CN114959998A - Flexible self-powered sensor and preparation method thereof - Google Patents

Abstract

The present invention provides a flexible self-powered sensor, which is formed by weaving a first core-spun yarn and a second core-spun yarn as warp yarns and weft yarns, respectively, wherein the first core-spun yarn includes a conductive core layer and a wrapping The first shell layer of the conductive core layer, the conductive core layer is a conductive yarn, the material of the first shell layer is polyamide 66, and the first shell layer has a compressible nanoscale first microstructure , the second core-spun yarn includes the conductive core layer and the second shell layer covering the conductive core layer, the material of the second shell layer is polyvinylidene fluoride trifluoroethylene, the first The bishell layer has a compressible nanoscale second microstructure. The flexible self-powered sensor provided by the present invention has better flexibility, comfort, air permeability and shape adaptability, and has higher sensitivity. The invention also provides a preparation method of the flexible self-powered sensor.

Description

Flexible self-powered sensor and preparation method thereof

technical field

The invention relates to the technical field of sensors, in particular to a flexible self-powered sensor and a preparation method thereof.

Background technique

Flexible sensing technology is developing rapidly as an emerging discipline. Among them, smart wearable devices are developing rapidly, and the performance requirements of flexible sensing devices in terms of wearability, comfort, and sensitivity are further improved. At present, the development of many flexible self-powered sensors mostly adopts the "sandwich"-like multi-layer structure, the preparation process is complicated, the softness, comfort and air permeability are poor, the shape adaptability is insufficient, and the modulus of the multi-layer structure cannot effectively adapt to the human body. Complex morphing of activities.

SUMMARY OF THE INVENTION

Based on this, it is necessary to provide a flexible self-powered sensor with better flexibility, comfort, air permeability and shape adaptability, and higher sensitivity.

In addition, it is also necessary to provide a preparation method of the above-mentioned flexible self-powered sensor.

One aspect of the present invention provides a flexible self-powered sensor, which is formed by weaving a first core-spun yarn and a second core-spun yarn as warp yarns and weft yarns, respectively, wherein the first core-spun yarn includes a conductive core layer and a wrapping The first shell layer covering the conductive core layer, the conductive core layer and the first shell layer are coaxially arranged, the conductive core layer is a conductive yarn, and the material of the first shell layer is polyamide 66 , the first shell layer is positively charged after friction, the first shell layer has a compressible nano-scale first microstructure, the second core-spun yarn includes the conductive core layer and wraps the The second shell layer of the conductive core layer, the conductive core layer and the second shell layer are coaxially arranged, the material of the second shell layer is polyvinylidene fluoride trifluoroethylene, the second shell layer friction After being negatively charged, the second shell layer has a compressible nanoscale second microstructure.

In a possible embodiment, the first shell layer is composed of a plurality of nano-scale polyamide 66 filaments interlaced with each other, and the second shell layer is composed of a plurality of nano-scale polyvinylidene fluoride trifluoride. Vinyl filaments are intertwined.

In a possible embodiment, the diameter of the polyamide 66 filament is 500-900 nm, and/or the diameter of the polyvinylidene fluoride trifluoroethylene filament is 500-900 nm.

In a possible embodiment, the conductive yarn is at least one of conductive silver fibers, conductive copper fibers, and conductive gold fibers.

In a possible embodiment, the diameter of the first core-spun yarn is 400-500 μm, and/or the diameter of the second core-spun yarn is 400-500 μm.

In a possible embodiment, the sensitivity of the flexible self-powered sensor is greater than or equal to 5.59V/kPa.

Another aspect of the present invention provides a preparation method of the above-mentioned flexible self-powered sensor, comprising the following steps:

dissolving polyamide 66 in the first solvent to obtain a polyamide 66 polymer solution;

The polyamide 66 polymer solution is formed into polyamide 66 nanofibers by using an electrospinning core-spun yarn device, and the polyamide 66 nanofibers are wrapped on the surface of the conductive core layer, so as to form the polyamide 66 nanofibers on the surface of the conductive core layer. forming the first shell layer on the surface, thereby obtaining the first core-spun yarn;

dissolving polyvinylidene fluoride trifluoroethylene in the second solvent to obtain a polyvinylidene fluoride trifluoroethylene polymer solution;

Using the electrospinning core-spun yarn device to form the polyvinylidene fluoride trifluoroethylene polymer solution into polyvinylidene fluoride trifluoroethylene nanofibers, and wrapping the polyvinylidene fluoride trifluoroethylene nanofibers on the surface of the other conductive core layer to form the second shell layer on the surface of the conductive core layer, so as to obtain the second core-spun yarn; and

The first core-spun yarn and the second core-spun yarn are woven as warp yarns and weft yarns, respectively, to obtain the flexible self-powered sensor.

