A triboelectric fiber with a dual-channel spiral structure, its preparation method and application

Abstract

The present invention belongs to the field of material processing, and specifically relates to a triboelectric fiber with a double-channel spiral structure, its preparation method and application. The fiber is made by subjecting an SEBS preform to hot stretching, twisting, and injecting electrodes. It has a core-sheath structure, where the core layer is formed by two liquid metal electrodes spirally wound around each other; a sheath layer is coated outside the core layer, and the sheath layer is a dielectric layer with a rectangular structure formed by heating and consolidation in a vulcanizer using a self-made mold. The hot-stretched triboelectric fiber of the present invention selects a spiral structure and has good stretching performance; the core layer selects liquid metal, which has good deformation ability and electrical conductivity; the sheath layer selects SEBS, which has excellent elasticity and elongation. The above-mentioned fiber can be used in the field of self-powered sensors.

Description

Technical Field

[0001] The present invention belongs to the field of material processing, and particularly relates to a triboelectric fiber with a double-channel spiral structure, a preparation method thereof, and an application thereof. Background Art

[0002] Currently, with the development of technology, deformation sensors are increasingly used in smart textiles. The skin, limbs, and organs of the human body are undergoing complex deformations at all times. Therefore, deformation sensors play a crucial role in flexible wearable electronics, human-computer interaction, and biomedical devices. However, deformation sensors are usually based on planar devices, which are incompatible with textile weaving processes and cannot be integrated onto any 3D planar object. Fiber-based optical fiber sensors have soft characteristics and can be woven into textiles or integrated onto any 3D object. Therefore, optical fiber sensors have become an ideal choice for the next generation of electronic products for monitoring complex human activities. Thermally stretching preforms to produce fibers is currently an efficient method for preparing functional fibers. The materials for producing fiber preforms mainly include glass, semiconductors, metals, and polymers, etc. It can achieve a large number of functions, including materials engineering, electrical sensing, optical sensing, nerve sensing, thermal detection, chemical sensing, acoustic emission, etc.

[0003] Flexible fibers and functional textiles are becoming ideal platforms for medicine, artificial intelligence, and materials engineering. The key to their sustainable operation lies in a safe and low-energy power system, which is particularly important for implantable systems or textile-integrated systems to free them from the constraints of frequent charging and battery replacement.

[0004] Most of the previous preforms used cylindrical shells, and the fibers prepared therefrom had unsatisfactory strength and were prone to breakage after a certain amount of stretching.

[0005] In the fields of wearable electronics and functional textiles, obtaining mechanical energy through triboelectrification is an excellent method. However, the performance they currently exhibit is still not satisfactory, and the effect is lower than that of the most advanced 2D planar structures. Patent No. CN111996641A uses a soluble nanofiber layer to coat a conductive core layer and wind it to form an inner layer. The fiber made is still a solid-state metal electrode and still cannot perform sensing in the 2D plane.

[0006] Traditional preforms generally use a single-electrode design. Publication No. CN110227208A proposes a flexible fiber electrode prepared by using a flexible filamentous conductive material as the core layer and polyether ether ketone as the coating and performing thermal stretching. However, its single-electrode structure has certain limitations on the stretching effect and voltage load capacity.

[0007] Patent number CN110320254A proposes a multi-stage spiral fiber sensor, whose metal core layer can conduct electrical signals in the body. This fiber sensor has a detection function but does not have a self-power supply effect.

[0008] Patent number CN101339820B discloses a preparation method of an optoelectronic fiber. The fiber is made of an organic polymer preform. The central axis of the preform is provided with a central hole for inserting an optical fiber and through holes for one or more metal wires to pass through. The preform is thermally stretched to pull out a fiber in which the optical fiber and the metal wire are wrapped by the polymer. Since the melting point of the metal wire is relatively high and it is in a solid state at room temperature, and the stretching performance of the fiber depends on the weakest part in the fiber composition, the stretching effect of the solid metal is very poor, which affects the overall stretching effect of the fiber.

[0009] Literature number 10.1002 / adma.202201081 proposes a bending electrode and a spiral electrode fiber prepared with a copper wire as the core layer and an SEBS and COCe composite material as the sheath layer. It proposes two novel preparation methods, which solve the problem that the copper wire has a high melting point and is difficult to soften and buckle. However, the Young's modulus of the copper wire reaches 110 GPa, which results in poor stretching effect of the prepared fiber. At the same time, due to the high melting point characteristics of the copper wire, the annealing process during the preparation of the spiral electrode is extremely slow, which significantly reduces the preparation efficiency. The single-electrode design also has certain limitations on the electrical properties of this fiber.

