A method for preparing radially oriented MXene fiber artificial muscle

Abstract

The application discloses a preparation method of a radially oriented MXene fiber artificial muscle. x MXene nanosheets and cellulose nanofibers are used as assembly units to prepare the radially oriented MXene fiber artificial muscle through wet spinning of an inflation pipe needle. When the uniformly mixed MXene / CNFs composite nanosheets pass through the needle of the inflation pipe with a narrow side width, the stress of inflation diffusion can eliminate the shear force of the composite nanosheets in the spinning process, which is parallel to the spinning direction, and then provide the arrangement of the composite nanosheets perpendicular to the spinning direction before the fiber is solidified. The MXene fiber artificial muscle with the radially oriented structure and the rich hydrogen bond network can quickly lift a 1 g weight when heated from 25 DEG C to 125 DEG C, and the stretching stroke reaches 21%, and the work is 1.1 J g ‑1 Under the stimulation of 808 nm near-infrared light, the artificial limb can repeatedly lift its own weight by more than 1000 times for more than 200 times, and the ability of fast, stable and multiple stimulation response is exhibited.

Description

Technical Field

[0001] This invention belongs to the field of artificial muscle preparation, specifically relating to a method for preparing radially oriented MXene fiber artificial muscle. Background Technology

[0002] When stimulated by external factors such as temperature, humidity, light, pH, and pressure, artificial muscles can reversibly perform muscle-like movements, such as contraction, expansion, bending, or rotation. They hold immense application potential in robotics, smart fabrics, reconfigurable IoT devices, and implantable medical devices (such as prostheses) (Chem. Soc. Rev. 2022, 57, 2377-2290). Generally, different materials can be chosen to fabricate artificial muscles, such as carbon nanotubes (CNTs), natural polymers, and synthetic polymers (Science, 2012, 338, 928-932). These twisted or coiled artificial muscles exhibit excellent actuation performance due to a stimulus-induced fiber untwisting mechanism that causes adjacent coils to cluster more tightly together (Science, 2014, 343, 868-872). However, the tensile actuation of these twisted or helical artificial muscles remains relatively low. While high elasticity index polymer fibers or yarns can achieve large tensile strokes at lower temperatures, these high elasticity index twisted fibers suffer from the following major problems. First, the only method for fabricating high-elasticity-index coiled fiber artificial muscles is to coil twisted polymer fibers around a mandrel much larger than the diameter of the polymer fibers (Nat. Nanotechnol. 2015, 10, 1077-1083). The problem is that, apart from dissolving the mandrel after the muscle is coiled, there is currently no work on using a mandrel to fabricate high-elasticity-index fibers. Second, the volume-normalized performance of these high-elasticity-index muscles, such as the mechanical energy generated during muscle movement, is far inferior to their weight-normalized performance (Science, 2019, 365, 150-155). Third, many key applications of artificial muscles require weaving them into a base textile containing polymer yarns with a diameter smaller than the spacing between the high-elasticity-index fiber coils. Therefore, fiber slippage between the base textile yarns or muscle coils can interfere with muscle actuation.

[0003] Transition metal carbides / nitrides—MXene (Ti3C2T) x ) is a novel two-dimensional (2D) nanomaterial with excellent electrical conductivity (>10). 5 S cm -1MXene exhibits a high photothermal conversion efficiency (~0.3 TPa) and a high Young's modulus (~0.3 TPa). Its near-100% photothermal conversion efficiency and rapid Joule effect enable its application in sensors, electronic devices, and energy storage (Science, 2021, 372, eabf1581). The surface of MXene nanosheets contains abundant polar functional groups (-OH, -F, -O), readily forming rich hydrogen bond networks with hydroxyl-containing polymers. Cellulose nanofibers (CNFs) are renewable plant fibers with high mechanical strength and large surface area, also containing abundant hydroxyl functional groups (Adv. Mater. 2018, 30, 1703779). While assembling these two materials into thin films has achieved some simple and weak lateral driven behavior, exhibiting larger thermally driven strain in volume or length remains challenging due to the fact that their driven behavior is mainly based on the thermal expansion difference caused by the asymmetric bilayer structure.

