A flexible self-driven sensing fiber based on solid-liquid friction power generation and preparation and application thereof

Abstract

The present application relates to a kind of flexible self-driven sensing fiber based on solid-liquid friction power generation and its preparation and application, the flexible self-driven sensing fiber includes flexible stretchable electrode skin, solid-liquid interface friction electric core layer.The present application realizes the continuous preparation of flexible self-driven multifunctional sensing fiber, and the multifunctional real-time monitoring capability of a variety of environment-sensitive magnetic fluid materials is endowed, and it has good application prospect in the field of self-driven multifunctional sensing.

Description

Technical Field

[0001] This invention belongs to the field of sensors and their preparation and application, and particularly relates to a flexible self-driven sensing fiber based on solid-liquid triboelectric power generation and its preparation and application. Background Technology

[0002] With the advent of the information age and the rapid development of science and technology, sensing devices with various functions have been widely used in production and daily life. The sensing devices people use daily are increasingly trending towards miniaturization and convenience, leading to the emergence of wearable sensing devices, which have broad application prospects in fields such as health monitoring, environmental monitoring, hazard warning, and industrial safety. However, most wireless sensors currently still use traditional batteries for power, requiring frequent battery replacements, resulting in high maintenance costs, and the disposal of used batteries also causes environmental pollution. Therefore, there is an urgent need for a pollution-free, well-fitting, scalable, multi-functional, self-powered sensing device.

[0003] Self-powered sensing is a novel sensing method that requires no external power supply and obtains energy from the environment for self-powering, providing a new solution to the power supply problem of wearable sensors. Triboelectric nanogenerators, as a mechanical energy harvesting device, can collect various forms of mechanical energy and convert them into electrical energy to drive other electronic components. Furthermore, utilizing their sensitivity to environmental disturbances, they can also be used as self-powered sensors, thus attracting significant attention in the field of smart wearable sensing. After years of development, researchers have developed various self-powered sensing devices based on triboelectric nanogenerators and successfully applied them in motion sensing, position sensing, ion concentration detection, environmental monitoring, pressure sensing, and gas detection [Nano Energy, 2020, 72: 237-249]. However, these devices have limited sensing and deformation capabilities, failing to achieve multi-functional sensing across multiple scenarios. Simultaneously, traditional solid-solid interface triboelectric nanogenerators suffer from poor cycle stability, short lifespan, and poor output performance, making it difficult to meet the rapidly developing needs of smart wearable sensing devices. In summary, flexible, self-driven, multifunctional sensor devices based on solid-liquid triboelectricity that can be continuously fabricated are a research hotspot that is urgently needed but has not yet been developed. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a flexible self-driven sensing fiber based on solid-liquid triboelectric power generation, its preparation and application, and to overcome the shortcomings of existing fiber sensor devices, such as single sensing mode, poor stability, strong electromagnetic shielding and low electrical output performance.

[0005] The present invention provides a flexible self-driven sensing fiber, wherein the flexible self-driven sensing fiber comprises a flexible stretchable electrode skin and a solid-liquid interface triboelectric core layer.

[0006] The flexible stretchable electrode skin is a conductive ion hydrogel electrode.

[0007] The solid-liquid interface triboelectric cell layer comprises a water-based magnetofluid and hollow polymer fibers with hydrophobic inner walls. Its structure is shown in the attached specification. Figure 1 As shown in a.

[0008] The ion hydrogel electrode material contains chloride salts; wherein the chloride salts are one or more of sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2).

[0009] The flexible, stretchable electrode is an ion-hydrogel electrode. Its conductivity is adjusted by adding chloride salts, and a suitable value combining conductivity and weak electromagnetic shielding properties is selected to maximize the electrical output performance of the multifunctional sensing fiber. Its ionic conductivity increases with the concentration of conductive ions in the gel, selected from one or more of sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2). Different ionic compounds have different suitable values ​​for combining conductivity and weak electromagnetic shielding properties.

[0010] The water-based magnetic fluid is placed inside hollow polymer fibers with hydrophobic inner walls.

