A flexible pressure sensor and its fabrication method

Abstract

This application discloses a flexible pressure sensor and its fabrication method, belonging to the field of sensors. The flexible pressure sensor includes: a first substrate layer, a second substrate layer, a barrier layer, and at least one conductive thin film; the first substrate layer and the second substrate layer are stacked, the barrier layer is disposed between the first substrate layer and the second substrate layer, and the barrier layer has mounting holes; at least one conductive thin film is stacked between the first substrate layer and the second substrate layer, and the at least one conductive thin film is located in the mounting holes; an electrode layer is disposed on the surface of the second substrate layer facing the first substrate layer, and the electrode layer is in contact with the conductive thin film; wherein, the surface of the conductive thin film has a multi-gradient microcone structure, and at least one of the first substrate layer and the second substrate layer is deformable.

Description

Technical Field

[0001] This application belongs to the field of sensors, specifically relating to a flexible pressure sensor and its fabrication method. Background Technology

[0002] With the rapid development of technologies such as 5G, the Internet of Things (IoT), and artificial intelligence (AI), the IoT, woven from emerging technologies, is permeating every corner of life. Sensors, as the cornerstone of the IoT, are a key component in realizing the interconnection of everything and intelligent sensing. Among them, pressure sensors, which collect pressure information and convert it into electrical signals, play an important role in many fields such as aerospace, aviation, medical diagnostics, and intelligent robotics. Flexible pressure sensors are widely used in related technologies, but existing flexible pressure sensors suffer from the problem of not being able to simultaneously achieve high sensitivity and wide linear response. Summary of the Invention

[0003] The purpose of this application is to provide a flexible pressure sensor and its fabrication method, at least to solve the problem that flexible pressure sensors cannot simultaneously achieve high sensitivity and wide linear response.

[0004] In a first aspect, embodiments of this application provide a flexible pressure sensor, the flexible pressure sensor comprising: a first base layer, a second base layer, a barrier layer, and at least one conductive film; The first substrate layer and the second substrate layer are stacked together, the barrier layer is disposed between the first substrate layer and the second substrate layer, and the barrier layer is provided with mounting holes. At least one conductive film is stacked between the first substrate layer and the second substrate layer, and the at least one conductive film is located in the mounting holes. An electrode layer is disposed on the surface of the second substrate layer facing the first substrate layer, and the electrode layer is in contact with one of the conductive films. The conductive thin film has a multi-gradient microcone structure on its surface, and at least one of the first substrate layer and the second substrate layer is deformable.

[0005] Optionally, the number of conductive films is at least two layers, and the at least two conductive films include a first conductive film and a second conductive film; The first conductive film is connected to the surface of the first substrate layer facing the second substrate layer, the second conductive film is in contact with the electrode layer, and both the first conductive film and the second conductive film are located in the mounting hole; There is a gap between the first conductive film and the second conductive film, and the surfaces of the first conductive film and the second conductive film are both provided with multi-gradient microcone structures.

[0006] Optionally, the first conductive film is bonded to the surface of the first substrate layer facing the second substrate layer by an adhesive.

[0007] Optionally, the conductive film includes TPU, Ti3C2Tx, and MWCNTs.

[0008] Optionally, the electrode layer has a positive electrode connection portion and a negative electrode connection portion, wherein the positive electrode connection portion is used to connect to the positive electrode of the power supply, and the negative electrode connection portion is used to connect to the negative electrode of the power supply.

[0009] In a second aspect, embodiments of this application provide a preparation method for preparing the flexible pressure sensor described in any one of the first aspects above, the preparation method comprising: The system provides a first base layer, a second base layer, a barrier layer, TPU powder, and sandpaper, wherein the surface of the sandpaper is provided with a multi-gradient microcone structure; The TPU powder is formed into a first solution, and the first solution is injected onto the surface of the sandpaper to form a first film; Ti3C2TX powder and MWCNTs solution are provided. The Ti3C2TX powder is used to form a second solution, and the second solution is mixed with the MWCNTs solution to obtain a mixed solution. The first film is placed in the mixed solution for a first time, and after the first time, the first film is removed from the mixed solution and dried, and the dried first film forms the conductive film. The conductive film, the first substrate layer, the second substrate layer, and the barrier layer are assembled to form a flexible pressure sensor.

