Flexible conductive fiber with multistage pore structure and preparation method thereof

Abstract

The invention discloses a flexible conductive fiber with a multistage pore structure and a preparation method thereof.The preparation method comprises the steps that polyurethane and graphene in a preset proportion are dissolved in a first solvent prepared from N, N-dimethylformamide and methylbenzene in a preset proportion to obtain a spinning solution, and then a pyrrole-aqueous solution serves as a first coagulating bath; according to the method, pyrrole-polyurethane fibers are prepared through wet spinning, and then a ferric chloride solution is used as a second coagulating bath to prepare the flexible conductive fibers with the multi-stage pore structure. The surface and the interior of a fiber material are filled with pyrrole through phase replacement of wet spinning, superposition of internal and external conductivity is achieved, the sensing performance of the fiber is improved, a multi-stage pore structure is constructed, the elastic performance of polyurethane is guaranteed, meanwhile, a conductive layer and a fiber matrix are deeply combined through the phase replacement process, and the sensing performance of the fiber is improved. And synchronous stretching change sensing of the conductive layer of the fiber and the elastic matrix is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of flexible conductive fibers, and in particular to a flexible conductive fiber with a multi-level pore structure and a preparation method thereof. Background Art

[0002] Traditional electronic systems are usually composed of rigid devices such as metal fibers and integrated circuit boards. With the massive increase in the demand for wearable devices, traditional electronic systems cannot match human skin due to their high mechanical properties, which leads to certain limitations in their application in wearable smart devices. In recent years, smart flexible electronic materials have received extensive attention in smart display, sustainable energy, wearable sensing, health care, energy management, human-computer interaction, etc. Flexible electronic devices refer to electronic devices that are flexible and can adapt to different working environments (stretching, compression, etc.). Due to their flexibility, extensibility, portability and other advantages, they can meet different deformation requirements and thus adapt to different working environments.

[0003] At present, the construction materials used for sensor devices are basically solid or fibrous materials. Among them, flexible fiber fabrics have an application basis in wearable smart applications due to their flexibility, light weight, low cost, and good biocompatibility. They are also more concerned by the market because of their ability to be woven into fabric sensing materials.

[0004] Polyurethane fiber is a fiber with excellent elasticity and resilience. It is an excellent matrix material for designing high-strain sensors. However, its electrical conductivity is poor. It can only be composited with other highly conductive materials to make strain sensors. The highly conductive materials mainly include graphene, carbon nanotubes, polyaniline, polypyrrole, etc. Common methods for imparting conductivity to polyurethane fibers include uniform mixing, coating, and in-situ polymerization. In the manufacture of wearable smart devices, common polyurethane-based elastic conductive fibers need to strengthen the bonding force between the conductive layer and the polyurethane layer to meet the performance requirements of flexible electronic sensors that can deform and effectively recover under external stimuli. Therefore, the conductive material is often filled into the elastomer or the conductive filler is surface modified to enhance the adhesion between the two. Increasing the amount of conductive filler can effectively improve the conductivity of the composite material, but it will cause a decrease in the flexibility and tensile properties of the composite material. In addition, the conductive fibers prepared by the prior art have different elastic properties between the conductive layer and the elastic matrix, which makes the conductive layer and the elastic matrix easily separate from each other, thereby affecting the conductive properties; the conductive fibers prepared by the blending method will cause the elastic properties of the elastic matrix itself to decrease. If the elastic matrix performance is guaranteed, the conductive properties will decrease. While improving the conductive properties while also ensuring the elastic matrix performance, the preparation steps used are too many and the process is complicated, so it cannot be put into use on a large scale. In addition, during the preparation process of the blending method, part of the conductive material will be wrapped by the elastic matrix, thereby reducing the conductivity of the conductive fiber.

[0005] In the prior art, the patent with publication number CN 108385201 A discloses a graphene / polyurethane composite stretchable conductive fiber and a preparation method thereof, comprising a polyurethane fiber, wherein the polyurethane fiber has holes, and graphene is doped in the holes of the polyurethane fiber to form a composite conductive fiber with stretchable properties. The graphene / polyurethane composite stretchable conductive fiber prepared by the above scheme has good tensile properties, but the way in which graphene is fixed in polyurethane by physical methods will cause slippage between the graphene sheets when the conductive fiber is deformed due to its different elastic properties from polyurethane, thereby affecting the sensing stability of the conductive fiber.