[0011] The inner wall hydrophobic polymer fiber tube is a hollow polymer fiber with a hydrophobic layer on the inner wall; the hollow polymer fiber material is one or more of polyvinylidene fluoride-trifluoroethylene copolymer P (VDF-TrFE), silicone, polystyrene PS, polylactic acid PLA, polyamide 6PA6, and polyurethane PU.

[0012] The solid-liquid interface triboelectric core layer comprises a water-based magnetic fluid and hollow polymer fibers with hydrophobic inner walls. The polymer fiber material needs to match the triboelectric polarity with the water-based magnetic fluid to improve the signal-to-noise ratio of the triboelectric signal between the solid and liquid triboelectric layers. Based on the triboelectric material's triboelectric sequence, it is selected from one or more of polyvinylidene fluoride-trifluoroethylene copolymer (P(VDF-TrFE)), silicone rubber, polystyrene (PS), polylactic acid (PLA), polyamide 6 (PA6), and polyurethane (PU). The water-conducting coating can effectively prevent the magnetic fluid from adhering to the inner wall of the hollow polymer fibers, thereby improving the stability and electrical output performance of the solid-liquid interface triboelectric fibers.

[0013] The flexible self-driven multifunctional sensing fiber has the following characteristics: under the action of magnetic field, sound field, electric field, tension, vibration, etc., the morphology of the water-based magnetic fluid changes, and phenomena such as protrusion, aggregation, and sliding occur, which leads to the triboelectric effect between the water-based magnetic fluid and the inner wall of the hydrophobic hollow polymer fiber, thereby generating an electrical signal.

[0014] The described method for testing the electrical signals of a flexible, self-driven, multifunctional sensing fiber involves fixing the fiber to one side of a linear motor, while a fixed magnet on the other side performs controlled reciprocating motion, changing the distance between the sensor and the magnet. The speed and displacement of the magnet are recorded. An ion-hydrogel electrode of the sensing fiber is connected to an electrical testing device to record electrical data. The speed, displacement, electrical, and optical signals can be simultaneously transmitted to a computer and plotted in real time.

[0015] The aforementioned multifunctional sensing characteristics allow the fiber to generate electrical signals when subjected to magnetic fields, sound fields, electric fields, tension, and vibration, which can be applied to environmental detection and motion definition. Specifically, when the fiber is near a magnetic field, sound field, or electric field, its electrical output signal increases as the distance decreases or the field strength increases; when the fiber is subjected to forces such as tension and vibration, its electrical output signal increases as the force increases.

[0016] A continuous fabrication method for flexible, self-driven, multifunctional sensing fibers based on solid-liquid triboelectric power generation includes: optimizing the impregnation method to prepare polymer fibers with hydrophobic inner walls; and improving the soft mold method to prepare flexible, stretchable electrode skins. The fabrication process is shown in the attached specification. Figure 1 As shown in d.

[0017] The present invention provides a method for preparing a flexible self-driven sensing fiber, comprising:

[0018] (1) A water-based magnetic fluid is injected into a hollow polymer fiber with a hydrophobic inner wall and sealed to obtain a triboelectric core layer at a solid-liquid interface.

[0019] (2) The triboelectric core layer at the solid-liquid interface is subjected to plasma treatment, and then a hollow flexible tube mold with a diameter larger than that of the triboelectric core layer is fitted on the outside, and a gap is made between the triboelectric core layer and the flexible tube mold. Then, liquid ion hydrogel is injected into the gap, solidified, and the flexible tube mold is peeled off to obtain a flexible self-driven sensing fiber.

[0020] The preferred embodiment of the above preparation method is as follows:

[0021] The hollow polymer fiber with a hydrophobic inner wall in step (1) is prepared by the following method: the hollow polymer fiber is subjected to plasma treatment, then one end of the fiber is sealed, filled with a silicon-based superhydrophobic coating stock solution with a mass percentage concentration of 50%-100%, poured out after impregnation, dried, filled with an acidic perfluorodecyltrimethoxysilane ethanol solution with a mass percentage concentration of 2%-5%, poured out after impregnation, dried, and the hydrophobic polymer fiber with an inner wall is obtained.

[0022] The plasma treatment time is 8-20 minutes; the sealing is hot melt adhesive sealing; the immersion time is 10-30 seconds; and the drying is carried out at 50-70°C for 3-8 minutes.