In a possible embodiment, the first solvent is hexafluoroisopropanol, and/or the second polymer solution is a mixed solution of N,N-dimethylformamide and acetone.

In a possible embodiment, using the electrospinning core-spun yarn device to form the polyamide 66 polymer solution into the polyamide 66 nanofibers specifically includes the following steps:

The polyamide 66 polymer solution is loaded in the first syringe and the second syringe, and the first metal needle of the first syringe and the first metal needle of the first syringe and the first metal needle of the first syringe are respectively charged by the first DC high voltage power supply and the second DC high voltage power supply. The second metal needles of the two syringes apply the first voltage and the second voltage, and simultaneously push the first syringe and the second syringe through the first infusion pump and the second infusion pump, respectively, so that the first syringe and the second The polyamide 66 polymer solution in the second syringe is spun out in the form of polyamide 66 nanofibers;

And/or using the electrospinning core-spun yarn device to form the polyvinylidene fluoride trifluoroethylene polymer solution into the polyvinylidene fluoride trifluoroethylene nanofibers specifically includes the following steps:

The polyvinylidene fluoride trifluoroethylene polymer solution is loaded in the first syringe and the second syringe, and the first metal of the first syringe is respectively charged by the first direct current high voltage power supply and the second direct current high voltage power supply. The needle and the second metal needle of the second syringe apply the first voltage and the second voltage, and simultaneously push the first syringe and the second syringe through the first infusion pump and the second infusion pump, respectively, so that all the The polyvinylidene fluoride trifluoroethylene polymer solutions in the first syringe and the second syringe are spun out in the form of polyvinylidene fluoride trifluoroethylene nanofibers.

In a possible embodiment, the first voltage is 10-13kV, the second voltage is 10-13kV, the polyamide 66 polymer solution and/or the polyvinylidene fluoride trifluoroethylene polymerize The flow rate of the polymer solution in the first metal needle is 2-3ml/h, the polyamide 66 polymer solution and/or the polyvinylidene fluoride trifluoroethylene polymer solution in the second metal needle The flow rate in 2-3 ml/h.

Based on the principle of triboelectric effect, the invention uses conductive yarn as the conductive core layer, and uses polyamide 66 and polyvinylidene fluoride trifluoroethylene with opposite triboelectric properties as the first shell layer and the second shell layer, respectively. The first core-spun yarn and the second core-spun yarn are woven, and the first core-spun yarn and the second core-spun yarn are woven as warp and weft respectively to form a flexible self-powered sensing fabric, that is, flexible Compared with the "sandwich"-like multi-layer structure of the flexible self-powered sensor prepared by the traditional technology, the flexible self-powered sensor provided by the present invention has better flexibility (ie bending, folding and twisting), comfort, Breathability and shape adaptability. In addition, since the first shell layer has a compressible nano-scale first microstructure, and the second shell layer has a compressible nano-scale second microstructure, the present invention can improve the flexible self-powered sensor sensitivity.

Description of drawings

FIG. 1 is a schematic diagram of the electrospinning core-spun yarn device provided by the present invention during operation.

2 is a scanning electron microscope image of the cross section of the first core-spun yarn prepared in Example 1 of the present invention.

3 is a scanning electron microscope image of the first core-spun yarn prepared in Example 1 of the present invention and a partial enlarged view of the first shell in the first core-spun yarn.

4 is a scanning electron microscope image of the cross section of the second core-spun yarn prepared in Example 1 of the present invention.

5 is a scanning electron microscope image of the second core-spun yarn prepared in Example 1 of the present invention and a partial enlarged view of the second shell in the second core-spun yarn.

6 is a graph showing the sensitivity of the flexible self-powered sensor prepared in Example 1 of the present invention.

