Highly ordered functional fibers and preparation methods

Abstract

The present invention belongs to the field of fiber preparation technology, and discloses highly ordered functional fibers and preparation methods. The highly ordered layered functional fibers are coaxial fibers having a core layer and a shell layer prepared by wet spinning. The core layer is a composite material having a stacked oriented structure obtained by self-assembly using shear flow technology after encapsulating MXene nanosheets with tannic acid, and the shell layer is polyvinyl pyrrolidone. The core layer of the coaxial fiber of the present invention has the characteristics of a stacked oriented structure. This structure significantly improves the conductivity of the MXene nanosheets, and comprehensively improves the sensing performance and shielding performance of the material. At the same time, due to the spatial confinement channel provided by the shell material, it not only promotes the directional arrangement of the MXene nanosheets, but also avoids their long-term contact with the complex environment, thereby extending the service life of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber preparation, and in particular to highly ordered functional fibers and a preparation method thereof. Background Art

[0002] With the continuous development of human civilization, people's lifestyles have also undergone tremendous changes. Textile fiber products are no longer just for warmth and decoration. Functional products are a new development direction for the fiber industry. Among them, coaxial fiber is a new fiber material with a unique structure and excellent performance, which has a wide range of applications. Traditional coaxial fiber preparation technology mainly focuses on combining different polymers or materials to achieve specific performance requirements. However, with the rapid development of fields such as the Internet of Things, flexible electronics, and biomedicine, the functional requirements for coaxial fibers are becoming increasingly higher. For example, humidity sensing, strain response, etc.

[0003] MXene, the full name of which is two-dimensional transition metal carbon / nitride, is prepared by selectively etching the A layer in the MAX phase of a ternary layered compound. M is one or more transition metal elements (such as Ti, Sc, Zr, Nb, etc.), X represents carbon or nitrogen, A represents Al, Si, Ga, etc., and T x It represents the functional groups (such as O, F, OH, Cl, etc.) generated on its surface during the chemical etching process. MXene materials have excellent mechanical properties and high electrical conductivity, and have broad application prospects in many high-tech fields.

[0004] Currently, the use of MXene to prepare flexible sensing fibers or fabrics often involves surface functionalization (such as impregnation and spraying) or the construction of a conductive network on the fiber surface. However, MXene flakes easily aggregate, and maintaining their dispersion and stability during the preparation process remains a technical challenge. Furthermore, MXene's strong reaction with water and oxygen results in poor chemical stability, which causes oxidized TiO2 to nucleate and grow and diffuse across the surface of the flakes, leading to structural defects in the MXene nanosheets and functional degradation. Furthermore, the weak interfacial bonding between MXene and the fiber or fabric makes it easily detachable, shortening the lifespan of the sensing fiber or fabric. Summary of the Invention

[0005] The present invention aims to solve at least one of the above technical problems and proposes a highly ordered functional fiber and a preparation method thereof.

[0006] In order to achieve the above object, the first technical solution adopted by the present invention is:

[0007] The highly ordered functional fibers are coaxial fibers with a core layer and a shell layer prepared by wet spinning. The core layer is tannic acid-encapsulated MXene nanosheets. The composite material obtained by self-assembly has a layer-by-layer oriented structure, and the shell layer is polyvinyl pyrrolidone.

[0008] Preferably, the mass ratio of the tannic acid to the MXene nanosheets is 1:(1-9).

[0009] Preferably, the shell layer also contains collagen.

[0010] Preferably, the mass ratio of the collagen to polyvinyl pyrrolidone is 1:(1-5). The second technical solution adopted by the present invention is:

[0011] A method for preparing highly ordered functional fibers, comprising:

[0012] Disperse MXene nanosheets in deionized water, add tannic acid, and magnetically stir for 1-12 hours at pH 7-10 to obtain a core spinning solution;

[0013] Dissolving polyvinyl pyrrolidone in water to obtain a shell spinning solution;

[0014] The core layer spinning solution and the shell layer spinning solution are wet-spinned to prepare coaxial fibers.

[0015] Preferably, the spinning speed ratio of the core layer to the shell layer is 1:(1-5).

[0016] The metering speed ratio of the shell layer and the core layer during wet spinning is (1-5):1.

