connected to the output end of the stimulation light source.

[0039] Preferably, the stimulation light source is a fiber laser, a semiconductor laser or an LED light source.

[0040] Preferably, the wavelength of the light source is full-band.

[0041] The application device of the present invention is composed of a single or multiple actuating units. The actuating device composed of a single actuating unit corresponds to a single-channel stimulation light source; while the actuating device composed of multiple actuating units corresponds to multiple-channel stimulation light sources, and by independently adjusting the stimulation light power, action duration and input timing of each actuating unit, programmable complex actions of the liquid crystal elastomer optical fiber array device are realized.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] (1) The liquid crystal elastomer optical fiber of the present invention draws on the core-cladding structure of the traditional quartz optical fiber. The existence of the cladding helps to limit the propagation of light in the core and improve the efficiency of light transmission. At the same time, the cladding can protect the core from damage by the external environment and extend its service life.

[0044] (2) Developed a coaxial extrusion technology to successfully and continuously produce uniform, diameter-adjustable, low-loss liquid crystal elastomer optical fibers, greatly shortening the preparation time and reducing the preparation cost.

[0045] (3) The present invention replaces the currently used electrothermal or spatial light driving modes with an optical waveguide driving mode, avoiding the potential safety hazards that electrothermal driving may cause to the human body, while overcoming the limitations of spatial light driving and providing a low-voltage, high-efficiency, and stable stimulus-response method. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of a device for continuously preparing a liquid crystal elastomer optical fiber in Embodiment 1, Embodiment 2, and Embodiment 3 of the present invention;

[0047] Figure 2 is a DSC test chart of the liquid crystal elastomer optical fiber in Example 1 of the present invention;

[0048] Figure 3 is a graph showing the relationship between light loss and transmission length of the liquid crystal elastomer optical fiber in Example 3 of the present invention;

[0049] Figure 4 is a schematic structural diagram of a liquid crystal elastomer optical fiber actuation unit device according to Embodiment 4;

[0050] Figure 5 is a curve diagram showing the relationship between the actuation strain of the liquid crystal elastomer optical fiber and the change in the stimulation light power in Example 4 of the present invention;

[0051] Figure 6 is a schematic structural diagram of a liquid crystal elastomer optical fiber actuated array device;

[0052] Figure 1 Middle: 1—stainless steel syringe, 2—heating jacket, 3—coaxial needle, 4—air pump and air inlet pipe, 5—ultraviolet lamp, 6—collection drum; H1—needle height, H2—height of ultraviolet lamps on both sides;

[0053] Figure 4 Middle: 401—liquid crystal elastomer optical fiber, 402—quartz optical fiber, 403—stimulation light source. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0055] Embodiment 1:

[0056] A liquid crystal elastomer optical fiber, the preparation method of which comprises the following steps:

[0057] (1) Preparation of liquid crystal elastomer optical fiber cladding precursor A: 4.7088 g of liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 1.04 mL of 3,6-dioxa-1,8-octanedithiol, 0.1174 g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 110 μL of catalyst triethylamine were dissolved in 30 mL of dichloromethane solvent. Preparation of liquid crystal elastomer optical fiber core precursor B: 2.3544 g of liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 2.6911 g of 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene, 1.04 mL of 3,6-dioxa-1,8-octanedithiol, 0.1242 g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 110 μL of catalyst triethylamine and 31 g of ultrasonically crushed carbon nanotubes were dissolved in 30 mL of dichloromethane solvent.

[0058] (2) After the cladding precursor A and the core precursor B were stirred and reacted at room temperature for 20 hours, part of the solvent was distilled off at 55° C. Then, they were placed in a vacuum oven at a temperature of 80° C. and a pressure of -90 psi for 15 hours to completely remove the solvent.