Icon: 100-preparation device; 10-first syringe; 101-first metal needle; 11-second syringe; 111-second metal needle; 20-first DC high-voltage power supply; 21-second DC high-voltage power supply; 30-first infusion pump; 31-second infusion pump; 40-spinning feeder; 50-metal round target; 51-metal rod; 52-first motor; 60-metal collecting tip; 70-second motor; 71 - Spinning collector.

Detailed ways

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the related drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that a thorough and complete understanding of the present disclosure is provided.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The present invention provides a flexible self-powered sensor, wherein the flexible self-powered sensor is formed by weaving a first core-spun yarn and a second core-spun yarn as warp yarns and weft yarns, respectively. That is, the flexible self-powered sensor is a flexible self-powered sensing fabric.

In one embodiment, the first core-spun yarn includes a conductive core layer and a first shell layer covering the conductive core layer. In one embodiment, the diameter of the first core-spun yarn may be 400-500 μm.

Wherein, the conductive core layer is a conductive yarn. In one embodiment, the conductive yarns may be at least one of conductive silver fibers, conductive copper fibers, and conductive gold fibers. Preferably, the conductive yarns are conductive silver fibers. In one embodiment, the diameter of the conductive core layer may be about 200 μm. In one embodiment, the electrical conductivity of the conductive silver fibers may be 5.8×10 ⁴ S/cm.

In one embodiment, the material of the first shell layer is polyamide 66 (PA66). Wherein, the first shell layer made of polyamide 66 is positively charged after friction. In one embodiment, the thickness of the first shell layer may be about 150 μm. Wherein, the first shell layer has a compressible nano-scale first microstructure. That is, the first shell layer is composed of a plurality of nano-scale polyamide 66 filaments interlaced with each other. In one embodiment, the diameter of the polyamide 66 filament may be 500-900 nm.

In one embodiment, the second core-spun yarn includes the conductive core layer and a second shell layer covering the conductive core layer. In one embodiment, the diameter of the second core-spun yarn may be 400-500 μm.

In one embodiment, the material of the second shell layer is polyvinylidene fluoride trifluoroethylene (PVDF-TrFE). Wherein, the second shell layer made of polyvinylidene fluoride trifluoroethylene is negatively charged after friction. In one embodiment, the thickness of the second shell layer may be about 150 μm. Wherein, the second shell layer has a compressible nano-scale second microstructure. That is, the second shell layer is composed of a plurality of nano-scale polyvinylidene fluoride trifluoroethylene fibrils interlaced with each other. In one embodiment, the diameter of the polyvinylidene fluoride trifluoroethylene fibrils may be 500-900 nm.

Since the first shell layer has the first microstructure at a compressible nanoscale, and the second shell layer has the second microstructure at a compressible nanoscale, the flexible self-powered sensor can be improved sensitivity. In one embodiment, the sensitivity of the flexible self-powered sensor is greater than or equal to 5.59V/kPa.

In use, the fabric formed by knitting the first core-spun yarn and the second core-spun yarn as warp yarns and weft yarns, respectively, is used as a sensing layer that directly contacts the body (eg, human body). When the first shell and the second shell are slightly deformed in response to the physiological activities of the body (such as pulse, heartbeat and respiration, etc.), the first shell and the second shell in the deformed part are The contact area of the layer with respect to the body changes. According to the principle of triboelectric charging, the first shell layer which is positively charged by friction and the second shell layer which is negatively charged by friction are respectively charged with the same amount and opposite polarity. The formed potential difference is derived through the conductive yarn, thereby realizing the conversion of mechanical signals into electrical signals, thereby completing the monitoring of physiological signals of the body. The frequency and amplitude of the derived output signal are also different according to the different monitoring parts.

Based on the principle of triboelectric effect, the invention uses conductive yarn as the conductive core layer, and uses polyamide 66 and polyvinylidene fluoride trifluoroethylene with opposite triboelectric properties as the first shell layer and the second shell layer, respectively. The first core-spun yarn and the second core-spun yarn are woven, and the first core-spun yarn and the second core-spun yarn are woven as warp and weft respectively to form a flexible self-powered sensing fabric, that is, flexible Compared with the "sandwich"-like multi-layer structure of the flexible self-powered sensor prepared by the traditional technology, the flexible self-powered sensor provided by the present invention has better flexibility (ie bending, folding and twisting), comfort, Breathability and shape adaptability.

The present invention also provides a preparation method of the above-mentioned flexible self-powered sensor, comprising the following steps:

In step S11, polyamide 66 is dissolved in the first solvent to obtain a polyamide 66 polymer solution.