[0010] Optionally, the step of forming a first solution from the TPU powder and injecting the first solution onto the surface of the sandpaper to form a first film includes: The TPU powder was dissolved in N,N-dimethylformamide to obtain the first solution; The first solution is injected into the surface of the sandpaper using a syringe in an electric field, so that the first solution forms a set film on the surface of the sandpaper; The pre-set film is peeled off from the sandpaper and dried to obtain the first film.

[0011] Optionally, dissolving the TPU powder in N,N-dimethylformamide to obtain the first solution includes: PVP powder is available. The TPU powder and the PVP powder were dissolved in N,N-dimethylformamide to obtain the first solution.

[0012] Optionally, the step of forming a second solution from the Ti3C2TX powder and mixing the second solution with the MWCNTs solution to obtain a mixed solution includes: The Ti3C2TX powder was dissolved in deionized water to form a second solution; The second solution is mixed with the MWCNTs solution, and the second solution and the MWCNTs solution are subjected to ultrasonic treatment to obtain the mixed solution.

[0013] Optionally, before the first film is placed in the mixed solution for a first duration, the preparation method further includes: The first membrane is placed in the ionized water for a second duration, and after the second duration, the first membrane is removed from the ionized water.

[0014] In this embodiment, since the first substrate layer and the second substrate layer are stacked, and the barrier layer is disposed between the first substrate layer and the second substrate layer, the barrier layer can block the first substrate layer and the second substrate layer, preventing the first substrate layer from contacting the second substrate layer. Furthermore, the barrier layer has mounting holes, and at least one conductive film is stacked between the first substrate layer and the second substrate layer, with at least one conductive film located in the mounting holes. Therefore, the barrier layer can block the conductive film, preventing external impurities from potentially contacting the conductive film. Furthermore, an electrode layer is disposed on the surface of the second substrate layer facing the first substrate layer. The electrode layer is in contact with a conductive thin film. The surface of the conductive thin film has a multi-gradient microcone structure. At least one of the first and second substrate layers is deformable. Therefore, once a power source is applied to the electrode layer, and pressure is applied to at least one of the deformable layers, deformation can occur, thereby causing at least one conductive thin film between the first and second substrate layers to be stressed. When the conductive thin film is multilayered, when at least one conductive thin film is stressed, the conductive thin film in contact with the electrode layer first becomes conductive with the electrode layer, and the remaining conductive thin films become conductive with the electrode layer. The conductive film of the first and second base layers has less contact. As the pressure on at least one of the deformable layers increases, the contact points between the two adjacent conductive film layers increase. As the pressure continues to increase, one of the two adjacent conductive film layers almost completely covers the other conductive film layer. The contact area between the two adjacent conductive film layers tends to saturate, the resistance approaches its minimum value, and the current reaches a stable saturation value. That is, when at least one of the first and second base layers is subjected to pressure, the contact area between the two adjacent conductive film layers gradually increases, causing the resistance of the flexible pressure sensor to gradually decrease, thereby gradually increasing the current until the resistance approaches its minimum value and the current reaches its saturation value.

[0015] In other words, in this embodiment, at least one conductive film is provided, and the surface of the conductive film has a multi-gradient microcone structure. Therefore, when the electrode layer is connected to a power source and pressure is applied to the flexible pressure sensor, the flexible pressure sensor can achieve a gradual transition from a high-resistance path to a low-resistance path, effectively delaying the current saturation trend. This results in a wider linear response range for the flexible pressure sensor. Simultaneously, the provision of at least one conductive film significantly enhances the contact area change rate and path conversion efficiency of the conductive film under unit pressure, increasing the resistance change rate caused by unit pressure change, thereby significantly improving the sensitivity of the flexible pressure sensor. In other words, the flexible pressure sensor provided in this embodiment has high sensitivity and a wide linear response range, thus achieving both high sensitivity and a wide linear response. Attached Figure Description

[0016] Figure 1 This diagram illustrates a flexible pressure sensor provided in an embodiment of this application. Figure 2 This is a schematic diagram illustrating an electrode layer provided in an embodiment of this application; Figure 3 This diagram illustrates a flexible pressure sensor provided in an embodiment of this application subjected to a first pressure. Figure 4 This diagram illustrates a flexible pressure sensor provided in an embodiment of this application subjected to a second pressure. Figure 5 This is a flowchart illustrating a preparation method provided in an embodiment of this application.

