High-stretch, leak-proof liquid metal conductive fiber and method of making same
By modifying liquid metal particles with nanocellulose and designing a core-sheath structure, the problem of insufficient electrical stability and mechanical properties of conductive fibers under high tensile conditions was solved, and the preparation of high tensile and leak-proof liquid metal conductive fibers was realized, which are suitable for wearable devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-24
- Publication Date
- 2026-06-30
AI Technical Summary
Existing conductive fibers have poor electrical stability under high tensile conditions, are prone to leakage when in contact with liquid metal, and have insufficient mechanical properties, making it difficult to meet the dynamic deformation requirements of wearable devices.
By modifying liquid metal particles with nanocellulose and combining them with a core-sheath structure design, high-strength, leak-proof liquid metal conductive fibers are prepared through coaxial wet spinning technology, which enhances interfacial bonding and improves mechanical properties.
It achieves electrical stability and mechanical strength of conductive fibers under high tensile conditions, effectively preventing liquid metal leakage and meeting the requirements for wearable devices.
Smart Images
Figure CN122304067A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of fiber material technology, specifically relating to a high-tensile, leak-proof liquid metal conductive fiber and its preparation method. Background Technology
[0002] With the rapid development of new materials and electronic technologies, wearable smart textiles have emerged. Flexible conductive fibers, as a core component of wearable smart textiles, often need to maintain conductivity stability under deformation conditions. Flexible conductive fibers typically consist of a flexible or stretchable substrate and conductive fillers. However, traditional conductive materials, including metallic materials (such as Au, Pt, and Ag), carbon materials (such as carbon nanotubes and graphene), and conductive polymers (such as polypyrrole and polyaniline), suffer from significant modulus differences between the conductive material and the polymer matrix, leading to the breakage of the conductive network under tension. Therefore, the fibers lose their electrical properties far below their tensile limits, severely limiting their application in smart textiles.
[0003] Gallium-based liquid metals (such as the gallium-indium eutectic alloy EGaIn: 75 wt% gallium and 25 wt% indium) are considered ideal materials for preparing stretchable conductive fibers due to their combination of fluidity and high conductivity, effectively avoiding the modulus mismatch problem between traditional rigid conductors and flexible substrates. However, the weak interfacial bonding between liquid metals and polymer substrates makes them prone to interfacial debonding or phase separation under tensile strain, leading to interruption of the conductive path and a sharp increase in fiber resistance. Furthermore, while the fluidity of liquid metals can impart a certain degree of stretchability to fibers, the mechanical properties of current liquid metal-based conductive fibers are insufficient to meet the durability and structural stability requirements of wearable devices under dynamic deformation. More importantly, due to their inherent fluidity, liquid metals still face the risk of leakage under long-term use or extreme mechanical loads, easily leading to conductivity decay or even short circuits. Therefore, how to achieve high stretchability while endowing fibers with high strength to resist deformation damage through a synergistic strategy of interface modification and microstructure design, and fundamentally solve the problems of electrical instability and leakage, is a core issue that urgently needs to be addressed. Summary of the Invention
[0004] To address the problems of poor electrical stability under high tensile conditions, easy leakage of liquid metal during repeated use, and insufficient mechanical properties of existing conductive fibers, this invention provides a high-tensile, leak-proof liquid metal conductive fiber and its preparation method. The liquid metal conductive fiber is composed of liquid metal, nanocellulose, and thermoplastic polyurethane. Nanocellulose enhances the interfacial interaction between the liquid metal and the polymer matrix, thereby effectively improving the electromechanical stability of the fiber. Furthermore, the introduction of rigid nanocellulose effectively improves the mechanical properties of the fiber. Simultaneously, the core-sheath structure design effectively prevents leakage of liquid metal during use.
[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing a high-tensile, leak-proof liquid metal conductive fiber, comprising the following steps:
[0006] (1) Preparation of liquid metal particles modified with nanocellulose: Large pieces of liquid metal were added to the nanocellulose dispersion and dispersed by ultrasonic-assisted dispersion to break up the liquid metal and disperse it evenly in the nanocellulose system. After drying to remove the solvent, liquid metal particles modified with nanocellulose were obtained.
[0007] (2) Preparation of core spinning solution: Add the nanocellulose-modified liquid metal particles obtained in step (1) to the polymer solution, mix and stir evenly to obtain the core spinning solution;
[0008] (3) Preparation of skin spinning solution: Dissolve the polymer in an organic solvent to prepare a homogeneous skin spinning solution;
[0009] (4) Coaxial wet spinning: The core spinning solution prepared in step (2) is used as the inner phase and the skin spinning solution prepared in step (3) is used as the outer phase. Coaxial wet spinning is carried out through a coaxial spinneret. After solidification in a coagulation bath, washing and drying, liquid metal conductive fibers with a core-skin structure are obtained.
