Temperature-humidity-pressure multi-mode self-powered composite flexible device and preparation method thereof

Abstract

The invention relates to the technical field of sensors, in particular to a temperature-humidity-pressure multi-mode self-energized composite flexible device and a preparation method thereof. The composite flexible device comprises a temperature and humidity sensing layer and a pressure sensing layer which are integrated and combined. The temperature and humidity sensing layer comprises an electrode layer, a poly (diallyldimethylammonium chloride) layer, a polystyrolsulfon acid-polyvinyl alcohol-silk protein layer and an electrode layer from bottom to top. The pressure sensing layer comprises an interdigital electrode layer, an electrode layer and a polydimethylsiloxane layer from bottom to top, the interdigital electrode layer comprises silver paste and a substrate, the substrate is arranged on the electrode layer on the uppermost layer of the temperature and humidity sensing layer, and the area of the substrate in the horizontal direction is smaller than that of the electrode layer. The temperature and humidity sensor layer and the pressure sensing layer are combined, and the temperature, humidity and pressure sensing functions can be achieved in one device at the same time.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a temperature-humidity-pressure multimodal self-powered composite flexible device and its fabrication method. Background Technology

[0002] With the continuous advancement of flexible electronics technology and its widespread application in emerging fields such as wearable devices, environmental monitoring, and biomedicine, traditional single-function flexible sensors can no longer meet the diverse and intelligent sensing needs. Especially in complex scenarios such as smart healthcare, health management, and human-computer interaction, there is an urgent need for a highly integrated device that can simultaneously sense multiple environmental information and has self-powering capabilities.

[0003] Currently, multimodal flexible sensors have become a research hotspot, as they can simultaneously monitor multiple physical quantities such as temperature, humidity, and pressure, and significantly improve the dimensionality and accuracy of information sensing. However, most multimodal devices still face key bottlenecks such as complex manufacturing processes, high integration difficulty, and reliance on external power supplies, which restrict their large-scale application in wearable systems and passive sensor networks. Summary of the Invention

[0004] This invention provides a temperature-humidity-pressure multimodal self-powered composite flexible device and its fabrication method, aiming to solve the problem that existing sensors cannot accurately detect temperature, humidity and pressure simultaneously.

[0005] To achieve the above objectives, the present invention provides a temperature-humidity-pressure multimodal self-powered composite flexible device. The composite flexible device comprises an integrated temperature and humidity sensing layer and a pressure sensing layer. The temperature and humidity sensing layer comprises, from bottom to top, an electrode layer, a polydiallyldimethylammonium chloride layer, a polystyrene sulfonate-polyvinyl alcohol-silk protein layer, and an electrode layer. The pressure sensing layer comprises, from bottom to top, an interdigitated electrode layer, an electrode layer, and a polydimethylsiloxane layer. The interdigitated electrode layer comprises silver paste and a substrate, with the substrate disposed on the uppermost electrode layer of the temperature and humidity sensing layer, and its horizontal area being smaller than that of the electrode layer.

[0006] This invention patent proposes a multimodal self-powered composite flexible device based on thin-film technology. This device has a simple structure, controllable cost, and the ability to simultaneously monitor multiple physical signals, including temperature (via capacitance change), humidity (via voltage response), and pressure (via resistance change). This application integrates a temperature and humidity sensing structure with a pressure sensing structure, constructing a comprehensive composite flexible device without affecting the functionality of either.

[0007] Temperature and humidity sensing structures typically need to be in close contact with the object or part being measured to achieve accurate temperature and humidity monitoring. Pressure sensors, on the other hand, do not have this requirement. Furthermore, to meet the requirements of high-precision detection, the temperature and humidity sensor layer needs to maintain temperature exchange with the environment, which imposes certain limitations on the air permeability and thickness of its outer structure. In this application, the substrate of the pressure sensing layer is placed on the top electrode layer of the temperature and humidity sensing layer, with a horizontal area smaller than that of the temperature and humidity sensing layer. Moreover, the substrate is usually not a complete layered structure. This design helps to maintain the heat exchange capacity of the temperature and humidity sensor layer and ensure its monitoring accuracy. On the other hand, to meet the monitoring function of the pressure sensor, its distance from the object being measured cannot be too high. In this application, the temperature and humidity sensing layer is provided with a multi-material polymer layer such as polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer, which can improve the film flexibility and temperature sensing performance, reduce the thickness of the temperature and humidity sensing layer to a certain extent, and ensure the monitoring performance of the pressure sensing layer.

