Core-sheath composite artificial muscle fiber system, its preparation method and application

Abstract

This invention discloses a core-sheath composite artificial muscle fiber system, its preparation method, and its applications. The core-sheath composite artificial muscle fiber system includes a fiber body and an electrolyte; the fiber body comprises a polymer fiber core and a carbon material sheath layer. The polymer fiber core is electrochemically inert and is twisted into an overtwisted spiral state; the electrolyte contains driving ions. The core-sheath composite artificial muscle fiber system provided by this invention uses a polymer material as the fiber core to replace part of the carbon material fiber, reducing the amount of carbon material used and significantly lowering material costs. Furthermore, due to the presence of the fiber core, each part of the carbon material sheath layer maintains a large twist angle and can significantly shorten the migration path of driving ions within the fiber, thus exhibiting a higher response rate, and also higher recovery rate and power density at high frequencies. It can be used for sewing and has broad application prospects in soft robotics, biomedical engineering, smart fabrics, and other fields.

Description

Technical Field

[0001] This invention relates to the field of artificial muscle technology in materials science, and particularly to a core-sheath composite artificial muscle fiber system, its preparation method, and its application. Background Technology

[0002] The advent and development of robots have brought great convenience and assistance to human society. However, traditional rigid robots suffer from problems such as complex connection devices, bulky size, and high energy consumption, which limits their application scenarios. Therefore, lightweight and efficient flexible power units are of great research significance.

[0003] In nature, biological muscle fibers can achieve interfilament sliding through ATP, enabling muscle tissue to contract and relax, thus performing complex movements; they are a highly efficient power unit. Inspired by biological muscles, a material with a shape and function similar to biological muscle fibers has been developed: artificial muscle fibers.

[0004] This material can undergo reversible contraction, rotation, and bending movements in response to external stimuli, offering numerous advantages over traditional rigid robots, such as greater lightness and flexibility, faster environmental stimulus response, and the ability to achieve complex movements through weaving and integration. Professor Ray Baughman's team in the United States discovered that twisting fiber materials to obtain helical fiber structures can significantly improve the driving performance of artificial muscle fibers. This greatly expands the material sources and application potential of artificial muscle fibers.

[0005] Based on the different stimuli, artificial muscle fibers can be classified into thermally driven, solvent adsorption-desorption driven, and electrochemically driven types. Among them, electrochemically driven fibers have many advantages and important research significance because they require lower voltages, the driving behavior can be controlled by voltage, and the energy conversion efficiency is not limited by the Carnot cycle.

[0006] However, the main material of existing electrochemical artificial muscles, carbon nanotube (CNT) fibers, are mostly obtained through chemical vapor deposition of CNT arrays, which is complex and expensive. Furthermore, the current twisting technology cannot achieve continuous fabrication, preventing the mass production of artificial muscle fibers and limiting their application in smart fabrics. Additionally, the twisted structure presents several problems: fiber angle and twist are key factors affecting the driving performance of artificial muscle fibers, and the fiber angle at the center of traditional muscle fibers is close to 0, making this part of the muscle ineffectively driven; secondly, twisting makes the internal structure of the fiber denser, increasing the difficulty and time required for electrochemical ions to move within the fiber, thus limiting the muscle's work capacity and recovery rate. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a core-sheath composite artificial muscle fiber system, its preparation method, and its application.

[0008] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0009] In a first aspect, the present invention provides a core-sheath composite artificial muscle fiber system, which includes a fiber body and an electrolyte that wets the fiber body;

[0010] The fiber body includes a polymer fiber core and a carbon material sheath layer that wraps the polymer fiber core. The polymer fiber core is electrochemically inert, and the fiber body is twisted into an overtwisted spiral state.

[0011] The electrolyte contains driving ions, which can migrate into or out of multiple constituent units in the carbon material sheath under the action of an electric field.

[0012] Secondly, the present invention also provides a method for preparing the above-mentioned core-sheath composite artificial muscle fiber system, comprising:

[0013] We provide carbon material membranes and polymer fibers;

[0014] The carbon material film is wrapped around the polymer fiber and twisted to form a fiber body;

[0015] The fiber body is brought into contact with the electrolyte to form a core-sheath composite artificial muscle fiber system.

[0016] Thirdly, the present invention also provides the application of the above-mentioned core-sheath composite artificial muscle fiber system in the field of smart fabrics.