[0017] Figure label: 10: First substrate layer; 20: Second substrate layer; 30: Barrier layer; 31: Mounting hole; 41: First conductive film; 42: Second conductive film; 50: Electrode layer; 51: Positive electrode connection; 52: Negative electrode connection. Detailed Implementation

[0018] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0019] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and 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, and therefore should not be construed as a limitation of this application.

[0020] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed 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 between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0021] like Figures 1 to 4 As shown, the flexible pressure sensor includes: a first base layer 10, a second base layer 20, a barrier layer 30, and at least one conductive film.

[0022] A first substrate layer 10 and a second substrate layer 20 are stacked together. A barrier layer 30 is disposed between the first substrate layer 10 and the second substrate layer 20, and the barrier layer 30 is provided with a mounting hole 31. At least one conductive film is stacked between the first substrate layer 10 and the second substrate layer 20, and the at least one conductive film is located in the mounting hole 31. An electrode layer 50 is disposed on the surface of the second substrate layer 20 facing the first substrate layer 10, and the electrode layer 50 is in contact with a conductive film. The surface of the conductive film is provided with a multi-gradient microcone structure, and at least one of the first substrate layer 10 and the second substrate layer 20 is deformable.

[0023] In this embodiment, since the first base layer 10 and the second base layer 20 are stacked, and the barrier layer 30 is disposed between the first base layer 10 and the second base layer 20, the barrier layer 30 can block the first base layer 10 and the second base layer 20, preventing the first base layer 10 from contacting the second base layer 20. Furthermore, the barrier layer 30 is provided with a mounting hole 31, and at least one conductive film is stacked between the first base layer 10 and the second base layer 20, with at least one conductive film located within the mounting hole 31. Therefore, the barrier layer 30 can block the conductive film, preventing external impurities from potentially contacting the conductive film. Furthermore, an electrode layer 50 is disposed on the surface of the second substrate layer 20 facing the first substrate layer 10. The electrode layer 50 is in contact with a conductive film. There is a gap between adjacent conductive film layers, and the surface of the conductive film is provided with a multi-gradient microcone structure. At least one of the first substrate layer 10 and the second substrate layer 20 is deformable. Therefore, once a power source is applied to the electrode layer 50, and at least one of the deformable layers of the first substrate layer 10 and the second substrate layer 20 is subjected to pressure, at least one of the deformable layers of the first substrate layer 10 and the second substrate layer 20 can be deformed, thereby causing at least one conductive film between the first substrate layer 10 and the second substrate layer 20 to be stressed. When the conductive film is multilayered, when at least one conductive film is stressed, it is in contact with the electrode layer 50. The conductive film first connects to the electrode layer 50, while the conductive films of the other layers have less contact. As the pressure on at least one of the deformable layers 10 and 20 increases, the number of contact points between adjacent conductive films increases. As the pressure continues to increase, one of the adjacent conductive films almost completely covers the other, and the contact area between the adjacent conductive films tends to saturate. The resistance approaches its minimum value, and the current reaches a stable saturation value. That is, when at least one of the first base layer 10 and 20 is subjected to pressure, the contact area between the adjacent conductive films gradually increases, causing the resistance of the flexible pressure sensor to gradually decrease, thereby gradually increasing the current until the resistance approaches its minimum value and the current reaches its saturation value.

[0024] In other words, in this embodiment, at least one conductive film is provided, and the surface of the conductive film has a multi-gradient microcone structure. Therefore, when the electrode layer 50 is connected to a power source and pressure is applied to the flexible pressure sensor, the flexible pressure sensor can achieve a gradual transition from a high-resistance path to a low-resistance path, effectively delaying the current saturation trend. This results in a wider linear response range for the flexible pressure sensor. Simultaneously, the provision of at least one conductive film significantly enhances the contact area change rate and path conversion efficiency of the conductive film under unit pressure, improving the resistance change rate caused by unit pressure change, thereby significantly improving the sensitivity of the flexible pressure sensor. In other words, the flexible pressure sensor provided in this embodiment has high sensitivity and a wide linear response range, thus achieving both high sensitivity and a wide linear response.