[0004] In recent years, there have been relatively few patents related to MXene-based artificial muscles. Examples include: a self-sensing material and its preparation method and application in artificial muscle fibers (CN117758518A); a torsionable double-helix fiber-like artificial muscle and its preparation method (CN112921461B); a core-sheath composite artificial muscle fiber system and its preparation method and application (CN117512838A); a fast-response thermally driven helical coiled artificial muscle (CN116276939A); and a multi-stimulus responsive liquid crystal elastomer / MXene composite fiber soft actuator and its preparation method and application (CN116289170B). However, these artificial muscles all require complex torsion processing of polymer fibers or yarns and suffer from drawbacks such as low response rate and limited response type.

[0005] In summary, achieving rapid and multi-stimulus-responsive non-torsional artificial muscles remains a challenge. This invention utilizes Ti3C2T... x MXene nanosheets and cellulose nanofibers were used as assembly units to prepare radially oriented MXene fiber artificial muscles with large stretching strokes through needle wet spinning assembly via expanded channels. Summary of the Invention

[0006] The technical problem solved by this invention is to overcome the shortcomings of existing technologies and provide a method for preparing radially oriented MXene fiber artificial muscles. Even without any torsion, the MXene fiber artificial muscle with a radially oriented structure and a rich hydrogen bond network can lift a 1 g weight when heated from 25°C to 125°C, with a stretching stroke of 21% and a working work of 1.1 J g. -1 Under stimulation with 808 nm near-infrared light, it can repeatedly pull up an artificial prosthesis weighing more than 1,000 times its own weight more than 200 times.

[0007] This invention is achieved through the following technical solution: First, Ti3C2T is obtained by in-situ hydrofluoric acid etching. x MXene solution, then Ti3C2T x MXene and cellulose nanofibers (CNFs) were uniformly mixed and concentrated at high speed to obtain MXene / CNFs spinning ink. Then, the ink was assembled by needle wet spinning with expansion channels, passed through an ethanol coagulation bath, and dried under vacuum to obtain radially oriented MXene fiber artificial muscle.

[0008] The specific implementation steps of this invention are as follows:

[0009] A method for preparing radially oriented MXene fiber artificial muscle includes the following steps:

[0010] (1) Preparation of Ti3C2T by in-situ hydrofluoric acid etching method x MXene solution;

[0011] (2) Disperse cellulose nanofibers in deionized water and prepare a uniformly dispersed cellulose nanofiber solution by ultrasonication using a cell disruptor;

[0012] (3) Ti3C2T x The MXene solution and the cellulose nanofiber solution were mixed evenly to obtain an MXene / CNFs mixed solution;

[0013] (4) The MXene / CNFs mixed solution from step (3) is concentrated at high speed by centrifugation to remove excess water, thereby obtaining a high-concentration MXene / CNFs spinning ink;

[0014] (5) Transfer the MXene / CNFs spinning ink from step (4) into a syringe with an expansion tube needle, and squeeze the MXene / CNFs spinning ink into an ethanol coagulation bath using a micro-injection pump.

[0015] (6) The MXene fibers assembled by wet spinning in step (5) are slowly collected onto a roll and vacuum dried to obtain radially oriented MXene fiber artificial muscle.

[0016] Furthermore, in step (1), Ti3C2T xThe preparation process of MXene solution is as follows: 3.2 g of lithium fluoride (LiF) was added to a polytetrafluoroethylene bottle containing 40 mL of hydrochloric acid (HCl) (9 M) solution. After stirring evenly, 2 g of Ti3AlC2 MAX powder was slowly added, and the mixture was stirred in a water bath at 50°C for 30 hours. After the reaction was completed, the solution was cooled to room temperature, and the resulting solution was evenly dispersed into 6 centrifuge tubes. Deionized water was added, and the mixture was centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded. This process was repeated 8-10 times until the pH of the supernatant exceeded 6. Then, deionized water was added to the precipitate, and the mixture was shaken for 5 minutes. The mixture was then centrifuged at 1500 rpm for 30 minutes, and the supernatant was collected. This process was repeated to collect more supernatant until the supernatant was light green. The collected supernatant was centrifuged at 4500 rpm for 20 minutes, and the precipitate was collected. The precipitate was diluted with deionized water to obtain 3 mg / mL Ti3C2T x MXene solution.