[0008] More importantly, the composite flexible device also possesses self-powering capabilities. The temperature and humidity sensing layer primarily utilizes the reaction of wet-electric materials to ambient moisture, enabling a certain output of electrical energy, with the output voltage value characterizing the corresponding humidity. Moisture power generation uses ambient moisture as an energy source, achieving energy harvesting at the micro-nano scale and exhibiting excellent self-powering characteristics. Different moisture power generation materials are used in the device's middle layer structure, each with varying ion dissociation capabilities, creating an internal ion concentration gradient and achieving directional diffusion of ion currents, which can improve moisture power generation performance to a certain extent. In the polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer, both polystyrene sulfonic acid and polyvinyl alcohol can perform moisture power generation, and the combination of these two materials further enhances moisture power generation performance. Polyvinyl alcohol and silk protein make the film more flexible and less prone to warping; silk protein helps this layer structure absorb moisture, further improving its hygroscopic performance. The polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer forms a gradient structure with polydiallyldimethylammonium chloride. The adsorbed water content affects the dissociated ion content, correspondingly creating an ion concentration gradient within the material to enhance the moisture power generation performance of this layer structure.

[0009] In summary, this device not only improves the energy independence of the system, but also provides new ideas for the integration and intelligence of low-power, multifunctional flexible electronic systems, and has broad application prospects and industrial value.

[0010] Preferably, in the polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer, the mass ratio of polyvinyl alcohol, polystyrene sulfonic acid and silk protein is 0.8~1.2:4.8~5.2:1-3.

[0011] The added silk protein can not only form a porous structure in the film, which helps moisture permeate and improves the performance of moisture power generation, but also changes the dielectric constant of the silk protein due to changes in ambient temperature. Therefore, the ambient temperature can be characterized by measuring the capacitance value of the device.

[0012] Preferably, the polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer has a thickness of 110~130μm; the polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer has a porous structure with a porosity of 0.08-0.12.

[0013] Preferably, the polydiallyldimethylammonium chloride layer has a thickness of 55-65 μm; the electrode layer is silver nanowire with a thickness of 12-22 μm. The electrode layers on both sides allow for easy access to test electrodes, enabling the acquisition and testing of the device's output voltage and capacitance. By comparing conductive carbon paste and silver nanowires as electrode layer materials, silver nanowires demonstrate better conductivity, a simpler and more stable preparation process, and a sparser structure at the microscale, allowing moisture to more easily permeate the electrode layer and improving the moisture absorption performance of the temperature and humidity layer. The combination of silver nanowires and the interdigitated electrodes of the pressure layer provides better sensitivity and stability for pressure sensing.

[0014] Preferably, the interdigitated electrode layer has a thickness of 190-210 μm, and the substrate includes a PI substrate and / or a paper-based substrate; more preferably, it is a paper-based substrate; by comparing the effects of the two substrates on the overall device's water permeability and thickness, the paper-based substrate has better performance; the polydimethylsiloxane layer has a thickness of 95-105 μm, and its single-sided surface has a pyramidal microstructure with a height difference of 10-15 μm.

[0015] The pressure sensing layer mainly consists of microstructured PDMS and an interdigitated electrode layer. Silver nanowires are spin-coated onto the surface of the PDMS microstructure to form an electrode layer, which covers the interdigitated electrode layer. By pressing the PDMS film, the silver nanowire electrode layer contacts the interdigitated electrodes, creating electrical conductivity between them. This allows the interdigitated electrodes to exhibit different resistance values ​​under different pressures, thus characterizing the pressure. Simultaneously, a paper-based substrate is used for printing the interdigitated electrodes, resulting in good printability and flexibility that meets the overall device's flexibility requirements.

[0016] PDMS has surface microstructures and interdigitated electrode contact, which can improve the stability of pressure sensing during the pressing process. Compared with PDMS without microstructures, the special microstructures can make the pressure sensing characterization data more obvious.

