Liquid crystal elastomer optical fiber with wide temperature range and adjustable phase change temperature

Abstract

The invention discloses a liquid crystal elastomer optical fiber with a wide temperature range and an adjustable phase change temperature. The liquid crystal elastomer optical fiber comprises a high-refractive-index liquid crystal elastomer fiber core and a low-refractive-index liquid crystal elastomer cladding which are both composed of liquid crystal elastomers with the phase change temperature capable of being regulated and controlled within the range of 30-80 DEG C; the wide-temperature-range phase-change-temperature-adjustable liquid crystal elastomer optical fiber contains a photothermal conversion material, and the photothermal conversion material can be independently distributed in a fiber core / cladding or simultaneously distributed in the fiber core and the cladding. The cross-linking density is controlled through a thiol-ene click reaction to realize wide-temperature-range phase change temperature regulation and control; the refractive indexes of the fiber core and the cladding are regulated and controlled by adjusting the ratio of the liquid crystal monomers containing different numbers of benzene rings, so that the preparation of the wide-temperature-range phase-change-temperature-adjustable liquid crystal elastomer optical fiber is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of flexible optical fiber actuators, and in particular relates to a liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range. Background Art

[0002] Liquid crystal elastomers are widely used in flexible robotics, biomedical engineering, and intelligent industrial manufacturing due to their biocompatibility, responsiveness to a variety of stimuli, and large reversible deformation properties. In the biomedical field, with the development of technology, the demand for high-performance liquid crystal elastomers has become increasingly urgent, among which phase change temperature control has become a key research point, which is related to the realization of functions such as disease diagnosis, treatment, and tissue repair.

[0003] In recent years, many teams have actively explored and achieved certain results in regulating the phase transition temperature of liquid crystal elastomers, but there are also many problems. At present, the azobenzene-containing liquid crystal elastomer prepared by the team of Northwestern Polytechnical University has made the phase transition temperature close to body temperature (36-37°C) through specific reaction polymerization, but its adjustment range is limited (invention patent 202410829773.4 already exists). The double dynamic covalent bond liquid crystal elastomer of Changzhou University is synthesized by a two-step method, and the phase transition temperature drops to 39-43.6°C. The comprehensive performance is good, but the preparation is complex and the conditions are harsh, which is not conducive to large-scale production (invention patent 202211321959.6 already exists). Although the cross-linker-free liquid crystal elastomer synthesis method of Jiangsu University reduces the storage modulus, the phase transition temperature of its liquid crystal elastomer is in the range of 60-62°C. Although it is driven by body temperature, it is far from the actual human body temperature, and the response is weak and unstable (invention patent 202411293844.X already exists).

[0004] The above teams have conducted a lot of research in the field of liquid crystal elastomer phase change temperature regulation, but their regulation range is narrow, and they are insufficient in wide temperature range regulation and environmental adaptability, and cannot simultaneously meet the needs of some high-temperature industrial detection or low-temperature medical operation scenarios with high environmental complexity. The problem of poor environmental adaptability of existing liquid crystal elastomers can be effectively solved through optical waveguide response. Although there are studies and patents specifically for improving the performance of liquid crystal elastomer optical fibers, it has not yet been possible to perfectly combine wide temperature range phase change temperature regulation with the advantages of optical waveguides (such as the existing invention patent 202310418855.5).

[0005] In summary, in the current technical field, there is still a research gap in the realization of light wave-induced actuation for liquid crystal elastomers with adjustable phase transition temperature. In the biomedical field, there is an urgent need for materials and equipment that can work safely and stably at low temperatures (30-50°C) to achieve delicate operations in bio-related applications such as endoscopy. At the same time, in some special industrial scenarios, it is also expected to have materials that can operate reliably and function at high temperatures (50-80°C). Summary of the invention

[0006] The purpose of the present invention is to develop a liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range. By combining the advantages of liquid crystal elastomer with adjustable phase transition temperature over a wide temperature range and optical fiber waveguide, the requirements for material versatility and environmental adaptability in biomedicine (such as endoscopic operations at low temperatures of 30-50°C) and special industrial scenarios (confined spaces at 50-80°C) can be met.