[0006] In view of this, it is necessary to design a flexible conductive fiber with a multi-level pore structure and a preparation method thereof to solve the above problems. Summary of the invention

[0007] The purpose of the present invention is to provide a flexible conductive fiber with a multi-level pore structure and a preparation method thereof. A flexible conductive fiber with conductive properties is prepared by a two-step molding method, i.e., using a binary system to prepare pyrrole-polyurethane fiber and inducing polymerization, thereby reducing the content of the blended material to reduce the influence on the tensile strength of the conductive fiber, while realizing the mesh connection inside the fiber through the mechanism of multi-system polyurethane molding, and forming a conductive path inside the fiber by pyrrole polymerization, optimizing the synthesis step of the conductive layer, and making the conductive layer deeply combined with the fiber matrix to ensure the synchronous tensile change sensing of the conductive layer of the fiber and the elastic matrix.

[0008] To achieve the above-mentioned object of the invention, the present invention provides a method for preparing a flexible conductive fiber with a multi-level pore structure, comprising the following steps:

[0009] S1, adding a predetermined ratio of polyurethane (hereinafter referred to as PU) and graphene to a first solvent, and mixing them to obtain a spinning solution;

[0010] S2, using a pyrrole-water solution of a certain concentration as the first coagulation bath, and preparing a pyrrole-polyurethane fiber having pyrrole on the surface and inside by wet spinning;

[0011] S3, using a ferric chloride solution of a certain concentration as a second coagulation bath, at a certain temperature, allowing the pyrrole-polyurethane fiber prepared in step S2 to stand for a certain period of time to obtain a flexible conductive fiber with a multi-level pore structure.

[0012] As a further improvement of the present invention, in step S1, the mass ratio of the polyurethane to the graphene is 50:2 to 50:4.

[0013] As a further improvement of the present invention, the first solvent is prepared by N,N-dimethylformamide (hereinafter referred to as DMF) and toluene (hereinafter referred to as TOL).

[0014] As a further improvement of the present invention, the mass ratio of the DMF to the TOL is 6:4 to 9:1.

[0015] As a further improvement of the present invention, the mass fraction of the polyurethane in the spinning solution is 15% to 25%.

[0016] As a further improvement of the present invention, the mass ratio of the pyrrole to the polyurethane is 4.2:5 to 10:5.

[0017] As a further improvement of the present invention, in step S3, the mass concentration of the ferric chloride solution is 20-30 g / L.

[0018] As a further improvement of the present invention, in step S3, the certain temperature is 0-4°C, and the certain time is 10-18h.

[0019] As a further improvement of the present invention, in step S1, the mixing operation is stirring at room temperature for 0.5 to 2 hours.

[0020] The present invention also provides a flexible conductive fiber with a multi-level pore structure, and the flexible conductive fiber is prepared according to the method for preparing a flexible conductive fiber with a multi-level pore structure described in any of the above technical solutions.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention prepares a first solvent by preparing DMF and TOL in a predetermined ratio, dissolving polyurethane and graphene in a predetermined ratio in the first solvent to obtain a spinning solution, and using a pyrrole-water solution of a certain concentration as a first coagulation bath. By utilizing the phase displacement molding principle of wet spinning, different displacement rates are caused by different solvent compatibility in a multi-solvent system, thereby preparing graphene / pyrrole / polyurethane conductive fibers with pyrrole on the surface and inside. The conductive fiber has obvious pore stratification inside. The internal large pores are mainly due to the fact that during wet spinning of the DMF system, since the compatibility of TOL with DMF is greater than the compatibility of DMF with the polymer, the solvent diffuses into the coagulation bath faster, forming an instantaneous phase separation process, and the polyurethane non-solvent quickly diffuses into the polymer, thereby accelerating the molding of the polyurethane and forming a large pore structure. The reason for the formation of small pores is mainly that the pyrrole in the coagulation bath is uniformly dispersed, and during the diffusion of the non-solvent into the fiber, the pyrrole will preferentially adhere to the outer layer of the fiber. Since the pyrrole dispersed in the non-solvent will affect the speed of the double diffusion process to a certain extent, the molding speed of the outer layer polymer slows down and gradually forms a small pore structure. As the non-solvent gradually diffuses into the interior, the pyrrole content will gradually decrease, and the fiber will undergo normal phase replacement, thus forming a multi-level pore structure with small pores on the outside and large pores on the inside. On this basis, ferric chloride solution is used as the second coagulation bath, and ferric chloride is used to induce the polymerization of pyrrole on the surface and inside of the pyrrole-polyurethane fiber, thereby constructing a flexible conductive fiber (G-PPY-PU) with a multi-level pore structure based on a multi-element system.

