A multilayer porous flexible pressure sensing film and its preparation method

Abstract

This invention belongs to the field of flexible sensor technology, and particularly relates to a multilayer porous flexible pressure sensing film and its preparation method. Addressing the problems of insufficient sensitivity and limited detection range in existing flexible pressure sensors, this application provides a multilayer porous flexible pressure sensing film. This film significantly improves the pressure sensing sensitivity of flexible pressure sensors, producing differentiated capacitance change responses under different pressures, achieving high-precision detection; it expands the detection pressure range, exhibiting good response linearity across the low-pressure to high-pressure range, enabling wide-range continuous monitoring; it shortens the sensor's response recovery time, improves dynamic response performance, and enhances signal cycle stability, meeting the application requirements of real-time dynamic monitoring.

Description

Technical Field

[0001] This invention belongs to the field of flexible sensor technology, and particularly relates to a multilayer porous flexible pressure sensing film and its preparation method. Background Technology

[0002] Capacitive flexible pressure sensors, due to their high sensitivity, fast response, low power consumption, and good compatibility with flexible electronic devices, have shown broad application prospects in cutting-edge fields such as electronic skin, wearable health monitoring, and human-computer interaction. Currently, one of the mainstream methods to improve sensor performance is to introduce a porous dielectric layer to increase compressive deformation capacity, thereby effectively improving the device's sensitivity. Common methods for fabricating porous structures include foaming, electrospinning, and template methods. Among these, the use of polydimethylsiloxane (PDMS) as a flexible substrate material combined with the sacrificial template method to construct porous structures has attracted widespread attention due to its process controllability and structural stability.

[0003] However, existing capacitive flexible pressure sensors based on PDMS porous structures typically employ dielectric layer designs with single or random pore sizes. This structure presents several technical bottlenecks in practical applications. First, regarding pressure response characteristics, a single-size porous structure struggles to balance a wide pressure range and high sensitivity: under low pressure, the large pores easily deform, resulting in high sensitivity. However, as pressure increases, the pores gradually compact, drastically reducing the compressible space of the dielectric layer and causing a rapid decrease in sensitivity. This severely limits the sensor's linear response range, making it difficult to meet the needs of various applications, from weak pulse detection to foot pressure monitoring. Second, concerning structural uniformity, porous layers prepared using traditional sacrificial template methods (such as sugar particles, salt particles, or microsphere templates) suffer from wide pore size distributions and highly random spatial arrangements due to the difficulty in precisely controlling the dispersion of sacrificial particles. This leads to uneven electric field distribution within the dielectric layer, causing significant signal hysteresis and drift during cyclic loading and unloading, severely impacting the device's repeatability and long-term reliability. At the same time, a single structure makes it difficult to provide effective stress buffering and protection for the upper and lower electrodes, which limits the lifespan of the sensor in complex mechanical environments.

[0004] Existing capacitive flexible pressure sensors still have significant shortcomings in terms of wide pressure response range, signal stability, and structural reliability, making it difficult to meet the practical application requirements of high-performance flexible electronic devices. Therefore, developing a flexible pressure sensor that can balance high sensitivity and a wide linear response range while also possessing good stability is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] Based on the above analysis, this application addresses the problems of insufficient sensitivity and limited detection range of existing flexible pressure sensors by providing a multilayer porous flexible pressure sensing film. This film significantly improves the pressure sensing sensitivity of the flexible pressure sensor, producing differentiated capacitance change responses under different pressures, thus achieving high-precision detection; it expands the detection pressure range, exhibiting good response linearity across the low-pressure to high-pressure range, enabling wide-range continuous monitoring; it shortens the sensor's response recovery time, improves dynamic response performance, and enhances signal cycle stability, meeting the application requirements of real-time dynamic monitoring.

[0006] Therefore, the first technical solution of this application discloses a method for preparing a multilayer porous flexible pressure sensing film, including the following steps:

[0007] Preparation of film slurry: Flexible polymer base liquid was mixed with three different particle sizes of soluble polymer microspheres L, M and S, and the gas was discharged to obtain three mixed slurries; wherein, the particle size of polymer microsphere-L > the particle size of polymer microsphere-M > the particle size of polymer microsphere-S.