[0025] It should be noted that the surface of the conductive film has a multi-gradient microconical structure, that is, the surface of the conductive film is uneven. So once the flexible pressure sensor is subjected to pressure, the raised points on the conductive film in contact with the electrode layer 50 deform first, increasing the contact area between the conductive film and the electrode layer 50. As the pressure on the flexible pressure sensor increases, the conductive film in contact with the electrode layer 50 is completely in contact with the electrode layer 50. The pressure on the flexible pressure sensor further increases, and the raised points on the other conductive films come into contact. With the pressure further increasing, the conductive films of adjacent layers can cover each other. At this time, the contact area of ​​the conductive films reaches the maximum, and the resistance of the flexible pressure sensor reaches the minimum.

[0026] Furthermore, in this embodiment, only the first substrate layer 10 may be deformable, only the second substrate layer 20 may be deformable, or both the first substrate layer 10 and the second substrate layer 20 may be deformable. The material of both the first substrate layer 10 and the second substrate layer 20 may be polyimide (PI). Of course, the materials of the first substrate layer 10 and the second substrate layer 20 may also be other deformable materials, such as polyphenylene sulfide (PPS) or polycarbonate (PC). The specific materials of the first substrate layer 10 and the second substrate layer 20 are not limited in this embodiment.

[0027] In addition, in this embodiment, the barrier layer 30 can be made of polyethylene terephthalate (PET). Of course, the barrier layer 30 can also be made of other materials, such as polypropylene (PP) or polyethylene (PE). The specific material of the barrier layer 30 is not limited in this embodiment.

[0028] Furthermore, in this embodiment, the number of barrier layers 30 can be set according to actual needs. For example, if there are two barrier layers 30, one barrier layer 30 is connected to the surface of the first base layer 10 facing the second base layer 20, and the other barrier layer 30 is connected to the surface of the second base layer 20 facing the first base layer 10. As another example, if there is only one barrier layer 30, it is connected to both the first base layer 10 and the second base layer 20. The specific number of barrier layers 30 is not limited in this embodiment. The barrier layers 30 can be bonded to the first base layer 10 and / or the second base layer 20 using adhesive.

[0029] Furthermore, the surface of the conductive film is provided with a multi-gradient micro-conical structure, that is, the surface of the conductive film has raised areas and recessed areas. The raised areas can be conical in shape, but they can also have other shapes, such as columnar. This application does not limit the shape of the raised areas. Similarly, the recessed areas can be conical in shape, but they can also have other shapes, such as columnar. This application does not limit the shape of the recessed areas. The raised areas of the conductive film refer to areas that bulge along the direction from the first surface to the second surface, and the recessed areas refer to areas that are recessed along the direction from the second surface to the first surface, with the first and second surfaces facing away from each other. Additionally, the conductive film also has planar areas, where there are neither raised nor recessed areas.

[0030] In addition, in some embodiments, the number of conductive films is at least two layers, including a first conductive film 41 and a second conductive film 42; the first conductive film 41 is connected to the surface of the first substrate layer 10 facing the second substrate layer 20, and the second conductive film 42 is in contact with the electrode layer 50. Both the first conductive film 41 and the second conductive film 42 are located in the mounting hole 31; wherein, there is a gap between the first conductive film 41 and the second conductive film 42, and the surfaces of the first conductive film 41 and the second conductive film 42 are provided with multi-gradient microcone structures.