[0017] Preferably, the drawing speed ratio of the spinneret, the first drawing machine and the second drawing machine during the wet spinning process is 1:1:(1-5).

[0018] Preferably, the preparation method of MXene nanosheets is as follows: selectively etching the aluminum layer of Ti3AlC2 in HCl / LiF solution, ultrasonically peeling the aluminum layer, centrifuging to obtain the supernatant, and freeze-drying the supernatant.

[0019] Preferably, polyvinyl pyrrolidone and collagen are dissolved in water to obtain a shell spinning solution.

[0020] Preferably, the coagulation bath used in wet spinning is a saturated anhydrous sodium sulfate solution.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The core material of the coaxial fiber of the present invention is MXene nanosheets encapsulated by tannic acid, which has a directional structure of stacked layers under the combined action of physical shear and TA adhesion. This structure significantly improves the conductivity of the MXene nanosheets, and comprehensively improves the sensing performance and shielding performance of the material. At the same time, due to the spatial confinement channel provided by the shell material, it not only promotes the directional arrangement of the MXene nanosheets, but also avoids its long-term contact with the complex environment, thereby extending the service life of the material. A stable and compatible interface network is constructed between the functional fiber core layer and the shell material provided by the present invention, which can not only optimize the interface structure inside the composite material, but also give full play to the performance advantages of each component, so that the composite material can maintain excellent functionality while also taking into account good mechanical properties.

[0023] The present invention uses tannic acid to encapsulate MXene nanosheets into stable TA-MXene nanosheets, improving the dispersion stability of the MXene nanosheets in water or other solvents and preventing aggregation and sedimentation. Furthermore, because TA contains a large number of hydroxyl groups, it can form multi-site hydrogen bonds with MXene. Water and oxygen preferentially react with TA, consuming the oxidation source. Water and oxygen that reach the vicinity of Ti atoms no longer react with Ti, effectively preventing MXene oxidation. The core-shell structure of the present invention solves the problem of MXene being easily oxidized when exposed to complex environments for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a digital photo of the MXene dispersion prepared in Example 1;

[0025] Figure 2 The monolayer Ti3C2T in the MXene dispersion prepared in Example 1 x Microscopic morphology of MXene nanosheets;

[0026] Figure 3 The raw material Ti3AlC2 in Example 1 and the single layer Ti3C2T in the prepared MXene dispersion x X-ray diffraction spectrum of MXene nanosheets;

[0027] Figure 4 The effect diagram of the TA-MXene dispersion prepared in Example 1 and the MXene dispersion after standing for 50 days;

[0028] Figure 5 Surface (a, b) and cross-section (c, d) microscopic morphologies of the Col / PVP@TA-MXene coaxial fibers prepared in Example 1;

[0029] Figure 6The small-angle diffraction patterns of the coaxial fibers prepared in Example 1 (a) and Comparative Examples 1-2 (b-c), where f is the orientation factor;

[0030] Figure 7 Graph showing resistance changes of the coaxial fibers prepared in Example 1 and Comparative Examples 1-2;

[0031] Figure 8 This is a diagram of the sensing performance of the coaxial fiber prepared in Example 1. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention clearer, the scheme of the present invention is further described in detail below in conjunction with embodiment.It will be appreciated by those skilled in the art that the following examples are exemplary only, and are not intended to limit the scope of the present invention.In addition, in the following description, in the examples, those not indicating specific conditions are carried out according to the conditions of normal conditions or manufacturer's advice. Reagents used or instruments not indicating manufacturers are conventional products that can be purchased commercially.

[0033] The first embodiment of the present invention provides a highly ordered functional fiber, which is a coaxial fiber having a core layer and a shell layer prepared by wet spinning. The core layer is a composite material with a layered stacked oriented structure obtained by self-assembly of MXene nanosheets encapsulated with tannic acid through shear flow technology, and the shell layer is polyvinyl pyrrolidone.