[0008] Thin film preparation: Three mixed slurries were coated, cured, and film-forming in a gradient manner, and then the polymer microspheres were removed to obtain a multilayer porous flexible pressure sensing film.

[0009] Furthermore, the polymer microsphere-L has a particle size range of 180 μm to 160 μm; the polymer microsphere-M has a particle size range of 160 μm to 120 μm; and the polymer microsphere-S has a particle size range of 120 μm to 70 μm.

[0010] Furthermore, the flexible polymer base liquid comprises a flexible polymer prepolymer and a curing agent in a mass ratio of 9:1 to 10:1.

[0011] Furthermore, the mass ratio of the flexible polymer base liquid to each polymer microsphere is 1:5 to 1:10.

[0012] Furthermore, the flexible polymer is a flexible, curable, and insulating polymeric elastic material.

[0013] Furthermore, the coating thickness of each layer is 180um~200um.

[0014] Furthermore, the curing temperature is 60~80℃, and the curing time is 20~30min.

[0015] And the multilayer porous flexible pressure sensing film prepared according to the above preparation method.

[0016] The second technical solution of this application discloses the application of the above-mentioned multilayer porous flexible pressure sensing film, which is used as a dielectric layer in a pressure sensor. The aperture of the multilayer porous flexible pressure sensing film is set from large to small from the side of the pressure sensor in contact with the external pressure to the pressure transmission direction.

[0017] The third technical solution of this application discloses a three-layer porous pressure sensor, wherein the aforementioned multi-layer porous flexible pressure sensing film serves as the dielectric layer, and the aperture of the multi-layer porous flexible pressure sensing film is set from large to small from the side of the pressure sensor in contact with the external pressure to the pressure transmission direction.

[0018] Beneficial effects: This invention utilizes PDMS and a PS sacrificial template to significantly improve the overall performance of flexible pressure sensing films through a simple coating and template removal method. Specific effects are as follows:

[0019] 1. The pressure sensing film prepared by this invention exhibits high sensitivity. It can produce a significant capacitance change under minute pressure variations, with a sensitivity of 0.004 kPa within the 0-100 kPa pressure range. -1 This enables high-precision identification and detection of minute pressure signals, meeting the application requirements of high-precision monitoring.

[0020] 2. The pressure sensing diaphragm exhibits excellent dynamic response performance. With a response and recovery time of 80ms, it effectively detects high-frequency dynamic pressure changes, significantly improving the sensor's real-time monitoring capabilities and dynamic response stability.

[0021] 3. The pressure sensing diaphragm has a wide detection range. The measurement range covers the low-pressure to high-pressure range of 0~600kPa, and it maintains good linear response characteristics in both low-pressure and high-pressure ranges, effectively overcoming the problems of narrow detection range and easy saturation of traditional flexible pressure sensors.

[0022] 4. The pressure sensing diaphragm exhibits excellent signal stability and durability. After 5000 cycles of pressure testing, the capacitor output signal showed no significant drift, demonstrating excellent fatigue resistance and stable response consistency, ensuring its long-term reliable operation in practical applications.

[0023] 5. Pressure sensing films possess excellent mechanical properties and structural stability. The films almost recover to their original state after large deformation (80%), and their energy dissipation is very small, demonstrating excellent mechanical flexibility.

[0024] In summary, the flexible pressure sensing membrane provided by this invention exhibits excellent performance in key performance indicators such as sensitivity, pressure detection range, response speed, and mechanical stability. Its overall performance surpasses that of existing commercial products and most literature reports, and it has broad application prospects and significant practical value in fields such as electronic skin, smart wearables, human-computer interaction, and medical health monitoring. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating the preparation process of the pressure sensing thin film of the present invention.

[0027] Figure 2 The sensitivity test graph for Example 1 is shown.

[0028] Figure 3 This is a response / recovery time test graph for Example 1;

[0029] Figure 4 The graph shows the cyclic stability test results for Example 1.

[0030] Figure 5 The graphs show the hysteresis characteristics of Example 1 under different strains. Detailed Implementation

[0031] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] The first embodiment of this application discloses a method for preparing a multilayer porous flexible pressure sensing film, such as... Figure 1 As shown, it includes the following steps:

[0033] Preparation of film slurry: Flexible polymer base liquid was mixed with three different particle sizes of soluble polymer microspheres L, M and S, and the gas was discharged to obtain three mixed slurries; wherein, the particle size of polymer microsphere-L > the particle size of polymer microsphere-M > the particle size of polymer microsphere-S.

