Liquid metal conductive fiber and preparation method and application thereof

Abstract

According to the liquid metal conductive fiber and the preparation method and application thereof provided by the invention, the liquid metal is used as a raw material, and the submicron conductive fiber which has a chain bead structure in which'balls' and'lines' are uniformly and alternately distributed and is adjustable in resistance is formed by adopting a high-pressure jet mode; the distribution density of the chain bead structure in the liquid metal conductive fiber is adjusted by changing the air pressure of the air storage bottle, so that the resistance of the liquid metal conductive fiber is adjustable. The preparation method disclosed by the invention is simple and controllable, the problem that the liquid metal conductive fiber has excellent tensile property and high conductivity can be solved, and the liquid metal conductive fiber is applied to the fields of electronic textiles, flexible wearable electronic equipment and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid metals, and more specifically, to a liquid metal conductive fiber, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of the digital health care industry, monitoring personal physiological parameters through wearable electronic devices to achieve personal health management has attracted wide attention, which requires meeting the requirements of flexibility, stretchability, miniaturization, and comfort. Compared with thin-film devices, conductive fibers are becoming key elements in wearable electronic products and have advantages due to their adaptability to various deformations, breathability, and ease of integration with textiles.

[0003] Currently, there are two strategies for preparing conductive fibers: one is to make traditional metals or conductive polymers into fibrous shapes; the other is to embed conductive fillers such as carbon nanotubes (CNTs), graphene, and silver nanowires / particles into an elastic fiber matrix. The former has the problem of being non-stretchable or having limited stretchability, and the common strategy is to design wave / twist structures or prestrain to improve it; while the latter has certain stretchability, but its conductivity is worse than that of the former. Therefore, how to achieve both excellent stretchability and high conductivity in conductive fibers is the main task in the current research on conductive fibers.

[0004] Gallium-based liquid metals, due to their excellent electrical conductivity as metals and being in a liquid state at room temperature, can balance high electrical conductivity and good stretchability, and are strong candidates for preparing conductive and intrinsically stretchable fibers. In addition, the low toxicity and good biocompatibility of liquid metals also make them highly concerned in the field of flexible wearables. However, the relatively high surface tension (632 mN / m, about ten times that of water) makes liquid metals usually spherical. Therefore, overcoming the surface tension of liquid metals and preparing them into conductive fibers poses a challenge.

[0005] In terms of patents, Patent Publication No. CN112030546B discloses a method of evenly spraying liquid metal on fibers by means of an airbrush, immediately vertically suspending them after spraying, and finally encapsulating the fibers sprayed with liquid metal using a packaging material. This method makes ordinary fibers become conductive fibers while effectively avoiding the destruction of the characteristics of the fibers themselves, and the fibers still have the advantages of good flexibility, elasticity, good shape change, and high elongation. However, the interfacial bonding force between the liquid metal and the ordinary fibers is weak, and it is difficult to ensure the conductive stability of this type of liquid metal fiber under deformations such as stretching or bending.

[0006] Publication Nos. CN115464122A and CN112647156B respectively disclose the use of injection technology to achieve the perfusion of liquid metal in hollow fibers to obtain liquid metal fibers and the electrochemically assisted preparation of liquid metal hydrogel fibers. The sizes of the liquid metal fibers obtained by these two methods are both in the order of hundreds of micrometers, and there are problems such as poor air permeability and comfort when used in flexible wearable electronic devices or electronic fabrics. Therefore, the preparation of liquid metal fibers with small sizes and adjustable electrical properties to achieve multifunctionalization is of great significance in flexible wearable electronic devices, electronic fabrics, etc. Summary of the Invention

[0007] In view of the above problems, the object of the present invention is to provide a liquid metal conductive fiber, its preparation method and application, so as to solve the problem that the liquid metal conductive fiber has excellent tensile properties while also having high conductivity. By adopting the method of high-pressure jet, submicron conductive fibers with a chain-bead structure and adjustable resistance are formed, and by changing the air pressure of the pressure storage gas cylinder, the distribution density of the chain-bead structure in the liquid metal conductive fiber is adjusted, thereby realizing the adjustable resistance of the liquid metal conductive fiber.