[0017] Based on the above technical solution, compared with the prior art, the beneficial effects of the present invention include at least the following:

[0018] The core-sheath composite artificial muscle fiber system provided by this invention uses a polymer material as the fiber core to replace part of the carbon fiber, reducing the amount of carbon material used and significantly lowering material costs. Furthermore, due to the presence of the fiber core, each part of the carbon sheath layer maintains a large twist angle, and compared to overall twisting, the migration path of driving ions in the active component is significantly shortened, and the migration difficulty is significantly reduced, thus resulting in a higher response rate and higher recovery rate and power density at high frequencies. It can be used for sewing and has greater advantages in practical applications, with broad application prospects in fields such as soft robotics, biomedical engineering, and smart fabrics.

[0019] The above description is merely an overview of the technical solution of the present invention. In order to enable those skilled in the art to better understand the technical means of this application and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described below in conjunction with detailed drawings. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the preparation process of core-sheath composite artificial muscle fibers provided in a typical embodiment of the present invention;

[0021] Figure 2a This is an electron microscope image of the overall structure of the core-sheath composite artificial muscle fiber provided in a typical embodiment of the present invention;

[0022] Figure 2b This is an electron microscope image of the cross-sectional structure of the core-sheath composite artificial muscle fiber provided in a typical embodiment of the present invention;

[0023] Figure 3 This is a voltage response test diagram of artificial muscle fibers provided in a typical embodiment and comparative case of the present invention;

[0024] Figure 4a This is a test graph showing the change in the driving force and functional capacity of artificial muscle fibers with frequency, provided in a typical embodiment and comparative case of the present invention.

[0025] Figure 4b This is a test graph showing the change of power density and average contraction rate of artificial muscle fibers with frequency, provided in a typical embodiment and comparative case of the present invention.

[0026] Figure 5 This is a diagram showing the relationship between the contraction drive and contraction work of artificial muscle fibers and the applied load, provided in a typical embodiment and comparative case of the present invention.

[0027] Figure 6a This is an example diagram of the sewing application of the core-sheath composite artificial muscle fiber fabric provided in a typical embodiment of the present invention;

[0028] Figure 6b This is an example diagram of a fabric driven by sewing core-sheath composite artificial muscle fibers, provided in a typical embodiment of the present invention. Detailed Implementation

[0029] In view of the shortcomings of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. The following will further explain and illustrate this technical solution, its implementation process, and its principles.

[0030] Many existing technologies use carbon nanotube fibers, twisted and then combined with an electrolyte to form artificial muscle fiber systems. Their main drawbacks are: 1) CNT fibers prepared from CNT arrays are complex to manufacture and expensive. 2) Existing twisting techniques are difficult to implement for continuous mass production, limiting their practical applications. 3) Pure CNT single-strand fibers are difficult to use for sewing, limiting their application in the field of smart fabrics. 4) The internal structure of CNT fibers is very dense due to twisting, restricting the movement of driving ions and resulting in a slow response rate for biomimetic muscle fibers.

[0031] The purpose of this invention is to provide a biomimetic muscle fiber that has a lower cost, a higher response rate, and higher driving performance and power density at high frequencies to solve the above problems. This muscle fiber can be mass-produced through a continuous twisting process and can be used in smart fabrics.

[0032] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0033] This invention provides a core-sheath composite artificial muscle fiber system, comprising a fiber body and an electrolyte impregnating the fiber body; the fiber body comprises a polymer fiber core and a carbon material sheath layer encapsulating the polymer fiber core, the polymer fiber core being electrochemically inert, and the fiber body being twisted into an overtwisted spiral state; the electrolyte contains driving ions, which can migrate into or out of multiple constituent units in the carbon material sheath layer under the action of an electric field.

[0034] In the above technical solutions, compared with pure carbon nanotube fibers, the core-sheath composite structure of artificial muscle fibers has superior frequency response performance in the electrochemical drive system and can adapt to higher switching frequencies. This is because the construction of the core-sheath structure increases the contact area between the active material carbon nanotubes and the electrolyte, shortens the migration path of ions, and thus has a fast drive response performance. Furthermore, the electrochemically inert fiber core does not consume drive ions, and the mechanical interaction between the tough fiber core and the sheath layer can also significantly improve the drive power and drive quantity.