[0017] Under the same technical concept, this application also provides a method for fabricating a temperature-humidity-pressure multimodal self-powered composite flexible device, comprising the following steps:

[0018] (1) Mix polystyrene sulfonic acid solution and polyvinyl alcohol solution thoroughly, then add silk protein solution, stir thoroughly, and remove air bubbles from the solution surface by vacuuming to obtain a mixed solution; dry the mixed solution once to obtain a mixed film; spin coat polydiallyldimethylammonium chloride solution onto the mixed film, dry it a second time, and then spin coat electrode layer material solution on both sides of the film to obtain a temperature and humidity sensor layer;

[0019] (2) Printing preparation of interdigitated electrodes; spin coating polydimethylsiloxane solution onto silicon wafer template, drying and demolding to obtain polydimethylsiloxane layer with single-sided surface microstructure; ion cleaning, spin coating electrode layer material onto the side with surface microstructure, drying again, combining interdigitated electrodes with it to obtain pressure sensing layer;

[0020] (3) Combine the temperature and humidity sensor layer and the pressure sensor layer, lead out wires from the corresponding electrode layer, and encapsulate to obtain a temperature-humidity-pressure multimodal self-powered composite flexible device.

[0021] Preferably, in step (1), the first drying is performed at 40℃-50℃ for 3-5 hours; the second drying is performed at 40℃-50℃ for 20-30 minutes; the parameters for spin coating of the polydiallyldimethylammonium chloride solution are set to 700r / min-800r / min for 10 seconds; and the parameters for spin coating of the electrode layer material solution are set to 700r / min-800r / min for 5-15 seconds.

[0022] Preferably, the amounts of polyvinyl alcohol, polystyrene sulfonic acid solution, polydiallyl dimethyl ammonium chloride and electrode layer material solution added in steps (1) and (2) are 5wt%-10wt%, 10wt%-15wt%, 35wt%-40wt%, and 90wt%-95wt%.

[0023] Preferably, the drying and demolding in step (2) is performed at 70℃-80℃ for 40min-50min; the re-drying is performed at 150℃-160℃ for 10min-20min; the ion cleaning is performed using an ion cleaner for 50s-60s; and the parameters of the spin-coated electrode layer material solution are set to 700r / min-800r / min for 5s-8s.

[0024] Preferably, the combination in step (3) specifically includes using PI tape to bond the substrate of the pressure sensing layer to the polydiallyl dimethyl ammonium chloride layer of the temperature and humidity sensor layer, thereby completing the encapsulation of the overall device.

[0025] The above-described solution of the present invention has the following beneficial effects:

[0026] (1) The temperature-humidity-pressure multimodal self-powered composite flexible device provided by the present invention is divided into a temperature and humidity sensing layer and a pressure sensing layer. The temperature and humidity sensing layer is mainly composed of silver nanowire layers on both sides, polydiallyl dimethyl ammonium chloride (PDDA) layer, and polystyrene sulfonic acid & polyvinyl alcohol & silk protein (PSS & PVA & Fibroin). Both the polydiallyl dimethyl ammonium chloride (PDDA) layer and the polystyrene sulfonic acid & polyvinyl alcohol & silk protein (PSS & PVA & Fibroin) layer can be used as good moisture power generation materials. Based on the interaction between moisture and functional material interface, the conversion of chemical energy caused by water molecules into electrical energy is realized through moisture adsorption, ion dissociation and ion directional diffusion. Compared with the use of single-layer moisture power generation materials, the two-layer moisture power generation materials have different charge dissociation performance under the same humidity environment, which effectively increases the type and number of charge carriers. The ion concentration difference between the two layers can also further promote charge orientation and improve the performance output of moisture power generation.

