A flexible pressure and temperature sensor based on conductive nanofibers and preparation method and application thereof
Conductive nanofiber membranes prepared by electrospinning, combined with conductive particles and thermoelectric materials, solve the problem that existing sensors cannot simultaneously detect pressure and temperature, realizing a low-cost, large-scale production flexible pressure and temperature sensor suitable for wearable electronic devices and human-computer interaction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2026-04-21
- Publication Date
- 2026-06-12
AI Technical Summary
Existing pressure and temperature sensors are difficult to simultaneously possess both low thermal conductivity and good electrical conductivity, and their fabrication process is complex and costly, making large-scale production and use difficult.
A flexible pressure-temperature sensor was formed by using polyvinyl butyral nanofiber membrane as a substrate, preparing conductive fiber membrane by electrospinning, loading conductive particles and thermoelectric materials by in-situ polymerization, and combining copper foil electrodes and adhesive tape encapsulation.
The manufacturing process is simple and low-cost, enabling long-term cyclic use. It possesses high sensitivity and a wide operating range, making it suitable for wearable electronic devices and human-computer interaction.
Smart Images
Figure CN122192569A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer nanofibers, specifically relating to a flexible pressure and temperature sensor based on conductive nanofibers, its preparation method, and its application. Background Technology
[0002] In recent years, with the development of fields such as electronic skin and intelligent robots, flexible sensors have been widely used. A flexible sensor is a device that can convert external stimuli (such as pressure, strain, temperature, and humidity) into detectable electrical signals to sense and distinguish different stimuli. It has gradually been applied to medical diagnosis, detection of human health signals, and more. For sensors, a single sensor can only measure a single physical stimulus and is insufficient to handle complex physical conditions and detect multiple forms of stimuli. Therefore, multimode sensors with multi-parameter data acquisition, mixed-signal decoupling, and information processing capabilities are attracting increasing attention. Among all existing physical stimuli, temperature and pressure are ubiquitous in our daily lives and, to some extent, reflect an individual's health status. Therefore, developing novel and effective temperature-pressure dual-mode sensors has become an urgent need.
[0003] For pressure and temperature sensors, a single sensor with both piezoresistive pressure detection and thermoelectric temperature detection capabilities is an effective way to solve signal coupling. However, the active sensing layer elements currently used in these sensors, such as conductive polymers, carbon materials, and conductive metal frameworks, are difficult to simultaneously possess low thermal conductivity and good electrical conductivity. Furthermore, these materials are expensive, and the sensor fabrication process is complex, hindering large-scale production and use. Therefore, further exploration is needed to achieve better overall sensing performance while controlling costs. Summary of the Invention
[0004] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for fabricating a flexible pressure and temperature sensor based on conductive nanofibers. This method aims to solve the problem that a single sensor cannot cope with multiple stimuli by assembling a pressure sensor and a temperature sensor made of flexible fibers together.
[0005] Another objective of this invention is to provide a flexible pressure-temperature sensor based on conductive nanofibers. This sensor has a simple fabrication process, can be used repeatedly over long periods, is easy to operate, and can be mass-produced.
[0006] Another object of the present invention is to provide an application of the above-mentioned flexible pressure and temperature sensor based on conductive nanofibers.
[0007] The technical solution adopted by the present invention to achieve the above objectives is as follows:
[0008] A method for fabricating a flexible pressure-temperature sensor based on conductive nanofibers includes the following steps:
[0009] S1. Preparation of polyvinyl butyral (PVB) nanofiber membrane: Polyvinyl butyral and a hydrophilic modifier were mixed and dissolved in an organic solvent to obtain a spinning solution; electrospinning was performed to obtain a polyvinyl butyral nanofiber membrane.
[0010] S2. Loading of conductive particles on nanofiber membrane: The obtained polyvinyl butyral nanofiber membrane was placed in a mixed solution of conductive monomer and oxidant for in-situ polymerization reaction, so that conductive particles were successfully loaded on the fiber surface to obtain a conductive fiber membrane; the obtained conductive fiber membrane was immersed in a thermoelectric material solution to obtain a fiber membrane with thermoelectric response function.
[0011] S3. The copper foil electrodes are bonded to both horizontal ends of the fiber membrane with thermoelectric response function obtained in step S2, and finally encapsulated with adhesive tape to obtain a flexible piezoresistive sensor.
[0012] Preferably, the organic solvent in step S1 is at least one of ethanol, N,N-dimethylformamide, acetone and propyl formate, and more preferably N,N-dimethylformamide.
