Nanosilver wire / modified polyvinyl alcohol nanofiber composite sensing film, preparation method and sensitive device

Abstract

The application discloses a nanometer silver wire / modified polyvinyl alcohol nanofiber composite sensing film, a preparation method and a sensitive device, wherein the film comprises a base film and nanometer silver wires formed on the base film, and the base film is obtained by electrospinning a spinning system of modified polyvinyl alcohol containing an amino-terminated hyperbranched polymer with nanometer silver; and the spinning system of modified polyvinyl alcohol containing the amino-terminated hyperbranched polymer with nanometer silver is obtained by taking a hyperbranched polymer with amino-terminated / nanometer silver composite and a polyvinyl alcohol modified intermediate as raw materials. The composite sensing film has good tensile properties and electrical sensing properties, and has good antibacterial properties and regenerative utilization.

Description

Technical Field

[0001] This invention relates to organic / inorganic composite nanofilm material technology, and in particular to a silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film, its preparation method, and a sensing device. Background Technology

[0002] Flexible strain sensors are widely used in electronic skin, health monitoring, and wearable electronic devices due to their excellent flexibility and ductility. A typical flexible strain sensor consists of two parts: a flexible substrate and a conductive material. Natural polymers such as gelatin and silk fibroin have excellent biodegradability and are environmentally friendly, but their poor mechanical properties limit their application in sensors. Therefore, organic polymers such as polyurethane, polyimide, and polydimethylsiloxane are widely used as substrates for flexible electronic devices. Conductive materials often employ carbon materials and metallic materials (such as carbon nanotubes and silver nanowires) to construct conductive networks. Since these materials are not recyclable after use, and the excessive use of electronic devices can easily lead to electronic waste accumulation and pollution. Furthermore, as wearable devices, flexible strain sensors are prone to bacterial growth during prolonged contact with the human body.

[0003] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0004] The purpose of this invention is to provide a composite sensing film of silver nanowires / modified polyvinyl alcohol nanofibers, its preparation method, and a sensing device. By optimizing the product and process, a flexible sensing material with good tensile elasticity and elastic recovery is achieved. Furthermore, this material maintains the fiber morphology while also exhibiting good antibacterial properties.

[0005] To achieve the above objectives, embodiments of the present invention provide a silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film, comprising a substrate film and silver nanowires formed on the substrate film. The substrate film is obtained by electrospinning a spinning system of polyvinyl alcohol modified with a terminal amino hyperbranched polymer containing silver nanowires. The spinning system of polyvinyl alcohol modified with a terminal amino hyperbranched polymer containing silver nanowires is obtained using a terminal amino hyperbranched polymer / silver nanowire composite and a polyvinyl alcohol modified intermediate as raw materials. Preferably, the content of silver nanowires loaded on the substrate film is 55.6–111.1 μg / cm³. 2 .

[0006] In one or more embodiments of the present invention, a method for preparing a silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film includes: using triethylamine as a catalyst, adding succinic anhydride to a polyvinyl alcohol aqueous solution and reacting at room temperature to obtain a polyvinyl alcohol modified intermediate with carboxyl groups at the end; adding silver nitrate to a terminal amino hyperbranched polymer solution and heating to react to obtain a terminal amino hyperbranched polymer / silver nanowire; forming a mixed solution of the terminal amino hyperbranched polymer / silver nanowire and the polyvinyl alcohol modified intermediate and heating to react to obtain a terminal amino hyperbranched polymer modified polyvinyl alcohol containing silver nanowire; electrospinning the spinning system of the terminal amino hyperbranched polymer modified polyvinyl alcohol containing silver nanowire to obtain a nanofiber membrane; and spraying silver nanowires onto the fiber membrane to prepare a silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film material.

[0007] In one or more embodiments of the present invention, the mass ratio of succinic anhydride to polyvinyl alcohol in the preparation of the polyvinyl alcohol modified intermediate is 1:(5-10).

[0008] In one or more embodiments of the present invention, the mass ratio of the catalyst triethylamine to succinic anhydride in the preparation of the polyvinyl alcohol modified intermediate is 1:(10-30).

[0009] In one or more embodiments of the present invention, the concentration of the terminal amino hyperbranched polymer / nano silver in the preparation of the terminal amino hyperbranched polymer / nano silver is 100-300 g / L, and / or the concentration of the silver nitrate aqueous solution is 0.004-0.02 mol / L.

