Fiber actuator with multi-mode and high degree of freedom deformation and its preparation and application

Abstract

The present invention provides a fiber actuator with multi-mode, high-degree-of-freedom deformation, and a preparation method and application thereof. A fiber deformer with multi-mode, high-degree-of-freedom deformation is prepared by using a mold with a threaded structure in combination with a two-step cross-linking method. Under external stimulation, five different deformation modes can be achieved: contraction, bending, torsion, winding and shortening of the pitch. Combined with the use of light control, a composite deformation behavior of a combination of two or more deformation modes can be achieved in the same fiber actuator.

Description

Technical Field

[0001] The present invention relates to the technical field of functional materials, and in particular to a fiber actuator with multi-mode and high-degree-of-freedom deformation, and the preparation and application thereof. Background Art

[0002] Liquid crystal polymers are a new type of intelligent material. Due to their unique molecular arrangement, they have both the anisotropy of liquid crystals and the elasticity of polymer networks. When subjected to external stimuli (such as temperature, electricity, light, magnetism, solvents, pH, etc.), they will undergo phase transitions and thus show changes in their external morphology. This type of material has very broad application prospects in biomedicine, micromechanics, soft robotics, smart wearable devices, and artificial muscles.

[0003] However, the deformation mode produced by liquid crystal polymer materials when subjected to external stimuli is relatively simple, and the main deformation mode is contraction / expansion or bending, and it is impossible to produce multiple deformation modes or a combination of multiple deformations under external stimuli. Specifically, the current liquid crystal polymer materials have few deformation modes and limited deformation freedom, and cannot achieve a composite deformation mode combining two or more deformation modes.

[0004] For example, CN106279745A discloses an intelligent composite material based on crystal photoinduced phase change and a preparation method thereof, which coats a small molecule light-responsive crystal material capable of photoinduced phase change on a flexible substrate to produce specific deformations under illumination of a specific wavelength, such as bending, curling, spiraling, walking, etc., which achieves the effects of large deformation amount and fast response speed. However, its preparation process requires cutting in a specific direction and the cut strips can only produce a specific single deformation mode.

[0005] For example, CN107033279B provides a deformable stimulus-responsive material, which can be transformed from a planar two-dimensional structure to a three-dimensional structure under external stimulation. It is modified on the back of a planar flexible microelectrode array to achieve three-dimensional deformation of the flexible microelectrode array through external stimulation. However, it requires complex circuit design and a double-layer composite film, and can only produce a single deformation mode.

[0006] Due to the shortcomings of the existing technology, there is an urgent need in the art for an intelligent polymer material that can achieve multi-mode and high-degree-of-freedom deformation to broaden the application of liquid crystal polymer materials. Summary of the invention

[0007] The purpose of the present invention is to provide a fiber actuator with multi-mode, high-degree-of-freedom deformation and its preparation and application. The fiber actuator can produce five different deformation modes under external stimulation: contraction, bending, torsion, winding and pitch shortening. It has the characteristics of diverse deformation modes and high degree of deformation freedom, and can realize a composite deformation mode of combining two or more deformation modes.

[0008] To achieve the above objectives, the present technical solution provides a fiber actuator with multi-mode and high-degree-of-freedom deformation. The liquid crystal elastomer material that can be processed in two steps is prepared by forming a mold with a threaded structure and then stretching and orienting it, wherein the spring-shaped liquid crystal elastomer fiber after the threaded mold forming is an oligomer formed by preliminary chemical cross-linking, and then the spring-shaped liquid crystal elastomer fiber is stretched to generate asymmetric stress and strain distribution on its cross section and make the liquid crystal uniaxially oriented, and the stress gradient and liquid crystal orientation on the cross section are fixed by further chemical cross-linking reaction, so as to obtain a fiber actuator with multi-mode and high-degree-of-freedom deformation, which undergoes multi-mode and high-degree-of-freedom deformation under light stimulation, wherein the multi-mode and high-degree-of-freedom deformation includes at least one of contraction, bending, torsion, winding and shortening of the pitch.

[0009] The present technical solution provides a method for adjusting a fiber actuator to undergo a single deformation, wherein the same light source is used to illuminate the same position of the fiber actuator, and the stimulation intensity of the light source irradiated on the fiber actuator and the size of the radiation area of ​​the light source are adjusted to adjust the fiber actuator to undergo a single deformation, wherein the deformation of the fiber actuator includes at least one of contraction, bending, torsion, winding, and shortening of the pitch.