[0007] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0008] A liquid crystal elastomer optical fiber with adjustable phase change temperature over a wide temperature range comprises a core and a cladding, both of which are composed of a liquid crystal elastomer with adjustable phase change temperature; the phase change temperature adjustment range is 30 to 80°C; the liquid crystal elastomer optical fiber with adjustable phase change temperature over a wide temperature range comprises a photothermal conversion material, which can be distributed in the core / cladding alone, or in the core and cladding at the same time; the core refractive index is greater than the cladding refractive index, the core and cladding have the same length, the core diameter is 100 to 500 μm, and the cladding thickness is 50 to 300 μm; this structural design ensures that the optical fiber can effectively realize light transmission and light actuation, laying a foundation for its good performance in various application scenarios.

[0009] Preferably, the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range is prepared from a liquid crystal monomer, a thiol chain extender, an olefin cross-linking agent, a catalyst and a photoinitiator; the liquid crystal monomer and the thiol chain extender undergo Michael addition reaction to form a thiol-terminated oligomer, and the thiol-terminated oligomer and the olefin cross-linking agent undergo free radical reaction under light initiation by utilizing the thiol-olefin click reaction mechanism, and a network system with different cross-linking densities and molecular topological structures is formed by precisely controlling the ratio of the reactants, thereby achieving regulation of the phase transition temperature of the liquid crystal elastomer within the range of 30-80°C.

[0010] Preferably, the liquid crystal monomer includes an acrylate monomer; further preferably, the acrylate monomer is at least one of 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene, 4-(3-acryloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester, and 4-((6-acryloxy)hexyloxy)benzoic acid phenyl ester.

[0011] Preferably, the olefin crosslinking agent is triene or tetraallyl isocyanurate.

[0012] Preferably, the thiol chain extender is a dithiol compound or a trithiol compound.

[0013] Preferably, the photoinitiator is at least one of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone and benzil dimethyl ether.

[0014] Preferably, the catalyst is at least one of n-dipropylamine, triethylamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

[0015] Preferably, the photothermal conversion material includes at least one of carbon nanomaterials, gold / silver nanoparticles, bismuth (III) compounds, IR780 series iodides, aniline black, and polydopamine.

[0016] Preferably, the molar ratio of the acrylate monomer to the olefin crosslinker is 1-6:1; the molar ratio of the acrylate monomer to the thiol chain extender is 0.6-1.2:1; the molar ratio of the acrylate monomer to the photoinitiator is 1:0.01-0.015.

[0017] Preferably, the molar ratio of the acrylic ester monomer to the photothermal conversion is 20 to 28:1.

[0018] Preferably, the refractive index difference between the core and cladding of the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range is achieved by adjusting the molar ratio of acrylate monomers. The principle is based on the influence of acrylate monomers containing different numbers of benzene rings on the optical properties of the material. Compared with monomers containing fewer benzene rings, monomers containing more benzene rings have larger and more complex electron clouds. The difference in electron cloud structure will affect the molecular polarity and thus affect the interaction between molecules and the propagation characteristics of light in the material, and finally achieve the refractive index regulation of the core and cladding of the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range.

[0019] Preferably, the core of the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range is prepared based on a high refractive index liquid crystal monomer containing three benzene rings, 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene / 4-(3-acryloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester;

[0020] Preferably, the molar ratio of the 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene to 4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester is 0.5 to 3:1;

[0021] Further preferably, the low refractive index cladding material is prepared by mixing 4-((6-acryloxy)hexyloxy)phenyl benzoate containing two benzene rings with an appropriate amount of 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene / 4-(3-acryloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester containing three benzene rings;

[0022] More preferably, the molar ratio of 4-((6-acryloyloxy)hexyloxy)phenyl benzoate to 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene / 4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester is 0.1 to 0.3:1.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] (1) The liquid crystal elastomer optical fiber with adjustable phase transition temperature prepared by the present invention has a wide range of phase transition temperature regulation capability of 30-80°C, which enables it to perform well in the fields of biomedicine (such as 30-50°C minimally invasive surgical instruments and in vivo detection equipment) and industry (50-80°C electronic equipment heat dissipation monitoring and high-temperature pipeline detection), and can adapt to the environment and work stably.