[0013] Preferably, the mass concentration of polyvinyl butyral in the spinning solution in step S1 is 12-20 wt%.
[0014] Preferably, the hydrophilic modifier mentioned in step S1 is at least one of polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer (F127), polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer (P123), and polyoxyethylene-polyoxypropylene block copolymer (F68), and the added hydrophilic modifier has a mass concentration of 1~6 wt% in the spinning solution.
[0015] Preferably, the parameters for electrospinning in step S1 include: a spinning voltage range of 6~14 kV, a spinning receiving distance of 15~25 cm, a syringe advance speed of 0.3~1 mL / h, a collecting roller rotation speed of 100~500 rpm, a spinning ambient temperature of 25~60℃, and a relative humidity of 20~80 RH.
[0016] Preferably, after electrospinning in step S1, the resulting fiber membrane is dried, wherein the drying temperature is 40~60℃ and the drying time is 6~12 h.
[0017] Preferably, the oxidant in step S2 is at least one of FeCl3·6H2O, ammonium persulfate, and sulfuric acid, and the concentration of the oxidant in the mixed solution is 1 g / L to 10 g / L.
[0018] Preferably, the conductive monomer in step S2 is pyrrole (Py) or aniline; the mass ratio of oxidant to conductive monomer is 1:1 to 5:1.
[0019] Preferably, the ambient temperature of the in-situ polymerization reaction in step S2 is -10℃ to 10℃, and the reaction time is 6-12 h.
[0020] Preferably, in step S2, the prepared conductive fiber membrane is further rinsed with deionized water, and after rinsing, it is dried at 40°C for 2-4 hours.
[0021] Preferably, the thermoelectric material solution in step S2 is at least one of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), carbon nanotubes, and graphene, and the concentration of the prepared thermoelectric material solution is 1 g / L to 10 g / L.
[0022] Preferably, the immersion temperature in step S2 is 40~60℃, and the immersion time is 1~5 h.
[0023] Preferably, after impregnation in step S2, the resulting fiber membrane is dried, wherein the drying temperature is 20~60℃ and the drying time is 4~6 h.
[0024] Preferably, the tape used for packaging the sensor in step S3 is one of PI medical tape, polycarbonate tape, or PU medical tape.
[0025] The sensor prepared in step S3 has a wide pressure detection range and high sensitivity. In terms of temperature detection, the sensor can respond to different temperature changes and can be widely used in wearable electronic devices, human-computer interaction, new health and medical fields.
[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0027] 1. The preparation method provided by the present invention uses simple and readily available raw materials and is easy to operate. It uses polyvinyl butyral nanofibers to prepare conductive fiber membranes. Through the interaction between polypyrrole and PDEDOT:PSS, the conductivity of the fibers and the performance of the sensor can be effectively improved.
[0028] 2. The present invention adopts a layered integration of pressure layer and temperature layer, which can effectively improve the sensitivity and stability of pressure response of pressure-temperature sensor.
[0029] 3. The technical solution of the present invention has the advantages of simple preparation process, low cost and mass production capability. At the same time, the prepared flexible piezoresistive sensor has high sensitivity and wide operating range. Attached Figure Description
[0030] Figure 1 The image shows a scanning electron microscope (SEM) image of the PVB / P123 hybrid fiber membrane prepared in Example 1. The image shows that the fiber membrane is relatively uniform in size.
[0031] Figure 2 The image shows a scanning electron microscope (SEM) image of the PVB / P123 hybrid fiber membrane prepared in Example 2. The polypyrrole particles can be clearly seen bound to the fibers.
[0032] Figure 3 The image shows a scanning electron microscope (SEM) image of the conductive fiber membrane prepared in Example 5. The polypyrrole particles can be clearly seen bound to the fiber.
[0033] Figure 4 The image shows a scanning electron microscope (SEM) image of the fiber membrane with thermoelectric response prepared in Example 9. The image shows that the fiber twisted with the addition of PEDOT:PSS, indicating the successful loading of PEDOT:PSS.
[0034] Figure 5 The image shows the actual conductive fiber membrane prepared in Example 12. It can be seen that after the fiber membrane without P123 modification underwent in-situ growth of PPy, the membrane surface still maintained its initial white state and did not show the black surface characteristics after polymerization, indicating that PPy failed to form an effective load on its surface.
[0035] Figure 6 The image shows the actual conductive fiber membrane prepared in Example 5. It can be seen that after PPy was grown, the entire fiber membrane turned black, indicating the loading of PPy conductive particles on the surface of the fiber membrane.