[0010] Literature number 10.1002 / adma.201707251 uses an elastic outer coating to coat a multi-channel PC layer, and a preform formed by injecting a gallium-based liquid metal into the channels of the PC layer is stretched into a fiber. When the fiber is stretched, the outer coating returns to its original length due to its elasticity, while the PC core is permanently stretched. Therefore, the PC core will be rolled into a spiral structure. The spiral structure manufactured in this way is unstable, and the spiral effect is uncontrollable, and its outer coating cannot form a spiral either, which has limited improvement on the stretching performance of the fiber. Summary of the Invention

[0011] The fibers prepared by the prior art have certain limitations in electrical properties, or have instability, and the spiral effect is uncontrollable. Its outer coating cannot form a spiral either, which has limited improvement on the stretching performance of the fiber.

[0012] In order to solve the above-mentioned existing technical problems, the present invention provides a preparation method of a triboelectric fiber with a double-channel spiral structure, including the following steps:

[0013] S1: Thermally press the high polymer SEBS (Styrene Ethylene Butylene Styrene, a linear triblock copolymer with polystyrene as the end segment and ethylene-butylene copolymer obtained by hydrogenating polybutadiene as the middle elastic block) to obtain a SEBS preformed rod; the cross-section of the SEBS preformed rod is a rectangle with chamfered corners.

[0014] S2: Open two through holes in the SEBS preformed rod to obtain a SEBS preformed drilled rod; the through holes are arranged diagonally along the length direction.

[0015] S3: After preheating the SEBS preformed drilled rod, perform heat treatment under the condition of twisting at one end and pulling at the other end, and then wind it to obtain a SEBS fiber with a helical structure; the heat treatment is divided into three heating temperature stages in chronological order: 155 - 165 °C, 205 - 215 °C, and 95 - 105 °C.

[0016] S4: Inject a gallium-indium-tin alloy into the through holes of the SEBS fiber with a helical structure obtained in step S3, and then connect the two ends of the through holes with metal wires to obtain the friction electricity-generating fiber with a double-channel helical structure; the connection between the metal wire and the through hole is sealed with resin.

[0017] The prefabricated part has a rectangular structure on the outer layer and a double-channel electrode inside. When drawing, by rotating both the inner and outer layers, a helical effect can be simulated. The helical fiber is more evenly stressed, and its elongation rate and strength are higher than those of ordinary cylindrical fibers, enabling it to respond to larger deformation sensing.

[0018] Preferably, in step S1, a flat vulcanizing machine is used for thermal pressing.

[0019] Preferably, the temperature of the thermal pressing is 180 - 220 °C, the pressure is 8 - 12 MPa, and the heating time is 25 - 35 min.

[0020] Preferably, the molecular weight of the high polymer SEBS is 80 - 120 kDa, and the Young's modulus is 1 - 2 MPa.

[0021] Preferably, the length of the SEBS preformed rod is 140 - 160 mm, and the side length of the cross-section is 20 - 30 mm.

[0022] Preferably, the aperture of the through hole is 4 - 6 mm.

[0023] Preferably, in step S3, the preheating temperature is 155 - 165 °C, and the time is 20 - 40 min.

[0024] Preferably, in step S3, the rotation speed of twisting is 5 - 15 rad / s.

[0025] Specifically, in step S3, the preform is placed in the three temperature zones of the drawing tower and preheated for 30 minutes before undergoing hot stretching. The preform remains in a fixed position throughout the stretching process. Due to the varying temperatures within the three temperature zones, the middle zone has the highest temperature, causing necking, while the lower zone has a lower temperature, providing a cooling effect. The upper zone serves as a preheating agent for the three zones. The overall stretching time varies, ranging from 3.5 to 7 hours, depending on the stretching speed.

[0026] Preferably, the melting point of the gallium indium tin alloy is 4-6°C, and the electrical conductivity is 3-4×10 6 s / m.

[0027] Generally, the solid-liquid transition temperature of liquid metal is around 20 to 30 degrees. Gallium indium tin alloy is used here. Gallium indium tin alloy will have slightly different melting points and electrical conductivity due to different proportions. It is more convenient to use if it is around 5°C.