[0034] Thin film preparation: Three mixed slurries were coated, cured, and film-forming in a gradient manner, and then the polymer microspheres were removed to obtain a multilayer porous flexible pressure sensing film.

[0035] In this embodiment, the flexible polymer is a flexible, curable, and insulating polymeric elastic material, such as Ecoflex series silicone rubber, polyurethane (PU), PDMS, and other thermoplastic elastomers or silicone elastomers. It can achieve uniform mixing and curing with the sacrificial template to construct the porous dielectric layer structure described in this invention. Among these materials, PDMS (polydimethylsiloxane) elastomer is most preferred.

[0036] In this embodiment, the soluble polymer microspheres are particulate materials with regular morphology, controllable particle size, and solubility and decomposability in specific solvents, such as polymethyl methacrylate (PMMA) microspheres, salt particles, sugar particles, and polystyrene (PS) microspheres. They act as sacrificial templates, occupying space and maintaining morphological stability within the matrix material, and are removed in subsequent processes using specific solvents without damaging the matrix structure. Among these materials, PS microspheres are most preferred in this application.

[0037] Through the above preparation method, this invention obtains a multilayer porous flexible pressure sensing film with a gradient pore size distribution. In the pressure sensor, the pore size decreases from the side of the pressure sensor contacting the external pressure to the pressure transmission direction. This three-layer gradient porous structure (with the side of the pressure sensor contacting the external pressure as the top layer) with progressively decreasing pore size from the pressure transmission direction has the core advantage of achieving a high-sensitivity linear response over a wide pressure range through a step-by-step compression mechanism: under low pressure, the upper layer's large pores deform first to ensure high sensitivity; as the pressure increases, the middle layer's medium pores compress to maintain a continuous response; in the high-pressure stage, the lower layer's small pores still provide compressible space to prevent premature signal saturation, effectively widening the detection range. Simultaneously, this gradient structure optimizes stress distribution, alleviates stress concentration at the interlayer interfaces, and improves the device's mechanical stability and fatigue resistance. The porous structure also provides a smooth path for rapid air expulsion and backfilling, significantly shortening response and recovery times, reducing signal hysteresis, and ensuring signal stability during long-term cyclic testing. The overall structural design cleverly resolves the contradiction between sensitivity, range, and stability that is difficult to balance in traditional sensors, achieving a synergistic improvement in overall performance.

[0038] The technical solution and the technical effects achieved by this application will be described in detail below through specific embodiments (using PDMS as a flexible polymer and PS as a soluble polymer microsphere).

[0039] Example 1: Fabrication of a multilayer porous flexible pressure sensing film, i.e., a sensor

[0040] (1) Prepare polystyrene (PS) microspheres of different particle sizes

[0041] Three different sizes of polystyrene (PS) microspheres were weighed out, with diameters of 180 μm, 150 μm, and 75 μm, respectively, and designated as PS-L, PS-M, and PS-S. The PS microspheres of each size were placed in anhydrous ethanol and ultrasonically dispersed. The microspheres were washed 2-3 times to remove impurities and dispersant from their surface, and finally dried in a vacuum drying oven for later use.

[0042] (2) Preparation of a mixed liquid of polydimethylsiloxane (PDMS) and PS microspheres

[0043] Weigh the PDMS prepolymer and its curing agent at a mass ratio of 10:1 and stir them evenly to obtain the PDMS base liquid. Mix the three types of PS microspheres with the PDMS base liquid prepared in (1) at a mass ratio of 5:1 and stir them thoroughly to obtain three mixed liquids containing PS-L, PS-M and PS-S microspheres respectively.

[0044] (3) Preparation of three-layer porous flexible pressure sensing film

[0045] a. Place the three mixed liquids prepared in (2) into a vacuum oven, evacuate to -0.1 MPa, and maintain for 15 minutes until no obvious bubbles escape from the solution.