[0010] The present technical solution provides a method for adjusting the combined deformation of a fiber actuator, which utilizes multiple light sources to illuminate different positions of the fiber actuator, and adjusts the stimulation intensity or the size of the light source radiation area irradiated on the fiber actuator to adjust the combined deformation of the fiber actuator, wherein the combined deformation of the fiber actuator includes a combination of at least two of: contraction, bending, torsion, winding and shortening of the pitch.

[0011] The present technical solution provides a method for winding and grasping a light-driven fiber actuator, wherein the fiber actuator is moved close to an object to be grasped, and light is irradiated on one end of the fiber actuator close to the object to be grasped to drive the fiber actuator at that end to wind around and grasp the object to be grasped.

[0012] A method for bending and grasping an object by a light-driven fiber actuator, wherein the fiber actuator is irradiated with light to cause winding deformation to form one or more annular structures, and the annular structures are driven to be wound around the object to be grasped and grasp the object to be grasped.

[0013] An application of a fiber actuator with multi-mode, high-degree-of-freedom deformation, characterized in that it is applied to artificial muscles or mechanical arms to achieve the grasping, moving, rotating, lifting and releasing of objects.

[0014] Compared with the prior art, this technical solution has the following characteristics and beneficial effects:

[0015] A fiber actuator with multi-mode and high-degree-of-freedom deformation is prepared by using a mold with a threaded structure combined with a two-step cross-linking method. Under external stimulation, five different deformation modes can be achieved: contraction, bending, twisting, winding and shortening of the pitch. Combined with the use of light source optical control, including remote, instantaneous and local control, by adjusting the number of light sources, stimulation intensity and stimulation position, a composite deformation behavior of two or more deformation modes can be achieved in the same fiber actuator, and multiple deformation modes can be switched by controlling the intensity of the light source and the size of the radiation area.

[0016] When the fiber actuator with multi-mode and high-degree-of-freedom deformation is used independently, it can be used as part of an artificial muscle. It can also realize the grasping function of the muscle by independently controlling the winding of the front end and the lower end, and realize the rising / moving function by independently controlling the rear end and the upper end. It can also be used as a mechanical claw by splicing and the bending and winding of the fiber. The contraction, bending, twisting, winding and shortening of the pitch of the fiber actuator can realize the multi-mode and high-degree-of-freedom movement of the arm. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the preparation flow chart of the fiber actuator with multi-mode and high degree of freedom deformation of this scheme.

[0018] Figure 2 This is a schematic diagram of the optically controlled fiber actuator with multi-mode and high-degree-of-freedom deformation to achieve five deformation modes.

[0019] Figures 3 to 5 It is a schematic diagram of the combination of various deformation modes of the optically controlled fiber actuator with multi-mode and high degree of freedom deformation.

[0020] Figure 6 This is a schematic diagram of the optically controlled fiber actuator with multi-mode and high degree of freedom deformation for wrapping around, grasping and moving a rod-shaped object.

[0021] Figure 7 It is a schematic diagram of a light-controlled robotic arm that can grasp, lift and release objects.

[0022] Figure 8 This is a schematic diagram of the optically controlled fiber actuator with multi-mode and high degree of freedom deformation to achieve the functions of winding, grasping, lifting and releasing.

[0023] Fig. 9 This is a schematic diagram of the optically controlled fiber actuator with multi-mode, high-degree-of-freedom deformation that imitates the ability of vines in nature to grasp and approach. DETAILED DESCRIPTION

[0024] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0025] Those skilled in the art should understand that, in the disclosure of the present invention, the orientation or position relationship indicated by the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the orientation or position relationship shown in the drawings, which 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, be constructed and operate in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0026] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the element may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0027] This solution provides a fiber actuator with multi-mode and high degree of freedom deformation and its preparation method, and provides practical applications of the fiber actuator. This solution uses liquid crystal polymer materials doped or bonded with photothermal conversion materials to prepare the fiber actuator with multi-mode and high degree of freedom deformation. The fiber actuator can be transformed from a linear structure to a spiral structure under external stimulation. By adjusting the intensity of the external light source and the size of the light spot radiation area, the fiber actuator can produce five deformation modes of contraction, bending, twisting, winding and shortening of the pitch. In combination with the means of light stimulation, optical control means (remote, instantaneous, local control, by adjusting the light intensity, light spot shape, light irradiation position, light spot number, incident light angle) can be used to achieve a composite deformation behavior of two or more deformation modes in the same fiber actuator.