[0031] Since the first conductive film 41 is connected to the surface of the first substrate layer 10 facing the second substrate layer 20, and the second conductive film 42 is in contact with the electrode layer 50, when the first substrate layer 10 and / or the second substrate layer 20 are subjected to pressure, and the electrode layer 50 is connected to a power source, the overall response of the flexible pressure sensor can be divided into two current channels: the conduction current I1 between the second conductive film 42 and the electrode layer 50, and the conduction current I2 between the first conductive film 41 and the second conductive film 42. When the pressure on the flexible pressure sensor is relatively small, such as... Figure 3As shown, the first conductive film 41 has limited contact with the second conductive film 42, and the current mainly flows through the electrode layer 50 via the second conductive film 42. At this point, the total current of the flexible pressure sensor is dominated by I1. As the pressure on the flexible pressure sensor gradually increases, the number of contact points between the first conductive film 41 and the second conductive film 42 gradually increases, and I1 approaches saturation. The contact area between the second conductive film 42 and the first conductive film 41 gradually increases, causing I2 to begin to increase. Figure 4 As shown, when the pressure on the flexible pressure sensor increases further, multiple effective contact points are formed between the first conductive film 41 and the second conductive film 42. These contact points constitute an equivalent parallel structure, causing I2 to rise sharply and gradually become dominant. The parallel conduction path at this stage includes: the contact between the protruding area of ​​the first conductive film 41 and the planar area of ​​the second conductive film 42, and the contact between the concave areas of the first conductive film 41 and the concave areas of the second conductive film 42. When the flexible pressure sensor is subjected to even higher pressure, the first conductive film 41 almost completely covers the second conductive film 42, the contact area between the first conductive film 41 and the second conductive film 42 tends to saturate, the resistance of the flexible pressure sensor approaches its minimum value, and the current of the flexible pressure sensor reaches a stable saturation value. In other words, during the process of applying pressure to the flexible pressure sensor, the sensor gradually transitions from a high-resistance path to a low-resistance path, effectively delaying the current saturation trend and widening the linear response range. Simultaneously, the double-layer structure of the first conductive film 41 and the second conductive film 42 significantly enhances the contact area change rate of the flexible pressure sensor under unit pressure, increasing the resistance change caused by unit pressure change and thus improving the sensitivity of the flexible pressure sensor. Furthermore, by incorporating the first conductive film 41 and the second conductive film 42, the structure of the flexible pressure sensor can be simplified, facilitating its fabrication.

[0032] It should be noted that the electrode layer 50 can be bonded to the second base layer 20 with adhesive.

[0033] In addition, in this embodiment, the number of conductive films in the at least one conductive film can be other numbers. For example, the number of conductive films in the at least one conductive film is one layer; or, for another example, the number of conductive films in the at least one conductive film is three layers. In this case, the first conductive film is connected to the first substrate layer 10, the second conductive film 42 is in contact with the electrode layer 50 of the second substrate layer 20, and the third conductive film is connected to the wall of the mounting hole 31, and the third conductive film is located between the first conductive film and the second conductive film 42. Alternatively, the number of conductive films in the at least one conductive film is four layers. In this case, the arrangement of three conductive films can be referenced, and will not be elaborated further. The specific number of conductive films in the at least one conductive film is not limited in this embodiment.

[0034] In addition, in this embodiment, the first conductive film 41 is bonded to the surface of the first substrate layer 10 facing the second substrate layer 20 by an adhesive. This arrangement ensures that the first conductive film 41 is less likely to shift relative to the first substrate layer 10, and makes the connection between the first conductive film 41 and the first substrate layer 10 easier.

[0035] In addition, in this embodiment, the conductive film may include TPU, Ti3C2Tx, and MWCNTs. TPU refers to thermoplastic polyurethane, and MWCNTs refers to multi-walled carbon nanotubes. Specifically, TPU can be used to form a film, and Ti3C2Tx and MWCNTs materials can be formed on the TPU film.

[0036] Additionally, in some embodiments, such as Figure 2 As shown, the electrode layer 50 has a positive electrode connection portion 51 and a negative electrode connection portion 52. The positive electrode connection portion 51 is used to connect to the positive terminal of the power supply, and the negative electrode connection portion 52 is used to connect to the negative terminal of the power supply. By providing the positive electrode connection portion 51 and the negative electrode connection portion 52, it is convenient to connect the electrode layer 50 to the power supply. That is, when it is necessary to connect the electrode layer 50 to the power supply, the positive terminal of the power supply can be directly connected to the positive electrode connection portion 51, and the negative terminal of the power supply can be directly connected to the negative electrode connection portion 52.

[0037] It should be noted that, in the embodiments of this application, as Figure 2 As shown, electrode layer 50 can be an interdigitated electrode.