[0046] b. Uniformly coat the mixed slurry containing PS-L microspheres onto a clean substrate (such as a glass slide or PET film), controlling the coating thickness and ensuring uniform thickness by placing it on a spin coater or blade coater. Then place the substrate in an oven and cure at 80°C for 20 minutes to obtain the first porous film layer.

[0047] c. After the first layer of film has cured, uniformly coat the surface with a mixed liquid containing PS-M microspheres, controlling the coating thickness. Then, place it back into the oven at 80℃ for 20 minutes to cure, ensuring a tight bond between the second and first layers.

[0048] d. On the surface of the second cured film, uniformly coat with a mixed liquid containing PS-S microspheres, controlling the coating thickness. Place it back in the oven at 80℃ for 20 minutes to form a three-layer porous film.

[0049] e. Peel the cured three-layer porous film from the substrate and cut it to the required size. Immerse the cut film in anisole solution and stir until the PS microspheres are fully dissolved and removed. Remove the film and repeatedly soak and wash it with anhydrous ethanol to remove residual anisole and dissolved PS residue.

[0050] f. Place the cleaned film in an oven to dry, and obtain a three-layer porous flexible pressure sensing film.

[0051] (4) Fabrication of a three-layer porous pressure sensor

[0052] Using the three-layer porous pressure sensing film prepared in (3) as the dielectric layer, an upper electrode layer and a lower electrode layer are formed on its upper and lower surfaces by bonding and other methods, respectively. Electrode leads are led out, and after encapsulation, a capacitive flexible pressure sensor is obtained.

[0053] Example 2: Fabrication of a multilayer porous flexible pressure sensing film, i.e., a sensor

[0054] A method for preparing a multilayer porous flexible pressure sensing film includes the following steps:

[0055] (1) Prepare polystyrene (PS) microspheres of different particle sizes

[0056] Three different sizes of polystyrene (PS) microspheres were weighed out, with diameters of 180 μm, 150 μm, and 100 μm, and designated as PS-L, PS-M, and PS-S, respectively. The PS microspheres of each size were placed in anhydrous ethanol and ultrasonically dispersed. The microspheres were washed 2-3 times to remove impurities and dispersant from their surface. Finally, they were dried in a vacuum drying oven for later use.

[0057] (2) Preparation of a mixed liquid of polydimethylsiloxane (PDMS) and PS microspheres

[0058] Weigh the PDMS prepolymer and its curing agent at a mass ratio of 10:1 and stir them evenly to obtain the PDMS base liquid. Mix the three types of PS microspheres with the PDMS base liquid prepared in (1) at a mass ratio of 5:1 and stir them thoroughly to obtain three mixed liquids containing PS-L, PS-M and PS-S microspheres respectively.

[0059] (3) Preparation of three-layer porous flexible pressure sensing film

[0060] a. Place the three mixed liquids prepared in (2) into a vacuum oven, evacuate to -0.1 MPa, and maintain for 15 minutes until no obvious bubbles escape from the solution.

[0061] b. Uniformly coat the mixed slurry containing PS-L microspheres onto a clean substrate (such as a glass slide or PET film), controlling the coating thickness and ensuring uniform thickness by placing it on a spin coater or blade coater. Then place the substrate in an oven and cure at 80°C for 20 minutes to obtain the first porous film layer.

[0062] c. After the first layer of film has cured, uniformly coat the surface with a mixed liquid containing PS-M microspheres, controlling the coating thickness. Then, place it back into the oven at 80℃ for 20 minutes to cure, ensuring a tight bond between the second and first layers.

[0063] d. On the surface of the second cured film, a mixed liquid containing PS-S microspheres is uniformly coated, controlling the coating thickness. The film is then placed back into the oven for curing, forming a three-layer porous film.

[0064] e. Peel the cured three-layer porous film from the substrate and cut it to the required size. Immerse the cut film in anisole solution and stir until the PS microspheres are fully dissolved and removed. Remove the film and repeatedly soak and wash it with anhydrous ethanol to remove residual anisole and dissolved PS residue.

[0065] f. Place the cleaned film in an oven to dry, and obtain a three-layer porous flexible pressure sensing film.

[0066] (4) Fabrication of a three-layer porous flexible pressure sensor

[0067] Using the three-layer porous pressure sensing film prepared in (3) as the dielectric layer, an upper electrode layer and a lower electrode layer are formed on its upper and lower surfaces by bonding and other methods, respectively. Electrode leads are led out, and after encapsulation, a capacitive flexible pressure sensor is obtained.