[0028] The technology of the present invention can be used to prepare multi-mode, high-degree-of-freedom deformation fiber actuators with light, temperature and electrical responses. This is a new method for preparing multi-mode, high-degree-of-freedom fiber actuators. It has considerable potential application value in the fields of micromechanical systems, artificial muscles, soft robots, etc.

[0029] Correspondingly, the light intensity, light position or spot size of the light source is adjusted to achieve control of the fiber actuator.

[0030] In a first aspect, the present invention provides a method for preparing the fiber actuator with multi-mode and high degree of freedom deformation, comprising the following steps:

[0031] 1) Prepare the helical fiber precursor as follows:

[0032] A monomer containing a liquid crystal unit and a material containing a light-to-heat conversion are bonded or doped to form a preliminary polymerization in a mold having a threaded structure by means of an enol click reaction, a Michael addition reaction, and free radical polymerization, and then peeled off to obtain an incompletely cross-linked spiral fiber precursor;

[0033] 2) Prepare the fiber actuator as follows:

[0034] The incompletely cross-linked helical fiber precursor is stretched and untwisted to obtain a straight fiber, which is then stretched to a set ratio and fixed so that the thiol groups and olefin groups are completely cross-linked and cured to obtain a multi-mode, high-degree-of-freedom fiber actuator with uniaxial orientation.

[0035] That is to say, the fiber actuator with multi-mode and high degree of freedom deformation prepared by the present scheme is completed by a two-step method. First, a liquid crystal elastomer oligomer is molded into a spirally wound helical fiber precursor using a mold with a threaded structure. The helical fiber precursor has a weakly cross-linked network formed by a chemical cross-linking reaction. After initial curing, the molded incompletely cross-linked helical fiber precursor is taken out from the screw mold; it is then used as a precursor for straightening, untwisting and further tensile strain. After fixing the tensile strain, the stress gradient on the cross section of the straightened helical fiber precursor is induced and fixed by a chemical cross-linking reaction, thereby obtaining a fiber actuator with multi-mode and high degree of freedom deformation.

[0036] In 1) preparing a helical fiber precursor,

[0037] The monomer containing liquid crystal unit and the material containing light-to-heat conversion are initially polymerized in a mold with a threaded structure by bonding or doping through enol click reaction, Michael addition reaction and free radical polymerization. The corresponding preparation process is as follows: Figure 1 shown.

[0038] In one embodiment of the present scheme, a weakly cross-linked liquid crystal polymer elastomer is obtained by enol click reaction polymerization, wherein the liquid crystal monomer containing acrylate double bonds is RM82, the monomer containing thiol groups is DODT or PETMP, and the light absorber is graphene. At this time, the corresponding fiber actuator can respond to near-infrared light. The molar ratio of RM82:DODT is 1.67:1, the molar ratio of DODT:PETMP is 3:1, and the mass ratio of graphene is 2%.

[0039] That is to say, the type of photothermal conversion material doped or bonded to the fiber actuator provided by the present solution is related to the type of light source that can photo-stimulate and regulate the fiber actuator.

[0040] In addition, the organic solvent used in this scheme is chloroform.

[0041] In "after ultrasonic dispersion of the mixed solution, adding the catalyst and oscillating and dissolving to obtain the precursor solution", the ultrasonic dispersion time can be 3-5 hours, and 4 hours is selected in this scheme. In addition, the embodiment of this scheme uses 2wt% DPA as a catalyst, and the catalyst can also be selected from (DPA di-n-propylamine, HexAM hexylamine, TEA triethylamine, N, N, N0, N0-tetramethyl-1,8-naphthalenediamine (PS) and 1,8-diazobicyclo[5.4.0]undec-7-ene; 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and 1 5-diazabicyclo[4.3.0]non-5-ene (DBN), etc. There are many choices of catalysts. The DPA selected in this scheme is to make the reaction more efficient, and other catalysts are also applicable.

