A double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor and its preparation method

Abstract

The present invention discloses a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor and a preparation method thereof, belonging to the technical field of underwater flexible pressure sensors. The flexible pressure sensor includes a first composite layer and a second composite layer, with a porous material disposed between the first composite layer and the second composite layer; the first composite layer and the second composite layer are symmetrically arranged on both sides of the porous material; the first composite layer includes, from the outside to the inside, a flexible substrate, a nickel cloth electrode, and an ion membrane layer, the flexible substrate being made by thermally bonding a fabric and a TPU film, with the fabric being on the outside; the ion membrane layer being formed by applying a first ion solution on the nickel cloth electrode by screen printing; the first composite layer, the porous material, and the second composite layer being thermally bonded, and then the outside of the first composite layer and the second composite layer being wrapped with PDMS to obtain the flexible pressure sensor. The flexible pressure sensor of the present invention has the advantages of ultra-high range, high linearity, and high sensitivity.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater flexible pressure sensors, and in particular to a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor and a preparation method thereof. Background Art

[0002] Ocean pressure is a key indicator that reflects a wide range of information about ocean morphology, structural characteristics, and dynamic behavior. Accurately monitoring this pressure is crucial for monitoring marine ecosystems, managing shipping routes, and supporting marine fisheries. Traditional ocean pressure sensors, limited by their rigid structure, struggle to capture minute pressure changes. Furthermore, these sensors often require the protection of a pressure chamber to withstand the high hydrostatic pressure of the ocean, limiting their flexibility for integration with various platforms and making them unsuitable for some applications.

[0003] Flexible pressure sensors have seen significant development in recent years due to their high sensitivity and adaptability. These sensors can be seamlessly integrated into various platforms, including ocean buoys and underwater robots, enabling high-precision, wide-range ocean pressure monitoring. Furthermore, flexible pressure sensors based on soft materials have broad application prospects in deep-sea sensing due to their incompressibility under high hydrostatic pressures and potential to eliminate pressure cavities. However, to date, research on the measurement range of these flexible pressure sensors has mostly been limited to the order of a few kPa, rarely reaching the MPa range. Maintaining high accuracy within the MPa range is even more difficult, making it difficult to extend their application to deep-sea environments. Summary of the Invention

[0004] Based on the above technical problems, the present invention proposes a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor and a preparation method thereof.

[0005] The technical solution adopted by the present invention is:

[0006] A double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor, comprising a first composite layer and a second composite layer, with a porous material disposed between the first composite layer and the second composite layer;

[0007] The first composite layer and the second composite layer are symmetrically arranged on both sides of the porous material;

[0008] The first composite layer includes, from the outside to the inside, a flexible substrate, a nickel cloth electrode, and an ion membrane layer. The flexible substrate is made by thermally bonding a fabric and a TPU film, with the fabric on the outside. The ion membrane layer is formed by screen-printing the first ion solution onto the nickel cloth electrode.

[0009] The first ionic solution is prepared by the following steps: adding thermoplastic polyurethane elastomer particles to N,N-dimethylformamide, heating and stirring, and dropwise adding ionic liquid, and then adding carbon nanotubes, hexagonal boron nitride or silicon dioxide and fully dissolving them to obtain the first ionic solution;

[0010] The first composite layer, the porous material and the second composite layer are thermally bonded, and then the outer sides of the first composite layer and the second composite layer are wrapped with PDMS to obtain the flexible pressure sensor.

[0011] Preferably, the porous material is fully immersed in the second ionic solution and then sandwiched between the first composite layer and the second composite layer; the second ionic solution is prepared by the following steps: adding the ionic liquid to deionized water and mixing well.

[0012] Preferably, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt; and the porous material is polyurethane sponge.

[0013] Preferably, a gold layer is pre-sputtered on one side of the nickel cloth electrode where the ion membrane layer is screen-printed.