[0008] The present invention provides a liquid metal conductive fiber, which uses liquid metal as a raw material to form submicron conductive fibers with a chain-bead structure and adjustable resistance, wherein the chain-bead structure is a uniformly alternating distribution structure of "balls" and "lines".

[0009] Preferably, the resistance of the liquid metal conductive fiber is adjusted by the distribution density of the chain-bead structure in the liquid metal conductive fiber.

[0010] Preferably, the cross-sectional area of the "balls" in the chain-bead structure is larger than the cross-sectional area of the "lines".

[0011] Preferably, the liquid metal is one or more of gallium, gallium-indium alloy, gallium-tin alloy, indium-tin alloy, gallium-indium-tin alloy, gallium-indium-tin-bismuth alloy, and gallium alloys or gallium-indium alloys doped with transition metals and solid non-metal elements.

[0012] The present invention also provides a preparation method for the above liquid metal conductive fiber, including the following steps:

[0013] S1: Load the liquid metal into a high-pressure jet device, install a glass micro-needle at the jet orifice of the high-pressure jet device, and connect a high-pressure gas storage cylinder to the tail of the high-pressure jet device;

[0014] S2: Under room temperature conditions, control the air pressure of the pressure storage gas cylinder, and the liquid metal is ejected from the glass micro-needle to form liquid metal conductive fibers with a chain-bead structure;

[0015] S3: When the liquid metal conductive fiber ejects from the needle orifice of the glass micro-needle, it quickly passes by a suspended baffle, and due to the oxide layer with certain mechanical properties formed on the surface of the liquid metal conductive fiber, the liquid metal conductive fiber is suspended on the baffle;

[0016] S4: Collect the liquid metal fibers suspended on the baffle on a substrate;

[0017] S5: Spray and encapsulate the surface of the liquid metal conductive fibers collected on the substrate with an encapsulating liquid to form liquid metal conductive fibers with various electrical properties.

[0018] Preferably, the inner diameter of the glass micro-needle is 5 μm to 0.9 mm.

[0019] Preferably, in S2, by changing the air pressure of the pressure storage gas cylinder, the distribution density of the bead structure in the liquid metal conductive fiber is adjusted.

[0020] Preferably, the air pressure of the pressure storage gas cylinder is 0.4 MPa to 1.5 MPa.

[0021] Preferably, the gas in the high-pressure storage gas cylinder includes but is not limited to one or several of air, nitrogen, and argon.

[0022] Preferably, in S3, the suspended height of the baffle is set according to the length of the liquid metal conductive fiber.

[0023] Preferably, the substrate is one or more of polydimethylsiloxane, polyurethane, hydrogel, Ecoflex (degradable plastic), SEBS (hydrogenated styrene-butadiene block copolymer), fabric, plant, glass, plastic, or silicon wafer.

[0024] Preferably, the encapsulating liquid is one or more of an alcohol suspension of polydimethylsiloxane, an alcohol suspension of polyurethane, an alcohol suspension of hydrogel, an alcohol suspension of Ecoflex, or an alcohol suspension of SEBS.

[0025] The present invention also provides an application of the above liquid metal conductive fiber in electronic textiles and flexible wearable electronic devices.

[0026] As can be seen from the above technical solutions, the liquid metal conductive fiber, its preparation method and application provided by the present invention can obtain the following beneficial effects compared with the prior art:

[0027] (1) Due to Rayleigh instability when the liquid metal ejects from the glass micro-needle through high-pressure jet, the liquid metal stream column is disturbed. By utilizing the synergistic effect of the large surface tension of the liquid metal and the resistance of the oxide layer, a bead structure with alternating "balls" and "lines" is formed;

[0028] (2) The bead structure of the liquid metal conductive fiber can regulate the density of the bead structure distributed in the liquid metal conductive fiber by changing the air pressure in the pressure storage cylinder; the distribution of the "balls" in the bead structure can optimize the electrical properties of the liquid metal conductive fiber; that is, the resistance can be adjusted by changing the air pressure to control the distance between the "balls".

[0029] (3) Under the action of large stretching, the resistance change rate of the liquid metal conductive fiber increases linearly, and liquid metal conductive fibers with arbitrary electrical properties can be obtained by regulating the distribution of the bead structure in the conductive fiber.

