Stretchable conductive fiber with high conductivity and high electrical stability and continuous preparation method thereof

Abstract

The invention discloses a stretchable conductive fiber with high conductivity and high electrical stability. The stretchable conductive fiber is composed of an elastic base body with a spiral groove structure on the surface and a conductive metal cladding loaded on the surface of the elastic base body. The conductive metal cladding comprises nano-silver wrapping the elastic base body and liquid metal filling the spiral groove structure, wherein the nano-silver and the liquid metal are arranged in sequence. The continuous preparation method comprises the following steps: preparing an elastic matrix preform with an open groove in the side surface; filling and coating the elastic matrix preform with a thermoplastic hard polymer, and carrying out vacuum heat treatment to obtain a composite preform; continuously heating and wiredrawing the composite preform, and synchronously rotating the composite preform in the wiredrawing process to obtain composite fibers; removing a thermoplastic hard polymer component in the composite fiber to obtain an elastic matrix with a spiral structure on the surface; and sequentially loading nano-silver and liquid metal on the surface of the elastic substrate with the spiral structure on the surface to obtain the stretchable conductive fiber.

Description

Technical Field

[0001] The present invention relates to the field of flexible electronic technology, and in particular to a stretchable conductive fiber with high electrical conductivity and high electrical stability and a continuous preparation method thereof. Background Art

[0002] Stretchable conductive fibers have important applications in flexible electronics, robotics, and other fields. Stretchable conductive fibers, with their high electrical conductivity and stability, can be used as functional modules in flexible electronic devices to significantly enhance the reliability and stability of electrical interconnects and increase the wearer comfort of these devices. Their use in robotic joints can significantly reduce wiring redundancy. They can also significantly improve the reliability and stability of electrical interconnects by replacing traditional brocade wire in voice coil connections for audio equipment.

[0003] In the past research on stretchable conductive fibers, most of the work focused on how to improve the conductivity and elongation of the fibers, while there was relatively little work on improving the electrical stability of the fibers. Some researchers have reported the preparation of elastomeric composite fibers with serpentine structured metal wires (or liquid metal particles) inside by hot drawing (or wet spinning). Although the fibers obtained by the above method have both high electrical conductivity and high electrical stability, the conductive part is coated inside the insulating matrix (the fiber surface is not conductive), which brings additional troubles to the actual electrical interconnection operation. There are also stretchable conductive fibers in the prior art that are produced by coating the surface of the elastic matrix with a corrugated structured conductive film or a spiral structured metal wire. Although this type of method can solve the above-mentioned problem of non-conductivity of the fiber surface, this type of method is very difficult to operate in practice, has low preparation efficiency, and is difficult to achieve continuous batch preparation.

[0004] In summary, although many types of stretchable conductors and various preparation methods have been reported, there is still a lack of stretchable conductive fibers that have high electrical conductivity, high electrical stability and surface conductivity, as well as methods that can achieve continuous batch preparation. Summary of the Invention

[0005] The purpose of the present invention is to provide a stretchable conductive fiber with high conductivity and high electrical stability and a continuous preparation method thereof, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is a stretchable conductive fiber with high electrical conductivity and high electrical stability, which is composed of an elastic matrix with a spiral groove structure on the surface and a conductive metal cladding supported on the surface of the elastic matrix;

[0008] The conductive metal cladding includes nanosilver coating the elastic matrix and liquid metal filling the spiral groove structure, which are sequentially arranged.

[0009] In the stretchable conductive fiber of the present invention, the nano silver in the conductive metal cladding loaded on the surface of the elastic matrix can form an alloy with the liquid metal, so that the liquid metal and the fiber surface present a state of super-wetting, thereby significantly enhancing the bonding force of the liquid metal and the elastic matrix, and the stable load of the liquid metal can improve the electrical conductivity and electrical stability of the fiber simultaneously. Moreover, the liquid metal can also play the role of a conductive adhesive when the fiber stretches and causes the nano silver layer to crack, thereby improving the electrical stability of the fiber from another aspect. The spiral groove structure on the fiber surface can load more nano silver and liquid metal (nano silver and liquid metal are mainly distributed in the spiral groove on the surface of the elastic matrix, wherein the nano silver layer is coated on the groove surface along the groove shape, and the liquid metal is filled in the inner space of the groove) to further improve the electrical conductivity of the fiber, and on the other hand, the tensile strain can be effectively released by the stretching of the spiral structure during stretching, thereby further improving the electrical stability of the fiber. Therefore, the stretchable conductive fiber provided by the present invention has high electrical conductivity and high electrical stability simultaneously.

[0010] Furthermore, the nano-silver and liquid metal are mainly distributed in the spiral groove structure of the elastic matrix, and are also distributed in the non-spiral groove structure. That is, nano-silver and liquid metal are present not only inside the groove but also outside the groove.

[0011] Furthermore, the elastic matrix is ​​thermoplastic elastomer (TPE).

[0012] Furthermore, the liquid metal is room temperature gallium-based liquid metal.

[0013] Furthermore, the room temperature gallium-based liquid metal is a gallium-based alloy having a melting point below room temperature (ie below 20° C.).

[0014] Further preferably, the room temperature gallium-based liquid metal comprises Galinstan (component is Ga 68 In 22 Sn 10 , melting point is -19 ℃), eutectic gallium-indium alloy (composition is Ga 75 In 25 , melting point 15.7 ° C) or Ga 62 In 25 Sn 13 (Melting point is 5°C).

[0015] Furthermore, the room temperature gallium-based liquid metal is preferably Galinstan.

[0016] Furthermore, the mass content of the nanosilver in the stretchable conductive fiber is 5-80wt%.

[0017] Furthermore, the mass content of the liquid metal in the stretchable conductive fiber is 10-85wt%.

[0018] Furthermore, the diameter of the stretchable conductive fiber is 0.05-2 mm.

[0019] Furthermore, the rise angle of the spiral groove structure is 5-80°.