[0042] In "filling the precursor solution into the threaded mold and reacting at room temperature for a period of time", the precursor solution is uniformly filled into the threaded mold, and the shape of the threaded mold is not restricted too much, as long as it has a threaded structure. In the embodiment of this scheme, the period of time for room temperature reaction can be 1-3 hours, and 2 hours is selected.

[0043] In 2) preparing the fiber actuator,

[0044] In "continue to stretch the straight fiber to a set ratio and then fix it", the straight fiber is continued to be stretched by 10%-100% and fixed for 18-30 hours. In an embodiment of this scheme, the straight fiber is stretched by 50%; in addition, in an embodiment of this scheme, the straight fiber is stretched and then fixed for 24 hours.

[0045] Correspondingly, Preparation Example 1:

[0046] The monomers were mixed and dissolved in chloroform according to the molar ratio of RM82:DODT of 1.67:1, DODT:PETMP of 3:1, the mass ratio of graphene of 2%, and the monomer ratio of carbon-carbon double bond and thiol group of 1:1. After ultrasonic dispersion for 4 hours, 2wt% DPA was added to the mixed solution as a catalyst. After oscillation and dissolution, the precursor solution was filled into a threaded mold. After reacting at room temperature for 2 hours, it was carefully peeled off from the mold to obtain an incompletely cross-linked spiral fiber precursor; the prepared incompletely cross-linked spiral fiber was stretched and untwisted to obtain a straight fiber, and the straight fiber was further stretched by 50% and fixed for 24 hours to completely cross-link and solidify the thiol and olefin to obtain a multi-mode, high-degree-of-freedom fiber actuator with uniaxial orientation.

[0047] In a second aspect, the present invention provides a fiber actuator with multi-mode and high-degree-of-freedom deformation, which is prepared according to the above preparation method.

[0048] The fiber actuator with multi-mode and high degree of freedom deformation is obtained by spiral molding of liquid crystal elastomer oligomer and then stretching it again, wherein the liquid crystal elastomer oligomer has a weak cross-linked network formed by chemical cross-linking reaction. The liquid crystal elastomer oligomer is a liquid crystal monomer containing acrylate double bonds, and a mixture of a cross-linking agent containing a thiol group and a light absorber monomer is dissolved in an organic solvent to undergo a weak chemical cross-linking reaction under the action of a catalyst, and the carbon-carbon double bond and the thiol group are 0.9-1.2:1; the liquid crystal elastomer oligomer that is not completely cross-linked during the secondary stretching is stretched and untwisted to obtain a straight fiber, and the straight fiber is further stretched to a set ratio and fixed, so that the thiol group and the olefin group are completely cross-linked and solidified to obtain a multi-mode and high degree of freedom fiber actuator with uniaxial orientation.

[0049] The cross-sectional area of ​​the fiber actuator with multi-mode and high degree of freedom deformation is 0.001 to 10 mm 2 , under light stimulation, multi-mode, high-degree-of-freedom deformation occurs, wherein the multi-mode, high-degree-of-freedom deformation includes at least one of contraction, bending, twisting, winding and pitch shortening.

[0050] In this embodiment, by doping graphene as the photothermal conversion material, near-infrared light can be converted into heat to achieve the effect of deformation caused by light stimulation. Similarly, other bands of photothermal conversion materials can be introduced to achieve deformation under other wavelengths of light, or heat source stimulation or electrothermal effect can be directly used to achieve deformation.

[0051] When the stimulus source is light, the deformation mode of the fiber actuator with multi-mode and high degree of freedom deformation can be controlled by adjusting the light intensity and the size of the light spot radiation area. At this time, the light source is any one of ultraviolet light, visible light, red light and near-infrared light; the light source can be moved arbitrarily; the light spot size and intensity of the light source can be adjusted; the light intensity of the light source is 0.01–100 W cm -2 .

[0052] The near-infrared light absorbing graphene used in this embodiment as the photothermal conversion material has a better photothermal conversion effect, so the required light intensity is relatively small. However, for other light absorbers or reducing the doping amount of graphene, the required light intensity will be different. Among the various deformation modes described in this embodiment, for an infinitely long fiber, only bending deformation needs to be produced under the irradiation of a small light spot, while for contraction, torsion, winding and shortening of the pitch, there is no limit on the size of the light spot, and the larger the irradiation range, the larger the length of the corresponding deformation area on the fiber.