[0068] Example 3: Fabrication of a multilayer porous flexible pressure sensing film, i.e., a sensor

[0069] A method for preparing a multilayer porous flexible pressure sensing film includes the following steps:

[0070] (1) Prepare polystyrene (PS) microspheres of different particle sizes

[0071] Three different sizes of polystyrene (PS) microspheres were weighed out, with diameters of 160 μm, 125 μm, and 75 μm, respectively, and designated as PS-L, PS-M, and PS-S. The PS microspheres of each size were placed in anhydrous ethanol and ultrasonically dispersed. The microspheres were washed 2-3 times to remove impurities and dispersant from their surface, and finally dried in a vacuum drying oven for later use.

[0072] (2) Preparation of a mixed liquid of polydimethylsiloxane (PDMS) and PS microspheres

[0073] Weigh the PDMS prepolymer and its curing agent at a mass ratio of 10:1 and stir them evenly to obtain the PDMS base liquid. Mix the three types of PS microspheres with the PDMS base liquid prepared in (1) at a mass ratio of 5:1 and stir them thoroughly to obtain three mixed liquids containing PS-L, PS-M and PS-S microspheres respectively.

[0074] (3) Preparation of three-layer porous flexible pressure sensing film

[0075] a. Place the three mixed liquids prepared in (2) into a vacuum oven, evacuate to -0.1 MPa, and maintain for 15 minutes until no obvious bubbles escape from the solution.

[0076] b. Uniformly coat the mixed slurry containing PS-L microspheres onto a clean substrate (such as a glass slide or PET film), controlling the coating thickness and ensuring uniform thickness by placing it on a spin coater or blade coater. Then place the substrate in an oven and cure at 80°C for 20 minutes to obtain the first porous film layer.

[0077] c. After the first layer of film has cured, uniformly coat the surface with a mixed liquid containing PS-M microspheres, controlling the coating thickness. Then, place it back into the oven at 80℃ for 20 minutes to cure, ensuring a tight bond between the second and first layers.

[0078] d. On the surface of the second cured film, uniformly coat with a mixed liquid containing PS-S microspheres, controlling the coating thickness. Place it back in the oven at 80℃ for 20 minutes to form a three-layer porous film.

[0079] e. Peel the cured three-layer porous film from the substrate and cut it to the required size. Immerse the cut film in anisole solution and stir until the PS microspheres are fully dissolved and removed. Remove the film and repeatedly soak and wash it with anhydrous ethanol to remove residual anisole and dissolved PS residue.

[0080] f. Place the cleaned film in an oven to dry, and obtain a three-layer porous flexible pressure sensing film.

[0081] (4) Fabrication of a three-layer porous flexible pressure sensor

[0082] Using the three-layer porous pressure sensing film prepared in (3) as the dielectric layer, an upper electrode layer and a lower electrode layer are formed on its upper and lower surfaces by bonding and other methods, respectively. Electrode leads are led out, and after encapsulation, a capacitive flexible pressure sensor is obtained.

[0083] Experimental Example 1: Sensitivity Test

[0084] The flexible pressure sensing film prepared by this invention exhibits high sensitivity, producing a significant resistance change even under minute pressure variations, thus achieving accurate detection of minute pressure signals and meeting the application requirements of high-precision monitoring. For detailed results, please refer to... Figure 2 The sensitivity of the three-layer porous flexible pressure sensor prepared in Example 1 was tested, and the sensitivity was 0.004 kPa in the pressure range of 0-100 kPa. -1This technology enables high-precision identification and detection of minute pressure signals, meeting the application requirements of high-precision monitoring. Furthermore, the pressure sensing film has a wide detection range, covering a low-pressure to high-pressure range of 0–600 kPa. It maintains good linear response characteristics in both low-pressure and high-pressure ranges, effectively overcoming the problems of narrow detection range and easy saturation of traditional flexible pressure sensors.