[0010] Furthermore, the liquid metal is one or more of eutectic gallium-indium alloy, gallium-indium alloy, gallium-tin alloy, and gallium-indium-tin alloy; the nanocellulose is cellulose nanocrystal, bacterial cellulose, chitin nanofiber, or nanolignin.
[0011] Furthermore, the ultrasonic-assisted dispersion power is 200-1000 W, and the time is 3-30 min; the mass fraction of the nanocellulose dispersion is 0.1-10.0 wt%; the mass ratio of liquid metal to nanocellulose is 20:1 to 100:1; the drying temperature is 40-70 ℃, and the drying time is 12-48 h.
[0012] Further, in step (2), the polymer is one or more of polyurethane, polyvinyl alcohol, polyamide, and polyacrylonitrile; and the mass fraction of the nanocellulose-modified liquid metal particles in the core spinning solution is 70-98 wt%.
[0013] Further, in step (2), the solvent in the polymer solution is one or more of N,N-dimethylformamide, dimethylacetamide, and tetrahydrofuran; the mass fraction of the polymer solution is 10-30 wt%; the mixing and stirring are carried out by mechanical stirring or magnetic stirring, with a stirring speed of 200-1500 rpm and a stirring time of 2-12 h.
[0014] Further, in step (3), the polymer is one or more of polyurethane, thermoplastic polyurethane, polyvinyl alcohol, polyamide, and polyacrylonitrile; the mass fraction of the polymer in the skin spinning solution is 10-30 wt.
[0015] Further, in step (4), the process parameters of the coaxial wet spinning are: core extrusion speed of 0.1~1.3 mL / min, sheath extrusion speed of 0.1~1.5 mL / min, spinneret inner diameter of 0.3~0.7 mm, and outer diameter of 0.7~1.6 mm.
[0016] Further, in step (4), the coagulation bath is water, ethanol or a mixture of the two; the temperature of the coagulation bath is 20~90 ℃; and the curing time is 1~10 min.
[0017] Further, in step (4), the washing is performed by washing with deionized water or ethanol 2 to 5 times; the drying is performed by air drying at room temperature or vacuum drying at 30 to 60 ℃ for 6 to 24 hours.
[0018] A liquid metal conductive fiber prepared by the above preparation method.
[0019] Compared with existing technologies, the beneficial effects of this invention are as follows: By modifying the surface of liquid metal with nanocellulose, the interfacial bonding force between the liquid metal microconductive domains and the polymer matrix is improved, thereby enhancing the electromechanical stability of the fiber. Simultaneously, the introduction of rigid nanocellulose significantly improves the mechanical strength of the fiber. Furthermore, the core-sheath structure of the fiber effectively suppresses leakage of the conductive liquid metal core layer. Attached Figure Description
[0020] Figure 1 This is a SEM image of the liquid metal conductive fiber prepared in Example 1 of the present invention;
[0021] Figure 2 EDS image of the liquid metal conductive fiber prepared in Example 1 of this invention;
[0022] Figure 3 This is an optical photograph of the liquid metal conductive fiber prepared in Example 1 of the present invention under 500% stretching.
[0023] Figure 4 Tensile stress-strain curves of liquid metal conductive fibers prepared in Comparative Examples 1-3, as shown in Example 1 of this invention;
[0024] Figure 5 This is a diagram showing the mass change of the liquid metal conductive fiber prepared in Comparative Examples 1-3 after 5MPa cyclic pressurization and depressurization, as shown in Example 1 of the present invention.
[0025] Figure 6 The relative resistance-strain curves of the liquid metal conductive fibers prepared in Comparative Examples 1-3 are shown in Example 1 of this invention. Detailed Implementation
[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.
[0027] The abbreviations used in this invention are all fixed abbreviations in the field, and the meanings of some of the letters are explained as follows: SEM image: electron scanning imaging image; EDS image: energy spectrum; XRD image: X-ray diffraction pattern; XPS image: X-ray photoelectron spectroscopy analysis spectrum.
[0028] Example 1
[0029] The liquid metal conductive fiber in this embodiment is prepared by the following steps:
[0030] (1) Preparation of cellulose nanoparticles modified with liquid metal: 4 g of eutectic gallium indium alloy (EGaIn, liquid metal) was added to 15 mL of cellulose nanoparticle (cellulose nanocrystal, CNC) dispersion with a mass fraction of 1 wt%, and the mass ratio of liquid metal to cellulose nanoparticle was 26:1; the liquid metal was ultrasonically treated at 700 W for 5 min to break it up and disperse it evenly; the resulting dispersion was dried in an oven at 60 ℃ for 24 h to obtain cellulose nanoparticles modified with liquid metal (CNC-LMPs).