[0017] Furthermore, in step (2), cellulose nanofibers are ultrasonically dispersed in deionized water at a concentration of 10 mg / mL.

[0018] Further, in step (3), the mass ratio of the MXene / CNFs mixed solution is 7:3 to 3:7; preferably, in step (3), the mass ratio of the MXene / CNFs mixed solution is 5:5.

[0019] Further, in step (4), the concentration of MXene / CNFs spinning ink is 20 mg / mL to 50 mg / mL; preferably, in step (4), the concentration of MXene / CNFs spinning ink is 30 mg / mL.

[0020] Further, in step (5), the initial diameter of the spinning needle is 210 μm, the expansion transition diameter is 510 μm, and the micro-injection pump extrudes the MXene / CNFs spinning ink into the ethanol coagulation bath at a rate of 100 μL / min to 400 μL / min; preferably, in step (5), the extrusion speed is 300 μL / min.

[0021] Further, in step (6), the collection rate of wet-spun MXene fibers is 100 μL / min to 400 μL / min; preferably, in step (6), the collection rate of MXene fibers is 300 μL / min; the collected fibers are vacuum dried at a temperature of 40°C for 24 hours to obtain radially oriented MXene fiber artificial muscle.

[0022] Furthermore, in step (6), wide-angle X-ray diffraction (WAXS) is used to characterize the orientation degree of the radially oriented MXene fiber artificial muscle, and its orientation degree f is 0.63; when heated from 25°C to 125°C, it can lift a 1 g weight, with a stretching stroke of 21%, and a working work of 1.1 J g. -1 Under stimulation by near-infrared light at 808 nm, it can repeatedly pull up an artificial prosthesis weighing more than 1,000 times its own weight more than 200 times.

[0023] The principle of this invention: This invention first uses Ti3C2T x MXene nanosheets and cellulose nanofibers were used as assembly units to fabricate radially oriented MXene fiber artificial muscles with a large tensile stroke through wet spinning using an expansion channel needle. When the uniformly mixed MXene / CNFs composite nanosheets were passed through an expansion channel needle with narrow sides, the stress from the expansion diffusion eliminated the shear force that caused the composite nanosheets to be parallel to the spinning direction during spinning, thus providing an alignment of the composite nanosheets perpendicular to the spinning direction before fiber solidification. Even without any twisting, this MXene fiber artificial muscle with a radially oriented structure and a rich hydrogen bond network could rapidly lift a 1 g weight when heated from 25°C to 125°C, with a tensile stroke of 7–21% and a work of 0.3–1.1 J g. -1 Furthermore, MXene's excellent photothermal effect endows MXene fiber artificial muscles with the ability to quickly lift heavy objects under near-infrared light stimulation.

[0024] The advantages of this invention compared to the prior art are:

[0025] (1) A continuous preparation method for MXene fiber artificial muscle was developed.

[0026] (2) Even before any twist is inserted, MXene fiber artificial muscles with radial orientation structure and rich hydrogen bond network have excellent driving performance.

[0027] (3) Radial orientation MXene fiber artificial muscle has the advantages of rapid and multiple (thermal, electrical, optical) stimulus response. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the fabrication process of the radially oriented MXene fiber artificial muscle of the present invention. Firstly, Ti3C2T is obtained via in-situ hydrofluoric acid etching. x MXene solution, then Ti3C2T xMXene and cellulose nanofibers (CNFs) were uniformly mixed and concentrated at high speed to obtain MXene / CNFs spinning ink. Then, the ink was assembled by needle wet spinning with expansion channels, passed through an ethanol coagulation bath, and dried under vacuum to obtain radially oriented MXene fiber artificial muscle.

[0029] Figure 2 Macroscopic photographs and orientation of the radially oriented MXene fiber artificial muscle in Example 1. A, Digital photograph of the radially oriented MXene fiber artificial muscle wound on a 100-meter-long scroll; B, Two-dimensional WAXS map of the radially oriented MXene fiber artificial muscle; C, Azimuth curve of the (002) peak of the radially oriented MXene fiber artificial muscle.