[0085] Experiment Example 2: Response / Recovery Time Test

[0086] The pressure sensing diaphragm exhibits excellent dynamic response performance. With both response and recovery times of 80 ms, it effectively detects high-frequency dynamic pressure changes, significantly improving the sensor's real-time monitoring capability and dynamic response stability. See details in [link to results]. Figure 3 The response / recovery time of the three-layer porous flexible pressure sensor prepared in Example 1 was tested. The results showed that after the sensor was subjected to pressure loading, ΔC / C0 rapidly increased to a steady state and recovered quickly after unloading. The response time and recovery time measured in the figure were both approximately 80 ms. Therefore, it can be seen that the multilayer porous pressure sensing film of this application has rapid response and recovery capabilities, and can monitor dynamic pressure changes in real time.

[0087] Experimental Example 3 Cyclic Stability Test

[0088] The pressure sensing membrane exhibits good signal stability and durability. See details for further information. Figure 4 Cyclic stability tests were conducted on the three-layer porous flexible pressure sensor prepared in Example 1. The main graph shows the stability of the sensor during long-term operation, with the capacitance change remaining stable and the capacitance change rate ΔC / C0 being 0.12. The inset shows that the sensor's response to periodic pressure signals remained consistent over two specific time periods, demonstrating good repeatability. Therefore, after 5000 cycles of pressure testing, the pressure sensing film exhibited no significant drift in the capacitance output signal, demonstrating excellent fatigue resistance and stable response consistency, thus ensuring its long-term reliable operation in practical applications.

[0089] Experimental Example 4: Hysteresis Characteristics Test under Different Strains

[0090] The pressure-sensing diaphragm exhibits excellent mechanical properties and structural stability. See details for further information. Figure 5 The hysteresis characteristics of the three-layer porous flexible pressure sensing film prepared in Example 1 under different strains were tested. The results showed that the film could recover to its initial state after deformation of 20%, 40%, 60%, and 80%, and the greater the degree of deformation, the greater the stress. The film almost recovered to its original state after large deformation (80%), and its energy dissipation was very small, showing excellent mechanical flexibility.

[0091] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A method for preparing a multilayered porous flexible pressure sensing film, characterized in that, The method comprises the following steps: Preparation of thin film slurry: the flexible polymer base fluid is mixed with three different sizes of soluble polymer microspheres L, M and S, and then the gas is discharged to obtain three mixed slurries; wherein, the particle size of polymer microsphere-L is greater than that of polymer microsphere-M, and the particle size of polymer microsphere-S is the smallest. Preparation of thin film: the three mixed slurries are coated, solidified and formed in turn, and then the polymer microspheres are removed to obtain a multi-layer porous flexible pressure sensing thin film.

2. The production method according to claim 1, characterized by, The particle size of the polymer microsphere-L ranges from 180um to 160um; the particle size of the polymer microsphere-M ranges from 160um to 120um; and the particle size of the polymer microsphere-S ranges from 120um to 70um.

3. The preparation method according to claim 1, characterized in that, The flexible polymer base fluid comprises a flexible polymer prepolymer and a curing agent, and the mass ratio of the flexible polymer prepolymer to the curing agent is 9:1 to 10:

1.

4. The production method according to claim 1, characterized by, The mass ratio of the flexible polymer base fluid to each polymer microsphere is 1:5 to 1:

10.

5. The preparation method according to claim 1, characterized in that, The flexible polymer is a flexible, curable and insulating high molecular elastic material.

6. The method of claim 1, wherein, The coating thickness of each layer is 180um to 200um.

7. The preparation method according to claim 1, characterized in that, The curing temperature is 60 to 80℃, and the curing time is 20 to 30min.

8. The multi-layer porous flexible pressure sensing thin film prepared by the preparation method of any one of claims 1-7.

9. Use of the multilayered porous flexible pressure sensing film according to claim 8, characterized in that, It is applied as a dielectric layer in a pressure sensor, wherein the pore size of the multi-layer porous flexible pressure sensing thin film from the side of the pressure sensor contacting the external pressure to the pressure transmission direction is arranged from large to small.

10. A three-layered multi-aperture pressure sensor, characterized by, It uses the multi-layer porous flexible pressure sensing thin film of claim 8 as a dielectric layer, and the pore size of the multi-layer porous flexible pressure sensing thin film from the side of the pressure sensor contacting the external pressure to the pressure transmission direction is arranged from large to small.

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