[0034] The functional fiber provided by this invention features a spatially confined shell-coated structure. The shell imposes a certain degree of spatial confinement on the core MXene nanosheets, which not only guides the MXene nanosheets into orderly, oriented alignment but also promotes structural order. Furthermore, the MXene nanosheets are encapsulated with tannic acid (TA), whose adhesive properties significantly enhance the interaction between the MXene nanosheets. The synergistic effect of physical shear force and TA adhesion enables MXene to exhibit remarkable self-assembly, spontaneously forming a layered, oriented structure. This layered, oriented structure positively impacts the material's electrical conductivity. The underlying mechanism is that when the MXene nanosheets are stacked in an orderly fashion, the electron transport path between them becomes more direct and efficient, reducing scattering and obstruction during electron transmission. This structural optimization enables electrons to flow quickly and smoothly within the composite material, significantly improving the material's electrical conductivity. This improvement is crucial for the material's sensing and shielding properties, making it more sensitive and efficient in receiving and transmitting signals.

[0035] It should be noted that the physical shear force referred to above refers to the physical shearing achieved during the wet spinning stage by applying different spinning speeds and drawing speeds through the coaxial spinning needle, thereby achieving the layer-by-layer stacking and self-assembly of MXene. Specifically, during the wet spinning process, the metering speed ratio of the shell layer to the core layer is (1-5):1, and the drawing speed ratio of the spinneret, the first drawing machine, and the second drawing machine is 1:1:(1-5).

[0036] The present invention proposes an innovative interface engineering strategy. Since TA has good interface affinity, its unique molecular structure can establish an effective interface bond between the layers of the composite material. Specifically, the multiple phenolic hydroxyl groups in the tannic acid molecule can form hydrogen bonds or chemical bonds with the different components in the composite material. This chemical interaction significantly improves the interfacial compatibility between the two phases. The mechanism is that TA constructs a stable and compatible interface network inside the composite material through chemical bonding and hydrogen bonding. This not only optimizes the interface structure inside the composite material, but also gives full play to the performance advantages of the different components. This allows the composite material to maintain excellent functionality while also taking into account good mechanical properties.

[0037] The functional fiber of this invention utilizes a shell-coated design, cleverly resolving the issues of surface functional particles easily falling off and oxidizing when using traditional methods such as surface impregnation and spraying. This not only prevents prolonged contact of the functional particles with complex environments but also prevents loss of core functional particles during the preparation process. These advantages combine to further extend the material's service life, ensuring its excellent performance and stability across a wide range of applications.

[0038] The present invention encapsulates MXene into stable TA-MXene nanosheets by introducing tannic acid (TA) with a polyhydroxy structure. Since TA contains a large number of hydroxyl groups, it can form multi-site hydrogen bonds with MXene. Water and oxygen will preferentially react with TA, consuming the oxidation source. Water and oxygen that reach the vicinity of Ti atoms no longer react with Ti, thereby preventing the oxidation of MXene.

[0039] In some preferred embodiments, the mass ratio of the tannic acid to the MXene nanosheets is 1:(1-9).

[0040] In some preferred embodiments, collagen is added to the shell layer to improve the biocompatibility of the functional fiber, so that the functional fiber of the present invention can be used to prepare medical devices such as wound dressings and tissue engineering scaffolds.

[0041] The mass ratio of the collagen to polyvinyl pyrrolidone is 1:(1-5).

[0042] The second embodiment of the present invention provides a method for preparing highly antioxidant functional fibers, comprising: dispersing MXene nanosheets in deionized water, adding tannic acid, and magnetically stirring at pH 8 to obtain a core spinning solution; dissolving polyvinyl pyrrolidone in water to obtain a shell spinning solution; and preparing the core spinning solution and the shell spinning solution into coaxial fibers using a wet spinning method.

[0043] The intensity of the physical shear force in the wet spinning process can be controlled by different injection speeds, and the action time lasts throughout the entire wet spinning stage, including spinning, coagulation, drawing and other processes.

[0044] In the embodiments of the present invention, the coaxial spinning needle used in the wet spinning stage is of commonly used dimensions in the art and does not require specific limitations. However, the metering speeds of the shell and core layers, as well as the speed ratio between the spinneret and the drafting machine, can affect the layer-by-layer stacking of MXene nanosheets in the resulting functional fibers. Therefore, in the embodiments of the present invention, the metering speed ratio of the shell and core layers during wet spinning is (1-5):1, and the drafting speed ratio of the spinneret, the first drafting machine, and the second drafting machine is 1:1:(1-5).