[0030] (4) According to the thickness of the liquid metal conductive fiber to be prepared, customized glass micro needles with different diameters are selected to make the diameter of the liquid metal conductive fiber.

[0031] To achieve the above and related purposes, one or more aspects of the present invention include the features described in detail later. The following description and the accompanying drawings detail certain exemplary aspects of the present invention. However, these aspects indicate only some of the various ways in which the principles of the present invention can be used. In addition, the present invention is intended to include all these aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] By referring to the following description in conjunction with the accompanying drawings, and with a more comprehensive understanding of the present invention, other objects and results of the present invention will become more apparent and easier to understand. In the drawings:

[0033] Figure 1 It is a schematic diagram of the device for preparing the liquid metal conductive fiber in the present invention and a schematic diagram of the bead structure in the liquid metal conductive fiber.

[0034] Figure 2 It is a scanning electron microscope image of the liquid metal conductive fibers with bead structures and adjustable resistance prepared in Example 1, Example 2 and Example 3 of the present invention under different air pressures.

[0035] Figure 3 It is a graph showing the change in the number of beads per unit length of the bead structure in the liquid metal conductive fibers prepared in Example 1, Example 2 and Example 3 of the present invention with the applied air pressure.

[0036] Figure 4 It is the static resistance values of the three liquid metal conductive fibers with bead structures and adjustable resistance prepared in Example 1, Example 2 and Example 3 of the present invention after 10 stretching cycles.

[0037] Figure 5This is a graph showing the variation of the relative resistance change rate of the liquid metal conductive fiber with a chain bead structure and adjustable resistance prepared in Example 1, Example 2, and Example 3 of the present invention with respect to air pressure when the tensile strain is 100%.

[0038] Among them, 1. High-pressure injection device; 2. Glass micro needle; 3. High-pressure gas storage cylinder; 4. Substrate.

[0039] In all the drawings, the same reference numerals indicate similar or corresponding features or functions. Detailed implementation manners

[0040] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0041] It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0042] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the description of the present invention, which are obvious to those skilled in the art. Other implementation manners obtained from the description of the present invention are obvious to those skilled in the art. The description and examples of this application are merely exemplary.

[0043] Aiming at the problem of how to solve the problem that the liquid metal conductive fiber has high conductivity while having excellent tensile properties as mentioned above, the present invention provides a liquid metal conductive fiber, its preparation method, and application. By using high-pressure jet and taking liquid metal as the raw material, the liquid metal overcomes its characteristics of low viscosity and high surface tension under the action of high pressure and high speed, and simply and quickly prints liquid metal conductive fibers with a line width of sub-micrometer level. Due to the resistance synergy between the large surface tension of the liquid metal itself and the oxide layer with a higher modulus, the "balls" and "lines" in the chain bead structure of the liquid metal fiber are evenly distributed alternately, and the density of the chain bead structure can be regulated by adjusting the air pressure, thereby realizing the adjustable resistance of the liquid metal conductive fiber. The liquid metal conductive fiber of the present invention has great application potential in the fields of electronic textiles, flexible wearable electronic devices, etc.

[0044] The present invention provides a liquid metal conductive fiber, which uses liquid metal as a raw material to form a sub-micron conductive fiber with a chain bead structure and adjustable resistance. Among them, the chain bead structure is a structure in which "balls" and "lines" are evenly and alternately distributed.

[0045] Among them, the resistance of the liquid metal conductive fiber is adjusted by the distribution density of the chain bead structure in the liquid metal conductive fiber, that is: by controlling the density of the chain bead structure distributed on the liquid metal conductive fiber to achieve the resistance regulation of the conductive fiber. In Figure 1 the embodiments in

[0046] show the specific structure of the chain bead structure. The chain bead structure includes "balls" and "lines", and the "balls" and "lines" are evenly and alternately distributed to form a chain bead structure. Moreover, the cross-sectional area of the "balls" in the chain bead structure is larger than that of the "lines"; the change in the distance between the "balls" can achieve the resistance adjustment of the liquid metal conductive fiber.