[0027] (2) The pressure sensing layer is mainly composed of a polydimethylsiloxane (PDMS) layer with microstructure, a silver nanowire layer, an interdigitated electrode layer, and a paper substrate. PDMS has good flexibility, and specific microstructures can be formed on the surface of the PDMS film by using a silicon wafer template. Such microstructures can improve the performance of pressure sensing to a certain extent. In order to realize pressure sensing, a silver nanowire layer needs to be added between PDMS and the interdigitated electrode so that the interdigitated electrode exhibits different conduction states under different pressure conditions, and pressure sensing is achieved through resistance values. Conductive silver paste is used as the printing material for the interdigitated electrode and is printed on PI and the paper substrate. After testing and analysis, the printing effect on the paper substrate is better, and it has better flexibility for subsequent pressure sensing tests. In addition, the paper substrate has better water permeability, which can further ensure the wet electrical output performance of the temperature and humidity sensing layer. The pressure sensing layer and temperature / humidity sensing layer of this application are mainly combined in a stacked manner. While both layers can be used independently, they are combined in a multi-layered structure, minimizing the influence between the various sensing functions. This ensures excellent sensing and energy harvesting performance while maintaining a slim profile. Through multi-layered integration, this device possesses multiple sensing and energy harvesting functions, achieving flexible miniaturization and promising wearable applications.

[0028] (3) The temperature sensing function of this device can realize temperature sensing from 25℃ to 60℃, and its capacitance temperature coefficient is approximately 2.714%℃. -1It exhibits good cycle stability. In humidity sensing, this device outputs different voltage values ​​under varying humidity conditions. By exploring different material ratios, the optimal performance device was obtained, capable of outputting a voltage of 0.35V-0.5V in high humidity environments (60%RH-90%RH) to characterize ambient humidity. Simultaneously, it can achieve a maximum power output of 0.18μW to drive small, low-power components. For pressure sensing, this device can achieve a three-segment measurement window: 0-25kPa, 25kPa-85kPa, and 85kPa-450kPa, exhibiting good linear sensing sensitivity of 4.45kPa in the low-pressure range of 0-25kPa. -1 Furthermore, it exhibits good sensing performance in repetitive pressing tests, sensing tests involving finger joint bending, and response tests to slight finger pressing.

[0029] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0030] Figure 1 This is a three-dimensional structural schematic diagram of the temperature-humidity-pressure multimodal self-powered composite flexible device of this application;

[0031] Figure 2 This is a side view of the temperature-humidity-pressure multimodal self-powered composite flexible device of this application;

[0032] Figure 3 The silicon wafer template microstructure for the temperature-humidity-pressure multimodal self-powered composite flexible device of this application;

[0033] Figure 4 The dimensions of the interdigitated electrode structure of the temperature-humidity-pressure multimodal self-powered composite flexible device of this application are shown.

[0034] Figure 5 The images show physical images of the temperature-humidity-pressure multimodal self-powered composite flexible device of this application, including (a) the temperature and humidity sensing layer; (b) the pressure sensing layer; (c) the printed image of the interdigitated electrodes; and (d) the dimensional details of the interdigitated electrodes.

[0035] Figure 6 This is a process flow diagram for fabricating the temperature and humidity sensing layer of the temperature-humidity-pressure multimodal self-powered composite flexible device of this application.

[0036] Figure 7 This is a flowchart illustrating the fabrication process of the printed interdigitated electrodes for the temperature-humidity-pressure multimodal self-powered composite flexible device of this application.

[0037] Figure 8This is a flowchart illustrating the fabrication process of the PDMS (microstructure) for the temperature-humidity-pressure multimodal self-powered composite flexible device of this application.

[0038] Figure 9 This is a flowchart illustrating the fabrication process of the silver nanowire electrode layer for the temperature-humidity-pressure multimodal self-powered composite flexible device of this application.

[0039] Figure 10 This is a complete process flow diagram for the fabrication of the composite device assembly of the temperature-humidity-pressure multimodal self-powered flexible composite device of this application.

[0040] Figure 11 Optical mirror images of thin films prepared with different material ratios for the temperature and humidity sensing layers of Example 1 and Comparative Example 1 of this application;

[0041] Figure 12 The wet voltage output performance of the device with different material ratios without the addition of silk protein is shown in Comparative Example 1.

[0042] Figure 13 The wet power output performance of the devices with different material ratios without the addition of silk protein in Comparative Example 1 is shown in the figure.

[0043] Figure 14 The graph shows the wet voltage output performance of the device with different material ratios when silk protein was added in Example 1.

[0044] Figure 15 The graph shows the wet power output performance of the device with different material ratios when silk protein was added in Example 1.