[0031] (2) Preparation of core spinning solution: 8 g of CNC-LMPs obtained in step (1) were added to a solution of N,N-dimethylformamide (DMF) containing 0.9 g of thermoplastic polyurethane (TPU) with a mass fraction of 15 wt%. The solution was mechanically stirred at 900 rpm for 6 h to obtain a uniform core spinning solution. The mass fraction of the liquid metal particles modified with nanocellulose in the core spinning solution was 89.9 wt%.
[0032] (3) Preparation of skin spinning solution: Thermoplastic polyurethane (TPU) is dissolved in DMF to prepare a homogeneous solution with a mass fraction of 18wt% to obtain the skin spinning solution;
[0033] (4) Coaxial wet spinning: A coaxial spinneret (inner diameter 0.4 mm, outer diameter 1.1 mm) was used. The core spinning solution prepared in step (2) was used as the inner phase, the extrusion speed was 0.3 mL / min, and the skin spinning solution prepared in step (3) was used as the outer phase, the extrusion speed was 0.6 mL / min. Coaxial wet spinning was carried out. The extruded nascent fibers were solidified in an 80 °C water coagulation bath for 10 min, then washed 3 times with deionized water, and vacuum dried at 50 °C for 12 h to obtain liquid metal conductive fibers with a core-skin structure.
[0034] Comparative Example 1: No nanocellulose modification
[0035] Comparative Example 1 follows the same steps as Example 1, except that in step (1), the nanocellulose dispersion is not used, and the liquid metal is directly dispersed in pure water by ultrasonication to obtain unmodified liquid metal particles. The remaining steps are the same as in Example 1.
[0036] Comparative Example 2: Low Liquid Metal Content
[0037] Comparative Example 2 is the same as Example 1 in terms of steps, except that in step (2), the ratio of CNC-LMPs to TPU is adjusted so that the mass fraction of CNC-LMPs in the core spinning solution is reduced to 50 wt% (i.e., outside the range of 70-98 wt% as defined in claim 4). The remaining steps are the same as in Example 1.
[0038] Comparative Example 3: Homogeneous structure without cortex
[0039] Comparative Example 3 follows the same steps as Example 1, except that steps (3) and (4) are replaced with the core spinning solution prepared in step (2) and homogeneous fibers without a skin are prepared by conventional wet spinning (uniaxial spinneret).
[0040] The fibers obtained in Example 1 and Comparative Examples 1-3 were subjected to the following performance tests:
[0041] The surface and cross-sectional morphology of the fibers were observed using scanning electron microscopy (SEM), and the elemental distribution was analyzed using energy dispersive spectroscopy (EDS). Figure 1 As shown, the fiber in Example 1 has a distinct core-sheath structure, with relatively coarse liquid metal particles in the core layer and a relatively smooth polyurethane shell. Figure 2 As shown, the corresponding elemental mapping image indicates that the liquid metal particles Ga and In are uniformly distributed in the fiber core layer; since both nanocellulose and polyurethane contain C, the C element is concentrated in the outer polyurethane layer, while it is sparsely distributed in the core layer.
[0042] Tensile property test: The fibers obtained in Example 1 and Comparative Examples 1-3 were sequentially clamped in a universal testing machine with a spacing of 1 cm and a tensile speed of 5 mm / min, until the fibers completely broke. Figure 3 , Figure 4 As shown, the tensile strength of the fiber in Example 1 is significantly higher than that in Comparative Examples 1 and 3, with an elongation at break exceeding 500%. This indicates that the liquid metal particles modified with nanocellulose can significantly improve the modulus and strength of conductive fibers. This is because a natural oxide layer exists on the surface of the liquid metal, and nanocellulose enhances the interfacial interaction through coordination bonds, resulting in efficient stress transfer during stretching. Comparative Example 2 exhibits higher tensile strength due to a reduced liquid metal content and an increased polymer ratio; however, the excessively low liquid metal content results in extremely poor fiber conductivity, making it difficult to apply.
[0043] Leakage prevention performance test: Take 5 cm of fiber prepared in Example 1 and Comparative Examples 1-3, and record the initial mass ( Using a universal testing machine, the pressure was uniformly increased to 5 MPa, maintained for 3 minutes, and then the pressure was slowly reduced to remove the fiber. The mass was recorded. Repeat the above experimental steps, and record the mass of the fiber after 5 pressure cycles. ), calculate weight retention rate .like Figure 5 As shown, the fibers of Example 1, Comparative Example 1 and Comparative Example 2 have a core-sheath structure. Since the liquid metal is protected in the sheath polymer, the leakage of liquid metal before and after pressurization is minimal, and the weight retention rate is higher than 90%. In addition, due to the enhanced interfacial chemical effect of the liquid metal particles by nanocellulose, the weight retention rate of the fiber of Example 1 is higher than that of Comparative Example 1, but slightly lower than that of Comparative Example 2, which has nanocellulose modification and low liquid metal content.
