Preparation method and application of visual flexible tension sensor

Abstract

The invention relates to the technical field of flexible tension sensors, in particular to a preparation method and application of a visual flexible tension sensor, and the preparation method comprises the following steps: preparation of conductive cashmere yarn, preparation of visual cashmere yarn and assembly of the visual flexible tension sensor. The one-dimensional silver nanowires are in lap joint with the two-dimensional lamellas, the one-dimensional silver nanowires and the two-dimensional lamellas jointly construct the three-dimensional conductive network with the synergistic effect, compared with a traditional conductive coating, the gap between one-dimensional conductive networks is filled, resistance is reduced, the electrical performance is improved, falling and sliding of the two-dimensional conductive network are avoided, stability is improved, and the conductive coating has the advantages of being high in practicability and the like. Secondly, the tensile strain degree is displayed through color change of the surface of the flexible tension sensor, the tensile force borne by the flexible tension sensor is visually expressed through color change, and the flexible tension sensor can be applied to mechanical detection such as portable detection which does not need quantification and only needs qualitative comparison of the mechanical change degree.

Description

Technical Field

[0001] The invention relates to the technical field of flexible tension sensors, and in particular to a preparation method and application of a visualized flexible tension sensor. Background Art

[0002] In recent years, with the continuous progress and development of electronic technology, people have put forward new application requirements for various electronic devices in daily life. The wide application of flexible wearable electronic devices in advanced fields such as wearable devices, electronic skin, human motion monitoring and intelligent medical sensing has attracted much attention. Among them, flexible tensile sensors that can monitor signals play an important role in the field of intelligent wearable electronic devices and are widely used in human motion monitoring, health monitoring, human-computer interaction, flexible robots, wearable electronic devices and electronic skin.

[0003] However, according to the continuous preparation method of electrochromic fiber disclosed in the invention patent with announcement number CN108873539B and the electrically driven thermochromic fiber and its preparation method disclosed in the invention patent with announcement number CN115710825B, it is found that most electrically driven color-changing fibers can only achieve color response in two states: power-on and power-off. They cannot perform real-time color response according to the strain applied to the fibers. The color change of the fibers can only be regulated by voltage, resulting in poor practicality. Therefore, the preparation method and application of visual flexible tensile sensors are urgently needed to improve the above problems. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method of overlapping one-dimensional silver nanowires with two-dimensional sheets to jointly construct a three-dimensional conductive network with a synergistic effect. Compared with traditional conductive coatings, it not only fills the gaps between the one-dimensional conductive network, reduces the resistance and improves the electrical performance, but also avoids the shedding and slippage of the two-dimensional conductive network and improves the stability. Secondly, the degree of tensile strain is displayed by the color change of its surface, and the magnitude of the tension exerted on the flexible tensile sensor is intuitively expressed by the change of color. Furthermore, there is a preparation method and application of a visualized flexible tensile sensor that can be applied to mechanical detection such as portable detection that does not require quantitative comparison but only qualitative comparison of the degree of mechanical change.

[0005] The method for preparing the visualized flexible tension sensor of the present invention comprises the following steps: Preparation of conductive cashmere yarn, preparation of visualized cashmere yarn and assembly of visualized flexible tensile sensor.

[0006] Preferably, the preparation of the conductive cashmere yarn comprises the following steps: A1, ultrasonically cleaning the cashmere yarn in deionized water to remove impurities, and performing surface modification treatment on the yarn after drying; A2, immersing the treated cashmere yarn into the PDA solution for 30 minutes, taking it out and drying it to obtain the PDA cashmere composite yarn; A3. The PDA cashmere composite yarn is immersed in the Mxene solution and the silver nanowire solution in turn, and then taken out and dried to obtain the conductive cashmere yarn.

[0007] Preferably, the surface modification treatment includes ultraviolet irradiation, electron beam irradiation, infrared irradiation and enzyme activation treatment.

[0008] Preferably, the preparation of the visualized cashmere yarn comprises: The conductive cashmere yarn is immersed in an electrochromic solution, taken out and dried, immersed in a resin again for sealing, and dried to obtain a visualized cashmere yarn.

[0009] Preferably, the preparation of the electrochromic solution comprises the following steps: B1, mixing deionized water and methanol in a volume ratio of 9:1, and the obtained mixed solution is used as a base solvent; B2. Add 0.8 M pyrrole monomer, 0.8 M FeCl3•6H2O oxidant and 0.5 M sodium 2,6-naphthalene disulfonate dopant into the base solution and mix to form a PPy growth solution, i.e., an electrochromic solution.