[0010] In one or more embodiments of the present invention, the volume ratio of silver nitrate solution to terminal amino hyperbranched polymer solution is 1:(2-10).

[0011] In one or more embodiments of the present invention, in the preparation of polyvinyl alcohol modified by terminal amino hyperbranched polymer containing nanosilver: the concentration of terminal amino hyperbranched polymer / nanosilver solution is 100 g / L-300 g / L; and / or the concentration of polyvinyl alcohol modified intermediate solution is 10 wt.%-17 wt.%.

[0012] In one or more embodiments of the present invention, the mixed solution is a solution with an amino-terminated hyperbranched polymer / nano silver solution and a polyvinyl alcohol modified intermediate solution in a volume ratio of 1:(1-2).

[0013] In one or more embodiments of the present invention, the reaction temperature during the reaction of the mixed solution is 90–100°C. Preferably, the reaction time is 8–16 h.

[0014] In one or more embodiments of the present invention, the sensitive device includes a sensitive element for acquiring a sensitive signal, the sensitive element comprising a composite sensing film of silver nanowires / modified polyvinyl alcohol nanofibers as described above. This can be used, for example, as electronic skin.

[0015] Compared with existing technologies, the nanofiber / modified polyvinyl alcohol nanofiber composite sensing film, its preparation method, and sensing device according to embodiments of the present invention specifically involve using succinic anhydride as an intermediate, modifying polyvinyl alcohol with a terminal amino hyperbranched polymer, and simultaneously utilizing the terminal amino hyperbranched polymer to control and generate nanosilver, thus preparing a renewable antibacterial electrospun fiber membrane. Nanofibers are sprayed onto the fiber membrane to construct a conductive network, thus preparing the nanofiber / modified polyvinyl alcohol nanofiber composite sensing film material, which is applied in the field of flexible strain sensors. Therefore, developing a biodegradable flexible sensor with antibacterial properties is of great significance.

[0016] The present invention has the following beneficial effects:

[0017] (1) Compared with polyvinyl alcohol film, electrospun nanofiber film has a much lower rigidity, making it suitable for preparing flexible device materials; compared with unmodified polyvinyl alcohol, modified polyvinyl alcohol nanofiber film exhibits better tensile elasticity and elastic recovery, making it more suitable for preparing sensing materials with flexible sensing properties.

[0018] (2) By capturing and reducing silver ions through terminal amino hyperbranched polymers, nano-silver was successfully introduced, giving the nano-silver wire-modified polyvinyl alcohol nanofiber composite sensing film excellent antibacterial properties.

[0019] (3) The polyvinyl alcohol nanofiber composite sensing film modified with silver nanowires exhibits excellent regeneration performance. The dissolution rate of the polyvinyl alcohol nanofiber composite sensing film modified with silver nanowires can be controlled by adjusting the degree of grafting of terminal amino hyperbranched polymers onto polyvinyl alcohol. Moreover, the regenerated fiber membrane still retains good fiber morphology and antibacterial properties.

[0020] (4) Due to the “co-solvent effect”, the silver nanowires are tightly attached to the fiber membrane to form a complete conductive network, which makes the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film material have good tensile resistance response behavior.

[0021] (5) Adjust the stability of the tensile resistance response behavior of the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film material by adjusting the content of silver nanowires. Attached Figure Description

[0022] Figure 1 This is a SEM image of modified polyvinyl alcohol fiber according to an embodiment of the present invention.

[0023] Figure 2 This is a TEM image of modified polyvinyl alcohol fiber according to an embodiment of the present invention;

[0024] Figure 3 This is a tensile cycle test of modified polyvinyl alcohol fiber according to an embodiment of the present invention;

[0025] Figure 4 This describes the dynamic dissolution process of the silver nanowire-modified polyvinyl alcohol nanofiber composite sensing film according to an embodiment of the present invention.

[0026] Figure 5 This is the preparation process and SEM image of recycled modified polyvinyl alcohol fiber according to an embodiment of the present invention.

[0027] Figure 6 This is an image showing the antibacterial effect of a nanosilver wire modified polyvinyl alcohol nanofiber composite sensing film and its regenerated fiber film according to an embodiment of the present invention.