[0053] The light intensity required for the fiber actuator to contract in this example can be 0.1-3 W cm -2 The light intensity and spot size required to produce bending are 1-10W cm -2 , 0.001-1cm 2 The light intensity required to produce the twist is 1-3W cm -2 The light intensity required to produce entanglement is 3-5W cm -2 The light intensity required to produce a shorter pitch is 5-100W cm -2 .

[0054] In addition, by combining optical manipulation, a composite deformation behavior of a combination of two or more deformation modes can be realized in the fiber actuator.

[0055] It is worth mentioning that the present solution can provide two or more light sources on the same fiber actuator to drive the fiber actuator to undergo different deformation mode combinations, and can also change its deformation mode by changing the intensity of the light source and the radiation area of ​​the light source.

[0056] Specifically, by controlling light, the fiber actuator with multi-mode, high-degree-of-freedom deformation can drive the fiber actuator to produce contraction deformation; can drive the fiber actuator to produce bending deformation; can drive the fiber actuator to produce torsional deformation; can drive the fiber actuator to produce winding deformation; can drive the fiber actuator to produce pitch shortening deformation; can drive the fiber actuator to produce bending and winding deformation; can drive the fiber actuator to produce bending and pitch shortening deformation; can drive the fiber actuator to produce bending, winding and pitch shortening deformation.

[0057] In addition, the fiber actuator with multi-mode and high-degree-of-freedom deformation has the shapes of triangle, circle, rectangle and polygon.

[0058] On the third aspect, the present solution provides an application of the fiber actuator with multi-mode, high-degree-of-freedom deformation. Specifically, the present solution provides a method for adjusting a single deformation of the fiber actuator: using the same light source to irradiate the same position of the fiber actuator, and adjusting the stimulation intensity of the light source irradiated on the fiber actuator or the size of the light spot radiation area to adjust the fiber actuator to undergo a single deformation, wherein the deformation of the fiber actuator includes at least one of contraction, bending, torsion, winding and shortening of the pitch.

[0059] In a fourth aspect, the present solution provides an application of a fiber actuator with multi-mode, high-degree-of-freedom deformation. Specifically, the present solution provides a method for adjusting the combined deformation of the fiber actuator: utilizing different lights to irradiate different positions of the fiber actuator, and utilizing adjusting the stimulation intensity of the light source irradiated on the fiber actuator or the size of the light spot radiation area to adjust the combined deformation of the fiber actuator, wherein the combined deformation of the fiber actuator includes a combination of at least two of: contraction, bending, torsion, winding, and shortening of the pitch.

[0060] Fifthly, the fiber actuator with multi-mode and high degree of freedom deformation provided by this solution can be applied to artificial muscles or robotic arms to achieve winding grasping, moving rod-shaped objects, grasping, rotating, lifting and releasing objects.

[0061] The present invention provides a method for winding and grasping a light-driven fiber actuator, comprising: moving the fiber actuator close to an object to be grasped, irradiating light on one end of the fiber actuator close to the object to be grasped, so as to drive the fiber actuator at this end to wind and grasp the object to be grasped.

[0062] Furthermore, the object can be lifted after grasping, which includes the following steps: irradiating light on the end of the fiber actuator away from the object to be grasped to drive the fiber actuator at the other end to change from a linear structure to a spiral structure, thereby lifting the object to be grasped.

[0063] The object can be moved after grasping, including the following steps: moving the fiber actuator wound with the object to be grasped.

[0064] The object can be released after grasping, including the following steps: the light source is turned off, and the fiber actuator returns to a linear structure to release the object to be grasped.

[0065] In order to demonstrate the crawling process more specifically, this solution provides the following specific examples:

[0066] A method for a light-driven fiber actuator to wrap around and grasp an object, wherein the object to be grasped is suspended at the lower end of the fiber actuator, light is irradiated to the lower end of the fiber actuator to drive the lower fiber actuator to wrap around and grasp the object to be grasped, and then the light source is irradiated to the upper end of the fiber actuator to drive the upper fiber actuator to transform from a linear structure to a spiral structure, thereby realizing the lifting of the object to be grasped.