[0010] Preferably, the assembly of the visual flexible tension sensor comprises the following steps: C1. Cut the prepared visualized cashmere yarn into 50 mm length; C2, cutting the conductive fabric into a size of 1 mm × 1 mm, wherein the conductive fabric includes nickel-plated fabric and copper-plated fabric; C3. Conductive silver glue is used to bond the two ends of the visualized cashmere yarn to the conductive fabric, which is then fixed and dried as electrode connection materials to prepare a visualized flexible tensile sensor.

[0011] The application of the visualized flexible tension sensor of the present invention can be applied in the fields of medical treatment, sports and health protection to detect various human body movements.

[0012] Preferably, the preparation method of the two-dimensional nanosheets includes a fluorine-containing etching method, a fluorine-free etching method, an organic solvent-assisted intercalation collection method, and the like; Preferably, the preparation method of silver nanowires includes chemical reduction method, electrochemical method, microwave method and other methods; Preferably, the electrochromic material includes various electrochromic materials such as PANI, PPy, PEDOT and the like; Compared with the prior art, the present invention has the following beneficial effects: 1. By overlapping one-dimensional silver nanowires with two-dimensional sheets, the two together construct a three-dimensional conductive network with a synergistic effect. Compared with traditional conductive coatings, it not only fills the gaps between the one-dimensional conductive network, reduces resistance and improves electrical properties, but also avoids the shedding and slippage of the two-dimensional conductive network and improves stability; 2. The degree of tensile strain is displayed by the color change on its surface. The magnitude of the tensile force on the flexible tensile sensor is intuitively expressed by the change of color; 3. It can be applied to mechanical testing such as portable testing that does not require quantitative analysis but only requires qualitative comparison of the degree of mechanical change. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the preparation steps of the present invention; Figure 2 It is a schematic diagram of the preparation method of the present invention. DETAILED DESCRIPTION

[0014] In order to facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

[0015] Example like Figure 1 and Figure 2 As shown, the preparation method and application of the visualized flexible tensile sensor include the following steps: Preparation of conductive cashmere yarn, preparation of visualized cashmere yarn and assembly of visualized flexible tensile sensor; The preparation of the conductive cashmere yarn comprises the following steps: S1. Preparation of MXene nanosheets: S1-1, select Ti3AlC2 as raw material, lithium fluoride and hydrochloric acid as etchants, put the Ti3AlC2 material into a mixed solution containing lithium fluoride and hydrochloric acid, the combination of lithium fluoride and hydrochloric acid can produce etching effect, at an appropriate temperature, magnetic stirring is performed to make the Ti3AlC2 material and the etchant fully react, after a period of reaction, remove the unreacted Ti3AlC2 material and the generated fluoride and other impurities by centrifugation and water washing, and obtain a precipitate containing MXene; S1-2, re-dispersing the obtained MXene precipitate in water to form a MXene nanosheet suspension, exfoliating the MXene nanosheet suspension by ultrasonic treatment to obtain a single-layer or few-layer MXene nanosheet, and removing impurities and incompletely exfoliated MXene multilayer structures in the suspension by centrifugation, water washing and other steps to obtain a pure MXene nanosheet suspension; S1-3, freeze-drying or other drying treatment of the pure MXene nanosheet suspension to remove moisture to obtain MXene nanosheet powder, collecting and storing the MXene nanosheet powder, and using the prepared MXene nanosheets for subsequent preparation of conductive cashmere yarn; S2. Preparation of PDA solution: S2-1, dissolving dopamine monomer in deionized water to form a dopamine solution, and adjusting the pH value of the solution to a weak alkaline state using an alkaline substance such as sodium hydroxide; S2-2, expose the dopamine solution to air, so that the dopamine monomers in it self-polymerize to form PDA through oxidation reaction. In this process, oxygen in the air acts as an oxidant to participate in the reaction. S2-3, washing the PDA solution obtained by polymerization by centrifugation, filtration or dialysis to remove residual alkaline agent and other impurities, and using the PDA solution prepared above for subsequent preparation of conductive cashmere yarn S3, preparation of conductive cashmere yarn; S3-1, ultrasonically cleaning the cashmere yarn in deionized water to remove impurities, and after drying, using a low-temperature plasma surface treatment machine to perform surface modification treatment on the cashmere yarn to increase the surface roughness, which is conducive to the bonding of conductive particles; S3-2, immersing the treated cashmere yarn in the PDA solution for 30 minutes, taking it out and drying it to obtain the PDA cashmere composite yarn; S3-3, dipping the PDA cashmere composite yarn into the Mxene solution and the silver nanowire solution in turn, taking out and drying to obtain the conductive cashmere yarn; S4. Preparation of PPy electrochromic solution: A mixed solution of deionized water and methanol was used as a solvent, and pyrrole monomer, FeCl3·6H2O oxidant, and sodium 2,6-naphthalene disulfonate dopant were added to form a PPy electrochromic solution; S5. Preparation of visualized cashmere yarn: The conductive cashmere yarn was immersed in the electrochromic solution and reacted at 5°C for 1 hour. After the reaction, it was taken out and washed and dried with deionized water and ethanol, immersed in the resin again for sealing, and dried to obtain the visualized cashmere yarn. S6. Visualized flexible tension sensor assembly: S6-1, cutting the prepared visualized cashmere yarn into 50 mm length; S6-2, cutting the conductive fabric into a size of 1 mm×1 mm, wherein the conductive fabric includes nickel-plated fabric and copper-plated fabric; S6-3. Conductive silver glue is used to bond the two ends of the visualized cashmere yarn to the conductive fabric, which is then fixed and dried as electrode connection materials to prepare a visualized flexible tension sensor.