[0023] 2. The present invention uses polyurethane as a matrix material and adds a certain amount of graphene to prepare a spinning solution, so that when a pyrrole-water solution is subsequently used for a coagulation bath, the π-π conjugated bond between pyrrole and graphene is used to induce the pyrrole to be regularly arranged on the surface of the polyurethane fiber, and the pyrrole will preferentially adhere to the outer layer of the fiber; at the same time, by using a predetermined ratio of DMF and TOL as the first solvent, the double diffusion phenomenon in the phase replacement process of the solvent (DMF) and the non-solvent (water) during the polyurethane molding process is used to diffuse the pyrrole dispersed in the non-solvent into the polyurethane fiber, so that the pyrrole is not only distributed on the fiber surface, but also can enter the fiber interior, thereby preparing a conductive fiber with higher strength and interconnected fiber pores, and through the first coagulation bath, the pyrrole enters the fiber interior through bidirectional diffusion in the phase replacement process; in addition, the polymerization of pyrrole inside and outside the fiber is simultaneously induced by ferric chloride, so that a polypyrrole conductive layer is formed on the surface and inside of the conductive fiber, respectively, and the conductivity of the pyrrole / graphene / polyurethane fiber is effectively enhanced.

[0024] 3. The present invention uses phase replacement to fill the surface and interior of the fiber material with pyrrole, and forms polypyrrole through in-situ polymerization of ferric chloride, thereby achieving the superposition of internal and external conductive properties and increasing the sensing performance of the fiber. While constructing a multi-level pore structure to ensure the elastic properties of the polyurethane, the conductive layer is deeply combined with the fiber matrix through the phase replacement process, ensuring the synchronous stretching change sensing of the conductive layer of the fiber and the elastic matrix.

[0025] 4. In the present invention, during the displacement process, the polyurethane content in the fiber center is higher and the displacement rate is lower, while the surface and the coagulation bath are more fully replaced at a higher rate, so that pyrrole is more adsorbed on the fiber surface and the outer layer inside the fiber during the initial molding process. Compared with traditional fiber sensing materials, the flexible conductive fiber with a multi-level pore structure of the present invention can form a conductive path inside the fiber molding structure to assist electrical performance. At the same time, the gas sensing performance of polypyrrole and the multi-level pore structure generated during the fiber molding process can increase the specific surface area of ​​the fiber, thereby realizing the construction of a multifunctional sensing material for motion sensing and gas sensing.

[0026] 5. While reducing the content of the blended substances to reduce the impact on the tensile strength of the conductive fiber, the present invention realizes the network connection inside the fiber through the mechanism of multi-system polyurethane molding, and uses pyrrole to form a conductive path inside the fiber, thereby optimizing the conductive layer synthesis steps and effectively reducing the production cost.