[0044] Electrical stability test: Copper wires were connected to both ends of the fibers prepared in Example 1 and Comparative Examples 1-3, and then connected to a digital source meter to record the fiber resistance changes. A universal testing machine was used in conjunction with the digital source meter to test the resistance change of a 1cm fiber at a tensile speed of 5mm / min within the range of 0-300% elongation. The resistance change rate ΔR / R under different strains was calculated. Figure 6 As shown, the fiber of Example 1 exhibits the best electrical conductivity due to the stable interface between the liquid metal particles modified with nanocellulose. Its relative resistance change at 600% strain is less than 5 ohms, demonstrating superior conductivity compared to Comparative Example 1 without nanocellulose modification. The fiber of Comparative Example 2 has an excessively low liquid metal content, making it difficult to activate conductivity. Although the fiber of Comparative Example 3 has comparable conductivity to that of Example 1, it lacks a polymer shell protection and fractures at 200% strain.
Claims
1. A method of making a high tensile, leak resistant, liquid metal conductive fiber, characterized by, Includes the following steps: (1) Preparation of liquid metal particles modified with nanocellulose: Large pieces of liquid metal were added to the nanocellulose dispersion and dispersed by ultrasonic-assisted dispersion to break up the liquid metal and disperse it evenly in the nanocellulose system. After drying to remove the solvent, liquid metal particles modified with nanocellulose were obtained. (2) Preparation of core spinning solution: Add the nanocellulose-modified liquid metal particles obtained in step (1) to the polymer solution, mix and stir evenly to obtain the core spinning solution; (3) Preparation of skin spinning solution: Dissolve the polymer in an organic solvent to prepare a homogeneous skin spinning solution; (4) Coaxial wet spinning: The core spinning solution prepared in step (2) is used as the inner phase and the skin spinning solution prepared in step (3) is used as the outer phase. Coaxial wet spinning is carried out through a coaxial spinneret. After solidification in a coagulation bath, washing and drying, liquid metal conductive fibers with a core-skin structure are obtained.
2. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, The liquid metal is one or more of eutectic gallium-indium alloy, gallium-indium alloy, gallium-tin alloy, and gallium-indium-tin alloy; the nanocellulose is cellulose nanocrystal, bacterial cellulose, chitin nanofiber, or nanolignin.
3. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, In step (1), the power of the ultrasonic-assisted dispersion is 200-1000 W, and the time is 3-30 min; the mass fraction of the nanocellulose dispersion is 0.1-10.0 wt%; the mass ratio of the liquid metal to the nanocellulose is 20:1 to 100:1; the drying temperature is 40-70 ℃, and the drying time is 12-48 h.
4. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, In step (2), the polymer is one or more of polyurethane, polyvinyl alcohol, polyamide, and polyacrylonitrile; in the core spinning solution, the mass fraction of the liquid metal particles modified with nanocellulose is 70-98 wt%.
5. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, In step (2), the solvent in the polymer solution is one or more of N,N-dimethylformamide, dimethylacetamide, and tetrahydrofuran; the mass fraction of the polymer solution is 10-30 wt%; the mixing and stirring are carried out by mechanical stirring or magnetic stirring, with a stirring speed of 200-1500 rpm and a stirring time of 2-12 h.
6. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, In step (3), the polymer is one or more of polyurethane, thermoplastic polyurethane, polyvinyl alcohol, polyamide, and polyacrylonitrile; the mass fraction of the polymer in the skin spinning solution is 10-30 wt.
7. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, In step (4), the process parameters for coaxial wet spinning are: core extrusion speed of 0.1~1.3 mL / min, sheath extrusion speed of 0.1~1.5 mL / min, spinneret inner diameter of 0.3~0.7 mm, and outer diameter of 0.7~1.6 mm.
8. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, In step (4), the coagulation bath is water, ethanol, or a mixture of the two; the temperature of the coagulation bath is 20~90 ℃; and the curing time is 1~10 min.
9. The method for preparing liquid metal conductive fibers according to claim 1, characterized in that, In step (4), the washing is performed by washing with deionized water or ethanol 2 to 5 times; the drying is performed by air drying at room temperature or vacuum drying at 30 to 60 ℃ for 6 to 24 hours.
10. A liquid metal conductive fiber prepared by the preparation method according to any one of claims 1 to 9.