Composite nano-silver conductive layer elastic fiber membrane as well as preparation method and application thereof

Abstract

The invention relates to the technical field of fiber membrane preparation, in particular to a composite nano-silver conductive layer elastic fiber membrane and a preparation method and application thereof. The preparation method comprises the steps that firstly, a thermoplastic polyurethane and styrene-butadiene-styrene block copolymer composite flexible elastic basement membrane is prepared through electrostatic spinning; a composite fiber membrane with a primary conductive network is formed by blade coating silver nanowires on a flexible elastic substrate membrane, and then a silver nanoparticle layer is formed on the surface of the composite fiber membrane through magnetron sputtering, so that the elastic fiber membrane with the composite nano-silver conductive layer is prepared. The electrostatic spinning fiber membrane substrate which is simple, easy to obtain, low in price and excellent in mechanical and physical and chemical properties serves as a good supporting material for product development. The conductive fiber membrane prepared by the electrostatic spinning method has good tensile strength and rebound resilience, and is suitable for being applied to various fields including intelligent textiles, motion monitoring, physiological signal monitoring, structural health detection and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber membrane preparation, and particularly relates to a composite silver nanowire conductive layer elastic fiber membrane, a preparation method thereof, and an application thereof. Background Art

[0002] With the progress of the times, flexible electronic devices have developed rapidly and have important application values in fields such as human-computer interaction and health monitoring, becoming one of the current research hotspots. Due to its characteristics such as breathability, durability, sustainability, flexibility, and light weight, elastic conductive fiber membranes are widely used in wearable electronic products, artificial electronic skins, biomedical components, etc., and can play a great role in the production of flexible electronic devices, especially intelligent wearable devices.

[0003] Thermoplastic polyurethane (TPU) is a widely used polymer material with characteristics such as high density, high strength, high toughness, and high wear resistance. It is insoluble in water but can be dissolved in organic solvents such as styrene and xylene, and its products can be applied in fields such as textiles, construction, aviation, ships, transportation, medicine, and electronics.

[0004] Styrene-butadiene-styrene block copolymer (SBS) is a triblock copolymer with styrene and butadiene as monomers, having the characteristics of both plastics and rubbers, and is known as the "third-generation synthetic rubber".

[0005] Nano silver metal (Ag) is an excellent material for the preparation of electronic devices, having excellent electrical conductivity, thermal conductivity, and optical properties. In addition, it also has important applications in fields such as antibacterial and catalytic. Among them, silver nanowires (AgNWs) are a kind of conductive filler with a high aspect ratio.

[0006] Electrospinning technology is a commonly used method for preparing nanofibers and submicron fibers. Its main principle is that conductive polymer droplets are subjected to forces such as electrostatic force and gravity in a high-voltage electrostatic field, continuously accelerating, stretching, and decreasing in diameter, while accompanied by the volatilization of the solvent, and finally solidifying into nanofibers or submicron fibers to be received by the receiving device. After peeling, a fiber membrane with regular shape can be obtained. The fiber diameter distribution prepared by electrospinning is generally between a few nanometers and a few micrometers, and the formed membrane material has a three-dimensional spatial structure. The membrane material not only has the advantages of small nanoparticle size and large specific surface area, but also has characteristics such as good mechanical stability, small pore size and high porosity of the fiber membrane, and good fiber continuity.

[0007] Existing fiber membranes do not have good tensile strength and resilience performance and cannot show good cyclic stability in cyclic tensile tests. Therefore, how to prepare an elastic conductive fiber membrane with certain flexibility, excellent mechanical properties, and excellent electrical properties is an urgent technical problem to be solved. Summary of the Invention

[0008] In view of this, the object of the present invention is to provide a composite silver nanowire conductive layer elastic fiber membrane, a preparation method and an application thereof, so as to solve the problems that the fiber membrane does not have good tensile strength and resilience performance and cannot exhibit good cyclic stability in the cyclic tensile test.