[0059] (3) The cladding precursor A and the core precursor B of the liquid crystal elastomer are placed in two stainless steel syringes connected by a 19G-14G (inner diameter 0.7mm, outer diameter 1.5mm) coaxial needle. After being kept at 80°C for 10 minutes, the two syringes are placed in a vacuum oven at a temperature of 80°C and a pressure of -75psi for 20 minutes to completely remove all bubbles. The syringes after the bubbles are removed are placed back in the heating sleeve and kept at 55°C for 30 minutes. The needle height is adjusted to 20cm and the height of the UV lamps on both sides is 12cm. The core cladding precursor is extruded synchronously by applying a pressure of 60psi to the two syringes through an air pump. During the extrusion process, the shear stress and gravity are used to induce the rearrangement of the liquid crystal primitives in the precursor to obtain the initial shape of the optical fiber with uniaxial orientation. Before reaching the collection drum, the 365nm UV lamps on both sides of the optical fiber are used for preliminary curing and crosslinking to lock its arrangement.

[0060] (4) After the extrusion is completed, the liquid crystal elastomer fiber initially cured in step (3) is further cured using a 365 nm ultraviolet lamp for 20 minutes to obtain a liquid crystal elastomer fiber.

[0061] In this embodiment, the refractive index of the core of the liquid crystal elastomer optical fiber is greater than the refractive index of the cladding, the core diameter and the cladding thickness are 300 μm and 200 μm respectively, and a liquid crystal elastomer optical fiber with a length of 10 m is prepared within 25 minutes.

[0062] Embodiment 2:

[0063] A liquid crystal elastomer optical fiber, the preparation method of which comprises the following steps:

[0064] (1) Preparation of liquid crystal elastomer optical fiber cladding precursor A: 2.1190 g of liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 292.5 μL of 3,6-dioxa-1,8-octanedithiol, 0.1223 g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 166 μL of catalyst di-n-butylamine were dissolved in 19.12 mL of toluene solvent. Preparation of liquid crystal elastomer optical fiber core precursor B: 0.7063 g of liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 1.6147 g of liquid crystal monomer 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene, 292.5 μL of 3,6-dioxa-1,8-octanedithiol, 0.1324 g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 179.4 μL of catalyst triethylamine and 20 μl of toluene solution (0.2 mol / L) of bismuth (III) compound were dissolved in 19.12 mL of toluene solvent.

[0065] (2) After the cladding precursor A and the core precursor B were stirred and reacted at room temperature for 15 hours, part of the solvent was distilled off at 110° C. and then placed in a vacuum oven at a temperature of 120° C. and a pressure of -95 psi for 24 hours to completely remove the solvent.

[0066] (3) The cladding precursor A and the core precursor B of the liquid crystal elastomer are placed in two stainless steel syringes connected by a 30G-22G (inner diameter 0.15mm, outer diameter 0.4mm) coaxial needle. After being kept at 80°C for 5 minutes, the two syringes are placed in a vacuum oven at a temperature of 80°C and a pressure of -60psi for 60 minutes to completely remove all bubbles. The syringes after the bubbles are removed are placed back in the heating sleeve and kept at 40°C for 15 minutes. The needle height is adjusted to 30cm and the height of the UV lamps on both sides is 25cm. A pressure of 200psi is applied to the two syringes through an air pump to extrude the core cladding precursor simultaneously. During the extrusion process, shear stress and gravity are used to induce the rearrangement of the liquid crystal primitives in the precursor to obtain the initial shape of the optical fiber with uniaxial orientation. Before reaching the collection drum, 395nm UV lamps are used on both sides of the optical fiber for preliminary curing and crosslinking to lock its arrangement.

[0067] (4) After the extrusion is completed, the liquid crystal elastomer fiber initially cured in step (3) is further cured for 10 minutes using a 395 nm ultraviolet lamp array to obtain a liquid crystal elastomer fiber.

[0068] In this embodiment, the refractive index of the core of the liquid crystal elastomer optical fiber is greater than the refractive index of the cladding, the core diameter and the cladding thickness are 120 μm and 100 μm respectively, and a total of 8 m long liquid crystal elastomer optical fiber is produced within 20 minutes.