[0038] In addition, in the embodiments of this application, a flexible multi-gradient microcone structure can be constructed by using a sandpaper template combined with conformal electrospinning technology, that is, a multi-gradient microcone structure is formed on a conductive film.

[0039] This application provides a method for fabricating a flexible pressure sensor in any of the above embodiments, such as... Figure 5 As shown, the preparation method includes: Step 501: Provide a first base layer, a second base layer, a barrier layer, TPU powder, and sandpaper, the surface of which has a multi-gradient microcone structure.

[0040] Both the first and second base layers can be base layers made of polyimide material.

[0041] Step 502: Form a first solution from TPU powder and inject the first solution onto the surface of sandpaper to form a first film.

[0042] The sandpaper has a multi-gradient micro-cone structure on its surface. When the first solution is injected onto the surface of the sandpaper, the surface of the first solution will also have a multi-gradient micro-cone structure when it forms a thin film. That is, the surface of the first thin film has a multi-gradient micro-cone structure, which facilitates the subsequent formation of a conductive thin film with a multi-gradient micro-cone structure on its surface.

[0043] In some implementations, step 502 can be implemented as follows: dissolving TPU powder in N,N-dimethylformamide to obtain a first solution; injecting the first solution into the surface of sandpaper in an electric field using a syringe to form a set film on the surface of the sandpaper; peeling the set film off the sandpaper and drying the set film to obtain the first film.

[0044] In this process, TPU powder can be placed in a beaker, and then N,N-dimethylformamide can be added to the beaker. The TPU powder can dissolve in the N,N-dimethylformamide to obtain a first solution. Specifically, the beaker can be placed on a magnetic stirrer for stirring to ensure that the TPU powder and N,N-dimethylformamide are mixed evenly. Furthermore, the mass ratio of TPU powder to N,N-dimethylformamide can be 1.3:5. Of course, the mass ratio of TPU powder to N,N-dimethylformamide can also be other ratios, for example, 1.5:7. This embodiment of the application does not limit the specific method used.

[0045] Furthermore, the grit of the sandpaper can be set according to actual needs, for example, 120 grit or 150 grit. This application does not limit the specific grit used in this embodiment.

[0046] Furthermore, when the first solution is injected onto the surface of sandpaper using a syringe in an electric field, the sandpaper can be fixed to a collector. Then, the first solution is injected onto the surface of the sandpaper using the syringe. Under the influence of the electric field, the first solution spins on the surface of the sandpaper, equivalent to electrospinning, allowing a predetermined thin film to form on the surface of the sandpaper. A 10 ml volume syringe can be used. The first solution in the syringe is injected onto the surface of the sandpaper using a syringe pump. The pump speed can be set according to actual needs, for example, 1 ml / h or 0.8 ml / h. This embodiment of the application does not limit this specific speed. Additionally, the high-voltage power supply forming the electric field can be +15 kV or -5 kV. Furthermore, during the injection of the first solution, the temperature can be controlled at 25 °C and the humidity at 30-40% RH.

[0047] Furthermore, after the first solution is injected onto the surface of the sandpaper to form a set film, the set film can be peeled off from the surface of the sandpaper and dried at a first preset temperature for a first preset time to ensure that no solution remains on the set film, i.e., to remove droplets from the set film. The first preset temperature can be set according to actual needs, for example, 50°C, or 60°C. The specific value of the first preset temperature is not limited in this embodiment. Similarly, the first preset time can be set according to actual needs, for example, 4 hours, or 5 hours. The specific value of the first preset time is not limited in this embodiment.

[0048] In some implementations, dissolving TPU powder in N,N-dimethylformamide to obtain a first solution can be achieved by: providing PVP powder; dissolving both TPU powder and PVP powder in N,N-dimethylformamide to obtain a first solution.

[0049] The process involves placing TPU powder and PVP powder in a beaker, then adding N,N-dimethylformamide to dissolve both powders. Specifically, the beaker can be placed on a magnetic stirrer and stirred until the TPU powder, PVP powder, and N,N-dimethylformamide are thoroughly mixed. PVP, or polyvinylpyrrolidone, is a water-soluble, non-toxic, and biocompatible synthetic polymer. Adding PVP improves the solution properties of TPU, reduces its viscosity, and enhances its fiber-forming ability. When combined with TPU, PVP reduces bead-like structures and improves fiber uniformity.