[0028] The liquid metal used for the core electrode of the preform is gallium indium tin alloy, which has low toxicity and minimal harm to humans. Due to the high degree of freedom of the internal molecules of the liquid metal and the active molecular motion, it not only has high deformability but also high conductivity (3.14×10 6 s / m), which makes the fibers prepared by liquid metal electrodes more sensitive to external reactions.

[0029] Preferably, the resin is epoxy resin.

[0030] Preferably, the metal wire is a copper wire.

[0031] Preferably, the diameter of the metal wire is 0.1-0.3 mm.

[0032] The present invention also provides a friction-generated fiber with a double-channel helical structure prepared by the above-mentioned preparation method.

[0033] The present invention also provides a self-powered sensor, which includes the above-mentioned frictional power generation fiber with a double-channel spiral structure.

[0034] The technical solution of the present invention has the following advantages over the prior art:

[0035] A heat-stretched friction-generating fiber, the preform sheath is made of SEBS, which has a strain of up to 1900% and a Young's modulus of only 1.6MPa. It has excellent mechanical deformation and can stretch to more than ten times its own length under extreme conditions, and can adapt to a wide range of deformation sensing.

[0036] The structure proposed in the present invention, in which a liquid metal core layer is covered by a highly elastic sheath, can generate frictional electricity through the movement of limbs, and then conduct it through the liquid metal, thereby achieving a self-powered effect.

[0037] The present invention manufactures highly elastic fibers using a thermal stretching process, integrating a highly elastic helical outer layer with two mutually twisted liquid metal electrodes, which exhibit high electrical conductivity and deformability, can perform strain sensing over a large range, and have an efficiency comparable to that of planar systems, meeting the need for sensing in a 2D plane.

[0038] The advanced elastic fibers manufactured by the present invention through a thermal stretching process combine a helical surface with a dual-channel liquid metal electrode. Even after repeated large deformations, it can still exhibit a high electrical output, can withstand strains of up to 1200%, and has a high electrical output.

[0039] The self-powered sensor of the triboelectric fiber with a dual-channel helical structure can record mechanical motion through the triboelectrification effect and the principle of electrostatic induction, and can achieve a self-powered effect through triboelectricity. It can be used in fields such as multifunctional wearable systems and smart textiles.

[0040] Due to its inherent advantages of waterproofness and easy processing, the sensor can also be used to study changes in underwater electrical signals and ion concentrations. Brief Description of the Drawings

[0041] Figure 1 It is a schematic diagram of the device for preparing thermally stretched triboelectric fibers of the present invention.

[0042] Figure 2 It is a schematic diagram of the preform hot pressing device of the present invention.

[0043] Figure 3 It is a schematic diagram of the stretching of the preform for preparing thermally stretched triboelectric fibers of the present invention.

[0044] Figure 4 It is a schematic diagram of the structure of the preform prepared in Example 1.

[0045] Figure 5 It is a schematic diagram of the fiber produced in Example 1 of the present invention.

[0046] Figure 6 It is a schematic diagram of the fiber produced in Example 1 of the present invention.

[0047] Figure 7 It is a schematic diagram of the fiber produced in Example 1 of the present invention.

[0048] Description of reference numerals in the drawings: 1 - rotating rod, 2 - wire, 3 - wire drawing tower, 4 - SEBS preform, 5 - drafting roller, 6 - collecting roller, 7 - SEBS fiber, 8 - pressing plate, 9 - heating plate, 10 - self-made mold, 11 - polymer SEBS, 12 - through hole, 13 - liquid metal, 14 - SEBS fiber with a twist of 360, 15 - SEBS fiber with a twist of 720, 16 - SEBS fiber with a twist of 1080. Detailed implementation mode

[0049] The present invention will be further described below in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the specific embodiments cited are not intended to limit the present invention.

[0050] Embodiment 1

[0051] This embodiment provides a thermally stretched triboelectric fiber with a double-channel spiral structure. First, a special preform 4 is prepared. As Figure 3 shown, the cross-section 9 of the preform is a rectangle with chamfered corners, and the internal structure is a double-channel structure.