[0020] The second technical solution of the present invention is a method for continuously preparing the above-mentioned stretchable conductive fiber with high conductivity and high electrical stability, comprising the following steps:

[0021] preparing an elastic matrix preform having open grooves on its side;

[0022] Filling and coating the elastic matrix preform with a thermoplastic hard polymer, and performing vacuum heat treatment to obtain a composite preform;

[0023] Continuously heating and drawing the composite preform rod, and synchronously rotating the composite preform rod during the drawing process (so that the thermoplastic hard polymer in the groove forms a spiral structure) to obtain a composite fiber;

[0024] removing the thermoplastic hard polymer component from the composite fiber to obtain an elastic matrix with a helical structure on the surface;

[0025] Nanosilver and liquid metal are sequentially loaded on the surface of the elastic matrix with a spiral structure to obtain the stretchable conductive fiber with high electrical conductivity and high electrical stability.

[0026] Furthermore, the elastic matrix preform rod is filled and coated with a thermoplastic rigid polymer, and vacuum heat treatment is performed to obtain a composite preform rod, including: inserting the elastic matrix preform rod with an open groove on the side into a thermoplastic rigid polymer circular tube, and then inserting a thin thermoplastic rigid polymer rod into a through hole formed between the open groove of the elastic matrix preform rod and the inner wall of the thermoplastic rigid polymer circular tube, and vacuum heat treatment (the elastic matrix preform rod, the thin thermoplastic rigid polymer rod and the thermoplastic rigid polymer circular tube are tightly combined together through vacuum heat treatment) to obtain a composite preform rod.

[0027] Furthermore, the open grooves are arranged longitudinally along the elastic matrix preform.

[0028] Furthermore, the number of the open grooves is ≥1.

[0029] Furthermore, the cross-section of the elastic matrix preform with open grooves on the side surface is circular, with a diameter of 5-100 mm.

[0030] Furthermore, the cross-sectional shape of the open groove (single groove) is a 1 / 5-4 / 5 arc, a rectangle or a trapezoid. The size of the open groove can be adjusted according to the number of open grooves. When the number of open grooves is greater than 1, the cross-sectional shape and size of each groove are the same.

[0031] Further preferably, the number of the open grooves is 1-30.

[0032] Furthermore, the elastic substrate with a spiral structure on the surface is sequentially loaded with nanosilver and liquid metal to obtain the stretchable conductive fiber with high conductivity and high electrical stability, which includes:

[0033] The elastic matrix with a spiral structure on the surface is immersed in a silver ion solution and a reducing solution in sequence to obtain an elastic matrix with nanosilver loaded on the surface (the nanosilver is mainly loaded in the grooves, and a nanosilver coating is formed along the shape of the grooves); the liquid metal is loaded on the elastic matrix with nanosilver loaded on the surface by an immersion pulling method (the liquid metal is mainly loaded in the grooves, filling the internal space of the grooves), thereby obtaining the stretchable conductive fiber with high conductivity and high electrical stability.

[0034] Furthermore, the silver ion solution comprises an alcohol solution of silver trifluoroacetate.

[0035] Furthermore, the solvent in the alcohol solution of silver trifluoroacetate includes ethanol or methanol.

[0036] Furthermore, the solute in the reducing solution is a reducing agent, and the solute includes ethanol or water.

[0037] Furthermore, the reducing agent includes hydrazine hydrate, ascorbic acid or sodium borohydride.

[0038] Furthermore, the concentration of the silver ion solution is 5-30wt%, and the soaking time in the silver ion solution is 5-60min; the concentration of the reducing solution is 3-80wt%, and the soaking time in the reducing solution is 1-60min.

[0039] Furthermore, the speed of the immersion pulling is 3-500 mm / s.

[0040] Furthermore, the elastic matrix preform with open grooves on the side surfaces is prepared by injection molding, extrusion or machining.

[0041] Furthermore, the method for removing the thermoplastic hard polymer component in the composite fiber includes solvent soaking.

[0042] Furthermore, the softening temperature of the thermoplastic rigid polymer (ie, the thermoplastic rigid polymer round tube and the thermoplastic rigid polymer thin rod) is higher than the softening temperature of the elastic matrix preform.

[0043] Furthermore, the thermoplastic rigid polymer round tube and the thermoplastic rigid polymer thin rod can both be dissolved by at least one solvent.

[0044] Furthermore, the material of the elastic matrix preform includes styrene butadiene rubber (SBS), hydrogenated styrene butadiene rubber (SEBS) or thermoplastic polyurethane (TPU).

[0045] Furthermore, the material of the thermoplastic rigid polymer tube includes polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), polycarbonate (PC), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyethylene glycol (PEG) or alginate.

[0046] Furthermore, the material of the thermoplastic rigid polymer thin rod includes polymethyl methacrylate, polyethyl methacrylate, polycarbonate, polyvinyl alcohol, polyethylene oxide, polyethylene glycol or avena sativa.

[0047] Further preferably, the thermoplastic rigid polymer round tube and the thermoplastic rigid polymer thin rod are made of the same material.

[0048] Furthermore, the inner diameter of the thermoplastic rigid polymer circular tube is slightly larger than the outer diameter of the elastic matrix preform rod with open grooves on the side surface.

[0049] Furthermore, the solvent used in the solvent soaking will not affect the elastic matrix.

[0050] Furthermore, the type of solvent used in the solvent immersion is selected according to the material of the thermoplastic rigid polymer tube and the thermoplastic rigid polymer rod. If the material is PMMA, PEMA or PC, the solvent can be glacial acetic acid; if the material is PVA, PEO, PEG or alginate, water can be used as a solvent to dissolve the thermoplastic rigid polymer component.

[0051] Furthermore, the drawing is carried out in an optical fiber drawing tower.

[0052] The third technical solution of the present invention: Application of the above-mentioned stretchable conductive fibers with high electrical conductivity and high electrical stability in the preparation of flexible electronic devices.

[0053] The present invention discloses the following technical effects:

[0054] The nanosilver attached to the surface of the stretchable conductive fiber provided by the present invention can form an alloy with liquid metal, so that the liquid metal and the fiber surface are in a super-wetting state, thereby enhancing the bonding force between the liquid metal and the fiber surface. The coating of liquid metal can simultaneously improve the electrical conductivity and electrical stability of the fiber. On the one hand, the spiral groove structure on the fiber surface can accommodate more nanosilver and liquid metal to further improve the electrical conductivity of the fiber. On the other hand, the spiral structure can effectively release tensile strain, thereby further improving the electrical stability of the fiber. Based on the above factors, the stretchable conductive fiber disclosed by the present invention has both high electrical conductivity and high electrical stability. The stretchable conductive fiber of the present invention has both high electrical conductivity and high electrical stability, and is suitable for various application scenarios that require stable electrical interconnection in a dynamic environment (for example, as voice coil wire, headphone wire, signal line and power line of wearable devices, etc.).