[0023] In step (1), the volume of water-based magnetic fluid injected into the hollow polymer fiber with a hydrophobic inner wall is 40%-90%.

[0024] The liquid ionic hydrogel components in step (2) are:

[0025] The ratio of water, ethylene glycol, chloride salt, N,N'-methylenebisacrylamide, acrylamide, tannic acid, and 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone is 5-8 mL: 2-5 mL: 0.5-2.5 g: 0.005-0.015 g: 1.5-2.5 g: 0.01-0.02 g: 0.05-0.15 g.

[0026] Taking the preparation of 10mL of ionized hydrogel solution as an example, the following ingredients are used: 5-8mL of deionized water, 2-5mL of ethylene glycol, 0.5-2.5g of chloride salt, 0.005-0.015g of N,N'-methylenebisacrylamide, 1.5-2.5g of acrylamide, 0.01-0.02g of tannic acid, and 0.05-0.15g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone.

[0027] The plasma treatment time in step (2) is 8-20 min; the UV curing time is 10-20 min, and the UV power is 40 kW-60 kW.

[0028] This invention provides an application of the flexible self-driven sensing fiber in magnetic field monitoring, noise monitoring, pulse detection, and intelligent wearable human-computer interaction.

[0029] Furthermore, application scenarios include (1) magnetic field monitoring: by being sensitive to magnetic fields, an electrical signal can be generated to trigger an alarm when approaching a strong magnetic field; (2) noise monitoring: by being sensitive to sound fields, an electrical signal can be generated to trigger an alarm when the noise level is too high; (3) pulse detection: based on its flexibility, it can be made into a health bracelet, which emits an electrical signal by being sensitive to pulse vibrations to realize real-time tracking and detection of the human pulse; (4) intelligent wearable human-computer interaction: multifunctional sensing fibers are integrated with clothing, and different human movements cause the sensor to generate different electrical signals for reading and control of electronic ports.

[0030] The flexible multifunctional sensing fiber of this invention comprises: a flexible stretchable electrode skin and a solid-liquid interface triboelectric core layer. The flexible stretchable electrode skin is composed of ion-hydrogel, and the solid-liquid interface triboelectric core layer is composed of a water-based magnetic fluid and a polymer fiber tube with a hydrophobic inner wall. Under the action of magnetic fields, sound fields, electric fields, stretching, vibration, etc., the morphology of the water-based magnetic fluid changes, exhibiting phenomena such as protrusion, aggregation, and sliding, leading to a triboelectric effect between the water-based magnetic fluid and the hydrophobic polymer fiber tube wall, thereby generating an electrical signal, which can be used in multifunctional sensor devices. Based on water-based magnetic fluid and hollow polymer fiber materials, this invention uses an optimized impregnation method and an improved soft mold method to achieve continuous fabrication of flexible self-driven multifunctional sensing fibers, endowing various environmentally sensitive magnetic fluid materials with multifunctional real-time monitoring capabilities, and showing good application prospects in the field of self-driven multifunctional sensing.

[0031] Beneficial effects

[0032] This invention, based on water-based magnetofluids and hollow polymer fiber materials, utilizes optimized impregnation and improved soft mold methods to fabricate a continuous, flexible, self-driven, multifunctional sensing fiber. This fiber possesses a novel magneto-electric sensing mode and can be used for high-precision environmental monitoring. The magnetofluid material, sensitive to various environmental sources, endows it with multifunctional real-time monitoring capabilities, demonstrating promising application prospects in the field of self-driven sensing. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the fabrication of the flexible self-driven multifunctional sensing fiber based on solid-liquid triboelectricity according to the present invention. (a) Schematic diagram of the structure of the flexible self-driven multifunctional sensing fiber; (b) Physical image of the flexible stretchable electrode skin prepared by the improved soft mold method; (c) Physical image of the hollow polymer fiber with hydrophobic inner wall prepared by the optimized impregnation method; (d) Flowchart of the fabrication process of the flexible self-driven multifunctional sensing fiber.