[0052] For the preform 4, the polymer SEBS 11 (YH-688) is first placed in a vacuum drying oven and vacuum dried at a temperature of 65 °C for 24 h to remove the moisture in the raw materials to prevent excessive bubbles from being generated in subsequent experiments. Then, the dried SEBS is placed in a special mold 10 with a cross-section of a rectangle with chamfered corners and an internal specification of 25*25*150 mm 3 , and heated in a vulcanizing furnace at 200 °C. During this period, the SEBS particles are tightly extruded and consolidated under a pressure of 10 MPa. After 30 min, the mold 10 is taken out, cooled, and demolded to obtain a solid SEBS preform. Two 6-mm through holes 12 are drilled along a diagonal line of the cross-section of the preform with a drill press to prepare the required SEBS preform 4.

[0053] As Figure 1 shown, the SEBS preform 4 is softened at high temperature and the SEBS fiber 7 is prepared by twisting with the rotating rod 1 and drawing with the collecting roller 6.

[0054] A rotating rod 1 is connected to the upper end of the SEBS preform 4 via a metal wire 2. This rotating rod 1 is placed atop a drawing tower 3, positioning the preform 4 squarely within the tower. A lower drawing guide rod is then connected to the lower end of the preform via a copper wire 2. The drawing tower 3 is set to 160°C at the top, 210°C in the middle, and 100°C at the bottom. After 30 minutes of preheating and softening, the preform is pulled downward and the rotating motor is turned on at a speed of 5 rpm. The SEBS preform 4 is preheated in the upper temperature zone, necked in the middle temperature zone, and annealed and cooled in the lower temperature zone, resulting in a fiber with a helical structure. The fiber is then secured to a collection roller 6, and the automatic preform feeding and fiber winding processes are activated. The feed speed is set at 3 mm / min, and the drawing speed is set at 85 cm / min. The hot-drawn fiber passes through the drafting roller 5 positioned below the drawing tower 3 and is finally wound onto the collection roller 6. The drawn fiber has a helical structure. A gallium-indium-tin alloy was injected into two circular holes in the fiber using a syringe, forming two liquid metal electrodes. Copper wires with a diameter of 0.2 mm were connected to each end and sealed with resin. The resulting fiber had a diameter of 0.85 mm, a length of 165 m, and a twist of 360°. The internal electrodes had a diameter of 0.2 mm, a maximum strain of 750%, and an elastic deformation of 650%.

[0055] The sensing performance of Example 1 was tested. The fiber was stretched 1500 times, the fiber sample was 4 cm long, and the stretching ratio was 200%. The results showed that its resistivity was maintained at 180%. The fiber was pressed 1500 times, the fiber sample was 4 cm long, the compression contact length was 1 mm, and the pressure was 2 MPa. The results showed that its resistivity was maintained at 1000%, which indicates that the fiber prepared in this example can still maintain stable sensing performance after 1500 uses.

[0056] The triboelectric performance test of Example 1 was conducted. When the pressure was 10N, the generated current was 4.2nA and the voltage was 8.1V.

[0057] Example 2

[0058] Two 4 mm through holes were drilled along a diagonal line in the preform's cross section using a drill. The preform was wound in the drawing tower at a speed of 10 r / s. All other steps and parameters were the same as in Example 1. The resulting fiber had a diameter of 0.75 mm, an internal liquid metal diameter of 0.12 mm, a length of 212 m, a twist of 720, a maximum strain of 1050%, and an elastic deformation of 700%.

[0059] The sensing performance of Example 2 was tested, and the fiber was stretched and pressed 1000 times. Other test conditions were consistent with Example 1. The measured resistance change rate during stretching and pressing remained stable, indicating that the fiber prepared in this example can still maintain stable sensing performance after 1000 uses.

[0060] The triboelectric performance test of Example 2 showed that when the pressure was 10N, the generated current was 4nA and the voltage was 7.8V.

[0061] Example 3

[0062] The preform feeding speed in the drawing tower was set to 1 mm / min, the drawing speed was set to 70 cm / min, and the winding speed was set to 15 r / s. The other processes and parameters were the same as in Example 1. The resulting fiber had a diameter of 0.65 mm, an internal liquid metal diameter of 0.16 mm, a length of 283 m, a twist of 1080, a maximum strain of 1200%, and an elastic deformation of 750%.