[0028] Figure 7 This is a SEM image of a nanosilver wire / modified polyvinyl alcohol fiber composite antibacterial material according to an embodiment of the present invention;

[0029] Figure 8 This is an example of the application of a nano-silver wire / modified polyvinyl alcohol fiber composite antibacterial material according to an embodiment of the present invention in the bending of a human finger, along with corresponding resistance change data. Detailed Implementation

[0030] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0031] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0032] Polyvinyl alcohol (PVA) is a flexible, long-chain polymer with a simple and inexpensive preparation process. It possesses excellent hydrophilicity, biocompatibility, gas barrier properties, and mechanical strength, and is also biodegradable, environmentally friendly, and exhibits strong film-forming properties and acid and alkali resistance, thus finding wide application in various fields. However, due to its linear polymer structure and the presence of numerous hydroxyl groups in its side chains, PVA's high stretchability is limited. Therefore, modification of PVA is necessary to improve its flexibility and stretchability, while also imparting other properties to broaden its application areas.

[0033] Amino-terminated hyperbranched polymers are low-viscosity, highly fluid, near-three-dimensional spherical molecules. While retaining the original water solubility of polyvinyl alcohol (PVA), these polymers can be used to modify PVA, reducing intermolecular forces and increasing its stretchability. Furthermore, the abundant terminal amino and imino groups in these polymers can be used to capture silver ions and successfully reduce them to nano-silver. Therefore, they can serve as stable and reducing nanoreactors for the synthesis of nanomaterials.

[0034] Electrospinning produces fibers with large specific surface area, high porosity, small size, and good mechanical flexibility, showing promising application prospects in flexible strain sensors. Therefore, electrospinning is used to prepare polyvinyl alcohol nanofiber membranes modified with terminal amino-terminated hyperbranched polymers containing silver nanoparticles. Simultaneously, the grafting degree of the terminal amino-terminated hyperbranched polymer onto polyvinyl alcohol can be adjusted to control the dissolution rate of the modified polyvinyl alcohol fiber membrane, thus preparing an easily recyclable flexible substrate material. Spraying silver nanowires onto this antibacterial fiber membrane to form a conductive network for preparing strain sensing materials is an excellent strategy. Due to its good water solubility, this electronic device can be recycled after use, alleviating the environmental pollution pressure caused by the misuse of electronic devices.

[0035] Specifically, the preparation method of the nanosilver wire / modified polyvinyl alcohol nanofiber composite sensing film of the present invention may include the following steps: (1) adding polyvinyl alcohol particles to deionized water, heating and mechanically stirring until fully dissolved to obtain a polyvinyl alcohol aqueous solution; (2) using triethylamine as a catalyst, adding succinic anhydride to the polyvinyl alcohol aqueous solution and reacting at room temperature to obtain a polyvinyl alcohol modified intermediate with a carboxyl group at the end; (3) adding silver nitrate aqueous solution to a terminal amino hyperbranched polymer solution and heating to obtain a terminal amino hyperbranched polymer / nanosilver solution; (4) adding the terminal amino hyperbranched polymer / nanosilver solution to the polyvinyl alcohol modified intermediate solution, mixing evenly, and heating to obtain a terminal amino hyperbranched polymer modified polyvinyl alcohol solution containing nanosilver; (5) using electrospinning technology to spin the above modified polyvinyl alcohol composite solution into a nanofiber membrane; (6) spraying nanosilver wires onto the fiber membrane to prepare a nanosilver wire / modified polyvinyl alcohol nanofiber composite sensing film material.

[0036] Preferably, in step (1): the heating temperature can be 80–98°C. The mass fraction concentration of the polyvinyl alcohol aqueous solution can be 10–19.2 wt.%.

[0037] Preferably, in step (2): the mass ratio of succinic anhydride to polyvinyl alcohol can be 1:(5-10). The mass ratio of the catalyst triethylamine to succinic anhydride can be 1:(10-30). The reaction time can be 0.5-2h.

[0038] Preferably, in step (3): the concentration of the silver nitrate aqueous solution can be 0.004–0.02 mol / L. The reaction temperature can be 80–100℃. The heating time can be 1–2 min.