[0025] (2) In terms of structure and performance, the waveguide structure is combined with photoresponsive materials to achieve efficient light transmission and reduce losses. The light-driven capability enables the liquid crystal elastomer fiber to respond quickly to light stimulation in high-precision drive-related applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a network structure diagram of a liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range at different crosslinking degrees in an embodiment of the present invention;

[0027] Figure 2 It is a schematic structural diagram of an actuation application device based on a liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to an embodiment of the present invention;

[0028] Figure 3 is a DSC curve diagram of the liquid crystal elastomer optical fiber in the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to Example 1 of the present invention;

[0029] Figure 4 is a curve diagram showing the relationship between the contraction strain and temperature of the liquid crystal elastomer optical fiber and the optical power in the liquid crystal elastomer optical fiber and the actuation application device based on the wide temperature range adjustable phase transition temperature of the embodiment 1 of the present invention;

[0030] Figure 5It is a curve diagram showing the relationship between the optical loss and transmission length of the liquid crystal elastomer optical fiber in the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range and the actuation application device according to Example 1 of the present invention.

[0031] In the figure: 1—image display, 2—light source, 3—quartz optical fiber, 4—wire, 5—integrated probe, 6—liquid crystal elastomer optical fiber cladding based on adjustable phase transition temperature, 7—liquid crystal elastomer optical fiber core based on adjustable phase transition temperature. DETAILED DESCRIPTION

[0032] 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.

[0033] Example 1: Preparation method of liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range

[0034] (1) A core liquid crystal elastomer oligomer A with a wide temperature range and adjustable phase transition temperature was prepared by dissolving 1.0012 g of a liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene and 1.1882 g of a liquid crystal monomer 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene, 0.8152 g of a chain extender 2,2'-(1,2-ethylenedioxy)bisethanethiol, 0.2250 g of a cross-linking agent triallyl isocyanurate, 0.0025 g of a photothermal conversion material multi-walled carbon nanotube, 0.0535 g of a photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 4.5 mg of a catalyst n-dipropylamine in 10 mL of a dichloromethane solvent. The mixed solution was placed at room temperature and vortex-stirred at 300 rpm for 20 h using a magnetic stirrer to obtain a core liquid crystal elastomer oligomer A with a wide temperature range and adjustable phase transition temperature.

[0035] (2) A cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature was prepared by dissolving 0.1874 g of 4-((6-acryloyloxy)hexyloxy)phenyl benzoate, 1.0301 g of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene, 1.1772 g of 1,4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester, 0.7976 g of chain extender 2,2'-(1,2-ethylenedioxy)bis(ethylenethiol), 0.2234 g of crosslinker triallyl isocyanurate, 0.0506 g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-propiophenone, and 5 mg of catalyst n-dipropylamine in 10 mL of dichloromethane solvent.

[0036] The mixed solution was placed at room temperature and vortex-stirred at 300 rpm for 20 h using a magnetic stirrer to obtain a cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature.

[0037] (3) The vortex-mixed liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B with adjustable phase transition temperature over a wide temperature range were transferred to a hot stirring table and evaporated at 45°C for 40 minutes until the dichloromethane solvent was completely volatilized. Liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B were injected into the core and cladding feed barrels, respectively, and the feed barrel temperature was adjusted to 36°C and kept at this temperature for 30 minutes. A cylindrical optical fiber was extruded by inputting air pressure into the feed barrel, and the optical fiber core diameter and cladding thickness were 400 μm and 200 μm, respectively.

[0038] (4) The liquid crystal elastomer optical fiber prepared by the extrusion method is placed under ultraviolet light for 15 minutes to solidify the oriented structure.