[0034] Figure 2Characterization tests of the hollow polymer fiber with hydrophobic inner wall and the flexible stretchable electrode skin in Example 1. (a) SEM image of the inner wall of the polymer fiber after water treatment; (b) Contact angle test of the inner wall of the hollow polymer fiber after water treatment; (c) Cross-sectional view of the flexible stretchable electrode covering the hollow polymer fiber; (d) Tensile performance test of the flexible stretchable electrode at different stretching rates.

[0035] Figure 3 Electrical output performance tests of multifunctional sensing fibers prepared with different electrode materials (hydrogel, copper wire, conductive yarn, silver wire). (a) Output current test; (b) Output charge test; (c) Output voltage test.

[0036] Figure 4 Electrical output performance tests of flexible self-driven multifunctional sensing fibers for solid-liquid triboelectric power generation under different magnetic field strengths. (a) Output current test; (b) Output charge test; (c) Output voltage test.

[0037] Figure 5 Electrical output performance tests of flexible, self-driven, multifunctional sensing fibers for magnetic field-based triboelectric power generation at different distances. (a) Output current test; (b) Output charge test; (c) Output voltage test.

[0038] Figure 6 Electrical output performance tests of flexible, self-driven, multifunctional sensing fibers prepared by solid-liquid triboelectricity using ion-hydrogel electrodes with different sodium chloride concentrations. (a) Output current test; (b) Output charge test; (c) Output voltage test. Detailed Implementation

[0039] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various modifications or alterations to the invention, and these equivalent forms also fall within the scope defined by the appended claims. Sources of raw materials and reagents in the embodiments: silicone rubber tubing (hardness 55A, lubricating fluid), water-based magnetic fluid (saturation magnetization 440 Gauss, Inkking nanomagnetic fluid), 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone (molecular weight M... w =224.25, Aladdin reagent), N,N'-methylenebisacrylamide (molecular weight M) w =54.17, Aladdin reagent), tannic acid (molecular weight M) w =701.2, Aladdin reagent), perfluorodecyltrimethoxysilane (molecular weight M) w=568.3 Deep Blue Reagent), Silicon-based Superhydrophobic Coating (Zixilai Technology Co., Ltd.), Acrylamide (Analytical Grade, Titan Technology), Ethylene Glycol (Analytical Grade, Maclean Biochemical Technology Co., Ltd.), Sodium Chloride (Analytical Grade, Shanghai Test).

[0040] The electrical output performance of the flexible, self-driven, multifunctional sensing fiber based on solid-liquid triboelectric power generation was tested using a Keithley 6514A, and the magnetic field strength was tested using a DX-102F gaussmeter.

[0041] Example 1

[0042] Polymer fibers with hydrophobic inner walls were prepared by an impregnation method. First, the hollow polymer fibers were subjected to plasma treatment (8 min). Then, one end of the fiber was sealed with hot melt adhesive and filled with a 100% concentration of silicon-based superhydrophobic coating stock solution. After impregnation for a period of time (10 s), the fiber was poured out and dried in a 70℃ oven (3 min). Next, the fiber was filled with a 2% concentration of acidic perfluorodecyltrimethoxysilane ethanol solution and impregnated for a period of time (10 s). After the fiber was poured out and dried in a 70℃ oven (3 min), a polymer fiber tube with hydrophobic inner walls was obtained. Finally, water-based magnetic fluid with a volume of about 60% was injected into the hollow fiber and sealed with hot melt adhesive to obtain a triboelectric core layer at the solid-liquid interface. Mix 7 mL of deionized water with 3 mL of ethylene glycol, add 1.0 g of sodium chloride, 0.01 g of N,N'-methylenebisacrylamide, 2.13 g of acrylamide, 0.015 g of tannic acid, and 0.1 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone to prepare an ionized hydrogel solution. A flexible, stretchable electrode skin is prepared using a soft mold method. The triboelectric core layer at the solid-liquid interface is subjected to plasma treatment (8 min). Then, a hollow flexible tube mold with a diameter larger than the triboelectric core layer is fitted onto the outside, leaving a gap between the triboelectric core layer and the flexible tube mold. Liquid ionized hydrogel is then filled into the gap, and the mixture is placed in a UV curing chamber (60 kW) for UV curing (10 min). Finally, the flexible tube mold is peeled off to obtain the flexible, stretchable electrode skin. The prepared multifunctional sensing fiber was subjected to electrical signal testing according to the electrical signal testing method for flexible self-driven multifunctional sensing fiber in the instruction manual. The distance between the fiber and the magnetic field was controlled at 5 mm, the magnetic field strength at 2.5 kg, and the electrode materials were sodium chloride hydrogel electrode, copper wire, conductive yarn, and silver wire, respectively. The electrical signals are as follows: Figure 3 As shown, the multifunctional sensing fiber fabricated with a sodium chloride hydrogel electrode achieves a current output of 80 μA / m. 2 The charge output reaches 0.05nC and the voltage output reaches 0.3V, which is a significant improvement in performance compared to multifunctional sensing fibers made of other traditional electrode materials.