[0030] Figure 3 The driving performance of the radially oriented MXene fiber artificial muscle in Example 1 is shown in Figure A. Digital and infrared thermal images of the reversible contraction drive of the radially oriented MXene fiber artificial muscle under cyclic heating / cooling; Figure B. Tensile stroke and working work of radially oriented MXene fiber artificial muscles with different MXene / CNFs ratios, with an applied load of 0.64 MPa.

[0031] Figure 4 This demonstrates the application of the radially oriented MXene fiber artificial muscle in Example 1. Under near-infrared light stimulation at 808 nm, the radially oriented MXene fiber artificial muscle can repeatedly pull up an artificial prosthesis with a weight of more than 1000 times its own body weight more than 200 times. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. However, the following embodiments are only for explaining the present invention, and the scope of protection of the present invention should include all the contents of the claims. Moreover, through the description of the following embodiments, those skilled in the art can fully implement all the contents of the claims of the present invention.

[0033] Figure 1 This is a schematic diagram illustrating the fabrication process of the radially oriented MXene fiber artificial muscle of the present invention. Specifically, Ti3C2T is first obtained by in-situ hydrofluoric acid etching. x MXene solution, then Ti3C2T x MXene and cellulose nanofibers (CNFs) were uniformly mixed and concentrated at high speed to obtain MXene / CNFs spinning ink. Then, the ink was assembled by needle wet spinning with expansion channels, passed through an ethanol coagulation bath, and dried under vacuum to obtain radially oriented MXene fiber artificial muscle.

[0034] In the following embodiments of the present invention, some of the raw materials and preparation equipment are as follows:

[0035] Ti3AlC2 MAX (Purity: 98%, 400 mesh, Jilin Yiyi Technology Co., Ltd.);

[0036] Lithium fluoride (purity: 98%, Aladdin);

[0037] Hydrochloric acid (purity: 36~38%, Sinopharm Chemical Reagent);

[0038] Cellulose nanofibers (NanoFC, average particle size ~5 nm);

[0039] Ethanol (purity: 99.7%, Beijing Chemical Plant);

[0040] The orientation degree of radially oriented MXene fiber artificial muscle was tested using a wide-angle X-ray diffractometer (Xenocs Xeuss SAXS / WAXS, Cu-Kα X-ray beam);

[0041] Thermal images of radially oriented MXene fiber artificial muscles driven by contraction during heating were recorded using an infrared thermal imager (FOTRIC 228s, Shanghai Thermal Imaging Technology Co., Ltd.).

[0042] Example 1

[0043] 3.2 g of lithium fluoride (LiF) was added to a polytetrafluoroethylene bottle containing 40 mL of hydrochloric acid (HCl) (9 M) solution. After stirring until homogeneous, 2 g of Ti3AlC2MAX powder was slowly added, and the mixture was stirred in a 50°C water bath for 30 hours. After the reaction was complete and cooled to room temperature, the resulting solution was evenly dispersed into 6 centrifuge tubes. Deionized water was added, and the tubes were centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded. This process was repeated 8-10 times until the pH of the supernatant exceeded 6. Then, deionized water was added to the precipitate, and the mixture was shaken for 5 minutes. The tubes were then centrifuged at 1500 rpm for 30 minutes, and the supernatant was collected. This process was repeated to collect more supernatant until it turned light green. The collected supernatant was centrifuged at 4500 rpm for 20 minutes, and the precipitate was collected. The precipitate was diluted with deionized water to obtain 3 mg / mL Ti3C2MAX. x MXene solution.

[0044] A cellulose nanofiber solution with a concentration of 10 mg / mL was prepared. Ti3C2T x The MXene solution and cellulose nanofiber solution were mixed evenly, and the mixture contained Ti3C2T xThe mass ratio of MXene to cellulose nanofibers was 5:5. Excess water was removed by high-speed centrifugation to obtain a high-concentration MXene / CNFs spinning ink with a total concentration of 30 mg / mL. The MXene / CNFs spinning ink was transferred into a syringe with an expansion tube needle, and the extrusion rate of the micro-injection pump was set to 300 μL / min. As the extruded MXene / CNFs composite nanosheets passed through the narrow-side-wide expansion tube needle, the stress from the expansion diffusion caused the MXene / CNFs composite nanosheets to align perpendicular to the spinning direction. After passing through an ethanol coagulation bath, the MXene fibers were collected on a spool at a rate of 300 μL / min and vacuum-dried at 40°C for 24 hours to obtain radially oriented MXene fiber artificial muscle (MFAM-II). Figure 2 As shown, radially oriented MXene fiber artificial muscles with an orientation degree f of over 100 mm were prepared.