[0039] In this embodiment, in the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range, the refractive index of the liquid crystal elastomer core is greater than the refractive index of the liquid crystal elastomer cladding; the lengths of the liquid crystal elastomer core and the cladding are the same.

[0040] After testing, the prepared liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range exhibited good comprehensive performance. Figure 1 The low cross-linked network liquid crystal elastomer optical fiber shown in FIG. 1 is tested for its phase transition temperature by differential scanning calorimetry (DSC) to obtain a DSC curve, as shown in FIG. Figure 3 As shown, its phase transition temperature is 45.6℃, which can realize low temperature zone type applications; in terms of optical performance, the input light with a starting wavelength of 650nm is input into the liquid crystal elastomer optical fiber with adjustable phase transition temperature through a commercial quartz optical fiber, and the grayscale value is extracted by photographing to calculate the optical loss fitting curve of the liquid crystal elastomer optical fiber with adjustable phase transition temperature, as shown in Figure 5 As shown, the optical loss of the liquid crystal elastomer optical fiber not doped with multi-walled carbon nanotube photoresponsive material is 0.76 dB / cm, and the optical loss of the liquid crystal elastomer optical fiber doped with multi-walled carbon nanotube photoresponsive material is 1.1 dB / cm, which reflects the excellent performance of the present invention in light transmission, so that it can maintain relatively stable signal transmission during light transmission, and at the same time, it can also achieve an actuation effect by relying on the action of the photoresponsive material in light-driven application scenarios.

[0041] Example 2: Preparation method of liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range

[0042] (1) A core liquid crystal elastomer oligomer A with a wide temperature range and adjustable phase transition temperature was prepared. 1.0340 g of a liquid crystal monomer 1,4-bis-[4-(3-acryloxypropoxy)benzoyloxy]-2-methylbenzene and 1.1759 g of a liquid crystal monomer 1,4-bis-[4-(6-acryloxyhexyloxy)benzoyloxy]-2-methylbenzene, 0.8097 g of a chain extender 2,2'-(1,2-ethylenedioxy)bisethanethiol, 0.2181 g of a cross-linking agent triallyl isocyanurate, 0.0032 g of a photothermal conversion material gold nanoparticles, 0.0506 g of a photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 4.5 mg of a catalyst n-dipropylamine were dissolved in 10 mL of a dichloromethane solvent and vortexed at room temperature for 20 h to obtain a wide temperature range liquid crystal elastomer oligomer A.

[0043] (2) Preparation of a cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature: 0.3058 g of 4-((6-acryloyloxy)hexyloxy)phenyl benzoate, 1.0025 g of liquid crystal monomer 1,4-bis-[4-(3-acryloyloxypropoxy)benzoyloxy]-2-methylbenzene and 1.1923 g of liquid crystal monomer 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene, 0.7955 g of chain extender 2,2 '-(1,2-ethylenedioxy)bis(ethyl mercaptan), 0.2203g of cross-linking agent triallyl isocyanurate, 0.0517g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 4.5mg of catalyst n-dipropylamine were dissolved in 10mL of dichloromethane solvent. The mixed solution was placed at room temperature and vortexed with a magnetic stirrer at 300 rpm for 20h to obtain a cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature.

[0044] (3) The vortex-mixed liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B with adjustable phase transition temperature over a wide temperature range were transferred to a hot stirring table and evaporated at 45°C for 40 minutes until the dichloromethane solvent was completely volatilized. Liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B were injected into the core and cladding feed barrels, respectively, and the feed barrel temperature was adjusted to 38°C and kept at this temperature for 30 minutes. A cylindrical optical fiber was extruded by inputting air pressure into the feed barrel, and the optical fiber core diameter and cladding thickness were 500 μm and 300 μm, respectively.

[0045] (4) The liquid crystal elastomer optical fiber prepared by the extrusion method is placed under ultraviolet light for 10 minutes to solidify the orientation structure.