[0055] The present invention can effectively improve the electrical stability of stretchable conductive fibers by introducing a spiral groove structure. Although there have been many reports on stretchable conductive fibers with spiral structures in the past, there has not yet been a method for continuously preparing stretchable conductive fibers with highly stable spiral structures. The method disclosed in the present invention can achieve the continuous preparation of stretchable conductive fibers with spiral structures, and a spiral structure can be formed in the fiber by synchronously rotating the composite preform rod during the drawing process. And the rise angle of the spiral structure can be flexibly controlled by the fiber drawing speed, the composite preform rod lowering speed and the composite preform rod rotation speed. The fiber drawing process and subsequent steps combined with the roll-to-roll online processing process can achieve the full-process continuous preparation of stretchable conductive fibers with high conductivity and high electrical stability. Therefore, the preparation method of stretchable conductive fibers with high conductivity and high stability disclosed in the present invention is suitable for industrial batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 Schematic diagrams of the structure of the stretchable conductive fiber of the present invention, wherein A is a schematic diagram of the overall structure of the stretchable conductive fiber of Example 1, B is a schematic diagram of the cross-sectional structure of the stretchable conductive fiber of Example 1, and CH are schematic diagrams of the cross-sectional structures of the stretchable conductive fibers of Examples 6-11, respectively.

[0058] Figure 2 Schematic diagram of the preparation process of the stretchable conductive fiber of the present invention.

[0059] Figure 3Resistance-strain curve of the stretchable conductive fiber obtained in Example 1.

[0060] Figure 4 This is a curve showing the change in resistance of the stretchable conductive fiber obtained in Example 1 as a function of the number of stretching times during repeated stretching at 60% strain. DETAILED DESCRIPTION

[0061] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0062] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0063] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0064] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0065] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0066] It should be pointed out that the matters not described in detail in the present invention are conventional operating means in this field and are not the focus of the present invention.

[0067] As a first aspect of the present invention, the present invention provides a stretchable conductive fiber with high electrical conductivity and high electrical stability, which is composed of an elastic substrate with a spiral groove structure on the surface and a conductive metal cladding supported on the surface of the elastic substrate;

[0068] The conductive metal cladding includes nanosilver coating the elastic matrix and liquid metal filling the spiral groove structure, which are sequentially arranged.

[0069] As a preferred embodiment of the present invention, the elastic matrix is ​​made of thermoplastic elastomer (TPE).

[0070] As a preferred embodiment of the present invention, the liquid metal is room temperature gallium-based liquid metal; the room temperature gallium-based liquid metal is a gallium-based alloy having a melting point below room temperature (ie below 20° C.).

[0071] As an optional embodiment of the present invention, the room temperature gallium-based liquid metal includes Galinstan (component is Ga 68 In 22 Sn 10 , melting point is -19 ℃), eutectic gallium-indium alloy (composition is Ga 75 In 25 , melting point 15.7 ° C) or Ga 62 In 25 Sn 13 (Melting point is 5°C).

[0072] As a preferred embodiment of the present invention, the room temperature gallium-based liquid metal is preferably Galinstan.

[0073] As an optional embodiment of the present invention, the mass content of the nanosilver in the stretchable conductive fiber is 5-80wt%, preferably 10-60wt%.

[0074] As an optional embodiment of the present invention, the mass content of the liquid metal in the stretchable conductive fiber is 10-85wt%, preferably 20-70wt%.

[0075] As an optional embodiment of the present invention, the diameter of the stretchable conductive fiber is 0.05-2 mm.

[0076] As an optional embodiment of the present invention, the rise angle of the spiral groove structure is 5-80°, preferably 30-60°.

[0077] As a second aspect of the present invention, the present invention provides a continuous preparation method of the above-mentioned stretchable conductive fiber with high conductivity and high electrical stability, comprising the following steps (the schematic diagram of the preparation process is shown in FIG. Figure 2 shown):

[0078] (1) preparing an elastic matrix preform with open grooves on the side;

[0079] (2) filling and coating the elastic matrix preform with a thermoplastic hard polymer, and performing vacuum heat treatment to obtain a composite preform;

[0080] (3) continuously heating and drawing the composite preform rod (i.e., drawing to obtain continuous composite fibers), and synchronously rotating the composite preform rod during the drawing process (so that the thermoplastic hard polymer in the groove forms a spiral structure) to obtain composite fibers;

[0081] (4) removing the thermoplastic hard polymer component in the composite fiber to obtain an elastic matrix with a helical structure on the surface;

[0082] (5) loading nanosilver on the surface of the elastic substrate having a spiral structure;

[0083] (6) Liquid metal is loaded on the surface of the elastic matrix loaded with nanosilver to obtain the stretchable conductive fiber with high electrical conductivity and high electrical stability.

[0084] As a preferred embodiment of the present invention, the elastic matrix preform rod is filled and coated with a thermoplastic hard polymer, and vacuum heat treatment is performed to obtain a composite preform rod, including: inserting the elastic matrix preform rod with an open groove on the side into a thermoplastic hard polymer round tube, and then inserting a thermoplastic hard polymer thin rod into a through hole formed between the open groove of the elastic matrix preform rod and the inner wall of the thermoplastic hard polymer round tube, and vacuum heat treatment (the elastic matrix preform rod, the thermoplastic hard polymer thin rod and the thermoplastic hard polymer round tube are tightly combined together through vacuum heat treatment) to obtain a composite preform rod.

[0085] As a preferred embodiment of the present invention, the open grooves are arranged longitudinally along the elastic matrix preform.

[0086] As a preferred embodiment of the present invention, the number of the open grooves is ≥1.

[0087] As a preferred embodiment of the present invention, the cross-section of the elastic matrix preform with open grooves on the side surface is circular with a diameter of 5-100 mm.

[0088] As a preferred embodiment of the present invention, the cross-sectional shape of the open groove is a 1 / 5-4 / 5 arc (i.e., the length of the arc is 1 / 5-4 / 5 of the circle), a rectangle, or a trapezoid. The size of the open groove can be adjusted according to the number of open grooves. When the number of open grooves is greater than 1, the cross-sectional shape and size of each groove are the same.