[0069] Embodiment 3:

[0070] A liquid crystal elastomer optical fiber, the preparation method of which comprises the following steps:

[0071] (1) Preparation of liquid crystal elastomer optical fiber cladding precursor A: 7.0632 g of liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 3.9 mL of 3,6-dioxa-1,8-octanedithiol, 0.0114 g of photoinitiator benzil dimethyl ether, and 15.5 μL of catalyst di-n-butylamine were dissolved in 264 mL of acetone solvent. Preparation of liquid crystal elastomer optical fiber core precursor B: 5.2974g of liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene, 2.0183g of liquid crystal monomer 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene, 975μL of 3,6-dioxa-1,8-octanedithiol, 0.0117g of photoinitiator benzil dimethyl ether, 15.8μL of catalyst di-n-butylamine and 1.17mg of organic dye IR780 were dissolved in 264mL of acetone solvent.

[0072] (2) After the cladding precursor A and the core precursor B were stirred and reacted at room temperature for 20 hours, most of the solvent was distilled off at 65° C. Then, they were placed in a vacuum oven at a temperature of 85° C. and a pressure of -90 psi for 20 hours to remove all the solvent.

[0073] (3) The cladding precursor A and the core precursor B of the liquid crystal elastomer are placed in two stainless steel syringes connected by a 16G-13G (inner diameter 1.15mm, outer diameter 2mm) coaxial needle. After being kept at 100°C for 60 minutes, the two syringes are placed in a vacuum oven at a temperature of 100°C and a pressure of -100psi for 20 minutes to completely remove all bubbles. The syringes after the bubbles are removed are placed back in the heating sleeve and kept at 70°C for 25 minutes. The needle height is adjusted to 15cm and the height of the UV lamps on both sides is 20cm. The core cladding precursor is extruded synchronously by applying a pressure of 20psi to the two syringes through an air pump. During the extrusion process, shear stress and gravity are used to induce the rearrangement of the liquid crystal primitives in the precursor to obtain the initial shape of the optical fiber with uniaxial orientation. Before reaching the collection drum, the 365nm UV lamp on both sides of the optical fiber is used for preliminary curing and crosslinking to lock its arrangement.

[0074] (4) After the extrusion is completed, the liquid crystal elastomer fiber initially cured in step (3) is further cured for 30 minutes using a 365 nm ultraviolet lamp array to obtain a liquid crystal elastomer fiber.

[0075] In this embodiment, the refractive index of the core of the liquid crystal elastomer optical fiber is greater than the refractive index of the cladding, the core diameter and the cladding thickness are 500 μm and 300 μm respectively, and a 15 m long liquid crystal elastomer optical fiber is prepared within 10 minutes.

[0076] In dark field, a commercial camera (Canon EOS 6D Mark II) was used to capture images of 650nm light signals transmitted by liquid crystal elastomer optical fibers. The images were processed using a computer Matlab program to obtain a curve of the relationship between the optical loss and transmission length of the liquid crystal elastomer optical fiber, as shown in Figure 2. Figure 3 It can be seen that the transmission loss of the liquid crystal elastomer optical fiber prepared in Example 3 is about 1.83 dB / cm, showing good light transmission performance, which reflects the feasibility and practicality of the liquid crystal elastomer optical fiber of the present invention as a flexible actuator.

[0077] By comparing Example 1, Example 2, and Example 3, the present invention successfully prepared liquid crystal elastomer optical fibers of different sizes and lengths by changing the precursor ratio and adjusting parameters such as syringe temperature, extrusion pressure, needle height, and height of ultraviolet lamps on both sides during coaxial extrusion, thereby achieving adjustable optical fiber diameter.

[0078] Embodiment 4:

[0079] Liquid crystal elastomer fiber actuation unit, such as Figure 4 As shown, it includes a liquid crystal elastomer optical fiber 401, a quartz optical fiber 402, and a stimulation light source 403;

[0080] The liquid crystal elastomer optical fiber is the liquid crystal elastomer optical fiber prepared in Example 1; the quartz optical fiber is a multimode quartz optical fiber; and the stimulation light source is a fiber laser with an output wavelength of 808 nm.