[0035] While some existing technologies provide a carbon nanotube-nylon core-sheath composite artificial muscle fiber, they utilize electrothermal actuation, which differs from the actuation principle in this invention. This actuation is merely driven by thermal expansion due to the electrothermal effect. Specifically, in electrothermal actuation, the fiber generates Joule heating as current flows, significantly increasing the fiber's temperature, causing thermal expansion and volume deformation, resulting in axial contraction. This process requires a relatively high operating voltage. In contrast, in electrochemical actuation, the driving ions migrate directionally under the influence of an electric field, undergoing reversible insertion and extraction within the carbon nanotubes, inducing volume changes and resulting in reversible axial contraction and elongation. This process does not involve significant temperature changes in the fiber, and the required voltage is far lower than that of electrothermal actuation.

[0036] Electrothermal drive does not involve the role of ions; it only involves the volume change caused by the heating of the material. It does not involve the improvement of the driving efficiency and migration rate of the fiber core for driving ions.

[0037] Regarding the specific structure and composition, in some embodiments, the material of the polymer fiber core includes any one or more combinations of nylon, polyester, aramid, spandex, etc., but is not limited to this.

[0038] In some implementations, the carbon material sheath is made of any one or more of carbon nanotubes, graphene, carbon fibers, etc., but is not limited to these.

[0039] In some embodiments, the carbon material sheath is formed by at least one continuous carbon nanotube film or narrow band encapsulating the polymer fiber core.

[0040] As a further optimization, in some embodiments, a friction-enhancing layer with a thickness of 0.5-2 μm is further provided between the polymer fiber core and the carbon material sheath;

[0041] In some more specific embodiments, the friction enhancement layer includes a carbon material layer; however, it is not limited to this, and other material coatings or materials that have undergone physical or chemical treatment to transform the surface of the polymer fiber core into a material layer with a certain roughness or strong bonding ability can also be understood as "friction enhancement layers".

[0042] For example, the nylon fiber in the core is coated with a 1μm thick carbon layer, which has a higher roughness compared to uncoated nylon. As a core fiber, it can increase the friction between the core fiber and the CNT layer, reducing mutual slippage between them during actuation. The synergistic effect of these factors results in the artificial muscle fiber in this invention exhibiting better, faster, and more efficient actuation behavior.

[0043] The preferred carbon material sheath uses CNTs prepared directly by a floating catalytic method, which are narrow-band CNTs with poor internal orientation (without orientation enhancement treatment). These are typically intertwined multi-walled CNT networks in a disordered state. During ion entry and exit from the CNT layer, the initially disordered, low-orientation CNT network undergoes a change in orientation from disorder to order under the pull of an external load. This allows for greater length variation, resulting in better driving performance.

[0044] In some embodiments, the diameter of the polymer fiber core is about 30-50 μm, preferably about 40 μm.

[0045] In some embodiments, the average thickness of the carbon material sheath is about 20-40 μm, preferably about 30 μm.

[0046] In some embodiments, the driving ion includes any one or a combination of two of BF4 and PF6-, but is not limited thereto.

[0047] In some embodiments, the solvent in the electrolyte includes any one or a combination of two of propylene carbonate and γ-butyrolactone, but is not limited thereto.

[0048] In some embodiments, the concentration of driving ions in the electrolyte is 0.5 to 1 mol / L.

[0049] In some embodiments, the twist of the fiber body is 15,000-25,000 r / m, preferably, for example, 20,970 r / m.

[0050] Corresponding to the composition and structure of the core-sheath composite artificial muscle fiber system described above, a second aspect of this invention also provides a method for preparing the core-sheath composite artificial muscle fiber system, comprising the following steps:

[0051] We provide carbon material membranes and polymer fibers;

[0052] The carbon material film is wrapped around the polymer fiber and twisted to form a fiber body;

[0053] The fiber body is brought into contact with the electrolyte to form a core-sheath composite artificial muscle fiber system.

[0054] In some implementations, the preparation method may specifically include:

[0055] The carbon material film and the ends of the polymer fiber are twisted together to form the initial twist.

[0056] The carbon material membrane and polymer fiber are continuously supplied, and the twisted fiber body is continuously collected to continuously prepare the fiber body with a helical structure.

[0057] In some embodiments, the twisting speed is 200-400 rpm, and the travel speed of the carbon material film and polymer fiber is 0.5-1.5 m / min.