[0009] Based on the above object, the present invention provides a preparation method of a composite silver nanowire conductive layer elastic fiber membrane. The preparation method is to first prepare a thermoplastic polyurethane and styrene-butadiene-styrene block copolymer composite flexible elastic base membrane by electrospinning, scrape silver nanowires on the flexible elastic base membrane to form a composite fiber membrane with a preliminary conductive network, and then magnetron sputter a layer of silver nanoparticles on the surface of the composite fiber membrane, thereby preparing a composite silver nanowire conductive layer elastic fiber membrane.

[0010] Preferably, the preparation method includes the following steps:

[0011] Step 1: Dissolve thermoplastic polyurethane and styrene-butadiene-styrene block copolymer in a mixed solvent to obtain an electrospinning solution with a mass fraction of 10-20%;

[0012] Step 2: Use the electrospinning solution in Step 1 to prepare a composite flexible elastic base membrane by electrospinning technology, that is, a TPU / SBS composite fiber membrane;

[0013] Step 3: After drying the TPU / SBS composite fiber membrane, scrape a 0.5-2 mg / ml silver nanowire dispersion on the surface of the TPU / SBS composite fiber membrane, and obtain a TPU / SBS / AgNWs composite fiber membrane after drying;

[0014] Step 4: Magnetron sputter a layer of silver nanoparticles on the surface of the TPU / SBS / AgNWs composite fiber membrane to prepare a composite silver nanowire conductive layer elastic fiber membrane.

[0015] The mass ratio of the thermoplastic polyurethane to the styrene-butadiene-styrene block copolymer in Step 1 is 1-9:1-1.5.

[0016] The mixed solvent in Step 1 is a mixed solvent of N,N-dimethylformamide and tetrahydrofuran, and the mass ratio of N,N-dimethylformamide to tetrahydrofuran is 1-1.6:1-1.2.

[0017] The process parameters of the electrospinning are: the distance between the spinneret and the receiving plate is 10-20 cm, the flow rate of the spinning solution is 0.2-1.2 ml / h, the applied voltage is 10-22 kV, and it is received by aluminum foil for 20 h.

[0018] In Step 3, the drying temperature is 40 - 50°C, and the silver nanowire dispersion of 0.5 - 2 mg / ml is prepared in absolute ethanol.

[0019] In the magnetron sputtering, set the flowmeter parameters: the flow rate is 10 - 35 ml / h, argon is passed, and the air pressure in the chamber is adjusted to 0.5 - 3.0 Pa; the power is set to 60 - 100 w, and the time is set to 600 - 1800 s.

[0020] The present invention also provides a composite nano - silver conductive layer elastic fiber membrane prepared by the above - mentioned preparation method.

[0021] The present invention also provides the application of the composite nano - silver conductive layer elastic fiber membrane of the present invention in textiles, motion monitoring, physiological signal monitoring, and structural health monitoring.

[0022] The present invention also provides the application of the composite nano - silver conductive layer elastic fiber membrane in flexible electronics, electronic skin, and soft robots.

[0023] The beneficial effects of the present invention:

[0024] 1. The present invention uses an electrospun fiber membrane substrate that is simple to obtain, inexpensive, and has excellent mechanical, physical, and chemical properties as a good supporting material for the development of this product. The conductive fiber membrane prepared by the electrospinning method has good tensile strength and resilience, and is suitable for applications in various fields including smart textiles, motion monitoring, physiological signal monitoring, and structural health detection.

[0025] 2. Through the simple and feasible doctor - blade method and magnetron sputtering method, two kinds of nano - silver metals as conductive fillers are stably loaded on the flexible substrate fiber membrane. The flexible carrier material prepared by this method has good mechanical properties, tensile properties, and the function of detecting electrical signal changes with controllable conductivity.