[0089] As a preferred embodiment of the present invention, the number of the open grooves is 1-30.

[0090] As a preferred embodiment of the present invention, when the cross-sectional shape of the open groove is an arc, the cross-sectional shape of the thermoplastic hard polymer thin rod is a circle with a diameter slightly smaller than the diameter of the arc; when the cross-sectional shape of the open groove is a rectangle or a trapezoid, the cross-sectional shape of the thermoplastic hard polymer thin rod is the same as the cross-sectional shape of the open groove, and the size of the thermoplastic hard polymer thin rod is slightly smaller than the size of the open groove. The size of the thermoplastic hard polymer thin rod needs to be slightly smaller, otherwise it will be difficult to insert into the groove. After the thermoplastic hard polymer thin rod is inserted into the groove, it will be tightly meshed with the elastic matrix preform rod after vacuum heat treatment, eliminating the gap between the thin rod and the groove wall.

[0091] As a preferred embodiment of the present invention, the surface of the elastic substrate with a spiral structure loaded with nanosilver comprises:

[0092] The elastic matrix with a spiral structure on the surface is immersed in a silver ion solution and a reducing solution in sequence to obtain an elastic matrix with nanosilver loaded on the surface (i.e., a nanosilver coating is formed on the surface of the elastic matrix, the nanosilver is mainly loaded in the grooves, and the nanosilver coating is formed along the shape of the grooves).

[0093] As a preferred embodiment of the present invention, the loading of liquid metal on the surface of the elastic matrix after loading nanosilver includes: loading the liquid metal on the elastic matrix with nanosilver loaded on the surface by an immersion pulling method (the liquid metal is mainly loaded in the grooves, filling the internal space of the grooves), thereby obtaining the stretchable conductive fiber with high conductivity and high electrical stability.

[0094] As a preferred embodiment of the present invention, the silver ion solution comprises an alcohol solution of silver trifluoroacetate.

[0095] As a preferred embodiment of the present invention, the solvent in the alcohol solution of silver trifluoroacetate includes ethanol or methanol.

[0096] As a preferred embodiment of the present invention, the solute in the reducing solution is a reducing agent, and the solute includes ethanol or water.

[0097] As a preferred embodiment of the present invention, the reducing agent includes hydrazine hydrate, ascorbic acid or sodium borohydride.

[0098] As an optional embodiment of the present invention, the concentration of the silver ion solution is 5-30wt%, preferably 10-25wt%; the immersion time in the silver ion solution is 5-60min, preferably 10-30min; the concentration of the reducing solution is 3-80wt%, preferably 5-20wt%; the immersion time in the reducing solution is 1-60min, preferably 5-20min.

[0099] As an optional embodiment of the present invention, the speed of the immersion pulling is 3-500 mm / s, preferably 10-100 mm / s.

[0100] As a preferred embodiment of the present invention, the elastic matrix preform with open grooves on the side is prepared by injection molding, extrusion or machining.

[0101] As a preferred embodiment of the present invention, the method for removing the thermoplastic hard polymer component in the composite fiber includes solvent soaking.

[0102] As a preferred embodiment of the present invention, the softening temperature of the thermoplastic rigid polymer (ie, the thermoplastic rigid polymer round tube and the thermoplastic rigid polymer thin rod) is higher than the softening temperature of the elastic matrix preform.

[0103] As a preferred embodiment of the present invention, the thermoplastic rigid polymer round tube and the thermoplastic rigid polymer thin rod can both be dissolved by at least one solvent.

[0104] As a preferred embodiment of the present invention, the material of the elastic matrix preform includes styrene butadiene rubber (SBS), hydrogenated styrene butadiene rubber (SEBS) or thermoplastic polyurethane (TPU).

[0105] As a preferred embodiment of the present invention, the material of the thermoplastic rigid polymer tube includes polymethyl methacrylate (PMMA), polyethyl methacrylate (PEMA), polycarbonate (PC), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyethylene glycol (PEG) or alginate.

[0106] As a preferred embodiment of the present invention, the material of the thermoplastic rigid polymer thin rod includes polymethyl methacrylate, polyethyl methacrylate, polycarbonate, polyvinyl alcohol, polyethylene oxide, polyethylene glycol or avena sativa.

[0107] As a preferred embodiment of the present invention, the thermoplastic rigid polymer round tube and the thermoplastic rigid polymer thin rod are made of the same material.

[0108] As a preferred embodiment of the present invention, the type of solvent used in the solvent immersion is selected according to the material of the thermoplastic rigid polymer round tube and the thermoplastic rigid polymer thin rod. If the material is PMMA, PEMA or PC, the solvent can be glacial acetic acid; if the material is PVA, PEO, PEG or alginate, water can be used as a solvent to dissolve the thermoplastic rigid polymer component.

[0109] As a preferred embodiment of the present invention, steps (3) to (6) can be combined with a roll-to-roll process to achieve online continuous preparation.

[0110] As a third aspect of the present invention, the present invention provides the use of the above-mentioned stretchable conductive fiber with high conductivity and high electrical stability in the preparation of flexible electronic devices.

[0111] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0112] When referring to room temperature in the specific embodiments of the present invention, it specifically refers to 20-30°C.

[0113] The raw materials used in the specific embodiments of the present invention are all common commercially available products.

[0114] Example 1

[0115] A stretchable conductive fiber with high electrical conductivity and high electrical stability, composed of a SEBS (Kraton G1657) elastic matrix and a conductive metal cladding loaded on the surface of the SEBS elastic matrix, wherein the conductive metal cladding is composed of nanosilver and room temperature gallium-based liquid metal Galinstan. The surface of the SEBS elastic matrix has a spiral groove structure; nanosilver and Galinstan room temperature gallium-based liquid metal are mainly distributed in the spiral groove structure (nanosilver coats the elastic matrix, and a nanosilver cladding is formed in the groove along the shape of the groove, and the liquid metal fills the spiral groove structure); the diameter of the stretchable conductive fiber is 0.5mm (including the maximum diameter of the groove part); the number of spiral grooves is 18, the rise angle (i.e., the inclination angle with the horizontal direction) is 45°, and the cross-section is a semicircular arc with a diameter of 0.075mm. The overall structural schematic diagram of the stretchable conductive fiber is shown as follows: Figure 1 As shown in A, its cross-sectional structure diagram is as follows Figure 1 As shown in B.