[0045] The present invention adopts coaxial wet spinning to avoid the coagulation of incompatible components in the PVP solution and the loss of MXene nanosheets during the spinning process.

[0046] It should be noted that the wet spinning method used in the present invention is a commonly used method in the field and is not specifically limited. The following operation steps are only given as an example of wet spinning: the core-shell spinning solution is connected to different injection pumps respectively, and injected into the coagulation bath through the coaxial spinning needle at different injection speeds to form nascent fibers; the nascent fibers pass through the drawing machine into the water washing bath to clean the coagulant attached to the fiber surface, and then the moisture is removed by slit heating and drying; the dried fibers are further subjected to dry heat stretching treatment to increase the strength of the fibers; and the fibers are collected into rolls by a winder.

[0047] For reference, the coagulation bath used in the wet spinning process in this embodiment is a saturated anhydrous sodium sulfate solution.

[0048] The preparation method of MXene nanosheets is also a common technical means in the prior art to use HF to etch the aluminum layer in Ti3AlC2, and is not specifically limited. The preparation method given below is only an example: Ti3AlC2 selectively etches the aluminum layer in HCl / LiF solution, and after ultrasonically stripping the aluminum layer, the supernatant is centrifuged and freeze-dried.

[0049] In some preferred embodiments, collagen can be added to the shell spinning solution to improve the biocompatibility of the functional fiber. Specifically, polyvinyl pyrrolidone and collagen are dissolved in water to obtain the shell spinning solution.

[0050] The following discloses specific embodiments of the present invention to illustrate the functional fiber, its preparation and specific performance.

[0051] Example 1

[0052] Preparation of MXene dispersion: First, Ti3AlC2 is etched. 40 mL of 9 mol / L hydrochloric acid solution and 3.2 g of lithium fluoride are added as etchants to a polytetrafluoroethylene beaker and stirred in an ice-water bath for 10 min. 2 g of Ti3AlC2 powder is slowly added to the beaker in small amounts and multiple times. The mixed solution is then stirred in a 45°C oil bath for 24 h to etch away the aluminum layer. After etching, the solution is centrifuged and washed with deionized water multiple times at 3500 rpm until the supernatant is close to neutral. The bottom precipitate is collected, an appropriate amount of deionized water is added, and ultrasonic vibration is performed under nitrogen protection for 1 hour. Finally, the solution is centrifuged at 3500 rpm for 45 min. After centrifugation, the supernatant is taken to obtain a single layer of Ti3C2T x MXene dispersion (hereinafter referred to as "MXene dispersion"), its digital photo is as follows Figure 1 As shown. Monolayer Ti3C2T in MXene dispersion x The microscopic morphology of MXene nanosheets is as follows Figure 2 As shown, from Figure 2 A clear lamellar structure can be observed, indicating that the preparation was successful. Figure 3 For single-layer Ti3C2T in MXene dispersion x The X-ray diffraction spectrum of MXene nanosheets shows that the MXene dispersion was successfully prepared.

[0053] Preparation of TA-MXene dispersion: The above dispersion was freeze-dried to obtain Ti3C2T x MXene nanosheets. Take 5 g of MXene nanosheets and dissolve them in deionized water with ultrasonic dispersion for 30 min. Then add the same amount of TA, adjust the pH value of the solution to 8 with tris buffer, and stir magnetically for 12 h to obtain a dark green TA-MXene dispersion. The effect after standing for 50 days with the MXene dispersion is shown in the figure below. Figure 4 As shown. Figure 4 It can be seen that the water dispersibility of the TA-MXene dispersion modified by TA is significantly improved, and the water stability is better.

[0054] Preparation of Col / PVP aqueous solution: Weigh 50 g of polyvinyl pyrrolidone granules and collagen powder respectively, add a certain amount of water in proportion, and transfer to a container with a stirring device. Stir at room temperature for 30 minutes until completely dissolved to obtain a 10 wt% Col / PVP aqueous solution.

[0055] A TA-MXene dispersion was used as the core spinning solution, and a Col / PVP solution was used as the shell spinning solution. A coaxial spinning needle with an inner diameter of 22G and an outer diameter of 17G was used as the spinning head. The core and shell spinning solutions were injected into a coagulation bath of saturated anhydrous sodium sulfate solution at injection rates of 7mL / h and 21mL / h, respectively, to produce nascent fibers. After coagulation in the coagulation bath, the fibers were transferred to a water washing bath via a drawing machine to remove residual coagulant on the fiber surface. The fibers then underwent slot-type heating drying and dry heat stretching before being collected and rolled to obtain the finished Col / PVP@TA-MXene fibers.