[0036] Figure 7 The dynamic pressure response of the sensor prepared in Example 13 under 20-100 kPa shows that the rate of change of current gradually increases with the increase of pressure. At 100 kPa, the rate of change of current is 240. For a piezoresistive sensor, its sensitivity is the ratio of the rate of change of current to the change of pressure. The greater the rate of change of current under the same pressure, the higher the sensitivity of the prepared sensor.
[0037] Figure 8 The sensor prepared in Example 14 exhibits a dynamic pressure response between 20 and 100 kPa. Similarly, its current change rate increases with increasing pressure, reaching 380 at 100 kPa.
[0038] Figure 9The sensor assembled from the fiber membrane with thermoelectric response function prepared in Example 9 shows the dynamic pressure response at 20-100 kPa. It can be seen that compared with the fiber membrane with PPy or PEDOT:PSS added alone, the rate of change of current is significantly improved. The rate of change of current can reach 1100 at 100 kPa, indicating that the simultaneous loading of PPy and PEDOT:PSS can greatly improve the overall sensing performance of the fiber membrane.
[0039] Figure 10 The IV curves of the sensor prepared in Example 9 under different pressures show that as the pressure increases, the resistance continuously decreases, causing the slope of the IV curve to increase with the increase of pressure, which verifies that it has a good ohmic effect.
[0040] Figure 11 The sensitivity curve of the sensor prepared in Example 9 shows that its pressure range is divided into three regions, with a sensitivity of 26.92 kPa in the range of 0–3 kPa. -1 The sensitivity is 8.33 kPa for 3–100 kPa. -1 The sensitivity is 0.854 kPa at 100–1000 kPa. -1 It exhibits a clear current signal response to different pressure levels.
[0041] Figure 12 The current curve of the sensor prepared in Example 9 under continuous dynamic pressure of 20 kPa for 10,000 load-unload cycles shows that the current signal of the sensor has a certain fatigue stability after 10,000 cycles.
[0042] Figure 13 The voltage response curves of the sensor prepared in Example 9 under different temperature differences are shown in the figure. As the temperature difference increases, the voltage generated by the thermoelectric effect also increases.
[0043] Figure 14 The graph of the sensor prepared in Example 9 after 40 cycles in a temperature difference range of 1-15 K shows that the prepared sensor has good cyclic stability in response to temperature under multiple heating and cooling cycles. Detailed Implementation
[0044] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. All raw materials involved in the present invention can be purchased directly from the market. For process parameters not specifically specified, conventional techniques can be referred to.
[0045] The raw materials used in the examples are all commercially available products, with many purchasing channels and reasonable costs.
[0046] Example 1
[0047] Preparation of PVB / P123 hybrid fiber membrane: Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 2 wt% P123. The resulting solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 kV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 hybrid fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0048] Example 2
[0049] Preparation of PVB / P123 hybrid fiber membrane: Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 3 wt% P123. The resulting solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 kV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 hybrid fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0050] Example 3
[0051] Preparation of PVB / P123 hybrid fiber membrane: Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The resulting solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 kV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 hybrid fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0052] Example 4
[0053] Preparation of PVB / P123 hybrid fiber membrane: Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 5 wt% P123. The resulting solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 kV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 hybrid fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0054] Example 5
[0055] Preparation of conductive fiber membranes:
[0056] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0057] (2) Add 2 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0058] Example 6
[0059] Preparation of conductive fiber membranes:
[0060] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0061] (2) Add 3 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0062] Example 7
[0063] Preparation of conductive fiber membranes:
[0064] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0065] (2) Add 4 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0066] Example 8
[0067] Sensor fabrication:
[0068] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0069] (2) Add 2 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0070] (3) Add 1 g of PEDOT:PSS and 0.05 g of DMSO to 8 mL of deionized water and stir to mix them. Then place the resulting solution in an ultrasonic instrument and sonicate for 4 h to ensure thorough mixing and dissolution. Then pour the solution into a glass dish and place the conductive fiber membrane prepared above into it for impregnation. The impregnation temperature is 30 ℃ and the impregnation time is 2 h. After impregnation, place the fiber membrane in a vacuum oven at 40 ℃ for drying for 8 h to obtain a fiber membrane with thermoelectric response function.
[0071] (4) Coat the left and right ends of the obtained fiber membrane with thermoelectric response function with silver paste and attach it with copper foil. Then, stack the prepared fiber membrane with thermoelectric response function in three layers neatly in the orthogonally placed fiber electrode. Finally, use medical PI tape to encapsulate and prepare the sensor.