[0116] Continuous preparation method of stretchable conductive fibers with high conductivity and high electrical stability (schematic diagram of the preparation process as shown in Figure 2 As shown), the steps are as follows:

[0117] (1) A SEBS round rod with open grooves on the side having a diameter of 35 mm and a length of 250 mm was prepared by heating and extruding in a twin-screw extruder. The cross-sectional shape of the open grooves was a semicircular arc with a diameter of 5.25 mm. There were 18 open grooves, which were evenly arranged longitudinally around the SEBS round rod and used as an elastic matrix preform rod with open grooves on the side.

[0118] (2) First, the SEBS round rod with open grooves on the side prepared in step (1) (i.e., preform rod) was inserted into a PMMA round tube with an inner diameter of 36 mm and an outer diameter of 45 mm. Then, 18 PMMA thin rods (round rods) with a diameter of 5 mm were respectively inserted into the through holes formed between the open grooves on the side of the SEBS round rod and the inner wall of the PMMA round tube. Then, the SEBS round rod with open grooves on the side, the PMMA thin rods, and the PMMA round tube were tightly combined to form an integrated composite preform rod by heating at 180°C for 10 minutes in a vacuum environment.

[0119] (3) The composite preform prepared in step (2) is fixed vertically on the preform fixture of the optical fiber drawing tower. The fixture for clamping the composite preform is controlled by a motor and can move up and down and rotate. The composite preform is lowered into the heating furnace of the optical fiber drawing tower, and then heated until the preform softens and begins to draw at a certain speed. The composite fiber obtained by drawing is wound through the winding device under the drawing tower. During the drawing process, the preform fixture is controlled to slowly descend and rotate synchronously (driving the composite preform to rotate around its center of the circle, so that the PMMA thin rods in the groove form a spiral structure). The diameter of the fiber is regulated by jointly controlling the lowering speed of the composite preform and the drawing speed of the fiber. The rise angle of the spiral structure is regulated by jointly controlling the rotation speed of the composite preform and the drawing speed of the fiber.

[0120] (4) The composite fiber obtained in step (3) is immersed in glacial acetic acid to dissolve the PMMA component therein, and after washing and drying, a SEBS fiber with a spiral groove structure on the surface (i.e., a SEBS elastic matrix with a spiral structure on the surface) is obtained.

[0121] (5) soaking the SEBS fiber with a spiral groove structure on the surface obtained in step (4) in an ethanol solution of silver trifluoroacetate (concentration of 17 wt%) for 20 min to absorb silver ions, and then soaking it in an ethanol solution of hydrazine hydrate (concentration of 8 wt%) for 10 min to reduce the generated nanosilver on the fiber, forming a nanosilver coating layer, and obtaining a fiber with nanosilver loaded on the surface (i.e., a SEBS elastic matrix with nanosilver loaded on the surface);

[0122] (6) The surface of the fiber loaded with nanosilver obtained in step (5) was loaded with room temperature gallium-based liquid metal Galinstan by immersion and pulling (at a speed of 100 mm / s) (the room temperature gallium-based liquid metal mainly fills the spiral groove structure), thereby obtaining a final stretchable conductor with high conductivity and high electrical stability. According to testing, in this embodiment, the mass fractions (i.e., loading amounts) of nanosilver and room temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber are 14 wt% and 60 wt%, respectively.

[0123] The above steps (3)-(6) are combined with a roll-to-roll process to achieve online continuous preparation of stretchable conductive fibers.

[0124] Example 2

[0125] A stretchable conductive fiber with high electrical conductivity and stability, differing from Example 1 only in that the elastic matrix is ​​replaced with SBS (Yanshan Petrochemical SBS1401) instead of SEBS. The remaining structure, parameters, and preparation method are the same as those of Example 1. Testing showed that the mass fractions of nanosilver and room-temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber in this example were 16 wt% and 63 wt%, respectively.

[0126] Example 3

[0127] A stretchable conductive fiber with high electrical conductivity and stability, differing from Example 1 only in that the elastic matrix is ​​replaced with PU (BASF 1170AU, Germany) instead of SEBS. The remaining structure, parameters, and preparation method are the same as those of Example 1. Testing showed that the mass fractions of nanosilver and room-temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber in this example were 6 wt% and 49 wt%, respectively.

[0128] Example 4

[0129] A stretchable conductive fiber with high electrical conductivity and stability. This fiber differs from Example 1 in that the spiral groove structure has a rise angle of 30°. Accordingly, the aforementioned rise angle is achieved during the fiber drawing process using a fiber drawing tower by controlling the rotational speed of the composite preform and the fiber drawing speed. Other than this, the structure, parameters, and preparation method are the same as those in Example 1. Testing indicates that the mass fractions of nanosilver and room-temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber in this example are 18% by weight and 65% by weight, respectively.

[0130] Example 5

[0131] A stretchable conductive fiber with high electrical conductivity and stability. This fiber differs from Example 1 in that the spiral groove structure has a rise angle of 60°. Accordingly, the aforementioned rise angle is achieved during the fiber drawing process using a fiber drawing tower by controlling the rotational speed of the composite preform and the fiber drawing speed. Other structures, parameters, and preparation methods are identical to those of Example 1. Testing indicates that the mass fractions of nanosilver and room-temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber in this example are 12 wt% and 57 wt%, respectively.

[0132] Example 6

[0133] A stretchable conductive fiber with high electrical conductivity and high electrical stability. The difference from Example 1 is that the cross section of the spiral groove of the stretchable conductive fiber is a 1 / 3 arc with a diameter of 0.075mm. The structure of the SEBS round rod in the composite preform rod used for drawing (specifically the cross-sectional shape of the groove) is adjusted accordingly according to the structure of the stretchable conductive fiber. The schematic diagram of the cross-sectional structure of the stretchable conductive fiber is shown in FIG. Figure 1 As shown in C. According to the test, in this embodiment, the mass fractions of nano silver and room temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber are 8wt% and 43wt% respectively.

[0134] Example 7

[0135] A stretchable conductive fiber with high electrical conductivity and high electrical stability. The difference from Example 1 is that the cross section of the spiral groove of the stretchable conductive fiber is a 2 / 3 arc with a diameter of 0.075mm. The structure of the SEBS round rod in the composite preform rod used for drawing is adjusted accordingly according to the structure of the stretchable conductive fiber. The cross-sectional structure diagram of the stretchable conductive fiber is shown in FIG. Figure 1 As shown in D. According to the test, in this embodiment, the mass fractions of nano silver and room temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber are 22wt% and 67wt% respectively.