[0014] The present invention also provides a method for preparing the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor as described above, comprising the following steps:

[0015] (1) Thermally bonding the fabric and TPU film to obtain a flexible substrate;

[0016] (2) Assembling a nickel cloth electrode on the flexible substrate and on the side of the TPU film;

[0017] (3) sputtering a gold layer on the surface of the nickel cloth electrode, and then screen-printing an ion membrane layer to assemble the first composite layer;

[0018] (4) Repeat steps (1) to (3) to assemble a second composite layer;

[0019] (5) Selecting a porous material and fully immersing it in a second ion solution to obtain a soaked porous material;

[0020] (6) sandwiching the soaked porous material between the first composite layer and the second composite layer, thermally bonding them to form a whole, and then completely wrapping them with PDMS to obtain the flexible pressure sensor;

[0021] In step (3), the first ion solution used for screen-printing the ion membrane layer is prepared by the following steps: adding thermoplastic polyurethane elastomer particles to N,N-dimethylformamide, heating and stirring, and dropping ionic liquid, and then adding carbon nanotubes, hexagonal boron nitride or silicon dioxide, stirring and dissolving them thoroughly to obtain;

[0022] In step (5), the second ionic solution is prepared by the following steps: adding the ionic liquid to deionized water and mixing well.

[0023] Preferably, in step (2): the nickel cloth electrode is an unplated high-purity nickel cloth or a gold-plated, platinum-plated, copper-plated, or silver-plated high-purity nickel cloth.

[0024] Preferably, in step (3): based on 2 g of thermoplastic polyurethane elastomer particles, the amount of N,N-dimethylformamide is 3-6 ml, the amount of ionic liquid is 0.8-1.2 ml, and the amount of carbon nanotubes, hexagonal boron nitride or silicon dioxide is 0.1-0.3 g;

[0025] Control the heating and stirring temperature to 90-120°C, the heating and stirring time to 30-45 minutes; and the sufficient stirring and dissolving time to 2-3 hours.

[0026] Preferably, the ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, the mass ratio of the ionic liquid to deionized water in the second ionic solution is 1:5-1:20; and the porous material is polyurethane sponge.

[0027] The flexible pressure sensor has a total thickness of no more than 0.5 mm and is capable of measuring water depths of 0-400 meters. It also has a minimum detection limit of 0.2 grams and a response time of 20 milliseconds.

[0028] The beneficial technical effects of the present invention are as follows:

[0029] The total thickness of the fabric-based flexible pressure sensor of the present invention does not exceed 0.5 mm. It can measure underwater water depth data of 0-400 meters. It has the advantages of ultra-high range, high linearity, high sensitivity, etc. It can be conformal with underwater unmanned equipment, which is of great significance for achieving high-precision and large-scale ocean pressure monitoring.

[0030] The flexible pressure sensor of the present invention achieves double-layer ion enhancement by screen-printing an ion membrane layer on the electrode and sandwiching a porous polyurethane sponge soaked in ionic liquid in the middle, thereby effectively improving the sensitivity and detection range of the sensor, especially ensuring high sensitivity in deeper underwater environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is an overall exploded view of a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to an embodiment of the present invention;

[0032] Figure 2 This is a flow chart for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to an embodiment of the present invention;

[0033] Figure 3This is a flowchart of a method for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to an embodiment of the present invention;

[0034] Figure 4 This is a performance comparison chart of flexible pressure sensors prepared by changing the concentration of different ionic liquids in the second ionic solution according to an embodiment of the present invention;

[0035] Figure 5 This is a diagram showing the minimum detection line of the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor manufactured in an embodiment of the present invention;

[0036] Figure 6 This is a response time diagram of a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor manufactured according to an embodiment of the present invention;

[0037] Figure 7 This is a long-term cycle graph of 4650 times of the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor produced in an embodiment of the present invention at a pressure of 1 MPa;

[0038] Figure 8 This is an experimental test chart of the underwater pressure 0-5MPa of the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor made in an embodiment of the present invention;

[0039] Figure 9 This is a performance comparison chart of the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor produced in an embodiment of the present invention and the existing flexible pressure sensor;

[0040] Figure 10 This is a sensitivity curve diagram of the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor produced in an embodiment of the present invention.

[0041] In the figure: 1-porous material, 2-nickel cloth electrode, 3-ion membrane layer, 4-fabric, 5-TPU film, 6-gold layer. DETAILED DESCRIPTION

[0042] The present invention discloses a double-layer ion-enhanced, high-range, high-linearity fabric-based flexible pressure sensor and its preparation method. The flexible pressure sensor comprises a flexible substrate with a TPU film thermally bonded to a fabric on one side; a nickel cloth electrode assembled on the flexible substrate, which can be cut into various shapes (such as circular, rectangular, or triangular) using a small UV laser cutter as needed. Gold is then sputtered onto the nickel cloth electrode using a high-vacuum magnetron ion sputtering instrument to improve the underwater performance of the pressure sensor. An ion layer is screen-printed using a prepared ion solution. The other side of the flexible pressure sensor is prepared using the same method. Finally, a porous polyurethane sponge is sandwiched between the two sides. The porous polyurethane sponge is fully soaked in the ion solution and then removed. Finally, the sensor is wrapped with PDMS to produce a double-layer ion-enhanced, high-range, high-linearity fabric-based flexible pressure sensor. This flexible pressure sensor boasts an ultra-high range, high linearity, and high sensitivity, and can conform to unmanned underwater equipment, making it a significant advancement in achieving high-precision, large-scale ocean pressure monitoring.