[0067] In addition, the fiber actuator of the present solution can not only be used to wrap around and grasp objects, but also be used to bend and grasp objects. Correspondingly, the present solution provides a light-driven fiber actuator that bends and grasps objects, including the following steps: irradiating light to the fiber actuator to cause wrapping deformation to form one or more ring structures, using the ring structure to wrap around an object to grasp the object, and then turning off the light source to release the object.

[0068] To illustrate the crawling process more specifically, this solution provides the following specific examples:

[0069] A method for wrapping a light-driven fiber actuator around and grasping an object. Light is irradiated on the short end of the fiber actuator to drive the short end of the fiber actuator to bend into an arc closed loop to grasp the object to be grasped. Light is irradiated on the long end of the fiber actuator to drive the upper fiber actuator to transform from a linear structure to a spiral structure to achieve the lifting of the object to be grasped.

[0070] Specifically, the following is a specific light control experiment using the fiber actuator with multi-mode and high degree of freedom deformation obtained in Example 1 as an example, and an example is given with the stimulus source being the light source:

[0071] Example 1: Optically controlled fiber actuators achieve multiple deformation modes

[0072] By stimulating the fiber actuator with near-infrared light, the shape of the fiber can be controlled by adjusting the spot size and light intensity of the light source. Figure 2 As shown in the figure, from left to right, the fiber actuator produces deformations of contraction, bending, twisting, winding, and pitch shortening. The light intensity and spot size that produce contraction deformation are 0.5 W cm -2 , 1.8cm 2 The light intensity and spot size that produce bending deformation are 1.5 W cm -2 , 0.05cm 2 ; The light intensity and spot size that produce torsional deformation are 1.5Wcm -2 , 2.0cm 2 The light intensity and spot size that produce winding deformation are 3W cm -2 , 2.0cm 2 The light intensity and spot size that produce the pitch shortening deformation are 5W cm -2 , 2.0cm 2 .

[0073] Example 2: Light-controlled fiber actuator realizes a combination of multiple deformation modes

[0074] The experiment of Example 1 is repeated, except that multiple light stimulations are used simultaneously to stimulate different regions of the fiber actuator, so that two or more deformation modes can be generated on the same fiber.

[0075] The results are as follows Figures 3 to 5 As shown, Figure 3As shown in the figure, when two lights are used to illuminate different parts of the fiber actuator, the upper light source spot is a circular light spot with a diameter of 1.4 cm and a light intensity of 1.4 W cm-2, and the lower light source is a strip light spot with a size of 2.5 mm × 3.5 mm and a light intensity of 5.0 W cm-2. Finally, winding deformation and bending deformation appear on the same fiber actuator.

[0076] like Figure 4 As shown in the figure, when two lights are irradiated on different parts of the fiber actuator, the light spot of the upper light source is a circular spot with a diameter of 1.4 cm and a light intensity of 2.2 W cm -2 The lower light source has a strip light spot with a size of 2.5×3.5 mm and a light intensity of 5.0 W cm -2 Finally, the same fiber experiences both pitch shortening and bending deformation.

[0077] like Figure 5 As shown in the figure, when three light sources are combined to illuminate different parts of the fiber, the light spot of the upper light source is a strip light spot with a diameter of 1.3×0.4cm and a light intensity of 1.1W cm -2 The light source in the middle is a circular light spot with a diameter of 1.4 cm and a light intensity of 2.2 W cm -2 The lower light source has a strip light spot with a size of 2.5×3.5 mm and a light intensity of 5.0 W cm -2 , and eventually winding deformation, pitch shortening deformation and bending deformation appear on the same fiber actuator.

[0078] Example 3: Light-controlled fiber actuator to achieve winding, grasping and moving of rod-shaped objects

[0079] A 2-cm-long fiber is fixed to a glass rod. A rod-shaped object is placed on a horizontal step. The fiber actuator is brought close to the rod-shaped object, and near-infrared light is used to irradiate different positions of the fiber actuator, causing the actuator to bend and twist.

[0080] Results: Figure 6 As shown, a circular spot with a diameter of 1.5 cm and a light intensity of 3.5 W cm -2 When near-infrared light is irradiated on the fiber actuator, the fiber actuator undergoes winding deformation and wraps around the rod-shaped object. The fiber actuator is moved to another higher step and the light source is turned off. The fiber actuator returns to its initial state from a spiral shape and releases the rod-shaped object to another higher step. The process is reversible.