[0046] In this embodiment, the refractive index of the liquid crystal elastomer core in the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range is greater than the refractive index of the liquid crystal elastomer cladding; the lengths of the liquid crystal elastomer core and the cladding are the same. Figure 1 The cross-linked network liquid crystal elastomer optical fiber shown in FIG. 1 is tested for its phase transition temperature by differential scanning calorimetry (DSC) to obtain a DSC curve, as shown in FIG. Figure 3 As shown, its phase transition temperature is 55.6℃.

[0047] Example 3: Preparation method of liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range (minimum end value)

[0048] (1) Prepare a core liquid crystal elastomer oligomer A with a wide temperature range and adjustable phase transition temperature. Weigh 1.0100 g of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene,

[0049] 0.3742g triallyl isocyanurate, 0.4561g chain extender 2,2'-(1,2-ethylenedioxy)bis(ethylenethiol), 0.0034g photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 0.0009g photothermal conversion material multi-walled carbon nanotubes, and 4.6mg catalyst n-dipropylamine were dissolved in 10mL dichloromethane solvent. The mixed solution was placed at room temperature and vortexed with a magnetic stirrer at 300 rpm for 20h to obtain a core liquid crystal elastomer oligomer A with a wide temperature range and adjustable phase transition temperature.

[0050] (2) Prepare a cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature. Weigh 0.5200 g of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene,

[0051] 0.9099 g of 2-methyl-1,4-phenyl 4-(3-acryloxypropoxy)benzoate, 0.0226 g of phenyl 4-((6-acryloxy)hexyloxy)benzoate, 0.2583 g of chain extender 2,2'-(1,2-ethylenedioxy)bis(ethylenethiol), 0.2119 g of crosslinker triallyl isocyanurate, 0.0019 g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 3.5 mg of catalyst n-dipropylamine were dissolved in 10 mL of dichloromethane solvent.

[0052] The mixed solution was placed at room temperature and vortex-stirred at 300 rpm for 20 h using a magnetic stirrer to obtain a cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature.

[0053] (3) The vortex-mixed liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B with adjustable phase transition temperature over a wide temperature range were transferred to a hot stirring table and evaporated at 40°C for 30 minutes until the dichloromethane solvent was completely volatilized. Liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B were injected into the core and cladding feed barrels, respectively, and the feed barrel temperature was adjusted to 30°C and kept at this temperature for 30 minutes. A cylindrical optical fiber was extruded by inputting air pressure into the feed barrel, and the optical fiber core diameter and cladding thickness were 100 μm and 200 μm, respectively.

[0054] (4) The liquid crystal elastomer optical fiber prepared by the extrusion method is placed under ultraviolet light for 15 minutes to solidify the oriented structure.

[0055] In this embodiment, the refractive index of the liquid crystal elastomer core in the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range is greater than the refractive index of the liquid crystal elastomer cladding; the lengths of the liquid crystal elastomer core and the cladding are the same. Figure 1 The low cross-linked network liquid crystal elastomer optical fiber shown in FIG. 1 is tested for its phase transition temperature by differential scanning calorimetry (DSC) to obtain a DSC curve, as shown in FIG. Figure 3 As shown, its phase transition temperature is 37.6℃.

[0056] Example 4: Preparation method of liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range (maximum end value)

[0057] (1) Prepare a core liquid crystal elastomer oligomer A with a wide temperature range and adjustable phase transition temperature. Weigh 2.0743 g of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene,

[0058] 0.1281g triallyl isocyanurate, 0.4684g chain extender 2,2'-(1,2-ethylenedioxy)bis(ethanethiol), 0.0103g photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 0.0013g photothermal conversion material multi-walled carbon nanotubes, 5mg catalyst n-dipropylamine, dissolved in 10mL dichloromethane solvent. The mixed solution was placed at room temperature and vortexed at 300 rpm for 20h using a magnetic stirrer to obtain a core liquid crystal elastomer oligomer A with a wide temperature range and adjustable phase transition temperature.