[0043] Example 2

[0044] Hollow polymer fibers with hydrophobic inner walls were prepared by an impregnation method. First, the hollow polymer fibers were subjected to plasma treatment (10 min). Then, one end of the fiber was sealed with hot melt adhesive and filled with a 50% concentration of silicon-based superhydrophobic coating stock solution. After impregnation for a period of time (15 s), the fiber was poured out and dried in a 65℃ oven (4 min). Next, the fiber was filled with a 3% concentration of acidic perfluorodecyltrimethoxysilane ethanol solution and impregnated for a period of time (15 s). After pouring out the solution, the fiber was dried in a 65℃ oven (4 min) to obtain a hollow polymer fiber tube with hydrophobic inner walls. Finally, a water-based magnetic fluid with a volume of approximately 40% was injected into the hollow fiber and sealed with hot melt adhesive to obtain a triboelectric core layer at the solid-liquid interface. Mix 5 mL of deionized water with 5 mL of ethylene glycol, add 1.0 g of sodium chloride, 0.005 g of N,N'-methylenebisacrylamide, 1.5 g of acrylamide, 0.01 g of tannic acid, and 0.05 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone to prepare an ionized hydrogel solution. A flexible, stretchable electrode skin is prepared using a soft mold method. The triboelectric core layer at the solid-liquid interface is subjected to plasma treatment (10 min). Then, a hollow flexible tube mold with a diameter larger than the triboelectric core layer is fitted over it, leaving a gap between the triboelectric core layer and the flexible tube mold. Liquid ionized hydrogel is then filled into the gap, and the mixture is placed in a UV curing chamber (50 kW) for UV curing (12 min). Finally, the flexible tube mold is peeled off to obtain the flexible, stretchable electrode skin. The prepared multifunctional sensing fiber was subjected to electrical signal testing according to the electrical signal testing method for flexible self-driven multifunctional sensing fibers in the instruction manual. The distance between the fiber and the magnetic field was controlled at 5 mm, the sodium chloride concentration of the hydrogel electrode was 0.1 g / ml, and the magnetic field strength was 0.5 kg, 1.5 kg, and 2.5 kg, respectively. The electrical signals are as follows: Figure 4 As shown, the electrical output performance of the multifunctional sensing fiber increases with increasing magnetic field strength. When the magnetic field strength is 2.5 kg, the output current of the multifunctional sensing fiber is 120 μA / m. 2 With an output charge of 0.2nC and an output voltage of 0.45V, it exhibits the characteristic of multifunctional sensing fiber being sensitive to magnetic field strength.