[0026] 3. In the cyclic tensile test, the conductive fiber membrane shows good cyclic stability, providing strong support for its application in the fields of flexible electronics, electronic skin, and soft robots. The composite fiber membrane based on nano - silver materials finally obtained by the present invention has the performance of being reusable and can be used for the development of subsequent flexible electronic devices and the preparation of sensor devices, etc. Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only those of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1This is a physical picture of the TPU / SBS / AgNWs / AgNps composite conductive fiber membrane obtained in Example 2 of the present invention;

[0029] Figure 2 This is an SEM picture of the TPU / SBS fiber membrane obtained in Example 2 of the present invention;

[0030] Figure 3 This is an SEM picture of the surface of the TPU / SBS / AgNWs / AgNPs composite conductive fiber membrane obtained in Example 2 of the present invention;

[0031] Figure 4 This is a cross-sectional SEM image of the TPU / SBS / AgNWs / AgNPs composite conductive fiber membrane obtained in Example 2 of the present invention;

[0032] Figure 5 This is a surface EDS map of the TPU / SBS / AgNWs / AgNPs composite conductive fiber membrane obtained in Example 2 of the present invention;

[0033] Figure 6 This is a cross-sectional EDS map of the TPU / SBS / AgNWs / AgNPs composite conductive fiber membrane obtained in Example 2 of the present invention;

[0034] Figure 7 This is a graph of the relative resistance (electrical signal) change of the composite conductive fiber membrane obtained in Example 2 of the present invention under partial strain stretching and cyclic stretching;

[0035] Figure 8 This is an XRD characterization graph of the TPU / SBS / AgNWs / AgNps composite conductive fiber membrane obtained in Example 2 of the present invention. Detailed implementation manners

[0036] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments.

[0037] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meanings understood by those with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects.

[0038] Example 1

[0039] 1. Weigh accurately 2.4 g of polyurethane (TPU) masterbatch and dissolve it in a mixed solvent of 8.8 g of N,N-dimethylformamide (DMF) and 8.8 g of tetrahydrofuran (THF). Stir with a magnetic stirrer at room temperature until the polyurethane is completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0040] 2. Use the spinning solution in Step 1 for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 15 cm, the flow rate of the spinning solution is 0.7 ml / h, the applied voltage is 15 kV, and receive for 20 h through aluminum foil to obtain a pure TPU fiber membrane.

[0041] 3. Place the composite fiber membrane in Step 2 in a vacuum drying oven at 45 °C. Take it out after drying and set it aside. Prepare a 1 mg / ml silver nanowire dispersion in absolute ethanol. Drop the solution on the surface of the fiber membrane and scrape it flat with a spatula to make the coating uniform. Then place it in a vacuum drying oven at 45 °C for drying to obtain a TPU / SBS / AgNWs composite fiber membrane.

[0042] 4. Prepare a target and install it under the shielding cover in the magnetron sputtering device, keeping a small gap between the shielding cover and the silver target to avoid short circuit. Cut the fiber membrane treated in Step 3 to an appropriate size and place it on the sample stage. Close the chamber and convert the inside of the chamber into a high vacuum according to the procedure. Open the gas valve, set the flowmeter parameters: the flow rate is 25 ml / h, pass argon gas, and adjust the air pressure in the chamber to 1 Pa. Open the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 60 w, set the time to 1200 s, and start the power supply. Wait for the magnetron sputtering process to end after observing the target glow. Completely turn off the magnetron sputtering device and open the inflation valve to balance the internal and external air pressures. Take out the silver-colored fiber membrane from the magnetron sputtering device, which is the prepared thermoplastic polyurethane / styrene-butadiene-styrene block copolymer conductive fiber membrane.

[0043] Example 2

[0044] 1. Weigh accurately 2.16 g of polyurethane (PU) masterbatch and 0.24 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, and dissolve them in a mixed solvent of 7.6 g of N,N-dimethylformamide (DMF) and 10 g of tetrahydrofuran (THF). Stir with a magnetic stirrer at room temperature until the polyurethane and the styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0045] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 17 cm, the flow rate of the spinning solution is 0.7 ml / h, the applied voltage is 18 kV, and receive for 20 h through aluminum foil to obtain the TPU / SBS composite fiber membrane.

[0046] III: Place the composite fiber membrane in Step II in a vacuum drying oven at 45 °C. Take it out after drying for later use. Prepare a 1.2 mg / ml silver nanowire dispersion solution in absolute ethanol. After dropping the solution on the surface of the fiber membrane, use a scraper to level it to make the coating uniform, and then place it in a vacuum drying oven at 45 °C for drying to obtain the TPU / SBS / AgNWs composite fiber membrane.