[0058] As a typical application example of the above technical solution, a preferred embodiment of the present invention uses inexpensive and readily available commercial nylon fibers as the core material and carbon nanotube (CNT) narrow strips prepared by floating catalytic chemical vapor deposition as the sheath material, ultimately obtaining a composite fiber with a core-sheath structure. The nylon fibers and CNT narrow strips are wound onto two parallel bobbins, each bobbin fixed to a motor. One end of the nylon fiber and CNT narrow strip is overlapped and fixed to the take-up shaft of a fiber twisting and winding device. By controlling the motor speed, the bobbins rotate, thus conveying the nylon fiber and CNT narrow strip towards the fiber twisting and winding device. By controlling this conveying speed and the winding speed of the fiber twisting and winding device, the tension on the fiber during twisting is controlled. By controlling the twisting speed of the fiber twisting and winding device, the fiber is fully twisted to form a helical structure, ultimately completing the preparation of an electrochemically driven core-sheath structure composite fiber. Figure 1 As shown.

[0059] In the above process, unsuitable tension will prevent successful twisting: excessive tension will cause the fibers to break easily; insufficient tension will cause the fibers to spontaneously coil into a ball. This is also a common understanding in the field and related fields for preparing fibers with overtwisted spiral characteristics. There is no definite tension value range in the implementation of this invention, because it is related to different materials, diameters and twisting conditions. Those skilled in the art can make appropriate adjustments based on the above principles.

[0060] The specific preparation steps are as follows:

[0061] Step 1: Wrap nylon fiber and CNT narrow strip around two vertically and parallel winding spools respectively, and fix the two winding spools to the motor respectively.

[0062] Step 2: Overlap the nylon fiber with one end of the CNT narrow strip and fix it on the take-up spool of the fiber twisting and winding device.

[0063] Step 3: Set the winding speed of the bobbin and the winding speed of the fiber twisting and winding device to 0, and control the twisting speed of the fiber twisting and winding device to 200 rpm to 400 rpm. After the composite fiber initially forms a helical structure, rotate the bobbin at a relatively low and appropriate speed to control the tension on the fiber and transport more fibers to form a helical structure. After most of the fibers between the bobbin and the fiber twisting and winding device have formed a helical structure, wind the composite helical fiber at an appropriate winding speed, thus achieving the continuous preparation of CNT@nylon biomimetic muscle fibers.

[0064] A third aspect of the present invention also provides the application of the core-sheath composite artificial muscle fiber system provided in any of the above embodiments in any of the fields of soft robotics, biomedical engineering, and smart fabrics.

[0065] The technical solution of the present invention will be further described in detail below through several embodiments and in conjunction with the accompanying drawings. However, the selected embodiments are only for illustrating the present invention and do not limit the scope of the present invention.

[0066] Example 1

[0067] This embodiment illustrates the construction process of a core-sheath composite artificial muscle fiber system, as detailed below:

[0068] use Figure 1 The preparation process shown involves twisting the polymer fibers and narrow carbon nanotubes together, specifically:

[0069] Step 1: Wrap nylon fibers coated with a 1μm thick carbon material layer and CNT narrow strips onto two vertically and parallelly placed winding drums, and fix the two winding drums to the motor respectively.

[0070] Step 2: Overlap the nylon fiber with one end of the CNT narrow strip and fix it on the take-up spool of the fiber twisting and winding device.

[0071] Step 3: Set the winding speed of the bobbin and the winding speed of the fiber twisting and winding device to 0, and control the twisting speed of the fiber twisting and winding device between 200 rpm and 400 rpm. After the composite fiber initially forms a helical structure, rotate the bobbin at a relatively low and appropriate speed to control the tension on the fiber and deliver more fiber to form a helical structure. After most of the fiber between the bobbin and the fiber twisting and winding device has formed a helical structure, wind the composite helical fiber at an appropriate winding speed, thus achieving the continuous preparation of the CNT@nylon biomimetic muscle fiber body.

[0072] The prepared biomimetic muscle fiber body has a fiber core diameter of about 40 μm, a sheath thickness of about 30 μm, and a twist of 20970 r / m.