[0063] The sensing performance of Example 3 was tested, and the fiber was stretched and pressed 2000 times. Other test conditions were consistent with Example 1. The measured resistance change rate during stretching and pressing remained stable, indicating that the fiber prepared in this example can still maintain stable sensing performance after 2000 uses.

[0064] The triboelectric performance test of Example 3 showed that when the pressure was 10N, the generated current was 5.5nA and the voltage was 10.4V.

[0065] Comparative Example 1

[0066] This comparative example describes a heat-stretched sensor fiber. First, SEBS2 was prepared: SEBS cores were pressed into thin sheets using a hot press at 180°C. The sheets were weighed, and then 11 wt% carbon black was added and sprinkled onto the SEBS1 sheet. The carbon black-deposited SEBS sheet was then hot-pressed at 180°C and 50 bar for 10 minutes to embed the carbon black into the SEBS1, resulting in a thicker carbon black-loaded SEBS1 sheet. The resulting sheet was then folded and hot-pressed at 180°C and 50 bar for 10 minutes. This folding and hot-pressing process was repeated eight times to ensure uniform dispersion of the carbon black throughout the SEBS1. The sheet was then cut into 1 mm x 1 mm sheets and extruded in a single-screw extruder to thoroughly mix the carbon black into the SEBS, producing the more viscous carbon black composite material, SEBS2.

[0067] Then prepare the preform rod: prepare a cylindrical preform with a diameter of 30 mm and a length of 150 mm. The preform consists of a retractable electrode located in the center, an insulating SEBS2 layer and a PMMA sacrificial layer. The retractable electrodes are arranged on opposite sides of the preform and have a diameter of 0.1 to 1 mm.

[0068] Then, prepare the fiber electrode by hot stretching: Install the preform in a three-zone wire drawing tower. Use a customized feeding table to make the preform rod translate and rotate simultaneously. The drawing speed is fixed at 85 cm / min, and the rotation speed is 5 r / s. Stretch the preform into a fiber at the top of the wire drawing tower at 150 °C, in the middle at 260 °C, and at the bottom at 120 °C. Finally, etch the PMMA sacrificial layer with acetone. Connect the fiber to a copper wire and then seal it with epoxy resin.

[0069] The fibers prepared in this way can withstand 580% elastic deformation and 750% strain, and are tested for durability 1000 times. The diameter is 0.85 mm, the twist is 360, and the length is 187 m.

[0070] Comparative Example 2

[0071] This comparative example is a flexible wire electrode coated with a polyether ether ketone coating. First, perform pre-treatment on the material: Pass a 304 stainless steel wire with a diameter of 50 μm through acetone, isopropyl acetone, and deionized water in sequence to remove the stains on its surface. Then wind the treated metal wire on a wire reel and store it in a vacuum drying oven. Wash the polyether ether ketone particles three times with absolute ethanol and dry them in a vacuum drying oven at 180 - 200 °C for 24 h.

[0072] Next, prepare a preform rod with a central hole: Fill the polyether ether ketone particles into a semi-cylindrical mold with a diameter of 15 mm and a length of 180 mm. Place the mold between the upper and lower heating plates of a hot press, set the temperature to 330 °C, and the hot pressing pressure to 20 MPa. Hot press the polyether ether ketone particles into a semi-cylindrical rod. Repeat the hot pressing step to prepare the other half-cylindrical rod. Put the two half-cylinders into two molds and stack the two molds so that they are spliced into a complete cylinder, and then put it into the hot press to hot press it into a solid cylindrical rod. Make it into a solid cylindrical rod with a diameter of 12 mm and a length of 180 mm by polishing. Drill a hollow hole with a diameter of 2 mm in the center of the solid rod with a drill press to obtain a hollow-structured preform rod.

[0073] Then, prepare the fiber electrode by hot stretching: Insert the stainless steel wire into the central through-hole of the preform rod, clamp the preform rod with a preform rod clamp, align the preform rod clamp with the center of the heating furnace and insert the preform rod into the heating furnace. Wait for the heating furnace to heat up to 480 °C. After the preform rod softens and turns around, make the fiber pass through the diameter measuring instrument and the auxiliary traction wheel in sequence, and finally reach the take-up reel. Control the feeding speed of the preform rod to be 0.1 mm / min, and adjust the wire take-up speed to control the fiber diameter at 0.3 mm. The diameter of the metal electrode is 0.05 mm. The fiber prepared in this way has a length of 48 m.