[0072] Example 9
[0073] Sensor fabrication:
[0074] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0075] (2) Add 2 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0076] (3) Add 2 g of PEDOT:PSS and 0.05 g of DMSO to 7 mL of deionized water and stir to mix them. Then place the resulting solution in an ultrasonic instrument and sonicate for 4 h to ensure thorough mixing and dissolution. Then pour the solution into a glass dish and place the conductive fiber membrane prepared above into it for impregnation. The impregnation temperature is 30 ℃ and the impregnation time is 2 h. After impregnation, place the fiber membrane in a vacuum oven at 40 ℃ for drying for 8 h to obtain a fiber membrane with thermoelectric response function.
[0077] (4) Coat the left and right ends of the obtained fiber membrane with thermoelectric response function with silver paste and attach it with copper foil. Then, stack the prepared fiber membrane with thermoelectric response function in three layers neatly in the orthogonally placed fiber electrode. Finally, use medical PI tape to encapsulate and prepare the sensor.
[0078] Example 10
[0079] Sensor fabrication:
[0080] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0081] (2) Add 2 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0082] (3) Add 3 g of PEDOT:PSS and 0.05 g of DMSO to 6 mL of deionized water and stir to mix them. Then place the resulting solution in an ultrasonic instrument and sonicate for 4 h to ensure thorough mixing and dissolution. Then pour the solution into a glass dish and place the conductive fiber membrane prepared above into it for impregnation. The impregnation temperature is 30 ℃ and the impregnation time is 2 h. After impregnation, place the fiber membrane in a vacuum oven at 40 ℃ for drying for 8 h to obtain a fiber membrane with thermoelectric response function.
[0083] (4) Coat the left and right ends of the obtained fiber membrane with thermoelectric response function with silver paste and attach it with copper foil. Then, stack the prepared fiber membrane with thermoelectric response function in three layers neatly in the orthogonally placed fiber electrode. Finally, use medical PI tape to encapsulate and prepare the sensor.
[0084] Example 11
[0085] Sensor fabrication:
[0086] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0087] (2) Add 2 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0088] (3) Add 4 g of PEDOT:PSS and 0.05 g of DMSO to 6 mL of deionized water and stir to mix them. Then place the resulting solution in an ultrasonic instrument and sonicate for 4 h to ensure thorough mixing and dissolution. Then pour the solution into a glass dish and place the conductive fiber membrane prepared above into it for impregnation. The impregnation temperature is 30 ℃ and the impregnation time is 2 h. After impregnation, place the fiber membrane in a vacuum oven at 40 ℃ for drying for 8 h to obtain a fiber membrane with thermoelectric response function.
[0089] (4) Coat the left and right ends of the obtained fiber membrane with thermoelectric response function with silver paste and attach it with copper foil. Then, stack the prepared fiber membrane with thermoelectric response function in three layers neatly in the orthogonally placed fiber electrode. Finally, use medical PI tape to encapsulate and prepare the sensor.
[0090] Example 12
[0091] Preparation of conductive fiber membranes:
[0092] (1) Polyvinyl butyral (PVB) was dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30°C for 5 h to prepare an electrospinning solution of 16 wt% PVB. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 11 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.6 mL / h, temperature 30°C, and humidity 48%RH to obtain a PVB fiber membrane. The obtained fiber membrane was then dried in an oven at 60°C for 6 h to remove residual organic solvents.
[0093] (2) Add 2 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0094] Example 13
[0095] Sensor fabrication:
[0096] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0097] (2) Add 2 g FeCl3·6H2O to a glass dish containing 500 mL of deionized water and let it dissolve completely. Cut the prepared PVB / P123 mixed fiber membrane into a suitable size and add it to the dish. Place it at 0 ℃ for 1 h. Then add 1 g of pyrrole (Py) to the dish for in-situ polymerization reaction. The reaction time is 8 h. After the reaction is completed, rinse the prepared conductive fiber membrane with deionized water multiple times. After rinsing, place it in an oven at 60 ℃ to dry for 8 h.
[0098] (3) Coat the left and right ends of the obtained conductive fiber membrane with silver paste and attach it with copper foil. In addition, stack the prepared conductive fiber membrane in three layers and place it in the orthogonally placed fiber electrode. Finally, encapsulate it with medical PI tape to prepare the sensor.