[0073] Figure 2a and Figure 2b All images are scanning electron microscopy (SEM) characterization results of the surface and cross-section of the CNT@nylon composite fibers prepared in this embodiment. The composite fibers, after twisting, form a uniform helical structure with a helical diameter of approximately 100 μm. Figure 2a As shown. Figure 2b The image shows a cross-sectional SEM image of the composite fiber. As can be seen from the image, the nylon fiber is completely wrapped inside by narrow carbon nanotube bands. This confirms that inexpensive commercial nylon fiber has replaced the relatively expensive carbon nanotube fiber core, which has almost no driving effect.

[0074] Comparative Example 1

[0075] This comparative example provides an artificial muscle fiber, which is prepared by referring to existing technical solutions, by directly twisting pure carbon nanotube narrow strips. The carbon nanotube narrow strips used in the comparative example are completely consistent with those used in the example (length, width, thickness).

[0076] The driving shrinkage performance of the aforementioned fiber body was characterized using a three-electrode system. Specifically, the composite fiber was used as the working electrode, the platinum black electrode as the counter electrode, and Ag / Ag... + The electrode served as a reference electrode, and a 0.5 M solution of 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMI][BF4]) in propylene carbonate (PC) was used as the electrolyte. A voltage was applied to the composite fiber using an electrochemical workstation. When the voltage was applied, the driving ions (BF4-) migrated into the CNT sheath layer in the composite fiber under the influence of the electric field, causing the CNT sheath layer to expand in volume. This, in turn, caused the fiber to expand radially and contract axially, ultimately resulting in the driving behavior.

[0077] Figure 3 The curves showing the driving amount of CNT@nylon composite fibers and pure CNT fibers under different voltages over time are displayed. When a driving voltage of 2.3V is applied to the composite fiber, BF4- ions migrate into the CNT layer, causing the fiber to shrink rapidly. When the driving voltage is maintained, the shrinkage curve of the composite fiber gradually flattens out, eventually reaching a plateau, with the driving amount reaching a maximum of 24.34% at 5s. Then, when the driving voltage is changed to a recovery voltage (-1V), BF4- ions are extracted from the CNT layer, and the driving amount of the composite fiber decreases rapidly. After 1s, the fiber returns to its original length. The driving amount of the composite fiber decreases as the driving voltage decreases.

[0078] In contrast, continue as Figure 3 As shown, the maximum driving amount of pure carbon nanotube fibers with similar twist and under the same load is only 17.45% at a driving voltage of 2.3V, which is even lower than that of composite fibers at 2V. The driving amount of composite fibers is 39.5% higher than that of pure carbon nanotube fibers. This is mainly because the twist angle of pure CNT fibers gradually decreases to 0 from the surface to the axis, which makes the core unable to play an effective driving role; while in CNT@nylon composite fibers with nylon fibers wrapped inside, the CNTs are located in the sheath layer, and during twisting, each part maintains a large twist angle, which greatly increases the content of effectively driven carbon nanotubes, thereby increasing the driving amount of the fiber.

[0079] In the process of driving artificial muscle fibers, the switching frequency of electrical stimulation has a significant impact on the driving performance. Figure 4a and Figure 4b This figure shows the relationship between the driving performance of CNT@nylon composite fiber and pure CNT fiber at 5 MPa, (-1V to 2V) voltage (83.3% duty cycle) and frequency. As can be seen from the figure, both the driving quantity and output power of the composite fiber decrease with increasing frequency. At 0.1 Hz, the driving quantity and output power are 17.58% and 1.22 J / g, respectively. When the switching frequency increases to 4.17 Hz, the driving quantity and output power decrease to 0.82% and 0.05 J / g, respectively. Figure 4a This is because as the frequency increases, the duration of the applied electric field decreases, leading to a mismatch between the ion migration rate and the switching frequency, thus causing a decrease in the fiber's driving performance. Under the same test conditions, the driving performance of CNT@nylon composite fiber is higher than that of pure CNT fiber at any frequency, and it still has a certain driving force at 4.17 Hz, while pure carbon nanotube fiber has already decayed to 0.69% at 0.83 Hz. The output power and shrinkage rate of the composite fiber also exceed those of pure carbon nanotube fiber. Specifically, at a frequency of 0.55 Hz, the average shrinkage rate of the composite fiber is approximately 4.17 times that of pure CNT fiber; the power density is approximately 14 times that of pure CNT fiber. Figure 4b Compared to pure carbon nanotube fibers, composite fibers exhibit superior frequency response performance and can adapt to higher switching frequencies. This is because the construction of the core-sheath structure increases the contact area between the active carbon nanotube material and the electrolyte, shortening the migration path of ions and thus providing rapid driving response performance.