[0059] (2) Prepare a cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature. Weigh 2.5917 g of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene,

[0060] 0.7558g of 4-(3-acryloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester, 0.3378g of 4-((6-acryloxy)hexyloxy)benzoic acid phenyl ester, 0.9558g of chain extender 2,2'-(1,2-ethylenedioxy)bis(ethyl mercaptan), 0.2614g of crosslinker triallyl isocyanurate, 0.0212g of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, and 7.5mg of catalyst n-dipropylamine were dissolved in 10mL of dichloromethane solvent. The mixed solution was placed at room temperature and vortexed at 300 rpm for 20h using a magnetic stirrer to obtain a cladding liquid crystal elastomer oligomer B with a wide temperature range and adjustable phase transition temperature.

[0061] (3) The vortex-mixed liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B with adjustable phase transition temperature over a wide temperature range were transferred to a hot stirring table and evaporated at 50°C for 30 minutes until the dichloromethane solvent was completely volatilized. Liquid crystal elastomer oligomer A and liquid crystal elastomer oligomer B were injected into the core and cladding feed barrels, respectively, and the feed barrel temperature was adjusted to 45°C and kept at this temperature for 30 minutes. A cylindrical optical fiber was extruded by inputting air pressure into the feed barrel, and the optical fiber core diameter and cladding thickness were 100 μm and 50 μm, respectively.

[0062] (4) The liquid crystal elastomer optical fiber prepared by the extrusion method is placed under ultraviolet light for 10 minutes to solidify the orientation structure.

[0063] In this embodiment, the refractive index of the liquid crystal elastomer core in the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range is greater than the refractive index of the liquid crystal elastomer cladding; the lengths of the liquid crystal elastomer core and the cladding are the same. Figure 1 The highly cross-linked network liquid crystal elastomer optical fiber shown in FIG. 1 is tested for its phase transition temperature by differential scanning calorimetry (DSC) to obtain a DSC curve, as shown in FIG. Figure 3 As shown, its phase transition temperature is 80.1℃.

[0064] Example 5: An actuation application device of a liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range

[0065] An actuation application device of a liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range, such as Figure 2 As shown, it includes an image display 1, a light source 2, a quartz optical fiber 3, an electric wire 4, an integrated probe 5, and a liquid crystal elastomer optical fiber with an adjustable phase transition temperature having a cladding 6 and a core 7 structure;

[0066] The image display 1 is an RGB liquid crystal display; the light source 2 is a semiconductor laser with an output wavelength of 808 nm; the quartz optical fiber 3 is a multimode quartz optical fiber; the integrated probe 5 is a biomedical endoscopy probe with model OV6946; the liquid crystal elastomer optical fiber with a cladding 6 and a core 7 structure and based on an adjustable phase change temperature is the flexible liquid crystal elastomer optical fiber prepared in Example 1.

[0067] When the device is started, the 808nm laser of the light source 2 is transmitted through the quartz optical fiber 3 to the liquid crystal elastomer optical fiber with a wide temperature range and adjustable phase change temperature having a cladding 6 and a core 7 structure in Example 1. The carbon nanophotothermal conversion material in the optical fiber has good absorption characteristics for 808nm near-infrared light, and generates heat accumulation after absorbing light energy. As the heat continues to accumulate, the temperature of the optical fiber gradually rises. When it approaches the phase change temperature of 38°C, the liquid crystal elastomer optical fiber undergoes a phase transition due to its own temperature response characteristics, thereby generating an actuation effect, driving the OV6946 biomedical endoscope probe 5 connected thereto to move.

[0068] Moreover, as the laser energy increases, more light energy is absorbed by the carbon nanophotothermal conversion material and converted into heat energy, which further increases the temperature of the optical fiber, thereby causing the actuation strain of the optical fiber to increase, achieving different degrees of actuation effects. By adjusting the input power of the 808nm laser, the axial shrinkage rate and temperature of the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range are measured, and a curve diagram showing the relationship between the shrinkage strain and surface temperature of the liquid crystal elastomer optical fiber with adjustable phase transition temperature and the change in stimulation light power is obtained, as shown in the figure. Figure 4 As shown, the maximum contraction strain is 32%, the maximum temperature is 48°C, and it has relatively excellent photoactuation performance. The temperature during actuation meets the requirements of the low temperature zone (30-50°C), which reflects the operability of the present invention in biomedical scenarios.