[0045] Figure 16 The following is a temperature output performance test diagram of the temperature and humidity sensing layer of Embodiment 1 of this application, wherein (a) is the temperature hysteresis curve; (b) is the relative change curve of the device's capacitance during the heating process; and (c) is the relative change curve of the device's capacitance during the cooling process.

[0046] Figure 17 The curves showing the change in sensing resistance of the pressure sensing layer in Embodiment 1 of this application under pressures ranging from 0 to 450 kPa are shown.

[0047] Figure 18 The curve showing the relative change in pressure sensing resistance of the pressure sensing layer in Embodiment 1 of this application under 0-450 kPa is shown.

[0048] Figure 19-21 (c)-(e) are the pressure sensing resistance variation curves of the pressure sensing layer in Embodiment 1 of this application under the three segments of low, medium and high pressure sensing resistance;

[0049] Figure 22-24 (f)-(h) show the relative changes and fitting curves of the pressure sensing resistance of the pressure sensing layer in Embodiment 1 of this application under the three segments of low, medium and high pressure sensing resistance;

[0050] Figure 25-27 This is a pressure sensing repeatability test chart of the pressure sensing layer prepared in Example 1 of this application, wherein... Figure 25 (a) Curve of repeated compressions for 20-40 seconds; Figure 26 (b) 0-110s repeated compression curve; Figure 27 (c) 100-110s repeated compression curve;

[0051] Figures 28-29 This is a finger joint bending sensing attempt of the pressure sensing layer in Embodiment 1 of this application, wherein... Figure 28 (a) Relative changes in resistance at different angles; Figure 29 (b) is a diagram showing the bending angle of the finger joints;

[0052] Figure 30 The following are test diagrams of the finger pressure response of the pressure sensing layer in Embodiment 1 of this application, including (a) the resistance response curve under multiple presses; (b) the resistance response curve under a single press; (c)-(d) the response time diagram under a single press; and (e) the finger press diagram. Detailed Implementation

[0053] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0054] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0056] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0057] Example 1:

[0058] This embodiment provides a temperature-humidity-pressure multimodal self-powered composite flexible device, the structural schematic of which is shown below. Figure 1-4 As shown in the picture, the actual product is as follows. Figure 5 As shown, the device comprises an integrated temperature and humidity sensing layer and a pressure sensing layer. The temperature and humidity sensing layer, from bottom to top, consists of a silver nanowire layer, a polydiallyldimethylammonium chloride layer, a polystyrene sulfonate-polyvinyl alcohol-silk protein layer, and another silver nanowire layer. The pressure sensing layer, from bottom to top, consists of an interdigitated electrode layer, a silver nanowire layer, and a polydimethylsiloxane layer. The interdigitated electrode layer comprises silver paste and a substrate. The thickness of each layer is as follows:

[0059] Silver nanowire layer: 20 μm;

[0060] Polydiallyl dimethylammonium chloride layer: 60 μm;

[0061] Polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer: 120μm;

[0062] Silver nanowire layer: 20 μm;

[0063] Interdigitated electrode layer (including paper substrate): 200 μm;

[0064] Silver nanowire layer: 20 μm;

[0065] The polydimethylsiloxane layer is 100 μm thick and has a single-sided surface microstructure. The surface microstructure is pyramidal, and the height difference of the pyramidal microstructure is 13 μm.

[0066] The polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer has a porous structure with a porosity of 0.1.

[0067] Its preparation process flow chart is as follows Figure 6-10 As shown, it includes the following steps:

[0068] Step 1: Thoroughly mix polystyrene sulfonic acid (PSS) solution (25 wt%) and polyvinyl alcohol (PVA) solution (5 wt%) to obtain a PSSA mixed solution.

[0069] Step 2: Add silk protein Fibroin solution to the PSSA mixed solution, stir thoroughly, and remove air bubbles from the solution surface by vacuuming to obtain PSSA & Fibroin mixed solution.

[0070] This embodiment provides different polystyrene sulfonic acid, polyvinyl alcohol, and silk protein mass concentration ratios to obtain temperature and humidity sensing layers for three temperature-humidity-pressure multimodal self-powered composite flexible devices, denoted as device 6 (PVA:PSS:Fibroin=1:5:1), device 7 (PVA:PSS:Fibroin=1:5:2), and device 8 (PVA:PSS:Fibroin=1:5:3).