[0039] Preferably, in step (3), the concentration of the terminal amino hyperbranched polymer can be 100–300 g / L. The volume ratio of silver nitrate solution to terminal amino hyperbranched polymer solution can be 1:(2–10).

[0040] Preferably, in step (4), the volume ratio of the terminal amino hyperbranched polymer / nano silver solution to the polyvinyl alcohol modified intermediate solution can be 1:(1-2).

[0041] Preferably, in step (4): the reaction temperature can be 90-100℃. The reaction time can be 8-16h.

[0042] Preferably, in step (5): the electrospinning voltage can be 15-25V. The receiving distance can be 15-25cm. The flow rate can be 0.1-0.5ml / h.

[0043] Preferably, the content of silver nanowires on the fiber membrane in step (6) can be 55.6–111.1 μg / cm³. 2 .

[0044] Example 1

[0045] 2.2g of polyvinyl alcohol granules were added to 19.8g of deionized water, heated at 80℃ and mechanically stirred until completely dissolved, resulting in a homogeneous polyvinyl alcohol aqueous solution. 0.22g of succinic anhydride was added to the polyvinyl alcohol aqueous solution, along with 0.011g of triethylamine catalyst. The mixture was reacted at room temperature for 0.5h to obtain a succinic anhydride-modified polyvinyl alcohol solution, namely a polyvinyl alcohol / succinic anhydride solution (a polyvinyl alcohol modified intermediate solution, hereinafter the same).

[0046] Take 5 ml of 0.004 mol / L silver nitrate solution and add it to 10 ml of 100 g / L terminal amino hyperbranched polymer solution. Heat the mixture at 90 °C for 1.5 min to obtain terminal amino hyperbranched polymer containing nano-silver, i.e., terminal amino hyperbranched polymer / nano-silver solution.

[0047] A 100 g / L terminal amino hyperbranched polymer / nano silver solution was prepared (here, preparation refers to adjusting the concentration, purity, etc. of the solution obtained from the aforementioned reaction to meet the requirements, the same below) and a 13 wt.% polyvinyl alcohol modified intermediate solution were mixed at a volume ratio of 1:1.5. The mixture was heated at 90°C for 12 h to obtain a terminal amino hyperbranched polymer modified polyvinyl alcohol solution containing nano silver, i.e., a modified polyvinyl alcohol solution.

[0048] A composite sensing film of silver nanowire modified polyvinyl alcohol nanofiber was obtained by setting the voltage to 20V, the flow rate to 0.1ml / h, and the receiving distance to 15cm using electrospinning technology.

[0049] A spray coating method was used to ensure that the silver nanowires adhered tightly to the fiber membrane (silver nanowire content was 55.6 μg / cm³). 2 A composite antibacterial material of silver nanowires / modified polyvinyl alcohol fibers was obtained.

[0050] Example 2

[0051] 3.4g of polyvinyl alcohol granules were added to 19.8g of deionized water, heated at 95℃ and mechanically stirred until completely dissolved, resulting in a homogeneous polyvinyl alcohol aqueous solution. 0.45g of succinic anhydride was added to the polyvinyl alcohol aqueous solution, along with 0.045g of triethylamine catalyst. The mixture was reacted at room temperature for 2 hours to obtain a succinic anhydride-modified polyvinyl alcohol solution, namely a polyvinyl alcohol / succinic anhydride solution.

[0052] Take 5 ml of 0.012 mol / L silver nitrate solution and add it to 15 ml of 300 g / L terminal amino hyperbranched polymer solution. Heat the mixture at 90 °C for 1 min to obtain terminal amino hyperbranched polymer containing nano-silver, i.e., terminal amino hyperbranched polymer / nano-silver solution.

[0053] A 200 g / L solution of terminal amino hyperbranched polymer / nano silver was mixed with a 15 t.% solution of polyvinyl alcohol modified intermediate at a volume ratio of 1:1.4. The mixture was heated at 100 °C for 8 h to obtain a polyvinyl alcohol solution modified with terminal amino hyperbranched polymer containing nano silver, i.e., a modified polyvinyl alcohol solution.

[0054] A composite sensing film of silver nanowire modified polyvinyl alcohol nanofiber was obtained by setting the voltage to 25V, the flow rate to 0.3ml / h, and the receiving distance to 25cm using electrospinning technology.