[0027] 6. The flexible conductive fiber with a multi-level pore structure of the present invention is highly comfortable for the human body. The fiber has a three-dimensional porous structure inside. The pores formed by the phase replacement process can form an internal connection channel with a certain degree of connectivity inside the fiber, and can load a large amount of conductive polymers. At the same time, the porous structure helps to insulate heat. During the stretching process, the flexible conductive fiber of the present invention changes the resistance by splitting the conductive layer itself. The conductive effect is excellent and stable, and it can be reused. In addition, it can be cut according to the length of use to achieve free size regulation, thereby meeting the needs of different situations. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The resistance sensing signal and sensitivity test results of the multi-level pore structure flexible conductive fiber prepared in Example 1;

[0029] Figure 2 SEM images of the surfaces of the conductive fibers prepared in Comparative Examples 1 to 3 (ac) and Examples 1 to 3 (df);

[0030] Figure 3 Thermal performance graphs (DTG) of the conductive fibers prepared in Examples 1 to 3 and Comparative Examples 1 to 3;

[0031] Figure 4 The stress-strain curves and Young's modulus bar graphs of the conductive fibers prepared in Examples 1 to 3 and Comparative Examples 1 to 3;

[0032] Figure 5 This is a cross-sectional SEM image of the conductive fiber prepared in Comparative Example 4;

[0033] Figure 6 is the conductivity measurement result of Comparative Example 5;

[0034] Figure 7 These are the mechanical properties test results for Example 6. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0037] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0038] The present invention provides a method for preparing a flexible conductive fiber with a multi-level pore structure, comprising the following steps:

[0039] S1, adding a predetermined ratio of polyurethane and graphene to a first solvent, and stirring at room temperature for 0.5-2h to obtain a spinning solution;

[0040] S2, using a certain concentration of pyrrole-water solution as the first coagulation bath, by wet spinning, setting the propulsion rate of the wet spinning machine push pump to 50 μL / h, the winding speed to 2 r / min, placing the spinning head in the pyrrole-water solution, and preparing a polyurethane fiber with pyrrole on the surface and inside;

[0041] S3. Using a ferric chloride solution with a mass concentration of 20 to 30 g / L as a second coagulation bath, the polyurethane fiber prepared in step S2 is allowed to stand at 0 to 4° C. for 10 to 18 hours to obtain a flexible conductive fiber with a multi-level pore structure.

[0042] Specifically, in step S1, the mass ratio of polyurethane to graphene is preferably 50:2 to 50:4, more preferably 50:3; and the mass fraction of polyurethane in the spinning solution is 15% to 25%.

[0043] Specifically, in step S1, the first solvent is prepared by DMF and TOL, wherein the mass ratio of DMF to TOL is 0.8:1 to 1.2:1.

[0044] Specifically, the mass ratio of pyridine to polyurethane is preferably 4.2:5 to 10:5, and more preferably 8.4:5.

[0045] The present invention also provides a flexible conductive fiber with a multi-level pore structure, and the flexible conductive fiber is prepared according to any one of the above technical solutions.

[0046] The preparation method of the flexible conductive fiber with a multi-level pore structure provided by the present invention is described below with reference to specific embodiments.

[0047] Example 1

[0048] This embodiment provides a method for preparing a flexible conductive fiber with a multi-level pore structure, comprising the following steps:

[0049] S1, preparing a first solvent with DMF and TOL in a mass ratio of 8:2, adding polyurethane and graphene to the first solvent so that the mass fraction of polyurethane in the first solvent is 25%, and the mass fraction of graphene is 1.5%, and stirring at room temperature for 1 hour to obtain a spinning solution;

[0050] S2, using a pyrrole-water solution with a mass concentration of 1.2 g / 100 mL as the first coagulation bath, and controlling the mass ratio of pyrrole in the first coagulation bath to the polyurethane in the spinning solution to be 8.4:5, by wet spinning, setting the propulsion rate of the wet spinning machine push pump to 50 μL / h, the winding speed to 2 r / min, placing the spinning head in the evenly dispersed pyrrole-water solution, and spraying the spinning solution through the spinning head to prepare a polyurethane fiber with pyrrole on the surface and inside;

[0051] S3, using a ferric chloride solution with a mass concentration of 24 g / L as the second coagulation bath, at 0°C, the polyurethane fiber prepared in step S2 was allowed to stand for 12 hours to obtain a flexible conductive fiber with a multi-level pore structure (named 1.5G-PPy-PU), and its conductive sensor signal was as follows Figure 1 shown.