[0047] IV: Prepare a target, install it under the shielding cover in the magnetron sputtering device, and keep a small gap between the shielding cover and the silver target to avoid short circuit. Cut the fiber membrane treated in Step III to an appropriate size and place it on the sample stage. Close the chamber and convert the inside of the chamber into a high vacuum according to the process. Open the gas valve, set the flowmeter parameters: the flow rate is 20 ml / h, pass argon gas, and adjust the air pressure in the chamber to 2.5 Pa. Open the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 80 w, set the time to 1500 s, and start the power supply. Wait for the magnetron sputtering process to end after observing the target glow. Completely turn off the magnetron sputtering device and open the inflation valve to balance the internal and external air pressures. Take out the silver-colored fiber membrane from the magnetron sputtering device, which is the prepared thermoplastic polyurethane / styrene-butadiene-styrene block copolymer conductive fiber membrane.

[0048] Example 3

[0049] I: Accurately weigh 1.92 g of polyurethane (PU) masterbatch and 0.48 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in a mixed solvent of 8 g of N,N-dimethylformamide (DMF) and 9.6 g of tetrahydrofuran (THF), and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0050] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 10 cm, the flow rate of the spinning solution is 0.8 ml / h, the applied voltage is 13 kV, and receive for 20 h through aluminum foil to obtain the TPU / SBS composite fiber membrane.

[0051] III: Place the composite fiber membrane obtained in Step II in a vacuum drying oven at 45°C. After drying, take it out and set it aside. Prepare a 2 mg / ml silver nanowire dispersion in absolute ethanol. Drop the solution onto the surface of the fiber membrane and use a scraper to level it to make the coating uniform. Then place it in a vacuum drying oven at 45°C for drying to obtain a TPU / SBS / AgNWs composite fiber membrane.

[0052] IV: Prepare a target and install it under the shielding cover inside the magnetron sputtering device, keeping a small gap between the shielding cover and the silver target to avoid short circuits. Cut the fiber membrane treated in Step III to an appropriate size and place it on the sample stage. Close the chamber and convert the inside of the chamber to a high vacuum according to the procedure. Open the gas valve and set the flowmeter parameters: flow rate 28 ml / h, pass argon gas, and adjust the pressure inside the chamber to 3 Pa. Turn on the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 100 w, set the time to 1800 s, and start the power supply. After observing the target glow, wait for the magnetron sputtering process to end. Completely turn off the magnetron sputtering equipment and open the inflation valve to balance the internal and external pressures. Take out the silver-colored fiber membrane from the magnetron sputtering equipment, which is the prepared thermoplastic polyurethane / styrene-butadiene-styrene block copolymer conductive fiber membrane.

[0053] Example 4

[0054] I: Accurately weigh 1.68 g of polyurethane (TPU) masterbatch and 0.72 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in a mixed solvent of 4.4 g of N,N-dimethylformamide (DMF) and 13.2 g of tetrahydrofuran (THF), and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0055] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 10 cm, the flow rate of the spinning solution is 0.5 ml / h, the applied voltage is 13 kV, and receive it through aluminum foil for 20 h to obtain a TPU / SBS composite fiber membrane.

[0056] III: Place the composite fiber membrane obtained in Step II in a vacuum drying oven at 45°C. After drying, take it out and set it aside. Prepare a 1.2 mg / ml silver nanowire dispersion in absolute ethanol. Drop the solution onto the surface of the fiber membrane and use a scraper to level it to make the coating uniform. Then place it in a vacuum drying oven at 45°C for drying to obtain a TPU / SBS / AgNWs composite fiber membrane.

[0057] IV: Prepare a target, install it under the shielding cover inside the magnetron sputtering device, and maintain a small gap between the shielding cover and the silver target to avoid short circuits. After cutting the fiber membrane processed in Step III to an appropriate size, place it on the sample stage, close the chamber, and convert the inside of the chamber into a high vacuum according to the process. Open the gas valve, set the flowmeter parameters: flow rate 20 ml / h, pass argon gas, and adjust the air pressure inside the chamber to 1.6 Pa. Open the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 80 w, set the time to 1000 s, and start the power supply. After observing the target glow, wait for the magnetron sputtering process to end. Completely turn off the magnetron sputtering equipment, open the inflation valve to balance the internal and external air pressures. Take out the silver-colored fiber membrane from the magnetron sputtering equipment, which is the prepared thermoplastic polyurethane / styrene-butadiene-styrene block copolymer conductive fiber membrane.