[0080] Figure 5The figure shows the relationship between the shrinkage properties of CNT@nylon composite fibers and pure fibers and the load. As can be seen from the figure, with the increase of load stress, the shrinkage rate of CNT@nylon composite fibers gradually decreases and the shrinkage work gradually increases. When the stress is about 7.44 MPa, the shrinkage work of the fiber is about 1.2 J / g, which is about 30 times that of skeletal muscle. Compared with pure carbon nanotube fibers, composite fibers still show advantages in driving force and output work.

[0081] like Figure 6a As shown, when CNT@nylon composite fibers are sewn onto white fabric, the composite fibers can be successfully sewn and woven. Figure 6b As shown, composite fibers are sewn onto white cloth, and an electrolyte is dripped onto the cloth to completely saturate it. Applying a voltage to the fibers allows the fabric to undergo electrochemical processes in an air environment, demonstrating its application potential in the field of smart fabrics.

[0082] It can be seen that the CNT@nylon composite fiber provided by this invention has at least the following advantages when used in an electrochemically driven system:

[0083] 1) The narrow carbon nanotubes used were prepared by floating catalytic chemical vapor deposition, which is less expensive than commonly used methods for preparing carbon nanotube arrays. The nylon fibers used are inexpensive and readily available, and can be obtained commercially.

[0084] 2): Composite fibers can be produced by continuous twisting, enabling mass production.

[0085] 3) Due to the construction of the core-sheath structure, the composite fiber increases the contact area between the carbon nanotube fiber and the electrolyte, shortens the migration path of ions, and improves the high-frequency response characteristics of the electrochemical artificial muscle. The CNT@nylon core-sheath structure composite fiber has a faster driving response rate and a higher power density. The driving rate at 0.55Hz is 6.95%, which is about 4.17 times that of pure CNT fiber; the power density is 0.454W / g, which is about 14 times that of pure CNT fiber.

[0086] 4) Inexpensive commercial nylon fibers are used as structural materials to replace the relatively expensive carbon nanotube fibers in the core, which have almost no driving effect. This improves the effective driving ability of the active carbon nanotube material and is of great significance for reducing the amount of relatively expensive carbon nanotube materials used.

[0087] 5): The composite fibers obtained can be used for sewing and weaving, and have application potential in the field of smart fabrics.

[0088] Comparative Example 2

[0089] This comparative example is largely the same as Example 1, with the main difference being:

[0090] The surface of the polymer nylon fiber is not coated with a carbon material layer.

[0091] The measured driving power density was approximately 11.01% of that in Example 1, showing a significant decrease.

[0092] Comparative Example 3

[0093] This comparative example is largely the same as Example 1, with the main difference being:

[0094] The original carbon nanotube narrow bands prepared by floating vapor deposition were subjected to chlorosulfonic acid stretching and orientation treatment before muscle fiber preparation.

[0095] The measured driving power density was approximately 16.7% of that in Example 1, showing a significant decrease. This indicates that the orientation and twisting of the carbon nanotube raw material actually leads to a loss of driving performance, and further demonstrates that intentionally using narrow carbon nanotube bands with poor orientation is a better implementation scheme.

[0096] Example 2

[0097] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0098] Step 1: Wrap the polyester fiber and CNT narrow tape around two vertically and parallel winding drums respectively, and fix the two winding drums to the motor respectively.

[0099] Step 2: Overlap the polyester fiber with one end of the CNT narrow strip and fix it on the take-up spool of the fiber twisting and winding device.

[0100] Step 3: Set the winding speed of the bobbin and the winding speed of the fiber twisting and winding device to 0, and control the twisting speed of the fiber twisting and winding device to 200 rpm to 400 rpm. After the composite fiber initially forms a helical structure, rotate the bobbin at a relatively low and appropriate speed to control the tension on the fiber and transport more fibers to form a helical structure. After most of the fibers between the bobbin and the fiber twisting and winding device have formed a helical structure, wind the composite helical fiber at an appropriate winding speed. Due to the accumulation of twist and the control of tension, the continuous preparation of CNT@polyester biomimetic muscle fiber is finally achieved.