[0099] Example 14
[0100] Sensor fabrication:
[0101] (1) Polyvinyl butyral (PVB) and polyethylene oxide-polypropylene oxide-polyethylene oxide (P123) were dissolved in N,N-dimethylformamide (DMF) solution and then stirred at 30 °C for 5 h to prepare an electrospinning solution of 16 wt% PVB and 4 wt% P123. The obtained solution was poured into a syringe and electrospinned under the following conditions: external voltage 8 KV, distance between spinning needle and roller 15 cm, roller speed 100 rpm, solution supply rate 0.5 mL / h, temperature 30 °C, and humidity 48 %RH to obtain a PVB / P123 mixed fiber membrane. The obtained fiber membrane was then dried in an oven at 60 °C for 6 h to remove residual organic solvents.
[0102] (2) Add 2 g of PEDOT:PSS and 0.05 g of DMSO to 6 mL of deionized water and stir to mix them. Then place the resulting solution in an ultrasonic instrument and sonicate for 4 h to ensure thorough mixing and dissolution. Then pour the solution into a glass dish and place the prepared PVB / P123 hybrid fiber membrane in it for impregnation. The impregnation temperature is 30 ℃ and the impregnation time is 2 h. After impregnation, place the conductive fiber membrane in a vacuum oven at 40 ℃ for drying for 8 h.
[0103] (3) Coat the left and right ends of the obtained conductive fiber membrane with silver paste and attach it with copper foil. In addition, stack the prepared conductive fiber membrane in three layers and place it in the orthogonally placed fiber electrode. Finally, encapsulate it with medical PI tape to prepare the sensor.
[0104] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for fabricating a flexible pressure-temperature sensor based on conductive nanofibers, characterized in that, Includes the following steps: S1. Polyvinyl butyral and a hydrophilic modifier are mixed and dissolved in an organic solvent to obtain a spinning solution; electrospinning is performed to obtain a polyvinyl butyral nanofiber membrane. S2. The obtained polyvinyl butyral nanofiber membrane is placed in a mixed solution of conductive monomer and oxidant for in-situ polymerization to obtain a conductive fiber membrane; the obtained conductive fiber membrane is immersed in a thermoelectric material solution to obtain a fiber membrane with thermoelectric response function. S3. The copper foil electrodes are bonded to both horizontal ends of the fiber membrane with thermoelectric response function obtained in step S2, and finally encapsulated with adhesive tape to obtain a flexible piezoresistive sensor.
2. The preparation method according to claim 1, characterized in that, The hydrophilic modifier mentioned in step S1 is at least one of polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, polyoxyethylene-polyoxypropylene-polyoxyethylene triblock copolymer, and polyoxyethylene-polyoxypropylene block copolymer, and the mass concentration of the hydrophilic modifier in the spinning solution is 1~6wt%.
3. The preparation method according to claim 1, characterized in that, The organic solvent mentioned in step S1 is at least one of ethanol, N,N-dimethylformamide, acetone and propyl formate; In step S1, the mass concentration of polyvinyl butyral in the spinning solution is 12-20 wt%. The parameters for electrospinning in step S1 include: spinning voltage range of 6~14 kV, spinning receiving distance of 15~25 cm, syringe advance speed of 0.3~1 mL / h, collecting roller rotation speed of 100~500 rpm, spinning ambient temperature of 25~60℃, and relative humidity of 20~80 RH.
4. The preparation method according to claim 1, characterized in that, The oxidant mentioned in step S2 is at least one of FeCl3·6H2O, ammonium persulfate, and sulfuric acid, and the concentration of the oxidant in the mixed solution is 1 g / L to 10 g / L.
5. The preparation method according to claim 1, characterized in that, The conductive monomer mentioned in step S2 is pyrrole or aniline; the mass ratio of oxidant to conductive monomer is 1:1 to 5:
1.
6. The preparation method according to claim 1, characterized in that, The ambient temperature for the in-situ polymerization reaction in step S2 is -10℃ to 10℃, and the reaction time is 6-12 h.
7. The preparation method according to claim 1, characterized in that, The thermoelectric material solution mentioned in step S2 is at least one of poly(3,4-ethylenedioxythiophene): polystyrene sulfonate, carbon nanotubes, and graphene, and the concentration of the prepared thermoelectric material solution is 1 g / L to 10 g / L.
8. The preparation method according to claim 1, characterized in that, The immersion temperature in step S2 is 40~60℃, and the immersion time is 1~5 h.
9. A flexible pressure-temperature sensor based on conductive nanofibers, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.
10. The application of the flexible pressure and temperature sensor based on conductive nanofibers as described in claim 9 in wearable electronic devices, human-computer interaction, or healthcare fields.