[0136] Example 8

[0137] A stretchable conductive fiber with high electrical conductivity and high electrical stability, which differs from Example 1 in that the number of spiral grooves of the stretchable conductive fiber is changed to 13, and its cross-section is a semicircular arc with a diameter of 0.1 mm. The number of grooves, cross-sectional shape and size of the SEBS round rod in the composite preform rod used for wire drawing are adjusted accordingly according to the structure of the stretchable conductive fiber (according to the stretching ratio, that is, the ratio of the diameter of the preform rod to the diameter of the SEBS elastic matrix, the diameter of the groove is adjusted accordingly), and at the same time, the size of the PMMA thin rod is adjusted accordingly according to the size of the groove (that is, the diameter of the PMMA thin rod is adjusted, and the diameter of the PMMA thin rod is slightly smaller than the diameter of the groove, so that the PMMA thin rod can be smoothly inserted into the groove). The schematic diagram of the cross-sectional structure of the stretchable conductive fiber is shown as follows. Figure 1 As shown in E. According to the test, in this embodiment, the mass fractions of nano silver and room temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber are 16 wt% and 63 wt% respectively.

[0138] Example 9

[0139] A stretchable conductive fiber with high electrical conductivity and high electrical stability. The difference from Example 1 is that the number of spiral grooves in the stretchable conductive fiber is changed to 26, and its cross-section is a semicircular arc with a diameter of 0.05 mm. The number and size of the grooves in the SEBS round rod in the composite preform rod used for drawing are adjusted accordingly according to the structure of the stretchable conductive fiber. The cross-sectional structure diagram of the stretchable conductive fiber is shown in FIG. Figure 1 As shown in F. According to the test, in this embodiment, the mass fractions of nano silver and room temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber are 7wt% and 45wt% respectively.

[0140] Example 10

[0141] A stretchable conductive fiber with high electrical conductivity and high electrical stability, which differs from Example 1 in that the cross-section of the spiral groove of the stretchable conductive fiber is a rectangle with a depth and width of 0.075 mm, and the number of the spiral grooves is 12. The number, shape and size of the grooves of the SEBS round rod in the composite preform rod used for wire drawing are adjusted accordingly according to the structure of the stretchable conductive fiber (according to the stretching ratio, that is, the ratio of the diameter of the preform rod to the diameter of the SEBS elastic matrix, the size of the groove is adjusted accordingly), and at the same time, the cross-sectional shape and size of the PMMA thin rod are adjusted accordingly according to the cross-sectional shape and size of the groove (the cross-sectional shape of the PMMA thin rod is consistent with the cross-sectional shape of the groove, and the size is slightly smaller than the size of the groove, so that the PMMA thin rod can be smoothly inserted into the groove). The schematic diagram of the cross-sectional structure of the stretchable conductive fiber is shown in FIG. Figure 1 As shown in G in FIG. According to detection, in this embodiment, the mass fractions of nano silver and room temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber are 11 wt % and 49 wt % respectively.

[0142] Example 11

[0143] A stretchable conductive fiber with high electrical conductivity and high electrical stability, which differs from Example 1 in that the cross-section of the spiral groove of the stretchable conductive fiber is a trapezoid with an upper base of 0.05mm, a lower base of 0.1mm, and a height of 0.075mm, and the number of the spiral grooves is 14. The groove shape and size of the SEBS round rod in the composite preform rod used for wire drawing are adjusted accordingly according to the structure of the stretchable conductive fiber (according to the stretching ratio, that is, the ratio of the diameter of the preform rod to the diameter of the SEBS elastic matrix, the size of the groove is adjusted accordingly), and the cross-sectional shape and size of the PMMA thin rod are adjusted accordingly according to the cross-sectional shape and size of the groove. The schematic diagram of the cross-sectional structure of the stretchable conductive fiber is shown in FIG. Figure 1 As shown in H. According to the test, in this embodiment, the mass fractions of nano silver and room temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber are 12 wt% and 53 wt% respectively.

[0144] Example 12

[0145] A stretchable conductive fiber with high electrical conductivity and high electrical stability, which differs from Example 1 only in that the room temperature gallium-based liquid metal Galinstan is replaced by a eutectic gallium-indium alloy, the composition of which is Ga 75 In 25 , with a melting point of 15.7°C. Other characteristics of the stretchable conductive fiber and relevant parameters of the preparation process are the same as those in Example 1. Testing shows that in this embodiment, the mass fractions of nanosilver and eutectic gallium-indium alloy in the stretchable conductive fiber are 13wt% and 54wt%, respectively.

[0146] Example 13

[0147] A stretchable conductive fiber with high electrical conductivity and high electrical stability is described. This fiber differs from Example 1 in that the thermoplastic rigid polymer material (PMMA thin rods and PMMA tubes) used in the composite preform preparation is replaced with PEMA. Other preparation conditions and parameters are the same as those in Example 1. The resulting stretchable conductive fiber has the same structure, loading levels of nanosilver and room-temperature gallium-based liquid metal Galinstan, and other parameters as those in Example 1.

[0148] Example 14

[0149] A stretchable conductive fiber with high electrical conductivity and high electrical stability is described. The difference from Example 1 is that, during the preparation of the composite preform, the thermoplastic rigid polymer material is replaced with alginate instead of PMMA, and the solvent used to soak and dissolve the thermoplastic rigid polymer is replaced with water. Other preparation conditions and parameters are the same as those in Example 1. The structure of the resulting stretchable conductive fiber, the loading amounts of nanosilver and room-temperature gallium-based liquid metal Galinstan, and other parameters are consistent with those of Example 1.

[0150] Example 15

[0151] A stretchable conductive fiber with high electrical conductivity and high electrical stability, differing from Example 1 in that the reducing agent in the reducing solution used to immerse the reduced silver ions is replaced with ascorbic acid. All other preparation conditions and parameters are the same as those in Example 1. The structure of the resulting stretchable conductive fiber is consistent with that of Example 1. Testing revealed that the mass fractions of nanosilver and room-temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber in this example are 13 wt% and 57 wt%, respectively.