[0081] Example 4: Preparation of a fully optically controlled soft robotic arm to achieve object grabbing, lifting and releasing:

[0082] The end of a 2-cm long fiber is glued to the middle of a 0.8-cm short fiber to assemble a robotic arm. When the short fiber is irradiated with near-infrared light, the fiber bends into an arc shape. When the long fiber is irradiated with near-infrared light, the long fiber undergoes a spiral transformation.

[0083] Results: Figure 7 As shown, near-infrared light is first used to illuminate the short fiber at the bottom, and the fiber forms a closed loop, which grabs a ring-shaped object at the lower end. Then, near-infrared light is used to illuminate the long fiber at the upper end, so that the object can be grabbed and lifted to a certain height. The near-infrared light is turned off, and the soft robotic arm releases the ring-shaped object.

[0084] Example 5: Functions of winding, grabbing, lifting and releasing of optical fiber actuator:

[0085] A fiber actuator about 3.5 cm long is hung vertically, and a rod-shaped object about 1 cm long is placed at the lower end. When light is irradiated on the lower end of the fiber actuator, the fiber can wrap around and grasp the object, and when near-infrared light is irradiated on the upper end, it can be lifted.

[0086] Results: Figure 8 As shown, when near-infrared light is irradiated on the lower end of the fiber, the lower fiber wraps around and grabs the rod-shaped object, and then near-infrared light is irradiated on the upper fiber, the fiber changes from a linear structure to a spiral structure, thereby lifting the object, and the object is released after the near-infrared light is turned off.

[0087] Example 6: Light-controlled fiber actuators mimic the ability of vines in nature to grab and approach

[0088] A fiber about 8 cm in length is glued to a plant vine and the other end is hung horizontally on a bamboo pole. When light is irradiated on a section close to the bamboo pole, the fiber bends, entangles and deforms, and is finally wrapped and fixed on the bamboo pole. When a large spot light source is used to irradiate the horizontal section of the fiber, the fiber shrinks, spirals, and shortens its pitch, pulling the plant vine closer to the bamboo pole.

[0089] Results: Fig. 9 As shown, under light stimulation, the fibers are wrapped around and fixed on the bamboo pole, and pull the plant vine towards the bamboo pole.

[0090] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A fiber actuator with multi-mode and high degree of freedom deformation, characterized in that: The invention is prepared by using a liquid crystal elastomer material that can be processed in two steps, which is formed by a mold with a thread structure and then stretched and oriented. The spring-shaped liquid crystal elastomer fiber after the thread mold is a oligomer formed by preliminary chemical cross-linking. Then, the spring-shaped liquid crystal elastomer fiber is stretched to generate asymmetric stress and strain distribution on its cross section and make the liquid crystal uniaxially oriented. The stress gradient and liquid crystal orientation on the cross section are fixed by further chemical cross-linking reaction. Multi-mode and high-degree-of-freedom deformation occurs under light stimulation. The fiber actuator has five basic deformation modes: contraction, bending, torsion, winding and shortening of pitch. Bending, twisting and winding are high-degree-of-freedom deformation modes; The fiber actuator with multi-mode and high-degree-of-freedom deformation is obtained by spirally molding a liquid crystal elastomer oligomer and then stretching it again, wherein the liquid crystal elastomer oligomer has a weakly cross-linked network formed by a chemical cross-linking reaction, wherein the liquid crystal elastomer oligomer is a liquid crystal monomer containing an acrylate double bond, a cross-linker containing a thiol group, and a mixture of a light absorber monomer are dissolved in an organic solvent and undergo a weak chemical cross-linking reaction under the action of a catalyst, and the carbon-carbon double bond and the thiol group are 0.9-1.2:

1.

2. The fiber actuator with multi-mode and high degree of freedom deformation according to claim 1, characterized in that: The liquid crystal elastomer oligomer is prepared by enol click reaction, Michael addition reaction or free radical polymerization, the initially cross-linked liquid crystal elastomer oligomer is stretched and oriented, and then the shape and orientation are fixed by further cross-linking reaction.