[0056] Example 2

[0057] Preparation of MXene dispersion: First, Ti3AlC2 is etched. 40 mL of 9 mol / L hydrochloric acid solution and 3.2 g of lithium fluoride are added as etchants to a polytetrafluoroethylene beaker and stirred in an ice-water bath for 10 min. 2 g of Ti3AlC2 powder is slowly added to the beaker in small amounts and multiple times. The mixed solution is then stirred in a 45°C oil bath for 24 h to etch away the aluminum layer. After etching, the solution is centrifuged and washed with deionized water multiple times at 3500 rpm until the supernatant is close to neutral. The bottom precipitate is collected, an appropriate amount of deionized water is added, and ultrasonic vibration is performed under nitrogen protection for 1 hour. Finally, the solution is centrifuged at 3500 rpm for 45 min. After centrifugation, the supernatant is taken to obtain a single layer of Ti3C2T x MXene dispersion.

[0058] Preparation of TA-MXene dispersion: The above dispersion was freeze-dried to obtain MXene nanosheets. 9 g of MXene nanosheets were ultrasonically dispersed in deionized water for 30 min. Then, 1 g of TA was added. The pH of the solution was adjusted to 8 using tris buffer. The solution was magnetically stirred for 12 h to obtain a TA-MXene dispersion.

[0059] Preparation of Col / PVP aqueous solution: Weigh 50 g of polyvinyl pyrrolidone granules and collagen powder respectively, add a certain amount of water in proportion, and transfer to a container with a stirring device. Stir at room temperature for 30 minutes until completely dissolved to obtain a 10 wt% Col / PVP aqueous solution.

[0060] A TA-MXene dispersion was used as the core spinning solution, and a Col / PVP solution was used as the shell spinning solution. Using a coaxial spinning needle with an inner diameter of 22G and an outer diameter of 17G, the core and shell spinning solutions were injected into a coagulation bath of saturated anhydrous sodium sulfate solution at injection rates of 7 mL / h and 21 mL / h, respectively, to produce nascent fibers. After coagulation in the coagulation bath, the fibers were transferred via a drafting machine to a water washing bath to remove any residual coagulant on the fiber surface. The fibers then underwent slot-type heating drying and dry-heat stretching before being collected and rolled to obtain the finished Col / PVP@TA-MXene fibers.

[0061] Example 3

[0062] Preparation of MXene dispersion: First, Ti3AlC2 is etched. 40 mL of 9 mol / L hydrochloric acid solution and 3.2 g of lithium fluoride are added as etchants to a polytetrafluoroethylene beaker and stirred in an ice-water bath for 10 min. 2 g of Ti3AlC2 powder is slowly added to the beaker in small amounts and multiple times. The mixed solution is then stirred in a 45°C oil bath for 24 h to etch away the aluminum layer. After etching, the solution is centrifuged and washed with deionized water multiple times at 3500 rpm until the supernatant is close to neutral. The bottom precipitate is collected, an appropriate amount of deionized water is added, and ultrasonic vibration is performed under nitrogen protection for 1 hour. Finally, the solution is centrifuged at 3500 rpm for 45 min. After centrifugation, the supernatant is taken to obtain a single layer of Ti3C2T x MXene dispersion.

[0063] Preparation of TA-MXene dispersion: The above dispersion was freeze-dried to obtain MXene nanosheets. 5 g of MXene nanosheets were ultrasonically dispersed in deionized water for 30 min. Then, 1 g of TA was added. The pH of the solution was adjusted to 8 using tris buffer. The solution was magnetically stirred for 12 h to obtain a TA-MXene dispersion.

[0064] Preparation of PVP aqueous solution: Weigh 50 g of polyvinylpyrrolidone granules, add a certain amount of water in proportion and transfer to a container with a stirring device. Stir at room temperature for 30 minutes. After complete dissolution, a 10 wt% PVP aqueous solution is obtained.