[0074] Comparative Example 3

[0075] This comparative example is a flexible wire electrode coated with a polyether ether ketone coating. First, the material is pre-treated: a 304 stainless steel wire with a diameter of 50 μm is successively passed through acetone, isopropyl acetone, and deionized water to remove the stains on its surface. Then, the treated metal wire is wound on a wire reel and stored in a vacuum drying oven. The polyether ether ketone film of the desired size is wiped with anhydrous ethanol.

[0076] Next, a preform rod with a central hole is prepared: using a smooth Teflon solid rod with a diameter of 3 mm and a length of 300 mm as the base, the polyether ether ketone film is wound layer by layer on the Teflon solid rod until the diameter reaches 23 mm. It is wrapped with high-temperature tape to prevent it from loosening, and then placed in a vacuum tube furnace at 350 °C for thermosetting for 30 min. After thermosetting, the Teflon solid rod is taken out to obtain a polyether ether ketone preform rod with a central hole.

[0077] Then, a fiber electrode is prepared by hot stretching: the stainless steel wire is inserted into the central through-hole of the preform rod, and the preform rod is clamped with a preform rod clamp. The preform rod clamp is aligned with the center of the heating furnace and the preform rod is inserted into the heating furnace. Wait for the heating furnace to heat up to 480 °C. After the preform rod softens and turns around, the fiber passes through the diameter measuring instrument and the auxiliary traction wheel in sequence, and finally reaches the take-up reel. The feeding speed of the preform rod is controlled at 0.1 mm / min, and the take-up speed is adjusted to control the fiber diameter at 1.75 mm and the metal electrode diameter at 0.3 mm. The fiber prepared in this way has a length of 31 m.

[0078] Effect evaluation 1

[0079] The fibers prepared by the present invention are subjected to performance tests. The selected fiber diameter is 0.85 mm, the twist is 360, and the internal hole is 0.2 mm. The specific test contents are as follows:

[0080] The underwater performance of the fibers prepared by the present invention was tested. Three 14-cm fibers were immersed in 0.3M / L NaCl, 0.6M / L NaCl, and 0.6M / L Na2SO4 solutions respectively, denoted as A, B, and C. Another 10-cm fiber was placed in the 0.6M / L NaCl solution, denoted as D. A DC rectangular wave signal of 0.2V, 0.4V, and 0.8V was applied to the solution through the multi-potential step mode of an electrochemical workstation. The results showed that at a voltage of 0.2V, A, B, C ≈ ±0.01nA, D ≈ ±0.005nA; when the voltage was 0.4V, A, B, C ≈ ±0.022nA, D ≈ ±0.01nA; when the voltage was 0.8V, A ≈ ±0.047nA, B ≈ ±0.049nA, C ≈ ±0.041nA, D ≈ ±0.023nA. This indicates that the detected signal is mainly related to the effective fiber length immersed in the solution; there is little difference in different solutes under the 0.2V and 0.4V signals, but there is a large difference under the 0.8V signal. It can be seen that the source signal value has an obvious impact on the detection result; there is no obvious correlation between the solution concentration and the detection result; the solute type has a certain impact on the detection result. The fibers prepared by the present invention can detect signals related to underwater ion changes.

[0081] The sensing performance of the fibers prepared by the present invention was tested. A self-built stretching platform was used to stretch the fibers, and a digital multimeter was used to measure the resistance. A 4-cm long fiber sample was taken for stretching, and the stretching test data are shown in Table 1. It can be seen that the fiber resistance changes significantly at different stretching ratios.

[0082] Table 1 Variation of fiber resistance with stretching degree

[0083] Stretch (%) 0 100 200 300 ΔR / R0(%) 0 50 180 310

[0084] The sensing performance of the fibers prepared by the present invention was tested. A self-built compression platform was used to press the fibers, and a digital multimeter was used to measure the resistance. A 4-cm long fiber sample was taken for stretching and pressing tests. The pressing contact length was 1 mm, and the pressing test data are shown in Table 2. It can be seen that the fiber resistance changes significantly under different pressures.

[0085] Table 2 Variation of fiber resistance with extrusion degree

[0086] Pressing pressure (MPa) 0 1 2 3 4 ΔR / R0(%) 0 0 1000 2050 3100

[0087] Based on the stretching and pressing tests of the present invention, it is shown that the present invention can be used as a fiber sensor.