[0152] Example 16

[0153] A stretchable conductive fiber with high electrical conductivity and high electrical stability, differing from Example 1 in that the reducing agent in the reducing solution for immersing reduced silver ions is replaced with sodium borohydride, and the solvent is replaced with water. Other preparation conditions and parameters are the same as those in Example 1. The structure of the resulting stretchable conductive fiber is consistent with that of Example 1. Testing showed that the mass fractions of nanosilver and room-temperature gallium-based liquid metal Galinstan in the stretchable conductive fiber in this example were 11 wt% and 52 wt%, respectively.

[0154] Comparative Example 1

[0155] A stretchable conductive fiber, which differs from Example 1 in that step (5) is omitted in the preparation method, that is, the loading of nanosilver is omitted, and the SEBS fiber with a spiral groove structure on the surface obtained in step (4) is directly immersed and pulled in room temperature gallium-based liquid metal Galinstan (at a speed of 100 mm / s).

[0156] Comparative Example 2

[0157] A stretchable conductive fiber is different from Example 1 in that step (6) is omitted in the preparation method, that is, the loading of room temperature gallium-based liquid metal Galinstan is omitted, and the parameters in step (5) are adjusted so that the stretchable conductive fiber finally obtained has the same structure as Example 1 except that there is no loading of room temperature gallium-based liquid metal Galinstan, and the loading amount of nanosilver is 74wt%.

[0158] Comparative Example 3

[0159] A stretchable conductive fiber, which differs from Example 1 in that, during the drawing process of step (3), the preform rod clamp is controlled not to rotate when it slowly descends.

[0160] Test Example 1

[0161] The elongation at break, electrical conductivity and electrical stability of the stretchable conductive fibers prepared in each embodiment and comparative example were tested using the following test methods. The test results are shown in Tables 1 and Figure 3-4 In addition, the loading amounts of nanosilver and liquid alloy in the stretchable conductive fibers prepared in various embodiments and comparative examples are also summarized in Table 1.

[0162] Elongation at break testing method: A fiber sample of 5 cm in length is clamped at each end by the sample clamps of a universal mechanical testing machine, with a stretchable section of 3 cm. During the tensile test, the stretching speed is 3 mm / s, and stress-strain data is recorded synchronously using computer software. Stretching is stopped immediately upon fiber breaking, completing the test.

[0163] Conductivity (line conductivity) test method: The length of the fiber sample (denoted as L) is 3 cm, and a laser diameter gauge is used to measure the exact radius of the fiber (denoted as r). The two ends of the fiber are clamped with copper clamps and fixed on the stator and moving platform of the automatic stretching machine. The clamps are connected to the two electrodes of the Keithley2400 source meter respectively. The length of the free section of the fiber is 1 cm. The resistance of the fiber in the relaxed state is measured using a source meter (denoted as R). The conductivity of the fiber (denoted as σ) is calculated using the formula σ=L / πr 2 R is calculated.

[0164] Electrical stability testing method: After the conductivity test is completed, the fiber is stretched using an automatic stretching machine. Computer software records the fiber's stretch distance and resistance in real time. The stretch distance is converted into the fiber's tensile strain, which provides the fiber's resistance at a specific tensile strain. This stretching process can be repeated with a specific tensile strain to assess the fiber's stability under repeated stretching.

[0165] Table 1

[0166]

[0167]

[0168] Among them, “ / ” means that this test is meaningless.

[0169] As shown in Table 1, the conductivity of the stretchable conductive fiber obtained in Example 1 reached 4.8×10 5 S / m, and the elongation at break reaches 900%. When stretched to 500% strain, the resistance increases by 1.6 times, and the corresponding Q value (the ratio of the relative change in length to the relative change in resistance, used to describe the electrical stability of stretchable conductive materials) exceeds 3 (the resistance-strain curve is shown in Figure 2). Figure 3 In addition, after repeated stretching at 60% strain for 18,000 times, the resistance of the fiber increased to 10% (the resistance variation curve with the number of stretching times is shown in Figure 2). Figure 4 , where R0 is the resistance in the relaxed state before repeated stretching, and R is the resistance in the relaxed state after repeated stretching). The above results indicate that the stretchable conductive fiber obtained in Example 1 has both high conductivity and high electrical stability.

[0170] The stretchable conductive fiber obtained in Example 2 is close to that in Example 1 in terms of conductivity and electrical stability, but its tolerance to repeated stretching is reduced. After repeated stretching 18,000 times at 60% strain, the resistance increases by about 18%.

[0171] Compared with Example 1, the loading amounts of nanosilver and liquid metal in Example 3 were significantly reduced to 6 wt% and 49 wt%, respectively. Correspondingly, the electrical conductivity of the fiber decreased to 2.6×10 5 The breaking strain and electrical stability have been significantly reduced, and the performance of endurance to repeated stretching is close to that of Example 1.

[0172] The stretchable conductive fiber obtained in Example 4 exhibited slightly higher conductivity than that in Example 1, and exhibited improved tensile stability. Its resistance at 500% tensile strain increased by 1.1 times, corresponding to a Q value of approximately 4.5. After repeated stretching for 18,000 cycles at 60% strain, its resistance increased by 7%.

[0173] The stretchable conductive fiber obtained in Example 5 exhibited poorer conductivity than that of Example 1, with decreased tensile stability. Its resistance at 500% tensile strain increased by 3.2 times, corresponding to a Q value of approximately 1.6. After repeated stretching for 18,000 cycles at 60% strain, its resistance increased by 38%.

[0174] In Example 6, compared with Example 1, the loading amounts of nanosilver and liquid metal decreased to 8 wt% and 43 wt%, respectively. Correspondingly, the electrical conductivity of the fiber decreased to 1.3×10 5 The electrical stability is significantly lower than that of Example 1, and the performance of endurance against repeated stretching is also lower than that of Example 1.

[0175] In Example 7, compared with Example 1, the loading amounts of nanosilver and liquid metal were increased to 22 wt% and 67 wt%, respectively. Accordingly, the electrical conductivity of the fiber was increased to 7.5×10 5 The electrical stability and the performance of enduring repeated stretching are also significantly improved compared with Example 1.

[0176] In Example 8, compared with Example 1, the loading amounts of nanosilver and liquid metal were increased to 16 wt% and 63 wt%, respectively. Accordingly, the electrical conductivity of the fiber was increased to 5.2×10 5 The electrical stability is slightly lower than that of Example 1, but the repeated stretching resistance is similar to that of Example 1.

