A type of elastic triboelectric nanofiber

Abstract

This invention discloses an elastic triboelectric nanofiber, comprising two different elastic structures as either the core or the shell layer to form the nanofiber. The two elastic structures have different Poisson's ratios, including cases where the Poisson's ratio is positive or negative. The contact surface materials of the core and shell elastic structures have different polarities. Due to the different Poisson's ratios of the shell and core elastic structures, stretching under natural conditions causes a change in the contact area. Therefore, during repeated stretching, the shell and core layers can separate, generating an electrical signal based on the principle of triboelectric nanofiber generation, which is then discharged by a conductive current collector. The stretching process of this invention is repeatable and can restore its original shape without external force.

Description

Technical Field

[0001] This invention relates to the field of energy conversion, and in particular to a power-generating fiber based on a triboelectric nanogenerator. Background Technology

[0002] With the development of economy and technology, people around the world attach great importance to health monitoring. Currently, there are many smart bracelet products that can be linked with smartphones and record users' daily health data. Health monitoring is moving from clinical to nationwide monitoring.

[0003] Regarding the selection of sensing principles, piezoresistive sensors, fabricated using the piezoresistive effect, offer strong load capacity, good robustness, and convenient signal measurement. However, they often exhibit significant hysteresis, large temperature drift, and poor linearity. Capacitive tactile sensors, on the other hand, offer high sensitivity and spatial resolution, but their measurement circuitry is complex and susceptible to electrical interference. Currently, the widely used rigid piezoelectric tactile sensors can achieve self-generation and electromechanical conversion, are portable, and offer good linearity and response sensitivity. However, their material rigidity is high, making them susceptible to noise interference, and their dielectric properties are affected by temperature. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an elastic triboelectric nanofiber for power generation. Triboelectric nanogenerators generate external current by changing the contact area between two materials with different electronegativity. Core-shell structured triboelectric nanofibers typically utilize this core-shell structure to achieve contact separation under stimulation. This invention utilizes this principle to obtain a triboelectric nanofiber that is sensitive to tensile strain and can generate electricity independently as a single fiber.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] An elastic triboelectric nanofiber is composed of two different elastic structures as the core layer or the shell layer, with different Poisson ratios for the two elastic structures, including cases where the Poisson ratio is positive or negative; the contact surface materials of the elastic structures of the core layer and the shell layer have different polarities.

[0007] Furthermore, different Poisson ratios include the cases where both the shell and the core have positive Poisson ratios, the shell has a positive Poisson ratio while the core has a negative Poisson ratio, the shell has a negative Poisson ratio while the core has a positive Poisson ratio, and both the shell and the core have negative Poisson ratios.

[0008] Furthermore, since the elastic structure of the shell and the elastic structure of the core have different Poisson's ratios, stretching under natural conditions can cause changes in the contact area.

[0009] Furthermore, the elastic triboelectric nanofibers can undergo contact separation between the shell and the core during repeated stretching, generating electrical signals based on the principle of triboelectric nanofiber generation, which are then discharged by a conductive current collector.

[0010] Furthermore, it can naturally return to its original shape after being stretched from its initial state.

[0011] Furthermore, contact surface materials of different polarities include any two of polyoxymethylene 1.3-1.4, ethyl cellulose, polyamide-11, polyamide-66, melamine, wool, silk, paper, cotton, hard rubber, cellulose acetate, synthetic fibers, polymethyl methacrylate, polyvinyl alcohol, polyester, polyisobutylene, polyurethane, polyethylene terephthalate (PET), polyvinyl butyral, chloroprene rubber, natural rubber, polypropylene, acrylonitrile, bisphenol A polycarbonate, poly3,3-dichloromethylbutoxycyclohexane, polyvinylidene chloride, polystyrene, polyethylene, polypropylene, polyimide, polyvinyl chloride, polydimethylsiloxane, and polytetrafluoroethylene.

[0012] Furthermore, elastic structures with a positive Poisson's ratio include tubular polyurethane fibers (PU), natural rubber (NR), styrene-butadiene rubber (SBR), cis-butadiene rubber (BR), isoprene rubber (IR), butadiene rubber (CR), butyl rubber (IIR), nitrile rubber (NBR), and silicone rubber (MFQ)—elastic polymers, or hollow elastic structures made of rigid materials, including helical structures.

[0013] Furthermore, elastic structures with a negative Poisson's ratio include concave structures, rotating polygonal structures, sheet-like pleated structures, perforated plate structures, interlocking polygonal structures, wound yarn structures, chiral structures, cellular negative Poisson's ratio structures, and water-bomb origami structures.

[0014] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0015] 1. This invention is simple, can be mass-produced, has a wide range of material options, and is lightweight.