[0050] It should be noted that the mass ratio of PU powder, PVP powder, and N,N-dimethylformamide can be set according to actual needs. For example, the mass ratio of PU powder, PVP powder, and N,N-dimethylformamide is 1.3:0.3:5, or 1.5:0.4:6. This application does not limit the specific ratio in this regard.

[0051] Step 503: Provide Ti3C2TX powder and MWCNTs solution, form a second solution from Ti3C2TX powder, and mix the second solution with the MWCNTs solution to obtain a mixed solution.

[0052] In some implementations, the Ti3C2TX powder is used to form a second solution, and the second solution is mixed with a MWCNTs solution to obtain a mixed solution. This can be achieved by: dissolving the Ti3C2TX powder in deionized water to form a second solution; mixing the second solution with the MWCNTs solution; and subjecting both the second solution and the MWCNTs solution to ultrasonic treatment to obtain a mixed solution.

[0053] In this process, a certain amount of Ti3C2TX powder is weighed and placed in a beaker. Deionized water is added to the beaker, and then the beaker is placed in an ultrasonic cell disruptor for sonication. This utilizes ultrasound waves to penetrate the solution in the beaker, allowing the Ti3C2TX powder to be uniformly dispersed in the deionized water. Furthermore, the concentration of the second solution can be set according to actual needs, for example, 5 mg / ml or 7 mg / ml. This embodiment of the application does not limit this specific concentration. Additionally, the duration of sonication of the second solution in the beaker can be set according to actual needs, for example, 1 hour or 1.5 hours.

[0054] Alternatively, the MWCNTs solution can be added to a beaker to mix with the second solution. The beaker is then placed in an ultrasonic cell disruptor for sonication to ensure uniform mixing of Ti3C2TX and MWCNTs, resulting in a mixed solution. Furthermore, the sonication duration can be set according to actual needs, for example, 0.5 hours or 1 hour.

[0055] Step 504: The first film is placed in the mixed solution for a first time, and after the first time, the first film is removed from the mixed solution and dried. The dried first film forms a conductive film.

[0056] In this process, after placing the first thin film in the mixed solution, both the mixed solution and the first thin film can be ultrasonicated. Ultrasonic waves penetrate the mixed solution and the first thin film, allowing Ti3C2TX and MWCNTs to adhere better to the first thin film. The duration of ultrasonication of the first thin film in the mixed solution can be a "first time." The first time can be set according to actual needs, for example, 1 hour, or 1.5 hours.

[0057] After removing the first film from the mixed solution, it can be dried to further prevent the oxidation of Ti3C2TX on the first film, which would affect the performance of the formed conductive film. Specifically, the first film can be dried in a vacuum drying oven. The temperature of the vacuum drying oven can be set according to actual needs, for example, 50°C or 60°C. After drying, the first film can be used as a conductive film.

[0058] In some implementations, before the time for which the first film is placed in the mixed solution reaches a first time, the preparation method may further include: placing the first film in deionized water for a second time, and after the second time, removing the first film from the deionized water.

[0059] Before placing the first film in the mixed solution, it can be placed in deionized water to remove impurities from its surface, ensuring that the surface of the first film has few or no impurities. Then, the first film is placed in the mixed solution. The second duration can be set according to actual needs, for example, 0.5 hours or 10 minutes. This embodiment of the application does not limit this specific setting.

[0060] Step 505: Assemble the conductive film, the first substrate layer, the second substrate layer and the barrier layer to form a flexible pressure sensor.

[0061] In this process, at least one conductive film can be fabricated according to steps 501 to 505. Then, the at least one conductive film, the first substrate layer, the second substrate layer, and the barrier layer are assembled. Specifically, during assembly, the barrier layer can be bonded to the first substrate layer with adhesive, and a conductive film can be bonded to the first substrate layer with the conductive film located in the mounting hole of the barrier layer. Then, another conductive film is brought into contact with the electrode layer on the second substrate layer. If the number of conductive films is greater than 2, the remaining conductive films are placed in the mounting holes, and then the first substrate layer and the second substrate layer are encapsulated to form a flexible pressure sensor. If the number of conductive films is 2, the first substrate layer and the second substrate layer are directly encapsulated to form a flexible pressure sensor.