[0052] Depend on Figure 1It can be seen that when the strain range is 0-20%, the sensor has the ability to respond to strain and realize real-time changes, and as the strain increases, the sensing ability increases steadily. When the strain is 10%, an inflection point appears, and the sensitivity coefficient of 0-10% is 11.4. When the strain reaches 20%, ΔR / R0 reaches 290%, and the sensitivity coefficient under 10-20% strain reaches 17.8, showing an excellent sensing response and good repeatability. This is mainly due to the in-situ polymerization of the polyurethane fiber-based surface, forming a polypyrrole conductive layer sufficient to form a crack sensing effect.

[0053] Embodiment 2-3

[0054] Examples 2 to 3 respectively provide a method for preparing a flexible conductive fiber with a multi-level pore structure. Compared with Example 1, the only difference is that the mass fraction of graphene in the spinning solution is changed. The remaining steps are consistent with Example 1 and will not be repeated here.

[0055] In Example 2, the mass fraction of graphene is 1%, and the obtained conductive fiber is named 1G-PPy-PU; in Example 3, the mass fraction of graphene is 2%, and the obtained conductive fiber is named 2G-PPy-PU.

[0056] Comparative Examples 1 to 3

[0057] Comparative Examples 1 to 3 respectively provide a method for preparing a flexible conductive fiber with a multi-level pore structure. Compared with Example 1, no pyrrole is added to the first coagulation bath of Comparative Examples 1 to 3, and the mass fraction of graphene in the spinning solution prepared in Comparative Examples 1 to 3 is 1%, 1.5%, and 2%, respectively. The prepared conductive fibers are named 1G-PU, 1.5G-PU, and 2G-PU, respectively. The other preparation methods and parameters in Comparative Examples 1 to 3 are consistent with those in Example 1 and are not repeated here.

[0058] The morphology, thermal properties and mechanical properties of Examples 1 to 3 and Comparative Examples 1 to 3 are as follows: Figure 2-4 As shown. Figure 2 It can be seen that the surface of the conductive fibers prepared in Comparative Examples 1 to 3 is relatively smooth, and the porous channels on the fiber surface are generated by the diffusion of solvent and non-solvent during the phase replacement process, while the surface of the conductive fibers prepared in Examples 1 to 3 forms a wrinkled layer. The formation of this structure proves that the in-situ polymerization of polypyrrole successfully constructs a conductive layer on the polyurethane surface. Figure 3 It can be seen that 1.5G-PPy-Pu has the best thermal performance. Figure 4 It can be seen that under the same polymerization conditions, when the mass fraction of graphene is 1.5%, the tensile properties of the fiber are the best; at the same time, compared with comparative examples 1 to 3, the Young's modulus of the conductive fibers prepared in embodiments 1 to 3 is significantly increased.

[0059] Comparative Example 4

[0060] This comparative example provides a method for preparing a flexible conductive fiber with a multi-level pore structure. Compared with Example 1, the only difference is that the first solvent is N,N-dimethylformamide, and the remaining steps are consistent with Example 1 and will not be repeated here.

[0061] The cross-sectional porous structure of the conductive fiber prepared in this comparative example was characterized by SEM, and the results were as follows: Figure 5 As shown by Figure 5 It can be seen that relatively large pores are formed inside the conductive fiber formed by wet spinning of a single-component solvent component. Compared with the conductive fiber formed in Example 1, pores supported by non-solvent water are quickly formed inside. When the conductive filler is physically blended into the fiber, the pores are too large to form a conductive path, resulting in unstable conductive properties of the flexible polyurethane fiber. In Example 1, DMF is more compatible with water than with polyurethane and TOL. Therefore, during the replacement process, water diffuses preferentially with DMF. TOL, which is originally compatible with polyurethane, has a lower compatibility with water and a slow diffusion rate. The slow diffusion rate leads to smaller pores slowly formed inside the polyurethane, which is more conducive to the formation of a path for the conductive filler.

[0062] Comparative Examples 5-6

[0063] Comparative Examples 5 to 6 respectively provide a method for preparing a flexible conductive fiber with a multi-level pore structure. Compared with Example 1, the only difference is that the mass fraction of graphene in the spinning solution is changed. The remaining steps are consistent with Example 1 and are not repeated here.