[0016] 2. The contact surface of the elastic triboelectric nanofiber electrode prepared by this invention has a nanofiber structure. Its ultra-large specific surface area and multi-level micro-nano structure are conducive to increasing the contact area of ​​the friction surface, thereby effectively improving the output power of the device. The fiber structure is conducive to its blending with ordinary fibers, has good wearability, and can be completely integrated with clothing. It is very suitable for collecting the mechanical energy generated by human movement such as walking and running and converting it into electrical energy. It can not only power small electronic devices, but also be used to build self-driven sensors for human movement pattern recognition and other applications. Attached Figure Description

[0017] Figures 1a to 1iHere are schematic diagrams of several types of negative Poisson's ratio structures;

[0018] Figure 2 A schematic diagram of one approach to fiberization of a planar negative Poisson's ratio structure;

[0019] Figure 3 This is a schematic diagram of the structure of the elastic triboelectric nanofiber yarn prepared in Example 1; Figure 3 Part (a) is the view before stretching, and part (b) is the view after stretching.

[0020] Figures 4a to 4e The output open-circuit voltage of the elastic triboelectric nanofiber yarn prepared in Example 1 under different tensile strains is shown below. Figures 4a to 4e The strains were 3%, 6%, 9%, 12%, and 15%, respectively.

[0021] Figures 5a to 5e The output open-circuit voltage of the elastic triboelectric nanofiber yarn prepared in Example 2 under different tensile strains is shown below. Figures 5a to 5e The strains were 5%, 6%, 7%, 8%, and 10%, respectively.

[0022] Figure 6 This is a schematic diagram of the structure of the elastic triboelectric nanofiber yarn prepared in Example 3; Figure 6 Part (a) is the view before stretching, and part (b) is the view after stretching. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0024] This invention provides an elastic triboelectric nanofiber, which comprises two different elastic structures as the core layer or shell layer, respectively, and these two elastic structures have different Poisson's ratios, including an elastic structure with a positive Poisson's ratio and an elastic structure with a negative Poisson's ratio. The contact surface materials of the elastic structures of the core layer and the shell layer have different polarities. The different Poisson's ratios include the following cases: both the shell and the core have positive Poisson's ratios; the shell has a positive Poisson's ratio and the core has a negative Poisson's ratio; the shell has a negative Poisson's ratio and the core has a positive Poisson's ratio; and both the shell and the core have negative Poisson's ratios.

[0025] Because the elastic structures of the shell and core have different Poisson's ratios, stretching under natural conditions will cause changes in the contact area. Furthermore, during repeated stretching, the shell and core can separate, generating electrical signals based on the principle of triboelectric nanogenerators, which are then discharged by a conductive current collector.

[0026] Preferably, the stretching process can be repeated, meaning that after stretching from the initial state, the object can return to its original state without external force.

[0027] In the triboelectric nanofiber structure of this invention, the surface materials with different polarities include two of the common triboelectric nanofiber materials with differences in electronegativity, such as polyoxymethylene 1.3-1.4, ethyl cellulose, polyamide (nylon)-11, polyamide (nylon)-66, melamine, wool, silk, paper, cotton, hard rubber, cellulose acetate, synthetic fiber, polymethyl methacrylate, polyvinyl alcohol, polyester, polyisobutylene, polyurethane, polyethylene terephthalate (PET), polyvinyl butyral, chloroprene rubber, natural rubber, polypropylene, acrylonitrile chlorofiber, bisphenol A polycarbonate, poly3,3-bis(chloromethyl)butoxycyclohexane, polyvinylidene chloride, polystyrene, polyethylene, polypropylene, polyimide, polyvinyl chloride, polydimethylsiloxane, and polytetrafluoroethylene.

[0028] The elastic structures with a positive Poisson's ratio in this invention include tubular polyurethane fibers (PU), natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), butadiene rubber (CR), butyl rubber (IIR), nitrile rubber (NBR), silicone rubber (MFQ), and other elastic synthetic or natural polymers, or elastic hollow structures made of rigid materials, such as helical structures. The elastic structures with a negative Poisson's ratio in this invention include concave structures (…). Figure 1a ), Rotational polygon structure ( Figure 1b ), sheet-like folded structure ( Figure 1c ), perforated plate structure ( Figure 1d ), interlocking polygonal structure ( Figure 1e ), wound yarn structure ( Figure 1f ), chiral structure ( Figure 1g ), cellular negative Poisson's ratio structure ( Figure 1h ), water-bomb origami structure ( Figure 1i Structures exhibiting negative Poisson's ratio characteristics, such as wound yarn structures which are inherently fibers, can be achieved through methods like... Figure 2 The fibers produced in the manner shown have a three-dimensional structure, such as a cellular negative Poisson's ratio structure, and can be made into fibers by cutting cylinders.