[0045] Example 2

[0046] 3.2 g of lithium fluoride (LiF) was added to a polytetrafluoroethylene bottle containing 40 mL of hydrochloric acid (HCl) (9 M) solution. After stirring until homogeneous, 2 g of Ti3AlC2MAX powder was slowly added, and the mixture was stirred in a 50°C water bath for 30 hours. After the reaction was complete and cooled to room temperature, the resulting solution was evenly dispersed into 6 centrifuge tubes. Deionized water was added, and the tubes were centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded. This process was repeated 8-10 times until the pH of the supernatant exceeded 6. Then, deionized water was added to the precipitate, and the mixture was shaken for 5 minutes. The tubes were then centrifuged at 1500 rpm for 30 minutes, and the supernatant was collected. This process was repeated to collect more supernatant until it turned light green. The collected supernatant was centrifuged at 4500 rpm for 20 minutes, and the precipitate was collected. The precipitate was diluted with deionized water to obtain 3 mg / mL Ti3C2MAX. x MXene solution.

[0047] A cellulose nanofiber solution with a concentration of 10 mg / mL was prepared. Ti3C2T x The MXene solution and cellulose nanofiber solution were mixed evenly, and the mixture contained Ti3C2T xThe mass ratio of MXene to cellulose nanofibers was 5:5. Excess water was removed by high-speed centrifugation to obtain a high-concentration MXene / CNFs spinning ink with a total concentration of 30 mg / mL. The MXene / CNFs spinning ink was transferred into a syringe with an expansion tube needle, and the extrusion rate of the micro-injection pump was set to 300 μL / min. As the extruded MXene / CNFs composite nanosheets passed through the narrow-side-wide expansion tube needle, the stress from the expansion diffusion caused the MXene / CNFs composite nanosheets to align perpendicular to the spinning direction. After passing through an ethanol coagulation bath, the MXene fibers were collected on a spool at a rate of 300 μL / min and vacuum-dried at 40°C for 24 hours to obtain radially oriented MXene fiber artificial muscle (MFAM-II). Figure 3 As shown in Figure A, radially oriented MXene fiber artificial muscle can lift a 1 g weight when heated from 25°C to 125°C, and returns to its original state upon cooling. Figure 3 As shown in B, its tensile stroke reaches 21%, and its working power is 1.1 J g. -1 .

[0048] Example 3

[0049] 3.2 g of lithium fluoride (LiF) was added to a polytetrafluoroethylene bottle containing 40 mL of hydrochloric acid (HCl) (9 M) solution. After stirring until homogeneous, 2 g of Ti3AlC2MAX powder was slowly added, and the mixture was stirred in a 50°C water bath for 30 hours. After the reaction was complete and cooled to room temperature, the resulting solution was evenly dispersed into 6 centrifuge tubes. Deionized water was added, and the tubes were centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded. This process was repeated 8-10 times until the pH of the supernatant exceeded 6. Then, deionized water was added to the precipitate, and the mixture was shaken for 5 minutes. The tubes were then centrifuged at 1500 rpm for 30 minutes, and the supernatant was collected. This process was repeated to collect more supernatant until it turned light green. The collected supernatant was centrifuged at 4500 rpm for 20 minutes, and the precipitate was collected. The precipitate was diluted with deionized water to obtain 3 mg / mL Ti3C2MAX. x MXene solution.