[0064] Among them, the graphene content in the spinning solution of Comparative Example 5 is 0.5%, and the conductivity of the conductive fiber obtained is poor. The resistance is too large under the test of a digital multimeter (such as Figure 6 As shown). The graphene content in the spinning solution of Comparative Example 6 is 2.5%, and the tensile strain of the obtained conductive fiber can only reach about 600% (as shown). Figure 7 ), indicating that too high a graphene content will lead to a decrease in flexible tensile strain.

[0065] In summary, the flexible conductive fiber with a multi-level pore structure and the preparation method thereof disclosed in the present invention, through phase replacement, pyrrole is filled with the surface and interior of the fiber material, thereby realizing the superposition of internal and external conductive properties and increasing the sensing performance of the fiber. Thus, while constructing a multi-level pore structure to ensure the elastic properties of the polyurethane, the conductive layer is deeply combined with the fiber matrix by the phase replacement process, thereby ensuring the synchronous stretching change sensing of the conductive layer of the fiber and the elastic matrix. By using polyurethane as a matrix material and adding a certain amount of graphene to prepare a spinning solution, when a pyrrole-water solution is subsequently used for a coagulation bath, the π-π conjugated bond between pyrrole and graphene is used to induce the pyrrole to be regularly arranged on the surface of the polyurethane fiber, thereby forming a conductive layer on the surface of the conductive fiber; at the same time, by using a predetermined ratio of DMF and TOL as the first solvent, the pyrrole will preferentially adhere to the outer layer of the fiber, and the double diffusion phenomenon in the phase replacement process of the solvent (DMF and TOL) and the non-solvent (water) during the polyurethane molding process is used to diffuse the pyrrole dispersed in the non-solvent into the polyurethane fiber, so that the pyrrole is not only distributed on the fiber surface, but also can enter the fiber interior, thereby preparing a conductive fiber with higher strength and connected fiber pores; in addition, ferric chloride is used to simultaneously induce the polymerization of pyrrole inside and outside the fiber, thereby forming a polypyrrole conductive layer on the surface and inside of the conductive fiber, respectively, effectively enhancing the conductivity of the pyrrole / graphene / polyurethane fiber.

[0066] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a flexible conductive fiber with a multi-level pore structure, characterized in that: The steps include: S1, adding a predetermined ratio of polyurethane and graphene to a first solvent, and mixing them to obtain a spinning solution; S2, using a pyrrole-water solution of a certain concentration as the first coagulation bath, and preparing a pyrrole-polyurethane fiber having pyrrole on the surface and inside by wet spinning; S3, using a ferric chloride solution of a certain concentration as a second coagulation bath, at a certain temperature, allowing the pyrrole-polyurethane fiber prepared in step S2 to stand for a certain period of time to obtain a flexible conductive fiber with a multi-level pore structure.

2. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 1, characterized in that: In step S1, the mass ratio of the polyurethane to the graphene is 50:2 to 50:

4.

3. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 2, characterized in that: The first solvent is prepared by mixing N,N-dimethylformamide and toluene.

4. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 3, characterized in that: The mass ratio of the N,N-dimethylformamide to the toluene is 6:4 to 9:

1.

5. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 2, characterized in that: The mass fraction of polyurethane in the spinning solution is 15% to 25%.

6. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 1, characterized in that: The mass ratio of the pyrrole to the polyurethane is 4.2:5 to 10:

5.

7. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 1, characterized in that: In step S3, the mass concentration of the ferric chloride solution is 20-30 g / L.

8. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 6, characterized in that: In step S3, the certain temperature is 0-4°C, and the certain time is 10-18 hours.

9. The method for preparing a flexible conductive fiber having a multi-level pore structure according to claim 1, characterized in that: In step S1, the mixing operation is stirring at room temperature for 0.5 to 2 hours.

10. A flexible conductive fiber with a multi-level pore structure, characterized in that: The flexible conductive fiber is prepared according to the method for preparing a flexible conductive fiber with a multi-level pore structure according to any one of claims 1 to 9.

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