[0055] A spray coating method was used to ensure that the silver nanowires adhered tightly to the fiber membrane (silver nanowire content was 83.3 μg / cm³). 2A composite antibacterial material of silver nanowires / modified polyvinyl alcohol fibers was obtained.

[0056] Example 3

[0057] 4.7g of polyvinyl alcohol granules were added to 19.8g of deionized water, heated at 98℃ and mechanically stirred until completely dissolved, resulting in a homogeneous polyvinyl alcohol aqueous solution. 0.96g of succinic anhydride was added to the polyvinyl alcohol aqueous solution, along with 0.032g of triethylamine catalyst. The mixture was reacted at room temperature for 1.5h to obtain a succinic anhydride-modified polyvinyl alcohol solution, namely a polyvinyl alcohol / succinic anhydride solution.

[0058] Take 5 ml of 0.02 mol / L silver nitrate solution and add it to 50 ml of 200 g / L terminal amino hyperbranched polymer solution. Heat the mixture at 100 °C for 1 min to obtain terminal amino hyperbranched polymer containing nano-silver, i.e., terminal amino hyperbranched polymer / nano-silver solution.

[0059] A 300 g / L solution of terminal amino hyperbranched polymer / nano silver was mixed with a 10 wt.% solution of polyvinyl alcohol modified intermediate at a volume ratio of 1:1. The mixture was heated at 90 °C for 10 h to obtain a polyvinyl alcohol solution modified with terminal amino hyperbranched polymer containing nano silver, i.e., a modified polyvinyl alcohol solution.

[0060] A composite sensing film of silver nanowire modified polyvinyl alcohol nanofiber was obtained by setting the voltage to 25V, the flow rate to 0.5ml / h, and the receiving distance to 20cm using electrospinning technology.

[0061] A spray coating method was used to ensure that the silver nanowires adhered tightly to the fiber membrane (the silver nanowire content was 111.1 μg / cm³). 2 A composite antibacterial material of silver nanowires / modified polyvinyl alcohol fibers was obtained.

[0062] Example 4

[0063] 2.7g of polyvinyl alcohol granules were added to 19.8g of deionized water, heated at 89℃ and mechanically stirred until completely dissolved, yielding a homogeneous polyvinyl alcohol aqueous solution. 0.3g of succinic anhydride was added to the polyvinyl alcohol aqueous solution, along with 0.02g of triethylamine catalyst. The reaction was carried out at room temperature for 1.2h to obtain a succinic anhydride-modified polyvinyl alcohol solution, i.e., a polyvinyl alcohol / succinic anhydride solution.

[0064] Take 5 ml of 0.012 mol / L silver nitrate solution and add it to 12 ml of 150 g / L terminal amino hyperbranched polymer solution. Heat the mixture at 90 °C for 1 min to obtain terminal amino hyperbranched polymer containing nano-silver, i.e., terminal amino hyperbranched polymer / nano-silver solution.

[0065] A 150 g / L solution of terminal amino hyperbranched polymer / nano silver was mixed with a 17 wt.% solution of polyvinyl alcohol modified intermediate at a volume ratio of 1:1. The mixture was heated at 93 °C for 10 h to obtain a polyvinyl alcohol solution modified with terminal amino hyperbranched polymer containing nano silver, i.e., a modified polyvinyl alcohol solution.

[0066] A composite sensing film of silver nanowire modified polyvinyl alcohol nanofiber was obtained by setting the voltage to 20V, the flow rate to 0.3ml / h, and the receiving distance to 20cm using electrospinning technology.

[0067] A spray coating method was used to ensure that the silver nanowires adhered tightly to the fiber membrane (silver nanowire content was 83.3 μg / cm³). 2 A composite antibacterial material of silver nanowires / modified polyvinyl alcohol fibers was obtained.

[0068] Example 5

[0069] 4g of polyvinyl alcohol granules were added to 19.8g of deionized water, heated at 95℃ and mechanically stirred until completely dissolved, resulting in a homogeneous polyvinyl alcohol aqueous solution. 0.5g of succinic anhydride was added to the polyvinyl alcohol aqueous solution, along with 0.03g of triethylamine catalyst. The mixture was reacted at room temperature for 1.5h to obtain a succinic anhydride-modified polyvinyl alcohol solution, namely a polyvinyl alcohol / succinic anhydride solution.