In one embodiment, the first solvent may be hexafluoroisopropanol (HFIP).

Step S12, referring to FIG. 1, the polyamide 66 polymer solution is formed into polyamide 66 nanofibers by using the electrospinning core-spun yarn device 100, and the polyamide 66 nanofibers are wrapped on the surface of the conductive core layer , so as to form the first shell layer on the surface of the conductive core layer, so as to obtain the first core-spun yarn.

That is, the first core-spun yarn is prepared by the method of electrospinning. Specifically, the specific preparation method of the first core-spun yarn includes the following steps:

In the first step, the polyamide 66 polymer solution is loaded into the first syringe 10 and the second syringe 11, and the first DC high voltage power supply 20 and the second DC high voltage power supply 21 respectively apply the first syringe 10 to the first syringe 10. A metal needle 101 and the second metal needle 111 of the second syringe 11 apply a first voltage and a second voltage, and simultaneously push the first syringe 10 and the second infusion pump 30 through the first infusion pump 30 and the second infusion pump 31 respectively. The second syringe 11 is used so that the polyamide 66 polymer solution in the first syringe 10 and the second syringe 11 is spun out in the form of polyamide 66 nanofibers.

In the second step, the spinning feeder 40 is rotated, so that the conductive core layer (such as conductive silver fibers) wound on the spinning feeder 40 passes through the hollow metal round target 50 and the hollow metal collecting tip 60, and The metal round target 50 is fixed with the hollow metal rod 51, and then the metal rod 51 is driven by the first motor 52 to drive the metal round target 50 to rotate, so as to realize the connection between the metal round target 50 and the metal round target 50. Wrapping, bundling and twisting of the conductive core layer by the tapered polyamide 66 nanofibers between the metal collecting tips 60, the spinning collector 71 is rotated by the second motor 70, so that the spinning collector 71 is rotated. The first core spun yarn is wound on the spinning collector 71 .

In one embodiment, the first voltage may be 10-13 kV. In one embodiment, the second voltage may also be 10-13kV. In one embodiment, the first voltage may be a positive voltage or a negative voltage. Wherein, when the first voltage is a positive voltage, the second voltage is a negative voltage; when the first voltage is a negative voltage, the second voltage is a positive voltage. That is, the electrical properties of the first voltage and the second voltage are opposite.

In one embodiment, the flow rate of the polyamide 66 polymer solution in the first metal needle 101 may be 2-3 ml/h. In one embodiment, the flow rate of the polyamide 66 polymer solution in the second metal needle 111 may also be 2-3 ml/h.

In one embodiment, the rotational speed of the metal round target 50 may be 80-100 rpm. In one embodiment, the diameter of the metal round target 50 may be 4 cm. In one embodiment, the distance between the metal round target 50 and the metal collecting tip 60 may be 8 cm.

In one embodiment, the rotational speed of the spinning collector 71 may be 10 rpm.

In one embodiment, the distance between the first metal needle 101 and the second metal needle 111 may be 8-10 cm.

It should be noted that the thickness of the first shell layer can be determined according to the parameters in the electrospinning process (such as the rotational speed of the spinning collector 71 , the distance between the first metal needle 101 and the second metal needle 111 , etc. distance, etc.) to adjust.

In step S13, polyvinylidene fluoride trifluoroethylene is dissolved in the second solvent to obtain a polyvinylidene fluoride trifluoroethylene polymer solution.

In one embodiment, the second solvent may be a mixture of N,N-dimethylformamide and acetone. In one embodiment, in the second solvent, the mass ratio of N,N-dimethylformamide to acetone may be 7:3.

Step S14, please refer to FIG. 1 again, the electrospinning core-spun yarn device 100 is used to form the polyvinylidene fluoride trifluoroethylene polymer solution into polyvinylidene fluoride trifluoroethylene nanofibers, and the polyvinylidene fluoride trifluoroethylene nanofibers are formed. The vinylidene fluoride trifluoroethylene nanofibers are wrapped on the surface of the other conductive core layer to form the second shell layer on the surface of the conductive core layer, thereby obtaining the second core-spun yarn.