3. The fiber actuator with multi-mode and high degree of freedom deformation according to claim 1, characterized in that: When the same light source is used to illuminate the same position of the fiber actuator, the fiber actuator will deform. The deformation mode of the fiber actuator can be actively adjusted by adjusting the intensity of the light source and the size of the light spot radiation area.

4. The fiber actuator with multi-mode and high degree of freedom deformation according to claim 1, characterized in that: A combination of multiple light sources is used to stimulate different positions of the same fiber actuator, and the same fiber actuator is cooperatively adjusted to undergo two or more modes of deformation. The intensity of the light source and the size of the light spot radiation area are adjusted to change the type of deformation mode of the fiber actuator.

5. A method for adjusting a fiber actuator to produce a single deformation, characterized in that: The same position of the fiber actuator is stimulated by the same light source, and the fiber actuator is adjusted to undergo a single deformation by adjusting the intensity of the light source irradiated on the fiber actuator or the size of the light spot radiation area, wherein the deformation of the fiber actuator includes at least one of contraction, bending, twisting, winding and shortening of the pitch, wherein a fiber actuator with multi-mode, high degree of freedom deformation as described in any one of claims 1 to 4 is used as the fiber actuator.

6. A method for adjusting the combined deformation of a fiber actuator, characterized in that: A plurality of light sources are used to illuminate different positions of a fiber actuator, and the fiber actuator is adjusted to undergo a combined deformation by adjusting the intensity or position of the stimulation irradiated on the fiber actuator, wherein the combined deformation of the fiber actuator includes a combination of at least two of contraction, bending, twisting, winding and shortening of the pitch, and the deformation mode produced at different positions can be changed by adjusting the intensity of light and the size of the light spot radiation area, wherein a fiber actuator with multi-mode, high degree of freedom deformation as described in any one of claims 1 to 4 is used as the fiber actuator.

7. A method for wrapping and grasping an object with a light-driven fiber actuator, characterized in that: The fiber actuator is moved close to the object to be grasped, and light is irradiated on one end of the fiber actuator close to the object to be grasped to drive the fiber actuator at this end to wrap around and grasp the object to be grasped, wherein a fiber actuator with multi-mode and high degree of freedom deformation as described in any one of claims 1 to 4 is used as the fiber actuator.

8. A method for bending and grasping an object by a light-driven fiber actuator, characterized in that: When light is irradiated on the fiber actuator, it undergoes winding deformation to form one or more annular structures, which drive the annular structures to wind around the object to be grasped and grasp the object to be grasped, wherein a fiber actuator with multi-mode, high degree of freedom deformation as described in any one of claims 1 to 4 is used as the fiber actuator.

9. An application of a fiber actuator with multi-mode and high degree of freedom deformation according to any one of claims 1 to 4, characterized in that: Applied in artificial muscles or robotic arms to grasp, move, rotate, lift and release objects.

10. A method for preparing a fiber actuator with multi-mode and high degree of freedom deformation, characterized in that: The following steps are involved: 1) Preparation of spiral fiber precursor: The monomer containing liquid crystal unit and the material containing light-to-heat conversion are preliminarily polymerized in a mold having a threaded structure by bonding or doping through an enol click reaction, a Michael addition reaction or a free radical polymerization, and then peeled to obtain an incompletely cross-linked spiral fiber precursor; 2) Preparation of fiber actuators: The incompletely cross-linked spiral fiber precursor is stretched and untwisted to obtain a straight fiber, and the straight fiber is further stretched to a set ratio and then fixed, so that the thiol group and the olefin group are completely cross-linked and cured to obtain a multi-mode, high-degree-of-freedom fiber actuator with a uniaxial orientation. The fiber actuator with a multi-mode, high-degree-of-freedom deformation is obtained by spirally molding a liquid crystal elastomer oligomer and then stretching it again, wherein the liquid crystal elastomer oligomer has a weakly cross-linked network formed by a chemical cross-linking reaction, wherein the liquid crystal elastomer oligomer is a liquid crystal monomer containing an acrylate double bond, and a mixture of a cross-linking agent containing a thiol group and a light absorber monomer is dissolved in an organic solvent to undergo a weak chemical cross-linking reaction under the action of a catalyst, and the carbon-carbon double bond and the thiol group are 0.9-1.2:1.

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