[0047] The present invention also provides a preparation method for the liquid metal conductive fiber, including the following steps:

[0048] S1: Load the liquid metal into a high-pressure spraying device, install a glass micro-needle at the spraying port of the high-pressure spraying device, and connect a high-pressure gas storage cylinder to the tail of the high-pressure spraying device;

[0049] S2: Under room temperature conditions, control the air pressure of the pressure gas storage cylinder, and the liquid metal sprays out from the glass micro-needle to form a liquid metal conductive fiber with a chain bead structure;

[0050] S3: When the liquid metal conductive fiber sprays out from the needle port of the glass micro-needle, quickly pass through a suspended baffle, and the liquid metal conductive fiber is suspended on the baffle through an oxide layer with certain mechanical properties formed on the surface of the liquid metal conductive fiber;

[0051] S4: Collect the liquid metal fiber suspended on the baffle on a substrate;

[0052] S5: Spray and encapsulate the surface of the liquid metal conductive fiber collected on the substrate through an encapsulating liquid to form a liquid metal conductive fiber with various electrical properties.

[0053] In Figure 1 the shown embodiments, the device for preparing the liquid metal conductive fiber includes but is not limited to: a high-pressure spraying device 1, a glass micro-needle 2, a high-pressure gas storage cylinder 3, and a substrate 4. Through this device, a liquid metal conductive fiber with adjustable resistance is prepared.

[0054] In the present invention, the inner diameter of the glass micro-needle 2 is 5 μm to 0.9 mm, and a suitable specific inner diameter is selected according to requirements. The high-pressure injection device 1 is a syringe without a needle. Different diameters of customized glass micro-needles are selected according to the thickness of the liquid metal conductive fiber to be prepared, so as to control the diameter of the liquid metal conductive fiber.

[0055] In S2, by changing the air pressure of the pressure storage cylinder 3, the distribution density of the chain bead structure in the liquid metal conductive fiber is adjusted. Among them, the air pressure of the pressure storage cylinder 3 is 0.4 MPa to 1.5 MPa. Different air pressures are used to obtain a chain bead structure with different distances between "balls", and the greater the air pressure, the greater the distance between "balls" in the chain bead structure.

[0056] In addition, the gas in the high-pressure storage cylinder 3 includes but is not limited to one or several of air, nitrogen, and argon. In specific applications, gases with different compositions are selected according to the actual situation.

[0057] In S3, the suspended height of the baffle is set according to the length of the liquid metal conductive fiber. In specific applications, the suspended height of the baffle is set according to the required length of the prepared liquid metal conductive fiber.

[0058] Among them, the substrate is one or more of polydimethylsiloxane, polyurethane, hydrogel, Ecoflex, SEBS, fabric, plant, glass, plastic, or silicon wafer.

[0059] Among them, the encapsulating liquid is one or more of an alcohol suspension of polydimethylsiloxane, an alcohol suspension of polyurethane, an alcohol suspension of hydrogel, an alcohol suspension of Ecoflex, or an alcohol suspension of SEBS.

[0060] The preparation method of the present invention is simple and controllable, and can solve the problem that while the liquid metal conductive fiber has excellent tensile properties, it also has high conductivity. The liquid metal conductive fiber has broad application prospects in the fields of electronic textiles, flexible wearable electronic devices, etc.

[0061] The present invention will be further described in detail below in conjunction with the embodiments and the drawings. It should be noted that the following embodiments are intended to facilitate the understanding of the present invention and do not limit it in any way.

[0062] Example 1:

[0063] The preparation device of the liquid metal conductive fiber in this embodiment is as Figure 1 shown.

[0064] In this embodiment, the preparation method of the liquid metal conductive fiber is as follows:

[0065] Step 1: Load 5 mL of gallium-indium eutectic alloy into the high-pressure injection device 1. Install a glass micro-needle 2 with an inner diameter of 30 μm in the high-pressure injection device, and evenly apply AB universal glue at each connection of the device to ensure airtightness.

[0066] Step 2: At room temperature of 25 °C, directly connect the trachea to the high-pressure injection device 1 and keep the valve of the nitrogen cylinder closed (0 MPa).