[0088] The fibers were subjected to 200, 400, 600, 800, and 1000 stretching tests respectively. The fiber specimens were 4 cm long and the stretching ratio was 150%. The results showed that their resistivity remained at 120%.

[0089] The fibers were subjected to 300, 600, 900, 1200, and 1500 pressing tests respectively. The fiber specimens were 4 cm long, the compression contact length was 1 mm, and the pressure was 1.4 MPa. The results showed that their resistivity remained at 600%.

[0090] Through the tensile and pressing durability tests on the fibers prepared by the present invention, it is shown that they have good durability.

[0091] The triboelectric performance of the fibers prepared by the present invention was tested. A self-built compression platform was used, the friction material was an acrylic plate, the pressure was 0 - 20 N, the contact length was 5 cm, and the distance between the friction layer and the fibers was 2 cm. The test results are shown in Table 3. The greater the pressure, the greater the current and voltage generated. This indicates that the fibers prepared by the present invention have good self-powered performance.

[0092] Table 3 Triboelectric Performance Test of Fibers

[0093] Pressure (N) 0 5 10 15 20 Current (nA) 0 17.5 42 82 100 Voltage (V) 0 -4.8 -8.1 -10.2 -12

[0094] The fiber triboelectric durability test was carried out on the fibers prepared by the present invention. A self-built compression platform was used, the friction material was an acrylic plate, the pressure was 15 - 20 N, the contact length was 5 cm, and the distance between the friction layer and the fibers was 2 cm. After testing the initial fibers, the current remained at -100 - 70 nA and the voltage remained at -17 - 0 V. The fibers were tested 500 and 1000 times respectively, and the data showed consistency with the initial data. This indicates that the fibers prepared by the present invention have excellent triboelectric durability.

[0095] The data of the examples and comparative examples are shown in Table 4:

[0096] Table 4 Comparison Table of Various Properties of Examples and Comparative Examples

[0097]

[0098] Obviously, the above examples are merely illustrations given for clear explanation and are not limitations on the implementation modes. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation modes here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A preparation method of a triboelectric fiber with a dual-channel spiral structure, characterized in that, The method includes the following steps: S1: Thermally press the polymer SEBS to obtain a SEBS preformed rod; the cross-section of the SEBS preformed rod is a rectangle with chamfered corners; S2: Open two through holes in the SEBS preformed rod to obtain a SEBS preformed drilled rod; the through holes are arranged diagonally along the length direction; S3: After preheating the SEBS preformed drilled rod, perform heat treatment under the condition of twisting one end and pulling the other end, and wind it up to obtain a SEBS fiber with a spiral structure; the heat treatment is divided into three heating temperature stages of 155-165 °C, 205-215 °C and 95-105 °C in chronological order; S4: Inject a gallium-indium-tin alloy into the through holes of the SEBS fiber with a spiral structure in step S3, and connect the two ends of the through holes with metal wires to obtain the triboelectric fiber with a double-channel spiral structure; the connection between the metal wire and the through hole is sealed with resin.

2. The preparation method according to claim 1, characterized in that, In step S1, the thermal pressing is carried out by a flat vulcanizing machine.

3. The preparation method according to claim 1 or 2, characterized in that, The temperature of the thermal pressing is 180-220 °C, the pressure is 8-12 MPa, and the time of the thermal pressing is 25-35 min.

4. The preparation method according to claim 1, characterized in that, The molecular weight of the polymer SEBS is 80-120 kDa, and the Young's modulus is 1-2 MPa.

5. The preparation method according to claim 1, characterized in that, The length of the SEBS preformed rod is 140-160 mm, and the side length of the cross-section is 20-30 mm.

6. The preparation method according to claim 1, characterized in that, The aperture of the through hole is 4-6 mm.

7. The preparation method according to claim 1, characterized in that, In step S3, the preheating temperature is 155-165 °C, and the time is 20-40 min.

8. The preparation method according to claim 1, characterized in that, The melting point of the gallium-indium-tin alloy is 4 - 6 °C, and the conductivity is 3 - 4×10 6 S / m.

9. A triboelectric fiber with a double-channel spiral structure prepared by the preparation method according to any one of claims 1-8.

10. A self-powered sensor, characterized in that, Comprising the triboelectric fiber with a double-channel spiral structure according to claim 9.

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