[0058] Example 5

[0059] I: Accurately weigh 1.44 g of polyurethane (TPU) masterbatch and 0.96 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in a mixed solvent of 10.8 g of N,N-dimethylformamide (DMF) and 10.8 g of tetrahydrofuran (THF), and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 10%.

[0060] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 18 cm, the flow rate of the spinning solution is 0.6 ml / h, the applied voltage is 17 kV, and receive for 20 h through aluminum foil to obtain the TPU / SBS composite fiber membrane.

[0061] III: Place the composite fiber membrane in Step II in a vacuum drying oven at 45 °C, take it out after drying, and set it aside. Prepare a 1.5 mg / ml silver nanowire dispersion in absolute ethanol, drop the solution on the surface of the fiber membrane, scrape it flat with a spatula to make the coating uniform, and then place it in a vacuum drying oven at 45 °C for drying to obtain the TPU / SBS / AgNWs composite fiber membrane.

[0062] IV: Prepare a target, install it under the shielding cover inside the magnetron sputtering device, and maintain a small gap between the shielding cover and the silver target to avoid short circuits. After cutting the fiber membrane treated in Step III to an appropriate size, place it on the sample stage, close the chamber, and convert the inside of the chamber into a high vacuum according to the process. Open the gas valve, set the flowmeter parameters: flow rate 35 ml / h, pass argon gas, and adjust the air pressure inside the chamber to 1.4 Pa. Turn on the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 100 w, set the time to 1600 s, and start the power supply. After observing the target glow, wait for the magnetron sputtering process to end. Completely turn off the magnetron sputtering equipment, open the inflation valve to balance the internal and external air pressures. Take out the silver-colored fiber membrane from the magnetron sputtering equipment, which is the prepared thermoplastic polyurethane / styrene-butadiene-styrene block copolymer conductive fiber membrane.

[0063] Example 6

[0064] I: Accurately weigh 1.2 g of polyurethane (TPU) masterbatch and 1.2 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in a mixed solvent of 4.8 g of N,N-dimethylformamide (DMF) and 4.8 g of tetrahydrofuran (THF), and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 20%.

[0065] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 20 cm, the flow rate of the spinning solution is 1.2 ml / h, the applied voltage is 22 kV, and receive for 20 h through aluminum foil to obtain a PU / SBS composite nanofiber membrane.

[0066] III: Place the composite fiber membrane in Step II in a vacuum drying oven at 45 °C, take it out after drying, and set it aside. Prepare a 1.5 mg / ml silver nanowire dispersion in absolute ethanol, drop the solution on the surface of the fiber membrane, scrape it flat with a spatula to make the coating uniform, and then place it in a vacuum drying oven at 45 °C for drying to obtain a TPU / SBS / AgNWs composite fiber membrane.

[0067] IV: Prepare a target, install it under the shielding cover inside the magnetron sputtering device, and maintain a small gap between the shielding cover and the silver target to avoid short circuits. After cutting the fiber membrane treated in Step III to an appropriate size, place it on the sample stage, close the chamber, and convert the inside of the chamber into a high vacuum according to the procedure. Open the gas valve, set the flowmeter parameters: flow rate 25 ml / h, pass argon gas, and adjust the air pressure inside the chamber to 1.2 Pa. Open the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 80 w, set the time to 1500 s, and start the power supply. After observing the target glow, wait for the magnetron sputtering process to end. Completely turn off the magnetron sputtering equipment, open the inflation valve to balance the internal and external air pressures. Take out the silver-colored fiber membrane from the magnetron sputtering equipment, which is the prepared thermoplastic polyurethane / styrene-butadiene-styrene block copolymer conductive fiber membrane.