That is, the method for preparing the second core-spun yarn by electrospinning is substantially the same as the method for preparing the first core-spun yarn. Specifically, the specific preparation method of the second core-spun yarn includes the following steps:

In the first step, the polyvinylidene fluoride trifluoroethylene polymer solution is loaded into the first syringe 10 and the second syringe 11, and the first DC high voltage power supply 20 and the second DC high voltage power supply 21 respectively apply The first metal needle 101 of a syringe 10 and the second metal needle 111 of the second syringe 11 apply a first voltage and a second voltage, and simultaneously push the first infusion pump 30 and the second infusion pump 31 respectively. A syringe 10 and the second syringe 11, so that the polyvinylidene fluoride trifluoroethylene polymer solution in the first syringe 10 and the second syringe 11 is made of polyvinylidene fluoride trifluoroethylene The form of nanofibers is spun out.

In the second step, the spinning feeder 40 is rotated, so that the conductive core layer (such as conductive silver fibers) wound on the spinning feeder 40 passes through the hollow metal round target 50 and the hollow metal collecting tip 60, and The metal round target 50 is fixed with the hollow metal rod 51, and then the metal rod 51 is driven by the first motor 52 to drive the metal round target 50 to rotate, so as to realize the connection between the metal round target 50 and the metal round target 50. The conductive core layer is wrapped, bundled and twisted by the tapered polyvinylidene fluoride trifluoroethylene nanofibers between the metal collecting tips 60, and the spinning collector 71 is rotated by the second motor 70 to spin the conductive core layer. The second core-spun yarn obtained after spinning is wound on the spinning collector 71 .

Wherein, the setting parameters of the electrospinning core-spun yarn device 100 when preparing the second core-spun yarn may refer to the setting parameters of the electrospinning core-spun yarn device 100 when preparing the first core-spun yarn , and will not be described in detail here.

Step S15, knitting the first core-spun yarn and the second core-spun yarn as warp yarns and weft yarns, respectively, to obtain the flexible self-powered sensor.

The present invention realizes the direct construction of the compressible nano-scale first microstructure of the first shell layer in the first core-spun yarn by means of electrospinning, and realizes the direct construction of the first microstructure in the second core-spun yarn of the second core-spun yarn. Direct construction of two-shell compressible nanoscale second microstructures. That is, the first shell layer is composed of a plurality of nano-level polyamide 66 filaments interlaced with each other, and the second shell is composed of a plurality of nano-level polyvinylidene fluoride trifluoroethylene filaments interlaced with each other, Due to the first microstructure and the second microstructure, the flexible self-powered sensor has high sensitivity.

In addition, the electrospinning core-spun yarn device 100 can realize the preparation of the first core-spun yarn and the second core-spun yarn with a core-shell structure that are light, thin and soft, have high coaxiality, and have no charge leakage, and The preparation method is simple, and the continuous, controllable and large-scale preparation of the flexible self-powered sensor can be realized.

The present invention will be further described below through specific examples.

Example 1

In the first step, PA66 (molecular weight 20000) was dissolved in hexafluoroisopropanol (HFIP), sealed and stirred at room temperature for 6 hours to prepare a PA66 polymer solution with a mass fraction of 12%.

In the second step, the PA66 polymer solution is loaded into the first syringe and the second syringe, and the first metal needle of the first syringe and the first metal needle of the first syringe and the second The second metal needles of the two syringes apply the first voltage and the second voltage, and simultaneously push the first syringe and the second syringe through the first infusion pump and the second infusion pump, respectively, so that the first syringe and the second The PA66 polymer solution in the second syringe was spun out in the form of PA66 nanofibers.

The third step is to rotate the spinning feeder, so that the conductive silver fibers wound on the spinning feeder pass through the hollow metal target and the hollow metal collecting tip, and make the metal target and the hollow metal The rod is fixed, and then the metal rod is driven by the first motor to drive the metal round target to rotate, so as to realize the pairing of the tapered PA66 nanofibers attached between the metal round target and the metal collecting tip. For wrapping, bundling and twisting of the conductive silver fibers, the spinning collector is rotated by the second motor to wind the first core-spun yarn obtained after spinning on the spinning collector.

The fourth step is to dissolve PVDF-TrFE (molecular weight of 200000) in a mixture of N,N dimethylformamide (DMF) and acetone with a mass ratio of 7:3, and seal and stir at room temperature for 6 hours to prepare the mass. Fraction 10% PVDF-TrFE polymer solution.