[0071] Step 3: Pour the PSSA & Fibroin mixed solution into a PET mold and dry it at 45°C for 4 hours to obtain a PSSA & Fibroin film.

[0072] Step 4: Add polydiallyldimethylammonium chloride (PDDA) solution (35 wt%) to the PSSA & Fibroin film by spin coating. The spin coating parameters are set to 800 r / min for 10 s, and then dried at 45°C for 30 min.

[0073] Step 5: Spin-coat silver nanowire solution (95wt%) on both sides of the film. Set the spin-coating parameters to 800r / min for 10s and dry at 45℃ for 20min to obtain the temperature and humidity sensing layer.

[0074] Step 6: Using a high-precision small screen printing machine, print interdigital electrodes with 5 pairs of interdigitated fingers, each interdigitated finger being 0.8 mm wide and the interdigitated fingers being 0.6 mm apart, on the printing paper using conductive silver paste. The printed interdigital electrodes are obtained by printing in one pass.

[0075] Step 7: Pour the prepared PDMS solution onto the silicon wafer template by spin coating, dry it at 70°C for 45 minutes, and then peel it off to obtain PDMS with surface microstructure.

[0076] Step 8: Place the PDMS film in a plasma cleaner for 60 seconds to improve the hydrophilicity of the film surface.

[0077] Step 9: Spin-coat the silver nanowire solution (95wt%) onto the side with the microstructure. Set the spin-coating parameters to 800 r / min for 5 s and dry at 160 °C for 10 min.

[0078] Step 10: Finally, combine the interdigitated electrode layer with PDMS to obtain the pressure sensing layer.

[0079] Step 11: Using PI tape, attach the back of the paper base layer of the pressure sensing layer to the temperature and humidity sensor layer near the PDDA layer to complete the overall device encapsulation and obtain a temperature-humidity-pressure multimodal self-powered composite flexible device.

[0080] The performance of the obtained temperature-humidity-pressure multimodal self-powered composite flexible device was tested, including the following steps:

[0081] Step 12: Test the humidity output performance of the device. Under high humidity conditions of 60%RH-90%RH, measure the output voltage and current values ​​at both ends of the electrodes to obtain the humidity power generation output voltage and output power of the device.

[0082] Step 13: Test the temperature sensing performance of the device, the relative change of its capacitance between 25℃ and 60℃, and the hysteresis curves of capacitance as temperature increases and decreases.

[0083] Step 14: Test the pressure sensing performance of the device, including the change in its resistance under pressures of 0-450 kPa, and perform repeatability tests.

[0084] Step 15: Test the change in resistance of the pressure sensing layer of the test device when the finger joint is bent, and test the response time when the finger is pressed lightly.

[0085] According to step 12, the wet current output performance of the temperature-humidity-pressure multimodal self-powered composite flexible device in this embodiment is as follows: Figure 11 , 14 As shown in Figure 15. Figure 14 , 15 In the diagram, D5 data represents device 3 (PVA:PSS=1:5) in Comparative Example 1.

[0086] Figure 11 Optical mirror images of thin films prepared with different material ratios for the temperature and humidity sensing layers of Example 1 and Comparative Example 1 of this application;

[0087] According to step 13, the temperature sensing performance of the multimodal self-powered composite flexible device in this embodiment is as follows: Figure 16 As shown, the temperature sensing characteristics of this device were tested in an environment of 25℃-60℃, and its temperature coefficient of capacitance was approximately 2.714%℃⁻¹; Figure 16 As can be seen from (b)-(c), the device exhibits good cycle stability during heating and cooling tests.

[0088] According to step 14, the pressure sensing performance of the multimodal self-powered composite flexible device in this embodiment is as follows: Figure 17-24 As shown, Figure 17 The curves showing the change in sensing resistance of the pressure sensing layer in Embodiment 1 of this application under pressures ranging from 0 to 450 kPa are shown.

[0089] Figure 18 The curve showing the relative change in pressure sensing resistance of the pressure sensing layer in Embodiment 1 of this application under 0-450 kPa is shown.