[0067] Step 3: Open the valve of the high-pressure gas storage cylinder 3. By controlling the magnitude of the air pressure, the distribution density of the bead structures on the liquid metal conductive fiber can be regulated, as Figure 3 shown.

[0068] Step 4: Apply an air pressure of 0.4 MPa. The liquid metal (gallium-indium eutectic alloy) is ejected from the glass micro-needle at high speed to form a liquid metal conductive fiber with bead structures. The scanning electron microscope image of its microscopic morphology is as Figure 2 shown.

[0069] Step 5: When the liquid metal conductive fiber ejects from the needle orifice of the glass micro-needle 2, it quickly passes through the suspended baffle. Utilize the oxide film of the liquid metal with certain mechanical properties to resist its gravity, so that the liquid metal fiber is suspended and hung on the baffle.

[0070] Step 6: Collect the above liquid metal fiber onto the polydimethylsiloxane substrate 4.

[0071] Step 7: Dissolve 2 g of PDMS with a prepolymer to curing agent ratio of 10:1 in 5 mL of absolute ethanol, spray and encapsulate the filamentous liquid metal to be encapsulated, and cure it in a 60 °C forced air drying oven for 3 h.

[0072] Step 8: Use the four-terminal method to conduct a force-electricity coupling test on the encapsulated liquid metal conductive fiber with bead structures.

[0073] Use an Instron 5943 material testing machine to apply strain to the conductive fiber at a tensile rate of 30 mm / min, and use a KEITHLEY 6221 current source to provide a constant current of 0.1 mA for the conductive fiber; use a Keithley 34420A nanovoltmeter to test the voltage output of the conductive fiber with strain changes. Finally, the resistance change law can be obtained through Ohm's law.

[0074] (1) Static electrical properties of liquid metal conductive fiber after tensile cycling

[0075] The resistance of the liquid metal conductive fiber is tested without tensile strain, and its resistance value is 9.25 Ω, as Figure 4 shown, and its resistance value remains stable after 10 tensile cycles.

[0076] (2) Resistance change of the liquid metal conductive fiber at a tensile strain of 100%

[0077] Apply a continuous strain of 0 - 100% to the liquid metal conductive fiber. When stretched to 100%, its relative resistance change rate is the smallest, which is 44.54%, as Figure 5 shown.

[0078] Example 2:

[0079] The preparation device of the liquid metal conductive fiber in this example is as Figure 1 shown.

[0080] In this example, the preparation method of the liquid metal conductive fiber is as follows:

[0081] Step 1: Load 5 mL of gallium-indium eutectic alloy into the high-pressure injection device 1. The high-pressure injection device is equipped with a glass micro-needle 2 with an inner diameter of 30 μm, and apply AB universal glue evenly at each connection of the device to ensure airtightness.

[0082] Step 2: Under the condition of room temperature of 25 °C, directly connect the trachea to the high-pressure injection device 1 and keep the valve of the nitrogen cylinder closed (0 MPa).

[0083] Step 3: Open the valve of the high-pressure gas storage cylinder 3. By controlling the magnitude of the air pressure, the distribution density of the bead structure on the liquid metal conductive fiber can be regulated, as Figure 3 shown.

[0084] Step 4: Apply an air pressure of 0.7 MPa. The liquid metal (gallium-indium eutectic alloy) is ejected from the glass micro-needle at a high speed to form a liquid metal conductive fiber with a bead structure. The scanning electron microscope image of its microscopic morphology is as Figure 2 shown.

[0085] Step 5: When the liquid metal conductive fiber ejects from the needle orifice of the glass micro-needle 2, it quickly passes through the suspended baffle. Utilize the oxide film with certain mechanical properties of the liquid metal to resist its gravity, so that the liquid metal fiber is suspended on the baffle.

[0086] Step 6: Collect the above liquid metal fiber onto the polydimethylsiloxane substrate 4.

[0087] Step 7: Dissolve 2 g of PDMS with a prepolymer to curing agent ratio of 10:1 in 5 mL of absolute ethanol, spray and encapsulate the filamentous liquid metal to be encapsulated, and cure it in a 60 °C blast drying oven for 3 h.

[0088] Step 8: Use the four-terminal method to conduct force-electricity coupling testing on the encapsulated liquid metal conductive fiber with a bead structure.