In the fifth step, the PVDF-TrFE polymer solution is loaded into the first syringe and the second syringe, and the first metal needle of the first syringe and the first metal needle of the first syringe are respectively charged by the first DC high voltage power supply and the second DC high voltage power supply. The second metal needle of the second syringe applies the first voltage and the second voltage, and simultaneously pushes the first syringe and the second syringe through the first infusion pump and the second infusion pump, respectively, so that the first The PVDF-TrFE polymer solution in the syringe and the second syringe was spun out in the form of PVDF-TrFE nanofibers.

The sixth step, rotating the spinning feeder, so that the conductive silver fibers wound on the spinning feeder pass through the hollow metal circular target and the hollow metal collecting tip, and make the metal circular target and the hollow metal The rod is fixed, and then the metal rod is driven by the first motor to drive the metal round target to rotate, so as to realize the tapered PVDF-TrFE nanofibers attached between the metal round target and the metal collecting tip For wrapping, bundling and twisting of the conductive silver fibers, the spinning collector is rotated by a second motor to wind the second core-spun yarn obtained after spinning on the spinning collector.

In the seventh step, the first core-spun yarn and the second core-spun yarn are woven into a flexible self-powered sensor fabric as warp yarns and weft yarns, respectively, to obtain a flexible self-powered sensor.

The surface topography test and size measurement were performed on the first core-spun yarn and the second core-spun yarn prepared in Example 1, respectively, and the flexible self-powered sensor (ie, the flexible self-powered sensing fabric) prepared in Example 1. Sensitivity test.

Among them, the method of sensitivity test is to use a universal testing machine to apply a certain pressure to the flexible self-powered sensor prepared in Example 1, use an oscilloscope to test the open-circuit voltage value of its response, and draw a sensitivity curve.

Referring to FIG. 2, it can be seen that the first core-spun yarn prepared in Example 1 includes a conductive core layer (ie, conductive silver fibers) and a first shell layer made of polyamide 66. The conductive silver fibers and the first shell layer are The shell layer forms a core-shell structure, and the conductive silver fibers and the first shell layer have high coaxiality. It can also be seen from FIG. 2 that the first shell layer is uniformly wrapped on the outer surface of the conductive silver fibers. The diameter of the conductive core layer is about 200 μm, the thickness of the first shell layer is about 150 μm, and the diameter of the first core-spun yarn is 400-500 μm.

Referring to FIG. 3 , it can be seen that the first shell layer is composed of a plurality of nano-scale polyamide 66 filaments interlaced with each other, that is, the first shell layer has a compressible nano-scale first microstructure. Wherein, the diameter of the polyamide 66 filament is about 500-900 nm.

Referring to FIG. 4, it can be seen that the second core-spun yarn prepared in Example 1 includes a conductive core layer (ie, conductive silver fibers) and a second shell layer made of polyvinylidene fluoride trifluoroethylene, and the conductive silver fibers A core-shell structure is formed with the second shell layer, and the conductive silver fibers and the second shell layer have high coaxiality. It can also be seen from FIG. 4 that the second shell layer is evenly wrapped on the outer surface of the conductive silver fibers. The diameter of the conductive core layer is about 200 μm, the thickness of the second shell layer is about 150 μm, and the diameter of the second core-spun yarn is 400-500 μm.

Referring to FIG. 5, it can be seen that the second shell layer is composed of a plurality of nano-level polyvinylidene fluoride trifluoroethylene filaments interlaced with each other, that is, the second shell layer has a compressible nano-level second shell layer. microstructure. Wherein, the diameter of the polyvinylidene fluoride trifluoroethylene filament is about 500-900 nm.

Referring to FIG. 6 , it can be seen that the sensitivity of the flexible self-powered sensor prepared in Example 1 is as high as 5.59V/kPa. This shows that the flexible self-powered sensor prepared in Example 1 has higher sensitivity.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can also be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. A flexible self-powered sensor is characterized in that the sensor is formed by weaving a first core-spun yarn and a second core-spun yarn as warp yarn and weft yarn respectively, the first core-spun yarn comprises a conductive core layer and a first shell layer for coating the conductive core layer, the conductive core layer and the first shell layer are coaxially arranged, the conductive core layer is made of conductive yarn, the first shell layer is made of polyamide 66 and is positively charged after being rubbed, the first shell layer has a compressible nanoscale first microstructure, the second core-spun yarn includes the conductive core layer and a second shell layer covering the conductive core layer, the conductive core layer and the second shell layer are coaxially arranged, the material of the second shell layer is polyvinylidene fluoride trifluoroethylene, the second shell layer is negatively charged after friction, and the second shell layer is provided with a compressible nano-scale second microstructure.