[0090] Figure 19-21 (c)-(e) are the pressure sensing resistance variation curves of the pressure sensing layer in Embodiment 1 of this application under the three segments of low, medium and high pressure sensing resistance;

[0091] Figure 22-24 (f)-(h) show the relative changes and fitting curves of the pressure sensing resistance of the pressure sensing layer in Embodiment 1 of this application under the three segments of low, medium and high pressure sensing resistance;

[0092] The pressure sensing resistance of this device was tested under pressure ranges of 0-450 kPa. The test results are mainly divided into resistance changes. Figure 17 (a) Figure 19 (c)-21(e) and the relative change in resistance Figure 18 (b) Figure 22 (f)-24(h); Based on the overall pressure sensing performance of the device, it can be mainly divided into three measurement windows: low pressure (0-25 kPa), medium pressure (25-85 kPa), and high pressure (85 kPa-450 kPa). In the 0-25 kPa low-pressure range, it exhibits good linear sensing sensitivity of 4.45% kPa^(-1); in the 25-85 kPa medium-pressure range, the device shows good sensitivity between 25 kPa and 40 kPa, with a relative resistance change range reaching 90%; in the 85 kPa-450 kPa high-pressure range, the device exhibits good sensitivity between 85 kPa and 300 kPa, with a relative resistance change range reaching 75%.

[0093] The device was subjected to a pressure sensing repeatability test for approximately 100 seconds. Figure 25-27 This is a pressure sensing repeatability test chart of the pressure sensing layer prepared in Example 1 of this application, wherein... Figure 25 (a) Curve of repeated compressions for 20-40 seconds; Figure 26 (b) 0-110s repeated compression curve; Figure 27 (c) 100-110s repeated pressing curve; As can be seen from Figures (a)-(c), under the same pressure repeated pressing, the resistance can maintain a stable downward trend, and the resistance drops to 5000kΩ.

[0094] According to step 15, the pressure sensing performance of the multimodal self-powered composite flexible device in this embodiment is as follows: Figures 28-29As shown, the device was attached to a finger joint for sensing tests at different bending angles. The device's resistance variation range reached 80% within the 0°-90° range.

[0095] like Figure 30 As shown, a pressure response test is performed by lightly pressing the device with a finger. Figure 30 As known from (c)-(d), the device response time under a single press is approximately 0.15s-0.2s.

[0096] Comparative Example 1:

[0097] The other schemes in this comparative example are completely consistent with those in Example 1, except that: no silk protein is added, and four different mass ratios of polystyrene sulfonic acid and polyvinyl alcohol are provided to prepare the temperature and humidity sensing layer. The resulting temperature-humidity-pressure multimodal self-powered composite flexible devices are respectively named as follows: Device 1 (PVA:PSS=1:2), Device 2 (PVA:PSS=1:3), Device 3 (PVA:PSS=1:5), and Device 4 (PVA:PSS=1:8).

[0098] Following step 12 in Example 1, the humidity output performance of the device in Comparative Example 1 was tested.

[0099] Figure 12 The wet voltage output performance of the device with different material ratios without the addition of silk protein is shown in Comparative Example 1.

[0100] Figure 13 The wet power output performance of the devices with different material ratios without the addition of silk protein in Comparative Example 1 is shown in the figure.

[0101] Figure 14 The graph shows the wet voltage output performance of the device with different material ratios when silk protein was added in Example 1.

[0102] Figure 15 The graph shows the wet power output performance of the device with different material ratios when silk protein was added in Example 1.

[0103] Depend on Figure 12-13 It can be seen that device 3 (PVA:PSS=1:5) has the best output performance, with a maximum output voltage of approximately 0.55V and a maximum output power of approximately 0.025μW; Figure 14-15 It can be seen that the output performance of the device is significantly improved after the addition of silk protein. Device 7 (PVA:PSS:Fibroin=1:5:2) has the best output performance, with a small increase in output voltage and a significant increase in output power of about 7 times, up to a maximum of 0.18μW. The combination of polystyrene sulfonic acid, polyvinyl alcohol and silk protein can improve the output performance of the device and has a certain synergistic effect.