[0065] A TA-MXene dispersion was used as the core spinning solution, and a PVP solution was used as the shell spinning solution. Using a coaxial spinning needle with an inner diameter of 22G and an outer diameter of 17G, the core and shell spinning solutions were injected into a coagulation bath of saturated anhydrous sodium sulfate solution at injection rates of 7 mL / h and 21 mL / h, respectively, to produce nascent fibers. After coagulation in the coagulation bath, the fibers were transferred via a drafting machine to a water washing bath to remove any residual coagulant on the fiber surface. The fibers then underwent slot-type heating drying and dry-heat stretching before being collected and rolled to obtain the finished PVP@TA-MXene fibers.

[0066] Comparative Example 1

[0067] Compared with Example 1, the difference is that TA is not used to encapsulate the MXene nanosheets, as follows:

[0068] Preparation of MXene dispersion: First, Ti3AlC2 is etched. 40 mL of 9 mol / L hydrochloric acid solution and 3.2 g of lithium fluoride are added as etchants to a polytetrafluoroethylene beaker and stirred in an ice-water bath for 10 min. 2 g of Ti3AlC2 powder is slowly added to the beaker in small amounts and multiple times. The mixed solution is then stirred in a 45°C oil bath for 24 h to etch away the aluminum layer. After etching, the solution is centrifuged and washed with deionized water multiple times at 3500 rpm until the supernatant is close to neutral. The bottom precipitate is collected, an appropriate amount of deionized water is added, and ultrasonic vibration is performed under nitrogen protection for 1 hour. Finally, the solution is centrifuged at 3500 rpm for 45 min. After centrifugation, the supernatant is taken to obtain a single layer of Ti3C2T x MXene dispersion.

[0069] Preparation of Col / PVP aqueous solution: Weigh 50 g of polyvinyl pyrrolidone granules and collagen powder respectively, add a certain amount of water in proportion, and transfer to a container with a stirring device. Stir at room temperature for 30 minutes until completely dissolved to obtain a 10 wt% Col / PVP aqueous solution.

[0070] A MXene dispersion was used as the core spinning solution, and a Col / PVP solution as the shell spinning solution. Using a coaxial spinning needle with an inner diameter of 22G and an outer diameter of 17G, the core and shell spinning solutions were injected into a coagulation bath of saturated anhydrous sodium sulfate solution at injection rates of 7 mL / h and 21 mL / h, respectively, to produce nascent fibers. After coagulation in the coagulation bath, the fibers were transferred via a drafting machine to a water washing bath to remove any residual coagulant on the fiber surface. The fibers then underwent slot-type drying and dry-heat stretching before being collected and rolled to yield the finished Col / PVP@MXene fibers.

[0071] Comparative Example 2

[0072] Compared with Example 1, the difference is that the metering speed of the core layer and shell layer has changed, as follows:

[0073] Preparation of MXene dispersion: First, Ti3AlC2 is etched. 40 mL of 9 mol / L hydrochloric acid solution and 3.2 g of lithium fluoride are added as etchants to a polytetrafluoroethylene beaker and stirred in an ice-water bath for 10 min. 2 g of Ti3AlC2 powder is slowly added to the beaker in small amounts and multiple times. The mixed solution is then stirred in a 45°C oil bath for 24 h to etch away the aluminum layer. After etching, the acid is washed by centrifugation at 3500 rpm using deionized water several times until the supernatant is close to neutral. The bottom precipitate is collected, an appropriate amount of deionized water is added, and ultrasonic vibration is performed under nitrogen protection for 1 hour. Finally, the solution is centrifuged at 3500 rpm for 45 min. After centrifugation, the supernatant is taken to obtain a single layer of Ti3C2T x MXene dispersion.

[0074] Preparation of TA-MXene dispersion: The above dispersion was freeze-dried to obtain MXene nanosheets. 5 g of MXene nanosheets were ultrasonically dispersed in deionized water for 30 minutes. An equal amount of TA was added, and the pH of the solution was adjusted to 8 using tris buffer. The solution was magnetically stirred for 12 hours to obtain a dark green TA-MXene dispersion.

[0075] Preparation of Col / PVP aqueous solution: Weigh 50 g of polyvinyl pyrrolidone granules and collagen powder respectively, add a certain amount of water in proportion, and transfer to a container with a stirring device. Stir at room temperature for 30 minutes until completely dissolved to obtain a 10 wt% Col / PVP aqueous solution.