[0068] Example 7

[0069] I: Accurately weigh 0.96 g of polyurethane (TPU) masterbatch and 1.44 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in a mixed solvent of 10.8 g of N,N-dimethylformamide (DMF) and 6.8 g of tetrahydrofuran (THF), and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0070] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 12 cm, the spinning solution flow rate is 0.6 ml / h, the applied voltage is 18 kV, and receive for 20 h through aluminum foil to obtain a TPU / SBS composite fiber membrane.

[0071] III: Place the composite fiber membrane in Step II in a vacuum drying oven at 45 °C, take it out after drying, and set it aside. Prepare a 0.8 mg / ml silver nanowire dispersion in absolute ethanol, drop the solution on the surface of the fiber membrane, scrape it flat with a spatula to make the coating uniform, and then place it in a vacuum drying oven at 45 °C for drying to obtain a TPU / SBS / AgNWs composite fiber membrane.

[0072] IV: Prepare a target, install it under the shielding cover inside the magnetron sputtering device, and maintain a small gap between the shielding cover and the silver target to avoid short circuit. After cutting the fiber membrane processed in Step III to an appropriate size, place it on the sample stage, close the chamber, and convert the inside of the chamber into a high vacuum according to the process. Open the gas valve, set the flowmeter parameters: flow rate 35 ml / h, pass argon gas, and adjust the air pressure inside the chamber to 2 Pa. Open the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 90 w, set the time to 1200 s, and start the power supply. After observing the target glow, wait for the magnetron sputtering process to end. Completely turn off the magnetron sputtering equipment, open the inflation valve to balance the internal and external air pressures. Take out the silver-colored fiber membrane from the magnetron sputtering equipment, which is the prepared thermoplastic polyurethane / styrene-butadiene-styrene block copolymer conductive fiber membrane.

[0073] Comparative Example 1

[0074] I: Accurately weigh 0.12 g of polyurethane (TPU) masterbatch and 2.16 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in 17.6 g of N,N-dimethylformamide (DMF) single solvent, and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0075] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 15 cm, the flow rate of the spinning solution is 0.7 ml / h, the applied voltage is 18 kV, and receive for 20 h through aluminum foil to obtain a TPU / SBS composite fiber membrane.

[0076] Result: The spun TPU / SBS composite fiber membrane shows obvious separation phenomenon and adheres to the aluminum foil paper, making it difficult for practical application.

[0077] Comparative Example 2

[0078] I: Accurately weigh 1.44 g of polyurethane (TPU) masterbatch and 0.96 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in a mixed solvent of 8.8 g of N,N-dimethylformamide (DMF) and 8.8 g of tetrahydrofuran (THF), and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0079] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 18 cm, the flow rate of the spinning solution is 0.7 ml / h, the applied voltage is 15 kV, and receive for 20 h through aluminum foil to obtain a TPU / SBS composite fiber membrane.

[0080] III: Place the composite fiber membrane in Step II in a vacuum drying oven at 45 °C. Take it out after drying for use. Prepare a 1 mg / ml silver nanowire dispersion in absolute ethanol. After dropping the solution on the surface of the fiber membrane, use a scraper to level it to make the coating uniform, and then place it in a vacuum drying oven at 45 °C for drying to obtain a TPU / SBS / AgNWs composite fiber membrane.

[0081] Result: The initial resistance range of the obtained TPU / SBS / AgNWs composite fiber membrane is 1123.43 - 1463.11 Ω, which is much higher than the average resistance of 3.27 Ω in Examples 1 - 7. At the same time, when the tensile strain exceeds 49.63%, the resistance will exceed 30 MΩ and quickly exceed the maximum range of the detection instrument.

[0082] Comparative Example 3

[0083] I: Accurately weigh 0.96 g of polyurethane (TPU) masterbatch and 1.44 g of styrene-butadiene-styrene block copolymer (SBS) cut blocks, dissolve them in a mixed solvent of 10.8 g of N,N-dimethylformamide (DMF) and 6.8 g of tetrahydrofuran (THF), and stir with a magnetic stirrer at room temperature until the polyurethane and styrene-butadiene-styrene block copolymer are completely dissolved to obtain a homogeneous and stable spinning solution with a mass fraction of 12%.