[0062] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0063] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A flexible pressure sensor, characterized in that, The flexible pressure sensor includes: a first base layer, a second base layer, a barrier layer, and at least one conductive film; The first substrate layer and the second substrate layer are stacked together, the barrier layer is disposed between the first substrate layer and the second substrate layer, and the barrier layer is provided with mounting holes. At least one conductive film is stacked between the first substrate layer and the second substrate layer, and the at least one conductive film is located in the mounting holes. An electrode layer is disposed on the surface of the second substrate layer facing the first substrate layer, and the electrode layer is in contact with one of the conductive films. The conductive thin film has a multi-gradient microcone structure on its surface, and at least one of the first substrate layer and the second substrate layer is deformable.

2. The flexible pressure sensor according to claim 1, characterized in that, The number of conductive films is at least two layers, and the at least two conductive films include a first conductive film and a second conductive film; The first conductive film is connected to the surface of the first substrate layer facing the second substrate layer, the second conductive film is in contact with the electrode layer, and both the first conductive film and the second conductive film are located in the mounting hole; There is a gap between the first conductive film and the second conductive film, and the surfaces of the first conductive film and the second conductive film are both provided with multi-gradient microcone structures.

3. The flexible pressure sensor according to claim 2, characterized in that, The first conductive film is bonded to the surface of the first substrate layer facing the second substrate layer by an adhesive.

4. The flexible pressure sensor according to any one of claims 1-3, characterized in that, The conductive film includes TPU, Ti3C2Tx, and MWCNTs.

5. The flexible pressure sensor according to any one of claims 1-3, characterized in that, The electrode layer has a positive electrode connection portion and a negative electrode connection portion. The positive electrode connection portion is used to connect to the positive electrode of the power supply, and the negative electrode connection portion is used to connect to the negative electrode of the power supply.

6. A preparation method, characterized in that, The method for preparing the flexible pressure sensor according to any one of claims 1-5 comprises: The system provides a first base layer, a second base layer, a barrier layer, TPU powder, and sandpaper, wherein the surface of the sandpaper is provided with a multi-gradient microcone structure; The TPU powder is formed into a first solution, and the first solution is injected onto the surface of the sandpaper to form a first film; Ti3C2TX powder and MWCNTs solution are provided. The Ti3C2TX powder is used to form a second solution, and the second solution is mixed with the MWCNTs solution to obtain a mixed solution. The first film is placed in the mixed solution for a first time, and after the first time, the first film is removed from the mixed solution and dried, and the dried first film forms the conductive film. The conductive film, the first substrate layer, the second substrate layer, and the barrier layer are assembled to form a flexible pressure sensor.

7. The preparation method according to claim 6, characterized in that, The step of forming a first solution from the TPU powder and injecting the first solution onto the surface of the sandpaper to form a first film includes: The TPU powder was dissolved in N,N-dimethylformamide to obtain the first solution; The first solution is injected into the surface of the sandpaper using a syringe in an electric field, so that the first solution forms a set film on the surface of the sandpaper; The pre-set film is peeled off from the sandpaper and dried to obtain the first film.

8. The preparation method according to claim 7, characterized in that, The step of dissolving the TPU powder in N,N-dimethylformamide to obtain the first solution includes: PVP powder is available; The TPU powder and the PVP powder were dissolved in N,N-dimethylformamide to obtain the first solution.

9. The preparation method according to claim 6, characterized in that, The step of forming a second solution from the Ti3C2TX powder and mixing the second solution with the MWCNTs solution to obtain a mixed solution includes: The Ti3C2TX powder was dissolved in deionized water to form a second solution; The second solution is mixed with the MWCNTs solution, and the second solution and the MWCNTs solution are subjected to ultrasonic treatment to obtain the mixed solution.

10. The preparation method according to claim 6, characterized in that, Before the first film is placed in the mixed solution for a first duration, the preparation method further includes: The first membrane is placed in the ionized water for a second duration, and after the second duration, the first membrane is removed from the ionized water.

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