[0089] Apply strain to the conductive fiber at a tensile rate of 30 mm / min using an Instron 5943 material testing machine, and use a KEITHLEY 6221 current source to provide a constant current of 0.1 mA to the conductive fiber; use a Keithley 34420A nanovoltmeter to measure the voltage output of the conductive fiber as the strain changes, and finally the resistance change law can be obtained through Ohm's law.

[0090] (1) Static electrical properties of the liquid metal conductive fiber after the tensile cycle

[0091] The liquid metal conductive fiber is tested for resistance without tensile strain. As the air pressure increases, the density of the bead structure decreases, and the static resistance of the liquid metal conductive fiber with a bead structure and adjustable resistance also increases accordingly. Its resistance value is 21.28 Ω, as Figure 4 shown, and its resistance value remains stable after 10 tensile cycles.

[0092] (2) Resistance change of the liquid metal conductive fiber when the tensile strain is 100%

[0093] Apply continuous strain of 0 - 100% to the liquid metal conductive fiber. As the air pressure increases, the density of the bead structure decreases, and the electrical properties of the liquid metal conductive fiber with a bead structure and adjustable resistance change. When stretched to 100%, its relative resistance change rate is 63.23%, as Figure 5 shown.

[0094] Example 3:

[0095] The preparation device of the liquid metal conductive fiber in this example is as Figure 1 shown.

[0096] In this example, the preparation method of the liquid metal conductive fiber is as follows:

[0097] Step 1: Load 5 mL of gallium-indium eutectic alloy into the high-pressure injection device 1. The high-pressure injection device is equipped with a glass micro-needle 2 with an inner diameter of 30 μm, and apply AB universal glue evenly at each connection of the device to ensure airtightness.

[0098] Step 2: At room temperature of 25 °C, directly connect the gas pipe to the high-pressure injection device 1 and keep the nitrogen cylinder valve closed (0 MPa).

[0099] Step 3: Open the valve of the high-pressure gas storage cylinder 3. By controlling the air pressure, the distribution density of the bead structure on the liquid metal conductive fiber can be regulated, as Figure 3 shown.

[0100] Step 4: Apply a gas pressure of 1.0 MPa. The liquid metal (eutectic gallium-indium alloy) sprays out of the glass micro-needles at high speed to form liquid metal conductive fibers with a bead-chain structure. The scanning electron microscope image of its microscopic morphology is as shown in Figure 2 shown.

[0101] Step 5: When the liquid metal conductive fiber sprays out of the needle orifice of the glass micro-needle 2, it quickly passes by the suspended baffle. Utilize the oxide film with certain mechanical properties of the liquid metal to resist its gravity, so that the liquid metal fiber hangs suspended on the baffle.

[0102] Step 6: Collect the above liquid metal fibers onto the polydimethylsiloxane substrate 4.

[0103] Step 7: Dissolve 2 g of PDMS with a prepolymer to curing agent ratio of 10:1 in 5 mL of absolute ethanol, spray and encapsulate the filamentous liquid metal to be encapsulated, and cure it in a blast drying oven at 60 °C for 3 h.

[0104] Step 8: Perform a force-electricity coupling test on the encapsulated liquid metal conductive fiber with a bead-chain structure using the four-terminal method.

[0105] Use an Instron 5943 material testing machine to apply strain to the conductive fiber at a tensile rate of 30 mm / min, use a KEITHLEY 6221 current source to provide a constant current of 0.1 mA for the conductive fiber; use a Keithley 34420A nanovoltmeter to test the voltage output of the conductive fiber with strain changes, and finally the resistance change law can be obtained through Ohm's law.

[0106] (1) Static electrical properties of liquid metal conductive fibers after tensile cycling

[0107] The liquid metal conductive fiber is tested for resistance without tensile strain. As the gas pressure increases, the density of the bead-chain structure decreases, and the static resistance of the obtained liquid metal conductive fiber with a bead-chain structure and adjustable resistance also further increases. Its resistance value is 28.77 Ω, as shown in Figure 4 shown, and its resistance value remains stable after 10 tensile cycles.