[0101] The prepared core-sheath composite artificial muscle fiber still exhibits excellent driving response performance and driving quantity / power in the electrochemical driving system.

[0102] Example 3

[0103] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0104] Step 1: Wrap the aramid fiber and CNT narrow strip around two vertically and parallel winding drums respectively, and fix the two winding drums to the motor respectively.

[0105] Step 2: Overlap the aramid fiber with one end of the CNT narrow strip and fix it on the take-up spool of the fiber twisting and winding device.

[0106] Step 3: Set the winding speed of the bobbin and the winding speed of the fiber twisting and winding device to 0, and control the twisting speed of the fiber twisting and winding device to 200 rpm to 400 rpm. After the composite fiber initially forms a helical structure, rotate the bobbin at a relatively low and appropriate speed to control the tension on the fiber and transport more fibers to form a helical structure. After most of the fibers between the bobbin and the fiber twisting and winding device have formed a helical structure, wind the composite helical fiber at an appropriate winding speed. Due to the accumulation of twist and the control of tension, the continuous preparation of CNT@aramid biomimetic muscle fibers is finally achieved.

[0107] The resulting core-sheath composite artificial muscle fiber still exhibits excellent drive response performance and drive quantity / power in the telephone-based drive system.

[0108] Example 4

[0109] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0110] Step 1: Wrap the spandex fiber and CNT narrow strip around two vertically and parallel winding drums respectively, and fix the two winding drums to the motor respectively.

[0111] Step 2: Overlap the spandex fiber with one end of the CNT narrow strip and fix it on the take-up spool of the fiber twisting and winding device.

[0112] Step 3: Set the winding speed of the bobbin and the winding speed of the fiber twisting and winding device to 0, and control the twisting speed of the fiber twisting and winding device to 200 rpm to 400 rpm. After the composite fiber initially forms a helical structure, rotate the bobbin at a relatively low and appropriate speed to control the tension on the fiber and transport more fibers to form a helical structure. After most of the fibers between the bobbin and the fiber twisting and winding device have formed a helical structure, wind the composite helical fiber at an appropriate winding speed. Due to the accumulation of twist and the control of tension, the continuous preparation of CNT@spandex biomimetic muscle fibers is finally achieved.

[0113] The resulting core-sheath composite artificial muscle fiber still exhibits excellent drive response performance and drive quantity / power in the telephone-based drive system.

[0114] Example 5

[0115] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0116] Step 1: Wrap nylon fibers and graphene narrow strips / tows onto two vertically and parallel winding drums, and fix the two winding drums to the motor respectively.

[0117] Step 2: Overlap one end of the nylon fiber with one end of the graphene narrow strip / tow and fix it on the take-up spool of the fiber twisting and winding device.

[0118] Step 3: Set the winding speed of the bobbin and the winding speed of the fiber twisting and winding device to 0, and control the twisting speed of the fiber twisting and winding device to 200 rpm to 400 rpm. After the composite fiber initially forms a helical structure, rotate the bobbin at a relatively low and appropriate speed to control the tension on the fiber and transport more fibers to form a helical structure. After most of the fibers between the bobbin and the fiber twisting and winding device have formed a helical structure, wind the composite helical fiber at an appropriate winding speed. Due to the accumulation of twist and the control of tension, the continuous preparation of graphene narrow strip / tow@nylon biomimetic muscle fibers is finally achieved.

[0119] The resulting core-sheath composite artificial muscle fiber still exhibits excellent drive response performance and drive quantity / power in the telephone-based drive system.

[0120] Example 6

[0121] This embodiment is largely the same as Embodiment 1, with the main difference being:

[0122] Step 1: Wrap nylon fibers and carbon fiber narrow strips / tows onto two vertically and parallel winding drums, and fix the two winding drums to the motor respectively.

[0123] Step 2: Overlap one end of the nylon fiber with one end of the carbon fiber narrow strip / tow and fix it on the take-up spool of the fiber twisting and winding device.

[0124] Step 3: Set the winding speed of the bobbin and the winding speed of the fiber twisting and winding device to 0, and control the twisting speed of the fiber twisting and winding device to 200 rpm to 400 rpm. After the composite fiber initially forms a helical structure, rotate the bobbin at a relatively low and appropriate speed to control the tension on the fiber and transport more fiber to form a helical structure. After most of the fiber between the bobbin and the fiber twisting and winding device has formed a helical structure, wind the composite helical fiber at an appropriate winding speed. Due to the accumulation of twist and the control of tension, the continuous preparation of carbon fiber narrow ribbon / tow@nylon biomimetic muscle fiber is finally achieved.