[0177] In Example 9, compared with Example 1, the loading amounts of nanosilver and liquid metal decreased significantly, to 7 wt% and 45 wt% respectively. Correspondingly, the electrical conductivity of the fiber decreased to 2×10 5 The electrical stability and the performance of enduring repeated stretching are close to those of Example 1.

[0178] In Example 10, compared with Example 1, the loading amounts of nanosilver and liquid metal decreased to 11 wt% and 49 wt%, respectively. Correspondingly, the electrical conductivity of the fiber decreased to 4×105 The electrical stability is improved compared with that of Example 1, and the repeated stretching resistance is similar to that of Example 1.

[0179] In Example 11, compared with Example 1, the loading amounts of nanosilver and liquid metal decreased to 12 wt% and 53 wt%, respectively. Correspondingly, the electrical conductivity of the fiber decreased to 4.4×10 5 The electrical stability is improved compared with that of Example 1, and the repeated stretching resistance is similar to that of Example 1.

[0180] In Example 12, compared with Example 1, the loading amounts of nanosilver and liquid metal decreased to 13 wt% and 54 wt%, respectively. Correspondingly, the electrical conductivity of the fiber decreased to 4.5×10 5 The electrical stability and the resistance to repeated stretching are lower than those in Example 1.

[0181] The properties of the stretchable conductive fibers prepared in Examples 13-16 are similar to those of the stretchable conductive fibers prepared in Example 1.

[0182] Compared with Example 1, Comparative Example 1 lacks nanosilver as the interface bonding layer between the liquid metal and the elastic matrix, and the liquid metal does not wet SEBS, resulting in the SEBS elastic matrix being completely unable to load the liquid metal.

[0183] Compared with Example 1, Comparative Example 2 shows a significant improvement in conductivity due to the lack of liquid metal as a conductive binder between the nanosilver particles. However, the elongation at break, tensile stability, and resistance to repeated stretching are significantly reduced compared with the Example. Compared with Example 1, Comparative Example 3 shows a significant improvement in conductivity due to the lack of a helical structure. However, the elongation at break, tensile stability, and resistance to repeated stretching are significantly reduced compared with the Example.

[0184] In summary, although the stretchable conductive fibers prepared in Examples 1-16 have different properties, they all have relatively high electrical conductivity and high electrical stability. However, the stretchable conductive fibers prepared in Comparative Examples 1-3 are significantly inferior to those in Example 1 in terms of electrical conductivity or electrical stability.

[0185] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A stretchable conductive fiber with high electrical conductivity and high electrical stability, characterized in that: It consists of an elastic substrate with a spiral groove structure on the surface and a conductive metal cladding loaded on the surface of the elastic substrate; The conductive metal cladding includes nanosilver coating the elastic matrix and liquid metal filling the spiral groove structure, which are sequentially arranged.

2. The stretchable conductive fiber with high electrical conductivity and high electrical stability according to claim 1, characterized in that: The elastic matrix is ​​a thermoplastic elastomer; And / or, the liquid metal is room temperature gallium-based liquid metal; And / or, the mass content of the nanosilver in the stretchable conductive fiber is 5-80wt%; And / or, the mass content of the liquid metal in the stretchable conductive fiber is 10-85wt%.

3. The stretchable conductive fiber with high electrical conductivity and high electrical stability according to claim 1, characterized in that: The diameter of the stretchable conductive fiber is 0.05-2 mm; And / or, the rise angle of the spiral groove structure is 5-80°.

4. A method for continuously preparing a stretchable conductive fiber with high electrical conductivity and high electrical stability according to any one of claims 1 to 3, characterized in that: The following steps are involved: preparing an elastic matrix preform having open grooves on its side; Filling and coating the elastic matrix preform with a thermoplastic hard polymer, and performing vacuum heat treatment to obtain a composite preform; continuously heating and drawing the composite preform rod, and synchronously rotating the composite preform rod during the drawing process to obtain a composite fiber; removing the thermoplastic hard polymer component from the composite fiber to obtain an elastic matrix with a helical structure on the surface; Nanosilver and liquid metal are sequentially loaded on the surface of the elastic matrix with a spiral structure to obtain the stretchable conductive fiber with high electrical conductivity and high electrical stability.

5. The continuous preparation method according to claim 4, wherein The open grooves are arranged longitudinally along the elastic matrix preform; and / or, the number of the open grooves is ≥1; and / or, the elastic matrix preform with open grooves on the side surface has a circular cross-section with a diameter of 5-100 mm; And / or, the cross-sectional shape of the open groove is a 1 / 5-4 / 5 arc, a rectangle or a trapezoid.

6. The continuous preparation method according to claim 4, wherein The elastic substrate with a spiral structure on the surface is sequentially loaded with nanosilver and liquid metal to obtain the stretchable conductive fiber with high conductivity and high electrical stability, which includes: The elastic matrix with a spiral structure on the surface is soaked in a silver ion solution and a reducing solution in sequence to obtain an elastic matrix with nanosilver loaded on the surface; the liquid metal is loaded on the elastic matrix with nanosilver loaded on the surface by an immersion pulling method to obtain the stretchable conductive fiber with high conductivity and high electrical stability.

7. The continuous preparation method according to claim 4, wherein The elastic matrix preform with open grooves on the side is prepared by injection molding, extrusion or machining; And / or, the method for removing the thermoplastic hard polymer component in the composite fiber includes solvent soaking.

8. The continuous preparation method according to claim 7, wherein The softening temperature of the thermoplastic hard polymer is higher than the softening temperature of the elastic matrix preform; And / or, the thermoplastic rigid polymer can be dissolved by at least one solvent.

9. The continuous preparation method according to claim 8, wherein The material of the elastic matrix preform includes styrene-butadiene rubber, hydrogenated styrene-butadiene rubber or thermoplastic polyurethane; And / or, the thermoplastic rigid polymer includes polymethyl methacrylate, polyethyl methacrylate, polycarbonate, polyvinyl alcohol, polyethylene oxide, polyethylene glycol or avena sativa.

10. Use of the stretchable conductive fiber with high electrical conductivity and high electrical stability according to any one of claims 1 to 3 in the preparation of flexible electronic devices.

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