[0016] Visual flexible tension sensor can be used in the fields of medicine, sports and health protection to detect various human movements.

[0017] The sensing color change mechanism of the visualized flexible tension sensor in the present invention is based on the excellent conductivity of the conductive layer in the yarn and the color change performance of the outer electrochromic material. When the corresponding current or voltage is applied for a period of time, the conductive layer generates Joule heat. When the temperature reaches the critical temperature of the color-changing material, the corresponding color change occurs on the surface of the yarn. When the yarn tension sensor is in a stretched state, the resistance value of the yarn increases, resulting in a decrease in the Joule heat generated under the same voltage, and the color change degree of the color-changing material is weakened. When the external voltage is constant, the higher the strain degree of the visualized flexible tension sensor, the lower the degree of its surface color change. The prepared visual flexible tensile sensor has a simple processing technology, low product cost, good tensile properties and high sensitivity. It can be used to detect various human movements, such as bending of legs and folding of fingers, etc., and has great application potential in the fields of medical treatment, sports, health protection, etc.

[0018] Technical personnel in this industry only need to install and operate it according to the accompanying instruction manual, without the need for technical personnel in this field to make creative efforts.

[0019] The one-dimensional silver nanowire and the two-dimensional nanosheet are both nanomaterials, and the one-dimensional silver nanowire has a length greater than 100 nanometers and a radius less than 100 nanometers, the two-dimensional nanosheet has a length and a width greater than 100 nanometers and a thickness less than 100 nanometers. When the two materials are mixed together, they will form a three-dimensional structure by static electricity, and it is a network structure that is interlaced with each other.

[0020] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a visual flexible tensile sensor, characterized in that: The following steps are involved: Preparation of conductive cashmere yarn, preparation of visualized cashmere yarn and assembly of visualized flexible tensile sensor.

2. The method for preparing a visual flexible tension sensor according to claim 1, characterized in that: The preparation of the conductive cashmere yarn comprises the following steps: A1, ultrasonically cleaning the cashmere yarn in deionized water to remove impurities, and performing surface modification treatment on the yarn after drying; A2, immersing the treated cashmere yarn into the PDA solution for 30 minutes, taking it out and drying it to obtain the PDA cashmere composite yarn; A3. The PDA cashmere composite yarn is immersed in the Mxene solution and the silver nanowire solution in turn, and then taken out and dried to obtain the conductive cashmere yarn.

3. The method for preparing the visual flexible tension sensor according to claim 2, characterized in that: The surface modification treatment includes ultraviolet irradiation, electron beam irradiation, infrared irradiation and enzyme activation treatment.

4. The method for preparing a visual flexible tension sensor according to claim 2, characterized in that: The preparation of the visualized cashmere yarn comprises: The conductive cashmere yarn is immersed in an electrochromic solution, taken out and dried, immersed in a resin again for sealing, and dried to obtain a visualized cashmere yarn.

5. The method for preparing the visual flexible tension sensor according to claim 4, characterized in that: The preparation of the electrochromic solution comprises the following steps: B1, mixing deionized water and methanol in a volume ratio of 9:1, and the obtained mixed solution is used as a base solvent; B2. Add 0.8 M pyrrole monomer, 0.8 M FeCl3•6H2O oxidant and 0.5 M sodium 2,6-naphthalene disulfonate dopant into the base solution and mix to form a PPy growth solution, i.e., an electrochromic solution.

6. The method for preparing a visual flexible tension sensor according to claim 4, characterized in that: The assembly of the visual flexible tension sensor comprises the following steps: C1. Cut the prepared visualized cashmere yarn into 50 mm length; C2, cutting the conductive fabric into a size of 1 mm × 1 mm, wherein the conductive fabric includes nickel-plated fabric and copper-plated fabric; C3. Conductive silver glue is used to bond the two ends of the visualized cashmere yarn to the conductive fabric, which is then fixed and dried as electrode connection materials to prepare a visualized flexible tensile sensor.

7. The application of the visualized flexible tension sensor is characterized in that: The visualized flexible tension sensor prepared according to claim 6 can be applied in the fields of medicine, sports and health protection to detect various human body movements.

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