[0125] The resulting core-sheath composite artificial muscle fiber still exhibits excellent drive response performance and drive quantity / power in the telephone-based drive system.

[0126] Based on the above test results, it is clear that this invention provides a composite artificial muscle fiber with a core-sheath structure. The sheath layer is an electrochemically driven active material, and the core is an electrochemically inert material. The CNT fibers used in the sheath layer are prepared by floating catalytic chemical vapor deposition, which is cheaper and more readily available than CNT arrays. This invention develops a method for continuously twisting biomimetic artificial muscle fibers. The tension experienced by the fiber during twisting is controlled by the rotational speed of a motor, and the composite fiber is twisted and wound using a fiber twisting and winding device. The composite fiber provided by this invention exhibits a high driving response rate and power density at a large duty cycle. The core fibers of the composite fiber provided by this invention include high-molecular polymer fibers with a certain degree of toughness and no electrochemical activity, such as nylon fibers, polyester fibers, aramid fibers, and spandex fibers. The sheath fibers of the composite fiber provided by this invention include electrochemically driven active carbon nanotube fibers / tows, graphene fibers / tows, carbon fibers / tows, and other electrochemically driven active fiber materials. The composite fiber provided by this invention is easy to sew and weave, and can be used in smart fabrics and other application fields.

[0127] It should be understood that the above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A core-sheath composite artificial muscle fiber system, comprising a fiber body and an electrolyte impregnating the fiber body, wherein the electrolyte contains driving ions; Its features are, The fiber body comprises a polymer fiber core and a carbon material sheath enveloping the polymer fiber core. The carbon material sheath is formed by enveloping the polymer fiber core with at least a continuous carbon nanotube film or narrow strip. A friction-enhancing layer with a thickness of 0.5-2 μm is further disposed between the polymer fiber core and the carbon material sheath. The friction-enhancing layer comprises a carbon material layer. The carbon material sheath is made of any one or a combination of two or more of carbon nanotubes, graphene, and carbon fibers. The average thickness of the carbon material sheath is 20-40 μm. The polymer fiber core is electrochemically inert, and the fiber body is twisted into an overtwisted spiral state. The fiber body is sewn onto the fabric, the electrolyte is impregnated therein, and the driving ions can migrate into or out of the multiple constituent units in the carbon material sheath under the action of an electric field.

2. The core-sheath composite artificial muscle fiber system according to claim 1, characterized in that, The polymer fiber core is made of any one or a combination of two or more of nylon, polyester, aramid, and spandex.

3. The core-sheath composite artificial muscle fiber system according to claim 1, characterized in that, The diameter of the polymer fiber core is 30-50 μm.

4. The core-sheath composite artificial muscle fiber system according to claim 1, characterized in that, The driving ion includes BF4. – PF6 - Any one or a combination of two of them; And / or, the solvent in the electrolyte includes any one or a combination of two of propylene carbonate and γ-butyrolactone.

5. The core-sheath composite artificial muscle fiber system according to claim 1, characterized in that, The concentration of driving ions in the electrolyte is 0.5~1 mol / L; And / or, the twist of the fiber body is 15000-25000 r / m.

6. A method for preparing the core-sheath composite artificial muscle fiber system according to any one of claims 1-5, characterized in that, include: We provide carbon material membranes and polymer fibers; The carbon material film is wrapped around the polymer fiber and twisted to form a fiber body; The fiber body is sewn onto the fabric and impregnated with electrolyte to form a core-sheath composite artificial muscle fiber system.

7. The preparation method according to claim 6, characterized in that, Specifically, it includes: The carbon material film and the ends of the polymer fiber are twisted together to form the initial twist. The carbon material membrane and polymer fiber are continuously supplied, and the twisted fiber body is continuously collected to continuously prepare the fiber body with a helical structure.

8. The preparation method according to claim 7, characterized in that, The twisting speed is 200-400 rpm, and the travel speed of the carbon material film and polymer fiber is 0.5-1.5 m / min.

9. The application of the core-sheath composite artificial muscle fiber system according to any one of claims 1-5 in any field of soft robotics, biomedical engineering, or smart fabrics.

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