[0070] Take 5 ml of 0.008 mol / L silver nitrate solution and add it to 30 ml of 100 g / L terminal amino hyperbranched polymer solution. Heat the mixture at 80 °C for 2 min to obtain terminal amino hyperbranched polymer containing nano-silver, i.e., terminal amino hyperbranched polymer / nano-silver solution.

[0071] A 250 g / L solution of terminal amino hyperbranched polymer / nano silver was mixed with a 16 wt.% solution of polyvinyl alcohol modified intermediate at a volume ratio of 1:2. The mixture was heated at 95 °C for 15 h to obtain a polyvinyl alcohol solution modified with terminal amino hyperbranched polymer containing nano silver, i.e., a modified polyvinyl alcohol solution.

[0072] A composite sensing film of silver nanowire modified polyvinyl alcohol nanofiber was obtained by setting the voltage to 25V, the flow rate to 0.2ml / h, and the receiving distance to 15cm using electrospinning technology.

[0073] A spray coating method was used to ensure that the silver nanowires adhered tightly to the fiber membrane (silver nanowire content was 100 μg / cm³). 2 A composite antibacterial material of silver nanowires / modified polyvinyl alcohol fibers was obtained.

[0074] Example 6

[0075] 4.1g of polyvinyl alcohol granules were added to 19.8g of deionized water, heated at 90℃ and mechanically stirred until completely dissolved, resulting in a homogeneous polyvinyl alcohol aqueous solution. 0.5g of succinic anhydride was added to the polyvinyl alcohol aqueous solution, along with 0.025g of triethylamine catalyst. The mixture was reacted at room temperature for 1 hour to obtain a succinic anhydride-modified polyvinyl alcohol solution, namely a polyvinyl alcohol / succinic anhydride solution.

[0076] Take 5 ml of 0.004 mol / L silver nitrate solution and add it to 10 ml of 100 g / L terminal amino hyperbranched polymer solution. Heat the mixture at 80 °C for 1.5 min to obtain terminal amino hyperbranched polymer containing nano-silver, i.e., terminal amino hyperbranched polymer / nano-silver solution.

[0077] A solution of terminal amino hyperbranched polymer / nano silver with a concentration of 100 g / L-300 g / L was mixed with a solution of polyvinyl alcohol modified intermediate with a concentration of 14 wt.% at a volume ratio of 1:1.6. The mixture was heated at 95 °C for 16 h to obtain a polyvinyl alcohol solution modified with terminal amino hyperbranched polymer containing nano silver, i.e., a modified polyvinyl alcohol solution.

[0078] A composite sensing film of silver nanowire modified polyvinyl alcohol nanofiber was obtained by setting the voltage to 15V, the flow rate to 0.1ml / h, and the receiving distance to 20cm using electrospinning technology.

[0079] A spray coating method was used to ensure that the silver nanowires adhered tightly to the fiber membrane (the silver nanowire content was 111.1 μg / cm³). 2 A composite antibacterial material of silver nanowires / modified polyvinyl alcohol fibers was obtained.

[0080] Taking the sample obtained in Example 1 as an example, the present invention will be verified: from Figure 1 It can be seen that the polyvinyl alcohol solution modified with terminal amino hyperbranched polymer containing nano-silver yielded a fiber membrane with good morphology under the above electrospinning process. From Figure 2 It can be seen that the silver nanoparticles are well distributed on the surface and inside of the fiber. Cyclic tensile tests were performed on the fiber membrane at 50% strain. Figure 3 This indicates that the fiber membrane has excellent resilience and durability. Figure 3The 10 curves shown by AE are curves obtained by stretching the same sample (excluding the stretching dimension of 3*1cm at the clamping part, stretching along the long side) for 10 consecutive stretching cycles. Figure 4 The dissolution performance of the polyvinyl alcohol nanofiber composite sensing film modified with silver nanowires is shown at a grafting rate of 0.6. Due to its good solubility, it can be electrospun again to achieve recyclability. Figure 5 SEM images show that recycled polyvinyl alcohol (PVA) fibers with similar morphology and diameter to the first-round fibers can be prepared. This provides a low-cost recycling route for modified PVA elastic fiber membranes, which is beneficial for realizing green economy industries. Additionally, as... Figure 6 The antibacterial experiments shown demonstrate that the nanosilver wire-modified polyvinyl alcohol nanofiber composite sensing film and its regenerated fiber membrane of this invention exhibit good antibacterial effects against both *Escherichia coli* and *Staphylococcus aureus*. Figure 7 As shown, the nanosilver wire-modified polyvinyl alcohol nanofiber composite sensing film of the present invention is used as a flexible substrate, and nanosilver wires are sprayed onto it to prepare a nanosilver wire / modified polyvinyl alcohol fiber film sensing material. This material can be attached to a human finger or similar object to detect surface deformation and movement. Figure 8 As demonstrated, this composite material can detect human finger bending and straightening activities through changes in resistance, with no interference noise, high sensitivity, rapid response, and high efficiency. Furthermore, it has passed over 1 million tests without significant performance degradation, indicating good practicality.