[0029] Example 1

[0030] Using a 0.265mm diameter nylon thread as the central axis, a 0.08mm diameter copper wire is spirally wound around the nylon central axis to obtain a rigid conductive fiber. Using a rubber-core elastic thread as the central axis, a nano-PTFE film obtained by layering commercial PTFE film is wrapped around the core thread surface, and the rigid conductive fiber obtained above is wound around it to form an elastically wound negative Poisson's ratio structure, wherein the angle between the wound nylon fiber and the central core thread is controlled at 45°. Figure 3 The diagram shows its structure. At a stretching frequency of 1 Hz, the open-circuit voltages generated by this sample at stretching rates of 3%, 6%, 9%, 12%, and 15% are approximately 0.15V, 0.25V, 0.49V, 0.75V, and 0.88V, respectively. Figures 4a to 4e As shown.

[0031] Example 2

[0032] Using a 0.265mm diameter nylon thread as the central axis, a 0.08mm diameter copper wire is spirally wound around the nylon central thread to obtain a rigid conductive fiber. Using a rubber-core elastic wire as the central axis, a nano-PTFE film obtained by layering commercial PTFE film is coated on the surface of the core wire, and the aforementioned rigid conductive fiber is wound around it to form an elastically wound negative Poisson's ratio structure, wherein the angle between the wound nylon fiber and the central core wire is controlled at 30°. At a stretch ratio frequency of 1Hz, the open-circuit voltages generated by this sample at stretch ratios of 5%, 6%, 7%, 8%, and 10% are approximately 0.5V, 0.55V, 0.65V, 0.8V, and 1V, respectively. Figures 5a to 5e As shown.

[0033] Example 3

[0034] Using a polyurethane fiber with a water-bomb origami negative Poisson's ratio structure and a diameter of 0.8 mm as the core, a nano-PTFE film obtained by layering commercial PTFE film is coated on the surface of the negative Poisson's ratio structure. Figure 6 The diagram shows its structure. At a stretching frequency of 1 Hz, the open-circuit voltages generated by this sample at stretching rates of 3%, 6%, 9%, 12%, and 15% are approximately 0.6V, 0.7V, 0.85V, 0.9V, and 1.2V, respectively.

[0035] This invention is not limited to the embodiments described above. The above description of specific embodiments is intended to illustrate and explain the technical solutions of this invention. The specific embodiments described above are merely illustrative and not restrictive. Without departing from the spirit and scope of the claims, those skilled in the art can make many specific modifications based on the teachings of this invention, and these modifications all fall within the scope of protection of this invention.

Claims

1. An elastic triboelectric nanofiber for generating electricity, characterized in that, Two different elastic structures are used as the core or shell to form nanofibers. The two elastic structures have different Poisson ratios, including cases where the Poisson ratio is positive or negative. The contact surface materials of the elastic structures of the core and shell have different polarities. The different Poisson ratios include cases where the Poisson ratio of the shell is positive and the Poisson ratio of the core is negative, or cases where the Poisson ratio of the shell is negative and the Poisson ratio of the core is positive. Because the elastic structure of the shell and the elastic structure of the core have different Poisson's ratios, stretching under natural conditions can cause changes in the contact area. Elastic triboelectric nanofibers can undergo contact separation between the shell and core layers during repeated stretching, generating electrical signals based on the principle of triboelectric nanofiber generation, which are then extracted by a conductive current collector. It can naturally return to its original shape after being stretched from its initial state; Contact surface materials of different polarities include any two of the following: polyoxymethylene, ethyl cellulose, polyamide-11, polyamide-66, melamine resin, wool, silk, paper, cotton, cellulose acetate, polymethyl methacrylate, polyvinyl alcohol, polyisobutylene, polyurethane, polyethylene terephthalate, polyvinyl butyral, chloroprene rubber, natural rubber, polyacrylonitrile, chloroprene fiber, bisphenol A polycarbonate, poly3,3-dichloromethylbutoxycyclohexane, polyvinylidene chloride, polystyrene, polyethylene, polypropylene, polyimide, polyvinyl chloride, polydimethylsiloxane, and polytetrafluoroethylene. Elastic structures with a positive Poisson's ratio include tubular elastic polymers, such as polyurethane fiber (PU), natural rubber (NR), styrene-butadiene rubber (SBR), cis-butadiene rubber (BR), isoprene rubber (IR), butyl rubber (IIR), nitrile rubber (NBR), or fluorosilicone rubber (MFQ), or hollow elastic structures made of rigid materials, wherein the hollow elastic structure is a helical structure. Elastic structures with a negative Poisson's ratio include one of the following: concave structure, rotating polygonal structure, sheet-like pleated structure, perforated plate structure, interlocking polygonal structure, winding yarn structure, chiral structure, and water-bomb origami structure.

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