[0076] A TA-MXene dispersion was used as the core spinning solution, and a Col / PVP solution was used as the shell spinning solution. Using a coaxial spinning needle with an inner diameter of 22G and an outer diameter of 17G, the core and shell spinning solutions were injected into a coagulation bath of saturated anhydrous sodium sulfate solution at injection rates of 14 mL / h and 7 mL / h, respectively, to produce nascent fibers. After coagulation in the coagulation bath, the fibers were transferred via a drafting machine to a water washing bath to remove any residual coagulant on the fiber surface. The fibers then underwent slot-type heating drying and dry-heat stretching before being collected and rolled to obtain the finished Col / PVP@TA-MXene fibers.

[0077] Test example

[0078] The functional fibers prepared in Example 1 and Comparative Examples 1-2 were subjected to various performance tests, as follows:

[0079] Field emission scanning electron microscopy (SEM) was used to observe the morphology of the Col / PVP@TA-MXene fiber in Example 1. The surface (ab) and cross-section (cd) micromorphologies are shown in Figure 2. Figure 5 As shown, the cross-sectional SEM image shows that the TA-MXene nanosheets in the core layer are stacked layer by layer and arranged along the fiber axis.

[0080] The orientation of the coaxial fibers obtained in Example 1 and Comparative Examples 1-2 was tested by small angle X-ray diffraction (SAXS). Figure 6 As shown. After calculation of Example 1 ( Figure 6 a) can reach a coaxial fiber orientation factor f of 0.874, which is much larger than that of comparative example 1-2 ( Figure 6 bc) The obtained fibers demonstrate that the fibers have good structural orientation.

[0081] The fibers in Example 1 and Comparative Examples 1-2 were washed with water, alkali and acid respectively, and then the resistance change of the fibers was tested using an electrochemical workstation. The results are shown in FIG. Figure 7 The results show that the resistance of the Col / PVP@TA-MXene fiber modified by TA in Example 1 does not change much, proving that it has good environmental stability.

[0082] The functionality of the fiber obtained in Example 1 was tested using the IT mode of the electrochemical workstation. Figure 8 As shown in the figure, the fiber can respond to different human behaviors (such as bending fingers, running and walking, etc.), proving that the fiber has good sensing capabilities. For example, bending and straightening a finger will cause the resistance of the fiber to change, and the change in current will be fed back through the electrochemical workstation, thus obtaining Figure 8 That is, the electrical signal changes once the finger bends and straightens, and the cycle repeats itself.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing highly ordered functional fibers, characterized in that: Include: Disperse MXene nanosheets in deionized water, add tannic acid, and magnetically stir for 1-12 hours at pH 7-10 to obtain a core spinning solution; dissolving polyvinyl pyrrolidone, or polyvinyl pyrrolidone and collagen in water to obtain a shell spinning solution; The core layer spinning solution and the shell layer spinning solution are wet-spinned to prepare coaxial fibers; Among them, the metering speed ratio of the shell layer and the core layer during the wet spinning process is (1-5):1; During the wet spinning process, the drawing speed ratio of the spinneret, the first drawing machine, and the second drawing machine is 1:1:(1-5).

2. The preparation method according to claim 1, wherein The preparation method of MXene nanosheets is as follows: Ti3AlC2 selectively etches the aluminum layer in HCl / LiF solution, ultrasonically peels off the aluminum layer, centrifuges to obtain the supernatant, and freeze-dries the supernatant.

3. The preparation method according to claim 1, wherein The coagulation bath used in wet spinning is a saturated anhydrous sodium sulfate solution.

4. The preparation method according to claim 1, wherein The mass ratio of the tannic acid to the MXene nanosheets is 1:(1-9).

5. The preparation method according to claim 1, wherein The mass ratio of the collagen to polyvinyl pyrrolidone is 1:(1-5).

6. Highly ordered functional fibers, characterized in that The composite material is prepared by the preparation method according to any one of claims 1 to 5, wherein the core layer is a composite material obtained by self-assembly of tannic acid-encapsulated MXene nanosheets, and has a layer-by-layer oriented structure.

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