[0050] A cellulose nanofiber solution with a concentration of 10 mg / mL was prepared. Ti3C2T x The MXene solution and cellulose nanofiber solution were mixed evenly, and the mixture contained Ti3C2T xThe mass ratio of MXene to cellulose nanofibers was 5:5. Excess water was removed by high-speed centrifugation to obtain a high-concentration MXene / CNFs spinning ink with a total concentration of 30 mg / mL. The MXene / CNFs spinning ink was transferred into a syringe with an expansion tube needle, and the extrusion rate of the micro-injection pump was set to 300 μL / min. As the extruded MXene / CNFs composite nanosheets passed through the narrow-side-wide expansion tube needle, the stress from the expansion diffusion caused the MXene / CNFs composite nanosheets to align perpendicular to the spinning direction. After passing through an ethanol coagulation bath, the MXene fibers were collected on a spool at a rate of 300 μL / min and vacuum-dried at 40°C for 24 hours to obtain radially oriented MXene fiber artificial muscle (MFAM-II). Figure 4 As shown, radially oriented MXene fiber artificial muscles can repeatedly pull up an artificial prosthesis weighing more than 1,000 times its own weight more than 200 times under near-infrared light stimulation at 808 nm, demonstrating stable photothermal driving performance.

[0051] Example 4

[0052] 3.2 g of lithium fluoride (LiF) was added to a polytetrafluoroethylene bottle containing 40 mL of hydrochloric acid (HCl) (9 M) solution. After stirring until homogeneous, 2 g of Ti3AlC2MAX powder was slowly added, and the mixture was stirred in a 50°C water bath for 30 hours. After the reaction was complete and cooled to room temperature, the resulting solution was evenly dispersed into 6 centrifuge tubes. Deionized water was added, and the tubes were centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded. This process was repeated 8-10 times until the pH of the supernatant exceeded 6. Then, deionized water was added to the precipitate, and the mixture was shaken for 5 minutes. The tubes were then centrifuged at 1500 rpm for 30 minutes, and the supernatant was collected. This process was repeated to collect more supernatant until it turned light green. The collected supernatant was centrifuged at 4500 rpm for 20 minutes, and the precipitate was collected. The precipitate was diluted with deionized water to obtain 3 mg / mL Ti3C2MAX. x MXene solution.

[0053] A cellulose nanofiber solution with a concentration of 10 mg / mL was prepared. Ti3C2T x The MXene solution and cellulose nanofiber solution were mixed evenly, and the mixture contained Ti3C2T xThe mass ratio of MXene to cellulose nanofibers was 7:3. Excess water was removed by high-speed centrifugation to obtain a high-concentration MXene / CNFs spinning ink with a total concentration of 30 mg / mL. The MXene / CNFs spinning ink was transferred into a syringe with an expansion tube needle, and the extrusion rate of the micro-injection pump was set to 300 μL / min. As the extruded MXene / CNFs composite nanosheets passed through the narrow-side-wide expansion tube needle, the stress from the expansion diffusion caused the MXene / CNFs composite nanosheets to align perpendicular to the spinning direction. After passing through an ethanol coagulation bath, the MXene fibers were collected on a spool at a rate of 300 μL / min and vacuum-dried at 40°C for 24 hours to obtain radially oriented MXene fiber artificial muscle (MFAM-I). Figure 3 As shown in Figure A, radially oriented MXene fiber artificial muscle can lift a 1 g weight when heated from 25°C to 125°C. Figure 3 As shown in B, its stretching stroke is 14%, and its working power is 0.5 Jg. -1 .

[0054] Example 5

[0055] 3.2 g of lithium fluoride (LiF) was added to a polytetrafluoroethylene bottle containing 40 mL of hydrochloric acid (HCl) (9 M) solution. After stirring until homogeneous, 2 g of Ti3AlC2MAX powder was slowly added, and the mixture was stirred in a 50°C water bath for 30 hours. After the reaction was complete and cooled to room temperature, the resulting solution was evenly dispersed into 6 centrifuge tubes. Deionized water was added, and the tubes were centrifuged at 3500 rpm for 5 minutes. The supernatant was discarded. This process was repeated 8-10 times until the pH of the supernatant exceeded 6. Then, deionized water was added to the precipitate, and the mixture was shaken for 5 minutes. The tubes were then centrifuged at 1500 rpm for 30 minutes, and the supernatant was collected. This process was repeated to collect more supernatant until it turned light green. The collected supernatant was centrifuged at 4500 rpm for 20 minutes, and the precipitate was collected. The precipitate was diluted with deionized water to obtain 3 mg / mL Ti3C2MAX. x MXene solution.