[0084] II: Use the spinning solution in Step I for electrospinning. Set the electrospinning process parameters as follows: the distance between the spinneret and the receiving plate is 12 cm, the flow rate of the spinning solution is 0.6 ml / h, the applied voltage is 18 kV, and receive for 20 h through aluminum foil to obtain a TPU / SBS composite fiber membrane.

[0085] III: Place the composite fiber membrane in Step II in a vacuum drying oven at 45 °C. Take it out after drying for use. Prepare a 0.8 mg / ml silver nanowire dispersion in absolute ethanol. Use a vacuum filtration device to filter the ethanol in the solution, so that the silver nanowire layer is loaded on the surface of the fiber membrane, and then place the fiber membrane in a vacuum drying oven at 45 °C for drying to obtain a TPU / SBS / AgNWs composite fiber membrane.

[0086] IV: Prepare a target, install it under the shielding cover inside the magnetron sputtering device, and keep a small gap between the shielding cover and the silver target to avoid short - circuit. After cutting the fiber membrane processed in Step III to an appropriate size, place it on the sample stage, close the chamber, and convert the inside of the chamber into a high vacuum according to the process. Open the gas valve, set the flowmeter parameters: flow rate 35 ml / h, pass argon gas, and adjust the chamber pressure to 2 Pa. Open the sample stage rotation switch to ensure more uniform coating. Turn on the DC power supply, set the power to 90 w, set the time to 1200 s, and start the power supply. After observing the target glow, wait for the magnetron sputtering process to end. Completely turn off the magnetron sputtering equipment, open the inflation valve to balance the internal and external pressures. Take out the silver - colored fiber membrane from the magnetron sputtering equipment, which is the prepared thermoplastic polyurethane / styrene - butadiene - styrene block copolymer conductive fiber membrane.

[0087] Results: Due to the influence of the suction filtration process, the silver nanowire conductive layer has greater rigidity and poorer interfacial bonding with the fiber membrane. When the strain exceeds 15%, peeling between the fiber membrane and the conductive layer will occur.

[0088] Mechanical property test

[0089] Further make the conductive fiber membranes prepared in Examples 1 - 7 into fiber membrane test samples (specification: width 10 mm, length 50 mm), place them on a tensile tester (model: INSTRON1185). The test results of the breaking strength and elongation at break of the composite fiber membranes are shown in Table 1.

[0090] Table 1. Test results of the breaking strength (MPa) and elongation at break (%) of the TPU / SBS elastic conductive composite fiber membranes prepared in Examples 1 - 7

[0091]

[0092] Characterize the TPU / SBS fiber membrane and the TPU / SBS / AgNWs / AgNps composite conductive fiber membrane obtained in Example 2 Figure 1 ) using a scanning electron microscope, and obtain the Figure 2 microscopic morphology of the fiber membrane as shown. It can be seen that the slender and uniform fibers are arranged in a net - like pattern, providing good support for the macroscopic mechanical properties of the fiber membrane. Figure 3 As can be seen from the microscopic view, each fiber on the surface of the fiber membrane has been evenly wrapped and tightly bonded by silver nanowires and silver nanoparticles. Figure 4 This is the cross - section SEM of the TPU / SBS / AgNWs / AgNps composite conductive fiber membrane. It can be seen that the fiber part showing a bright color is the side with surface - loaded nano - silver. The Figure 3 , Figure 4 corresponding EDX elemental analysis images are shown in Figure 5, Figure 6 Among them, the colored dots are the areas where silver elements are scanned, which coincide with the SEM image, corroborating the successful loading of the silver nanolayer.

[0093] The reusability of the TPU / SBS / AgNWs / AgNps composite conductive fiber membrane obtained in Example 2 was tested, as Figure 7 shown: (a) The change in electrical signal (ΔR / R0) during stretching to 300% strain and the change in gauge factor (GF) value in the corresponding interval; (b) The change in electrical signal (ΔR / R0) during cyclic stretching at larger strains (10%, 20%, 50%); (c) The change in electrical signal (ΔR / R0) during cyclic stretching at smaller strains (1%, 2%, 5%); (d) The change in electrical signal (ΔR / R0) during cyclic stretching at a tiny strain (0.1%); (e) The response-recovery time detected during cyclic stretching at 2% strain; (f) The change in electrical signal (ΔR / R0) during more than 1000 cycles of cyclic stretching. Through Figure 7 the result analysis, it can be seen that the TPU / SBS / AgNWs / AgNps composite conductive fiber membrane has good tensile properties and strain electromechanical functions, high sensitivity, a wide detection range, a low detection limit, and excellent response and recovery speeds. More than a thousand cycles of cyclic stretching prove its good recyclability.