[0081] The liquid crystal elastomer fiber was connected to the quartz fiber to ensure that the two maintained coaxial alignment inside a silicone tube with an inner diameter of 600 μm and a length of 6 mm. The coupling parts were bonded and fixed with UV-curable adhesive (AA3491, Loctite), completing the construction process of the actuator unit.

[0082] Turn on the 808nm wavelength stimulation light source, and the light signal is transmitted axially through the quartz fiber to the liquid crystal elastomer fiber. The excellent absorption ability of the carbon nanotubes in the fiber core to the near-infrared spectrum is used to quickly convert light energy into heat energy, causing the liquid crystal elastomer fiber to contract. By adjusting the input power of the excitation light and measuring the axial length of the liquid crystal elastomer fiber, a curve diagram of the relationship between the actuation strain of the liquid crystal elastomer fiber and the change in the stimulation light power is obtained, as shown in the figure below. Figure 5 As shown, with the continuous increase of optical power, the optical fiber achieves a maximum contraction of 32.5%, showing excellent photo-actuated performance, which reflects the feasibility and practicality of the liquid crystal elastomer optical fiber of the present invention as a flexible actuator.

[0083] The actuation unit in this embodiment is a single-channel actuation device, that is, a single liquid crystal elastomer optical fiber corresponds to a single-channel stimulation light source.

[0084] Embodiment 5:

[0085] Liquid crystal elastomer fiber actuated array device, such as Figure 6 As shown, it includes a liquid crystal elastomer optical fiber actuator unit, a quartz optical fiber, a bendable sheet, a light disk, and a stimulation light source;

[0086] The liquid crystal elastomer optical fiber is the liquid crystal elastomer optical fiber prepared in Example 3; the quartz optical fiber is a multimode quartz optical fiber; the bendable sheet is a 5mm×30mm polypropylene (PP) sheet; the lightweight disc is a 4cm diameter, 1mm thick, perforated polymethyl methacrylate (PMMA) disc; the stimulation light source is a semiconductor laser with an output wavelength of 808nm.

[0087] The liquid crystal elastomer fiber is connected to the quartz fiber to ensure that the two maintain coaxial alignment inside the silicone tube with an inner diameter of 900μm and a length of 8mm. The coupling part is bonded and fixed by UV curing glue (AA3491, Loctite) to complete the construction process of the actuator unit. Subsequently, the ends of the optical fiber are fixed on a polypropylene (PP) sheet (30×5mm) to construct a bending actuator unit. Subsequently, four identical bending actuator units are combined with a polymethyl methacrylate (PMMA) disc with holes to form an actuator array device as shown in the figure. Ensure that the quartz fiber and the silicone tube pass through the hole of the disc, and the adjacent actuator units below are placed in a vertical state.

[0088] The array device is composed of 4 identical bending actuation units, corresponding to multiple stimulation light sources, and each stimulation light source has a separate output. Turn on the stimulation light source with a wavelength of 808nm, and control the movement of each optical fiber in the array device by adjusting the input optical power, action duration, input timing and other parameters of each liquid crystal elastomer optical fiber, so that the array device can achieve different movements, such as grasping, walking, etc. The continuous preparation method of the liquid crystal elastomer optical fiber and its actuation device of the present invention reduce the process difficulty and cost of the liquid crystal elastomer optical fiber, pave the way for industrial-scale production, and provide strong technical support and innovative ideas for the development of soft robotics technology.