[0045] Example 3

[0046] Hollow polymer fibers with hydrophobic inner walls were prepared by an impregnation method. First, the hollow polymer fibers were subjected to plasma treatment (14 min). Then, one end of the fiber was sealed with hot melt adhesive and filled with a 70% concentration of silicon-based superhydrophobic coating stock solution. After impregnation for a period of time (20 s), the fiber was poured out and dried in a 60℃ oven (5 min). Next, the fiber was filled with a 4% concentration of acidic perfluorodecyltrimethoxysilane ethanol solution and impregnated for a period of time (20 s). After pouring out the solution, the fiber was dried in a 60℃ oven (5 min) to obtain hollow polymer fibers with hydrophobic inner walls. Finally, water-based magnetic fluid with a volume of about 70% was injected into the hollow fiber and sealed with hot melt adhesive to obtain a triboelectric core layer at the solid-liquid interface. Mix 6 mL of deionized water with 4 mL of ethylene glycol, add 1.0 g of sodium chloride, 0.008 g of N,N'-methylenebisacrylamide, 1.8 g of acrylamide, 0.013 g of tannic acid, and 0.08 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone to prepare an ionized hydrogel solution. A flexible, stretchable electrode skin is prepared using a soft mold method. The triboelectric core layer at the solid-liquid interface is subjected to plasma treatment (14 min). Then, a hollow flexible tube mold with a diameter larger than the triboelectric core layer is fitted over it, leaving a gap between the triboelectric core layer and the flexible tube mold. Liquid ionized hydrogel is then filled into the gap, and the mixture is placed in a UV curing chamber (50 kW) for UV curing (15 min). Finally, the flexible tube mold is peeled off to obtain the flexible, stretchable electrode skin. The prepared multifunctional sensing fiber was subjected to electrical signal testing according to the electrical signal testing method for flexible self-driven multifunctional sensing fiber in the instruction manual. The sodium chloride concentration of the hydrogel electrode was controlled at 0.1 g / ml, the magnetic field strength at 2.5 KG, and the distance between the fiber and the magnetic field at 5 mm, 10 mm, 15 mm, 20 mm, and 25 mm, respectively. The electrical signals are as follows: Figure 5 As shown, the electrical output performance of the multifunctional sensing fiber increases as the distance between the multifunctional sensing fiber and the magnetic field with constant strength decreases. When the distance to the magnetic field is 5 mm, the output current of the multifunctional sensing fiber is 75 μA / m. 2 With an output charge of 0.055nC and an output voltage of 0.3V, it exhibits the characteristic of multifunctional sensing fiber being sensitive to magnetic fields in relation to the distance between it and the magnetic field.

[0047] Example 4

[0048] Hollow polymer fibers with hydrophobic inner walls were prepared by an impregnation method. First, the hollow polymer fibers were subjected to plasma treatment (20 min). Then, one end of the fiber was sealed with hot melt adhesive and filled with a 90% concentration of silicon-based superhydrophobic coating stock solution. After impregnation for a period of time (30 s), the fiber was poured out and dried in a 50℃ oven (8 min). Next, the fiber was filled with a 5% concentration of acidic perfluorodecyltrimethoxysilane ethanol solution and impregnated for a period of time (30 s). After pouring out the solution, the fiber was dried in a 50℃ oven (8 min) to obtain hollow polymer fibers with hydrophobic inner walls. Finally, water-based magnetic fluid with a volume of approximately 90% was injected into the hollow fiber and sealed with hot melt adhesive to obtain a triboelectric core layer at the solid-liquid interface. 9 mL of deionized water was mixed with 1 mL of ethylene glycol, and 0.5 g, 1.0 g, 1.5 g, and 2.0 g of sodium chloride were added respectively. Then, 0.015 g of N,N'-methylenebisacrylamide, 2.5 g of acrylamide, 0.02 g of tannic acid, and 0.015 g of 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone were added respectively to prepare different sodium chloride ion hydrogel solutions. A flexible and stretchable electrode skin was prepared using a soft mold method. The triboelectric core layer at the solid-liquid interface was subjected to plasma treatment (20 min). Then, a hollow flexible tube mold with a diameter larger than the triboelectric core layer was placed on the outside, with a certain gap between the triboelectric core layer and the flexible tube mold. The gap was then filled with liquid ion hydrogel, and then placed in a UV curing chamber (40 kW) for UV curing (20 min). Finally, the flexible tube mold was peeled off to obtain the flexible and stretchable electrode skin. The prepared multifunctional sensing fiber was subjected to electrical signal testing according to the electrical signal testing method for flexible self-driven multifunctional sensing fiber in the instruction manual. The magnetic field strength was controlled at 2.5KG, the distance between the fiber and the magnetic field was 5mm, and the sodium chloride concentration of the hydrogel electrode was 0.05g / ml, 0.10g / ml, 0.15g / ml, and 0.20g / ml, respectively. The electrical signals are as follows: Figure 6 As shown, the conductivity of the ion-hydrogel electrode increases with increasing sodium chloride concentration, while its electrical output performance initially increases and then decreases with increasing sodium chloride concentration. This is because increasing sodium chloride concentration also enhances the electromagnetic shielding effect of the hydrogel electrode. To maximize the electrical output performance of the multifunctional sensing fiber, it is necessary to adjust the appropriate sodium chloride concentration to make the hydrogel electrode possess both conductivity and a weak electromagnetic shielding effect. The multifunctional sensing fiber exhibits the best electrical output performance with an output current of 80 μA / mL when the sodium chloride concentration is 0.15 g / mL. 2 The output charge is 0.07nC and the output voltage is 0.35V.