[0104] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A temperature-humidity-pressure multimodal self-powered composite flexible device, characterized in that, The composite flexible device comprises an integrated combination of a temperature and humidity sensing layer and a pressure sensing layer, the temperature and humidity sensing layer comprises, from bottom to top, an electrode layer, a polydiallydimethylammonium chloride layer, a polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer, and an electrode layer; the pressure sensing layer comprises, from bottom to top, an interdigital electrode layer, an electrode layer, and a polydimethylsiloxane layer, the interdigital electrode layer comprises silver paste and a substrate, the substrate is arranged on the electrode layer of the uppermost layer of the temperature and humidity sensing layer, and the area in the horizontal direction is smaller than that of the temperature and humidity sensing layer.

2. The composite flexible device of claim 1, wherein, In the polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer, the mass ratio of polyvinyl alcohol, polystyrene sulfonic acid, and silk protein is 0.8-1.2:4.8-5.2:1-3.

3. The composite flexible device of claim 1, wherein, The thickness of the polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer is 110-130 μm; the polystyrene sulfonic acid-polyvinyl alcohol-silk protein layer has a porous structure, and the porosity is 0.08-0.

12.

4. The composite flexible device of claim 1, wherein, The thickness of the polydiallydimethylammonium chloride layer is 55-65 μm; the electrode layer is silver nanowire, and the thickness is 12-22 μm.

5. The composite flexible device of claim 1, wherein, The thickness of the interdigital electrode layer is 190-210 μm, the substrate comprises a PI base and / or a paper base substrate; the thickness of the polydimethylsiloxane layer is 95-105 μm, and the single-sided surface has a pyramid-shaped microstructure, and the height difference size of the pyramid-shaped microstructure is 10-15 μm.

6. A method of manufacturing a temperature-humidity-pressure multi-modal self-powered composite flexible device according to any one of claims 1-5, characterized in that, The method comprises the following steps: (1) mixing a polystyrene sulfonic acid solution and a polyvinyl alcohol solution by stirring, then adding a silk protein solution, stirring thoroughly, and removing bubbles on the surface of the solution by vacuumizing to obtain a mixed solution; once-drying the mixed solution to obtain a mixed film; spin-coating a polydiallydimethylammonium chloride solution on the mixed film, twice-drying, spin-coating electrode layer material solution on both sides of the film to obtain a temperature and humidity sensor layer; (2) printing an interdigital electrode; spin-coating a polydimethylsiloxane solution on a silicon wafer template, drying and demolding to obtain a polydimethylsiloxane layer with a single-sided surface microstructure; ion cleaning, spin-coating an electrode layer material on the side with the surface microstructure, again drying, combining the interdigital electrode to obtain a pressure sensing layer; (3) combining the temperature and humidity sensor layer and the pressure sensing layer, leading wires to the corresponding electrode layers, packaging to obtain a temperature-humidity-pressure multi-modal self-powered composite flexible device.

7. The production method according to claim 6, wherein In step (1), the once-drying is drying at 40-50 °C for 3-5 h; the twice-drying is drying at 40-50 °C for 20-30 min; the spin-coating of the polydiallydimethylammonium chloride solution is performed at a speed of 700-800 r / min for 5-15 s; the spin-coating of the electrode layer material solution is performed at a speed of 700-800 r / min for 5-15 s.

8. The production method according to claim 6, wherein In steps (1) and (2), the addition amounts of the polyvinyl alcohol solution, the polystyrene sulfonic acid solution, the polydiallydimethylammonium chloride solution, and the electrode layer material solution are 5-10 wt%, 25-50 wt%, 35-40 wt%, and 90-95 wt%, respectively.

9. The production method according to claim 6, wherein The drying demolding in step (2) is drying at 70-80 DEG C for 40-50 min; the re-drying is drying at 150-160 DEG C for 10-20 min; the ion cleaning uses an ion cleaning machine to clean for 50-60 s, and the parameter setting of the spin-coated electrode layer material solution is 700-800 r / min, lasting for 5-8 s.

10. The production method according to claim 6, wherein The combining in step (3) specifically includes using a PI adhesive tape to adhere the substrate of the pressure sensing layer to the temperature and humidity sensor layer close to the polydiallyldimethylammonium chloride layer, thereby completing the packaging of the whole device.

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