[0069] The present invention fills the gap in the prior art in the field of liquid crystal elastomer optical fibers with adjustable phase change temperature, and provides an innovative and highly adaptable material and technical solution for fields such as biomedicine (such as endoscopic operations in low-temperature ranges) and special industries (such as high-temperature environmental monitoring).

[0070] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. 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 liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range, characterized in that: The invention comprises a core and a cladding, wherein the core and the cladding are both composed of a liquid crystal elastomer with an adjustable phase transition temperature over a wide temperature range, the refractive index of the liquid crystal elastomer with an adjustable phase transition temperature over a wide temperature range is adjustable, and the core refractive index is greater than the cladding refractive index; the core diameter of the liquid crystal elastomer optical fiber with an adjustable phase transition temperature over a wide temperature range is 100-500 μm, and the cladding thickness is 50-300 μm; the liquid crystal elastomer optical fiber with an adjustable phase transition temperature over a wide temperature range comprises a photothermal conversion material, and the photothermal conversion material is distributed in the core or the cladding alone, or in both the core and the cladding.

2. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 1, characterized in that The phase transition temperature of the liquid crystal elastomer with adjustable phase transition temperature over a wide temperature range can be controlled within the range of 30-80°C.

3. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 1, characterized in that: In the core and cladding liquid crystal elastomers, the thiol-ene click reaction mechanism is utilized, and the thiol-terminated oligomers and ene crosslinkers undergo free radical reactions under light initiation. By regulating the ratio of the reactants, a network system with different crosslinking densities and molecular topological structures is formed, thereby achieving regulation of the phase transition temperature of the liquid crystal elastomer within the range of 30-80°C.

4. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 3, characterized in that: The types of reactants include acrylic ester monomers, olefin crosslinking agents, mercapto chain extenders, photoinitiators and catalysts.

5. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 4, characterized in that: The molar ratio of the acrylic acid ester monomer to the olefin crosslinking agent is 1 to 6:1; the molar ratio of the acrylic acid ester monomer to the thiol chain extender is 0.6 to 1.2:1; and the molar ratio of the acrylic acid ester monomer to the photoinitiator is 1:0.01 to 0.

015.

6. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 4, characterized in that: The acrylic ester monomer is at least one of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene (RM82), 4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester (RM257), and 4-((6-acryloyloxy)hexyloxy)benzoic acid phenyl ester (C6BAPE); the olefin crosslinking agent is triene or tetraallyl isocyanurate; the thiol chain extender is a dithiol compound or a trithiol compound; the photoinitiator is at least one of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and benzil dimethyl ether; the catalyst is at least one of n-dipropylamine, triethylamine, and 1,8-diazabicyclo[5.4.0]undec-7-ene.

7. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 1, characterized in that The refractive index difference between the core and the cladding of the liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range is achieved by adjusting the molar ratio of acrylic ester monomers.

8. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 1, characterized in that The photothermal conversion material includes at least one of carbon-based nanomaterials, metal nanoparticles, bismuth (III) compounds, IR780 series iodides, aniline black, and polydopamine.

9. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 1, characterized in that: The high refractive index core material contains 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene (RM82) / 4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester (RM257); The low refractive index cladding material adopts 4-((6-acryloyloxy)hexyloxy)phenyl benzoate containing two benzene rings and an appropriate amount of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene / 4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester monomer containing three benzene rings.

10. The liquid crystal elastomer optical fiber with adjustable phase transition temperature over a wide temperature range according to claim 9, characterized in that: The molar ratio of 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene to 4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester is 0.5 to 3:1; The molar ratio of the 4-((6-acryloyloxy)hexyloxy)phenyl benzoate to 1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylbenzene / 4-(3-acryloyloxypropoxy)benzoic acid-2-methyl-1,4-phenyl ester is 0.1-0.3:1.

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