2. The flexible self-powered sensor of claim 1 wherein the first shell layer is comprised of a plurality of nano-scale filaments of polyamide 66 interlaced with each other and the second shell layer is comprised of a plurality of nano-scale filaments of polyvinylidene fluoride trifluoroethylene interlaced with each other.

3. The flexible self-powered sensor of claim 2, wherein the polyamide 66 filaments have a diameter of 500-.

4. The flexible self-powered sensor of claim 1, wherein the conductive yarn is at least one of conductive silver fibers, conductive copper fibers, and conductive gold fibers.

5. The flexible self-powered sensor of claim 1, wherein the diameter of the first core-spun yarn is 400-.

6. The flexible self-powered sensor of claim 1 wherein the sensitivity of the flexible self-powered sensor is greater than or equal to 5.59V/kPa.

7. A method of making a flexible self-powered sensor as claimed in any one of claims 1 to 6, comprising the steps of:

dissolving polyamide 66 in a first solvent to obtain a polyamide 66 polymer solution;

forming polyamide 66 nano fibers from the polyamide 66 polymer solution by using an electrostatic spinning core-spun yarn device, and wrapping the polyamide 66 nano fibers on the surface of the conductive core layer to form the first shell layer on the surface of the conductive core layer, so as to obtain the first core-spun yarn;

dissolving polyvinylidene fluoride trifluoroethylene in a second solvent to obtain a polyvinylidene fluoride trifluoroethylene polymer solution;

forming polyvinylidene fluoride trifluoroethylene nano-fibers by using the electrostatic spinning core-spun yarn device and wrapping the polyvinylidene fluoride trifluoroethylene nano-fibers on the surface of another conductive core layer so as to form a second shell layer on the surface of the conductive core layer, thereby obtaining a second core-spun yarn; and

weaving the first core-spun yarn and the second core-spun yarn as warp yarn and weft yarn respectively to obtain the flexible self-powered sensor.

8. The flexible self-powered sensor of claim 7 wherein the first solvent is hexafluoroisopropanol and/or the second polymer solution is a mixture of N, N-dimethylformamide and acetone.

9. The flexible self-powered sensor of claim 7, wherein the forming the polyamide 66 nanofiber from the polyamide 66 polymer solution using the electrospun core spun yarn device specifically comprises the steps of:

loading the polyamide 66 polymer solution into a first syringe and a second syringe, respectively applying a first voltage and a second voltage to a first metal needle of the first syringe and a second metal needle of the second syringe by a first direct-current high-voltage power supply and a second direct-current high-voltage power supply, and simultaneously pushing the first syringe and the second syringe by a first infusion pump and a second infusion pump respectively, so that the polyamide 66 polymer solution in the first syringe and the second syringe is spun in the form of polyamide 66 nanofibers;

and/or the step of forming the polyvinylidene fluoride trifluoroethylene nanofiber from the polyvinylidene fluoride trifluoroethylene polymer solution by using the electrostatic spinning core-spun yarn device specifically comprises the following steps:

loading the polyvinylidene fluoride trifluoroethylene polymer solution in a first syringe and a second syringe, respectively applying a first voltage and a second voltage to a first metal needle of the first syringe and a second metal needle of the second syringe by a first direct-current high-voltage power supply and a second direct-current high-voltage power supply, and simultaneously respectively pushing the first syringe and the second syringe by a first infusion pump and a second infusion pump, so that the polyvinylidene fluoride trifluoroethylene polymer solution in the first syringe and the second syringe is spun in the form of polyvinylidene fluoride trifluoroethylene nanofibers.

10. The flexible self-powered sensor of claim 9, wherein the first voltage is 10-13kV, the second voltage is 10-13kV, the flow rate of the polyamide 66 polymer solution and/or the polyvinylidene fluoride trifluoroethylene polymer solution in the first metal needle is 2-3ml/h, and the flow rate of the polyamide 66 polymer solution and/or the polyvinylidene fluoride trifluoroethylene polymer solution in the second metal needle is 2-3 ml/h.

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