[0056] A cellulose nanofiber solution with a concentration of 10 mg / mL was prepared. Ti3C2T x The MXene solution and cellulose nanofiber solution were mixed evenly, and the mixture contained Ti3C2T xThe mass ratio of MXene to cellulose nanofibers was 3:7. Excess water was removed by high-speed centrifugation to obtain a high-concentration MXene / CNFs spinning ink with a total concentration of 30 mg / mL. The MXene / CNFs spinning ink was transferred into a syringe with an expansion tube needle, and the extrusion rate of the micro-injection pump was set to 300 μL / min. As the extruded MXene / CNFs composite nanosheets passed through the narrow-side-wide expansion tube needle, the stress from the expansion diffusion caused the MXene / CNFs composite nanosheets to align perpendicular to the spinning direction. After passing through an ethanol coagulation bath, the MXene fibers were collected on a spool at a rate of 300 μL / min and vacuum-dried at 40°C for 24 hours to obtain radially oriented MXene fiber artificial muscle (MFAM-III). Figure 3 As shown in Figure A, radially oriented MXene fiber artificial muscle can lift a 1 g weight when heated from 25°C to 125°C. Figure 3 As shown in B, its stretching stroke is 16% and its working power is 0.7 J g. -1 .

[0057] It should be noted that, according to the above embodiments of the present invention, those skilled in the art can fully realize the scope of claim 1 and its dependent rights, and the implementation process and method are the same as those in the above embodiments; and the parts of the present invention not described in detail belong to the well-known technology in the art.

[0058] The above description is only a part of the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a radially oriented MXene fiber artificial muscle, characterized in that, The method comprises the following steps: Step 1, Ti3C2T was prepared by in-situ hydrofluoric acid etching method x MXene solution; Step 2, dispersing cellulose nanofibers in deionized water to prepare a uniformly dispersed cellulose nanofiber solution by means of a cell crusher ultrasonic; Step 3, the Ti3C2T prepared in step 1 is mixed with the cellulose nanofiber solution prepared in step 2 to obtain a MXene / CNFs mixed solution. x MXene solution and the cellulose nanofiber solution prepared in step 2 are mixed uniformly to obtain a MXene / CNFs mixed solution; Step 4, removing excess water from the MXene / CNFs mixed solution prepared in step 3 by high-speed concentration with a centrifuge to obtain a MXene / CNFs spinning ink; Step 5, transferring the MXene / CNFs spinning ink prepared in step 4 to a syringe with an expansion pipe needle, and extruding the MXene / CNFs spinning ink into an ethanol coagulation bath by means of a micro-injection pump; Step 6, slowly collecting the wet-spun assembled MXene fibers in step 5 onto a reel, and vacuum drying to obtain a radially oriented MXene fiber artificial muscle; In step 3, the mass ratio of MXene to CNFs in the MXene / CNFs mixed solution is 7:3~3:7; In step 5, the diameter of the spinning needle is 210 μm, the expansion transition diameter is 510 μm, and the micro-injection pump extrudes the MXene / CNFs spinning ink into the ethanol coagulation bath at a rate of 100 μL / min~400 μL / min; the extruded MXene / CNFs composite nanosheets are arranged vertically to the spinning direction due to the stress of expansion diffusion when passing through the narrow-to-wide expansion pipe needle.

2. The method of claim 1, wherein the method of preparing a radial oriented MXene fiber artificial muscle is characterized by: In the step 1, Ti3C2T x The preparation process of MXene is as follows: raw material Ti3AlC2MAX powder is added into a solution containing hydrochloric acid and lithium fluoride, and the reaction is fully stirred under heating condition; the mixed solution after complete reaction is centrifuged, the upper liquid is poured off, and the mixed solution is repeatedly washed with deionized water until the pH is more than 6; then the precipitate after centrifugation is dispersed in deionized water, and Ti3C2T x MXene solution.

3. The method of claim 1, wherein: In step 2, the concentration of cellulose nanofibers in the cellulose nanofiber solution is 5 mg / mL~20 mg / mL.

4. The method of claim 1, wherein: In step 4, the concentration of the MXene / CNFs spinning ink is 20 mg / mL~50 mg / mL.

5. The method of claim 1, wherein: In step 6, the wet-spun assembled MXene fibers are collected at a speed of 100 μL / min~400 μL / min. In step 6, the wet-spun assembled MXene fibers are collected at a speed of 100 μL / min~400 μL / min.

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