[0094] Those of ordinary skill in the art should understand that the discussion of any above embodiment is only exemplary and is not intended to imply that the scope of the present invention is limited to these examples; under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the present invention as described above, which are not provided in detail for the sake of brevity. Any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a composite nano - silver conductive layer elastic fiber membrane, characterized in that The preparation method comprises the following steps: first preparing a composite flexible elastic base film of thermoplastic polyurethane and styrene-butadiene-styrene block copolymer by electrospinning; then forming a composite fiber membrane with a preliminary conductive network by scraping silver nanowires on the flexible elastic base film; and then magnetron sputtering a layer of silver nanoparticles on the surface of the composite fiber membrane to prepare a composite nano-silver conductive layer elastic fiber membrane.

2. The preparation method of the composite silver nanowire conductive layer elastic fiber membrane according to claim 1, characterized in that, The steps include: Step 1: dissolving thermoplastic polyurethane and styrene-butadiene-styrene block copolymer in a mixed solvent to obtain an electrospinning solution with a mass fraction of 10-20%; Step 2: Using the electrospinning solution of step 1 to prepare a composite flexible elastic base membrane through an electrospinning process, namely a TPU / SBS composite fiber membrane; Step 3: After the TPU / SBS composite fiber membrane is dried, 0.5-2 mg / ml of silver nanowire dispersion is applied by knife coating on the surface of the TPU / SBS composite fiber membrane, and the TPU / SBS / AgNWs composite fiber membrane is obtained after drying; Step 4: magnetron sputtering a layer of silver nanoparticles on the surface of the TPU / SBS / AgNWs composite fiber membrane to obtain a composite nano-silver conductive layer elastic fiber membrane.

3. The preparation method of the composite silver nanowire conductive layer elastic fiber membrane according to claim 2, wherein The mass ratio of the thermoplastic polyurethane to the styrene-butadiene-styrene block copolymer in step 1 is 1-9:1-1.

5.

4. The preparation method of the composite silver nanowire conductive layer elastic fiber membrane according to claim 2, characterized in that, The mixed solvent in step 1 is a mixed solvent of N,N-dimethylformamide and tetrahydrofuran, and the mass ratio of N,N-dimethylformamide to tetrahydrofuran is 1-1.6:1-1.

2.

5. The preparation method of the composite nano-silver conductive layer elastic fiber membrane according to claim 1 or 2, characterized in that, The process parameters of the electrospinning are: the distance between the spinneret and the receiving plate is 10-20 cm, the spinning solution flow rate is 0.2-1.2 ml / h, the applied voltage is 10-22 kV, and the receiving is carried out through the aluminum foil for 20 hours.

6. The preparation method of the composite nano-silver conductive layer elastic fiber membrane according to claim 2, characterized in that, The drying temperature in step 3 is 40-50° C., and the silver nanowire dispersion at a concentration of 0.5-2 mg / ml is prepared in anhydrous ethanol.

7. The preparation method of the composite silver nanowire conductive layer elastic fiber membrane according to claim 2, characterized in that, During the magnetron sputtering, the flow meter parameters were set as follows: flow rate 10-35 ml / h, argon gas was passed, and the air pressure in the chamber was adjusted to 0.5-3.0 Pa; the power was set to 60-100 W, and the time was set to 600-1800 s.

8. A composite nano-silver conductive layer elastic fiber membrane, characterized in that, The method is prepared according to any one of claims 1 to 7.

9. Application of the composite nanosilver conductive layer elastic fiber membrane according to claim 8 in textiles, sports monitoring, physiological signal monitoring, and structural health monitoring.

10. Use of the composite nanosilver conductive layer elastic fiber membrane according to claim 8 in flexible electronics, electronic skin, and soft robots.

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