[0089] The above is only a preferred embodiment of the present invention, but the implementation of the present invention is not limited to the above embodiment. Any equivalent changes, modifications or evolutions made by those skilled in the art to the above embodiment using the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for continuously preparing a liquid crystal elastomer optical fiber, characterized in that: The following steps are involved: 1) Dispersing liquid crystal monomers, chain extenders, photoinitiators and catalysts in a solvent in proportion and reacting them fully to form a cladding precursor; changing the type and ratio of liquid crystal monomers based on the components of the cladding precursor, and adding photothermal conversion materials to form a core precursor; 2) The core and cladding precursors are respectively loaded into two stainless steel syringes connected by a coaxial needle, kept warm and de-bubbled, and then the syringe temperature, extrusion pressure and needle height are adjusted to a suitable extrusion condition; 3) Synchronously extrude the core and cladding precursors, rely on the shear force during the extrusion process and the gravity during the falling process to achieve uniaxial orientation of the liquid crystal primitives to form the initial shape of the optical fiber; use ultraviolet lamps on both sides of the optical fiber to preliminarily solidify it and collect it on a drum; 4) After the extrusion is completed, the optical fiber is further photocured using an ultraviolet lamp on the outside of the drum to obtain a permanently cross-linked liquid crystal elastomer optical fiber with a core-cladding structure.

2. The preparation method according to claim 1, characterized in that: Step 1) The liquid crystal monomer in the cladding precursor is 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene (RM257); the liquid crystal monomers in the core precursor are 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene (RM82) and 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene (RM257), and the molar ratio of the two liquid crystal monomers RM82 and RM257 is 1:0.5~3.

3. The preparation method according to claim 1, characterized in that: The photoinitiator is 2-hydroxy-4'- At least one of (2-hydroxyethoxy)-2-methylpropiophenone (photoinitiator 2959) and benzil dimethyl ether (photoinitiator 651); the catalyst is di-n-butylamine, triethylamine, 1,8-diazabicyclo [5.4.0] at least one of undec-7-ene; the photothermal conversion material in the core precursor is at least one of carbon nanomaterials, carbon black, MXene, organic dyes, bismuth (III) compounds, polydopamine, and metal nanoparticle materials.

4. The preparation method according to claim 1, characterized in that: The solvent is at least one of dichloromethane, acetone, toluene, dichloroethane, chloroform and tetrahydrofuran; and the chain extender is a dithiol compound.

5. The preparation method according to claim 1 or 2, characterized in that: Step 1) The molar ratio of liquid crystal monomer to chain extender in the cladding precursor and the core precursor is 0.5-2:1; the mass of the photoinitiator accounts for 0.1%-5% of the total mass of the liquid crystal monomer and the chain extender; the mass of the catalyst accounts for 0.1%-5% of the total mass of the liquid crystal monomer and the chain extender; the molar ratio of the solvent to the liquid crystal monomer is 50-300:1; in the core precursor, the mass of the photothermal conversion material accounts for 0.01%-5% of the total mass of the liquid crystal monomer and the chain extender.

6. The preparation method according to claim 1, characterized in that: Step 2) The inner diameter of the coaxial needle is 0.15mm~1.15mm, and the outer diameter is 0.4mm~2mm; the insulation temperature is 80℃~100℃, and the insulation time is 5min~60min; the bubble removal pressure is -60psi~-100psi, and the time is 1min~120min; the syringe temperature is 40℃~70℃; the extrusion pressure is 20psi~200psi.

7. The preparation method according to claim 1, characterized in that: Step 2) The needle height is 1 cm to 60 cm; the ultraviolet lamp is placed at a height of 0.5 cm to 59.5 cm; Step 3) The roller diameter is 2 cm to 20 cm, and the rotation speed is 0.5 r / min to 50 r / min; Step 4) The ultraviolet lamp light source is an LED ultraviolet lamp, an ultraviolet mercury lamp, a xenon ultraviolet lamp, an ultraviolet metal halide lamp or an ultraviolet deuterium lamp, etc., with an output wavelength of 200-400 nm and an irradiation energy density of 1000 mJ / cm 2 ~25000mJ / cm 2 ; The UV curing time is 1min to 60min.

8. The liquid crystal elastomer optical fiber prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The refractive index of the liquid crystal elastomer core is greater than the refractive index of the cladding.

9. The liquid crystal elastomer optical fiber according to claim 8, characterized in that The core diameter is 50 μm to 1000 μm, and the cladding thickness is 50 μm to 1000 μm.

10. An application device, characterized in that: A liquid crystal elastomer optical fiber prepared by the preparation method according to any one of claims 1 to 7.

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