[0081] Products including, but not limited to, those described in the above embodiments all meet the performance requirements mentioned above.

[0082] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A composite sensing film of silver nanowires / modified polyvinyl alcohol nanofibers for wearable devices, comprising a substrate film and silver nanowires formed thereon, wherein the content of the silver nanowires is 55.6~111.1 µg / cm³. 2 , The substrate film was obtained by electrospinning a spinning system of polyvinyl alcohol modified with a terminal amino hyperbranched polymer containing nano-silver. A spinning system containing silver nanoparticles was obtained by using terminal amino hyperbranched polymer / nano silver composite and polyvinyl alcohol modified intermediate as raw materials to obtain a polyvinyl alcohol modified by terminal amino hyperbranched polymer.

2. A method for preparing a composite sensing film of silver nanowires / modified polyvinyl alcohol nanofibers, comprising: Using triethylamine as a catalyst, succinic anhydride was added to a polyvinyl alcohol aqueous solution system and reacted at room temperature to obtain a polyvinyl alcohol modified intermediate with a carboxyl group at the end. Silver nitrate was added to a solution of amino-terminated hyperbranched polymer and heated to obtain amino-terminated hyperbranched polymer / silver nanoparticles. The terminal amino hyperbranched polymer / nano silver and the polyvinyl alcohol modified intermediate form a mixed solution, which is heated to react and obtain polyvinyl alcohol modified with terminal amino hyperbranched polymer containing nano silver. Electrospinning was used to obtain nanofiber membranes from a spinning system of polyvinyl alcohol modified with terminal amino hyperbranched polymers containing nanosilver. A composite sensing film material of silver nanowires / modified polyvinyl alcohol nanofibers was prepared by spraying silver nanowires onto a fiber membrane.

3. The method for preparing the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film as described in claim 2, characterized in that, In the preparation of the polyvinyl alcohol modified intermediate, the mass ratio of succinic anhydride to polyvinyl alcohol is 1:(5~10).

4. The method for preparing the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film as described in claim 3, characterized in that, In the preparation of the polyvinyl alcohol modified intermediate, the mass ratio of the catalyst triethylamine to succinic anhydride is 1:(10~30).

5. The method for preparing the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film as described in claim 2, characterized in that, In the preparation of the terminal amino hyperbranched polymer / nano silver, the concentration of the terminal amino hyperbranched polymer is 100~300 g / L, and / or the concentration of the silver nitrate aqueous solution is 0.004~0.02 mol / L.

6. The method for preparing the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film as described in claim 5, characterized in that, The volume ratio of the silver nitrate solution to the terminal amino hyperbranched polymer solution is 1:(2~10).

7. The method for preparing the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film as described in claim 2, characterized in that, In the preparation of polyvinyl alcohol modified with terminal amino hyperbranched polymer containing nano-silver: the concentration of the terminal amino hyperbranched polymer / nano-silver solution is 100 g / L-300 g / L; and / or the concentration of the polyvinyl alcohol modified intermediate solution is 10 wt.%-17 wt.%.

8. The method for preparing the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film as described in claim 7, characterized in that, The mixed solution is prepared by a volume ratio of the terminal amino hyperbranched polymer / nano silver solution to the polyvinyl alcohol modified intermediate solution of 1:(1~2).

9. A sensitive device, comprising a sensitive element for acquiring a sensitive signal, said sensitive element comprising the silver nanowire / modified polyvinyl alcohol nanofiber composite sensing film as described in claim 1.

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