[0108] (2) Resistance change of liquid metal conductive fibers at a tensile strain of 100%

[0109] Apply 0 - 100% continuous strain to the liquid metal conductive fiber. As the gas pressure increases, the density of the bead-chain structure decreases, and the electrical properties of the obtained liquid metal conductive fiber with a bead-chain structure and adjustable resistance change. Its relative resistance change rate increases linearly with the increase of gas pressure, as shown in Figure 5 shown. When stretched to 100%, its relative resistance change rate is 77.42%.

[0110] The embodiments described above have elaborated on the technical solutions of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, supplements, or substitutions in a similar manner made within the scope of the principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A liquid metal conductive fiber, which uses liquid metal as a raw material to form a submicron conductive fiber with a chain bead structure and adjustable resistance, wherein, The bead structure is a structure in which "balls" and "threads" are evenly and alternately distributed.

2. The liquid metal conductive fiber according to claim 1, characterized in that, The resistance of the liquid metal conductive fiber is adjusted by the distribution density of the bead structure in the liquid metal conductive fiber.

3. The liquid metal conductive fiber according to claim 1, wherein The cross-sectional area of the "balls" in the bead structure is larger than the cross-sectional area of the "threads".

4. The liquid metal conductive fiber according to claim 1, characterized in that, The liquid metal is one or more of gallium, gallium-indium alloy, gallium-tin alloy, indium-tin alloy, gallium-indium-tin alloy, gallium-indium-tin-bismuth alloy, and gallium alloy or gallium-indium alloy doped with transition metals and solid non-metal elements.

5. A method for preparing the liquid metal conductive fiber according to any one of claims 1 to 4, comprising the following steps: S1: Load the liquid metal into a high-pressure spraying device, install a glass micro-needle at the spraying port of the high-pressure spraying device, and connect a high-pressure gas storage cylinder to the tail of the high-pressure spraying device; S2: Under room temperature conditions, control the air pressure of the pressure gas storage cylinder, and the liquid metal is ejected from the glass micro-needle to form a liquid metal conductive fiber with a bead structure; S3: When the liquid metal conductive fiber ejects from the needle port of the glass micro-needle, it quickly passes through a suspended baffle, and the liquid metal conductive fiber is suspended on the baffle through an oxide layer with certain mechanical properties formed on the surface of the liquid metal conductive fiber; S4: Collect the liquid metal fiber suspended on the baffle on a substrate; S5: Spray and encapsulate the surface of the liquid metal conductive fiber collected on the substrate with an encapsulating liquid to form a liquid metal conductive fiber with various electrical properties.

6. The preparation method of the liquid metal conductive fiber according to claim 5, characterized in that, The inner diameter of the glass micro-needle is 5 μm to 0.9 mm.

7. The preparation method of the liquid metal conductive fiber according to claim 5, wherein, In S2, by changing the air pressure of the pressure gas storage cylinder, the distribution density of the bead structure in the liquid metal conductive fiber is adjusted.

8. The preparation method of the liquid metal conductive fiber according to claim 7, characterized in that, The air pressure of the pressure gas storage cylinder is 0.4 MPa to 1.5 MPa.

9. The preparation method of the liquid metal conductive fiber according to claim 5, characterized in that, The gas in the high-pressure gas storage cylinder includes but is not limited to one or several of air, nitrogen, and argon.

10. The preparation method of the liquid metal conductive fiber according to claim 5, wherein, In S3, the suspended height of the baffle is set according to the length of the liquid metal conductive fiber.

11. The preparation method of the liquid metal conductive fiber according to any one of claims 5-10, characterized in that, The substrate is one or more of polydimethylsiloxane, polyurethane, hydrogel, Ecoflex, SEBS, fabric, plant, glass, plastic, or silicon wafer.

12. The preparation method of the flexible liquid metal conductive fiber according to any one of claims 5-10, characterized in that, The encapsulating liquid is one or more of an alcohol suspension of polydimethylsiloxane, an alcohol suspension of polyurethane, an alcohol suspension of hydrogel, an alcohol suspension of Ecoflex, or an alcohol suspension of SEBS.

13. Application of the liquid metal conductive fiber according to any one of claims 1-4 in electronic textiles and flexible wearable electronic devices.

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