Claims

1. A flexible self-driven sensing fiber, characterized in that, The flexible self-driven sensing fiber includes a flexible stretchable electrode skin and a solid-liquid interface triboelectric core layer, wherein the flexible stretchable electrode skin is wrapped around the solid-liquid interface triboelectric core layer. The flexible stretchable electrode skin is an ion-hydrogel electrode. The solid-liquid interface triboelectric cell layer includes a water-based magnetic fluid and a hollow polymer fiber with a hydrophobic inner wall, wherein the water-based magnetic fluid is located in the hollow part inside the hollow polymer fiber.

2. The flexible self-driven sensing fiber according to claim 1, characterized in that, The ion hydrogel electrode material contains chloride salts; wherein the chloride salts are one or more of sodium chloride (NaCl), potassium chloride (KCl), magnesium chloride (MgCl2), and calcium chloride (CaCl2).

3. The flexible self-driven sensing fiber according to claim 1, characterized in that, The water-based magnetic fluid is placed inside hollow polymer fibers with hydrophobic inner walls.

4. The flexible self-driven sensing fiber according to claim 1, characterized in that, The hollow polymer fiber with a hydrophobic inner wall has a hydrophobic layer on its inner wall; the hollow polymer fiber material is one or more of polyvinylidene fluoride-trifluoroethylene copolymer P (VDF-TrFE), silicone rubber, polystyrene PS, polylactic acid PLA, polyamide 6 PA6, and polyurethane PU.

5. A method for preparing a flexible self-driven sensing fiber, comprising: (1) A water-based magnetic fluid is injected into a hollow polymer fiber with a hydrophobic inner wall and sealed to obtain a triboelectric core layer with a solid-liquid interface. (2) The triboelectric core layer at the solid-liquid interface is subjected to plasma treatment, and then a hollow flexible tube mold with a diameter larger than that of the triboelectric core layer is fitted on the outside, and a gap is made between the triboelectric core layer and the flexible tube mold. Then, liquid ion hydrogel is injected into the gap, solidified, and the flexible tube mold is peeled off to obtain flexible self-driven sensing fiber.

6. The preparation method according to claim 5, characterized in that, The hollow polymer fiber with a hydrophobic inner wall in step (1) is prepared by the following method: the hollow polymer fiber is subjected to plasma treatment, then one end of the fiber is sealed, filled with a silicon-based superhydrophobic coating stock solution with a mass percentage concentration of 50%-100%, poured out after impregnation, dried, filled with an acidic perfluorodecyltrimethoxysilane ethanol solution with a mass percentage concentration of 2%-5%, poured out after impregnation, dried, and the hollow polymer fiber with a hydrophobic inner wall is obtained.

7. The preparation method according to claim 6, characterized in that, The plasma treatment time is 8-20 minutes; the sealing is hot melt adhesive sealing; the immersion time is 10-30 seconds; and the drying is carried out at 50-70°C for 3-8 minutes.

8. The preparation method according to claim 5, characterized in that, In step (1), the volume of water-based magnetic fluid injected into the hollow polymer fiber with a hydrophobic inner wall is 40%-90%.

9. The preparation method according to claim 5, characterized in that, The plasma treatment time in step (2) is 8-20 min; the UV curing time is 10-20 min, and the UV power is 40 kW-60 kW.

10. An application of the flexible self-driven sensing fiber according to claim 1, characterized in that, This includes applications in magnetic field monitoring, noise monitoring, pulse detection, or smart wearable human-computer interaction.

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