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] Example 1

[0045] like Figure 1 As shown, a double-layer ion-enhanced high-range, high-linearity fabric-based flexible pressure sensor includes a first composite layer and a second composite layer, with a porous material 1 disposed between the first composite layer and the second composite layer. The first composite layer and the second composite layer are symmetrically arranged on both sides of the porous material. The first composite layer includes, from the outside to the inside, a flexible substrate, a nickel cloth electrode 2, and an ion membrane layer 3. The flexible substrate is made by thermally bonding a fabric 4 and a TPU film 5, with the fabric 4 being on the outermost side. The first composite layer, the porous material, and the second composite layer are thermally bonded to form a whole, which is then placed in a mold, and the outer sides of the first composite layer and the second composite layer are wrapped with PDMS to obtain the flexible pressure sensor.

[0046] The ion membrane layer is formed by screen-printing a first ion solution onto the nickel cloth electrode 2. The first ion solution is prepared using the following steps: 2g of thermoplastic polyurethane elastomer (TPU) particles are added to 5ml of N,N-dimethylformamide, followed by magnetic beads. The solution is heated to 100°C and magnetically stirred for 30 minutes. During this stirring process, 1ml of ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) is added dropwise. After magnetic stirring for a period of time, 0.1g of carbon nanotubes is added and magnetic stirring is continued for 2 hours to allow for complete dissolution. The addition of carbon nanotubes effectively increases the stiffness of the TPU and reduces hysteresis. Furthermore, it significantly prevents material loss in the ion membrane when the sensor is under pressure.

[0047] The porous material 1 is fully immersed in the second ionic solution and then sandwiched between the first composite layer and the second composite layer. The second ionic solution is prepared by the following steps: adding the ionic liquid to deionized water and mixing well.

[0048] The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt; and the porous material is polyurethane sponge.

[0049] Example 2

[0050] A double-layer ion-enhanced, high-range, high-linearity fabric-based flexible pressure sensor has the same basic structure as Example 1, except that a gold layer 6 is pre-sputtered on one side of the screen-printed ion membrane layer of the nickel cloth electrode to further improve the sensitivity and stability of the pressure sensor in underwater depth detection.

[0051] The flexible pressure sensor, with a total thickness of no more than 0.5 mm, can measure water depths from 0 to 400 meters. It boasts an ultra-high range, high linearity, high sensitivity, and high stability. It can conform to unmanned underwater equipment, making it crucial for high-precision, wide-area ocean pressure monitoring.

[0052] The flexible pressure sensor can further transmit data to the device via a Bluetooth module.

[0053] The outermost layer of the flexible pressure sensor is cast in a mold using polydimethylsiloxane (PDMS), a colorless, transparent, and highly viscous liquid or silicone. It is odorless, highly transparent, and offers advantages such as heat and cold resistance, minimal viscosity change with temperature, water resistance, low surface tension, and good thermal conductivity. PDMS encapsulates the flexible sensor, imparting excellent water and corrosion resistance to the structure.

[0054] Example 3

[0055] like Figure 2 、 Figure 3 As shown, a method for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor includes the following steps:

[0056] (1) The fabric 4 and the TPU film 5 are thermally bonded to obtain a flexible substrate. The fabric can be made of natural fibers such as cotton and linen, or synthetic fibers such as polyester. The fabric can be cut into any desired shape using a small UV laser cutting machine.

[0057] (2) Assemble a nickel cloth electrode 2 on the flexible substrate and on one side of the TPU film 5. The nickel cloth electrode is similar to a tape, and one side of the nickel cloth electrode can be directly bonded to the TPU film.

[0058] (3) Gold is sputtered on the surface of the nickel cloth electrode 2 using a high vacuum magnetron ion sputtering apparatus, and then an ion membrane layer 3 is screen-printed to assemble and obtain a first composite layer.

[0059] (4) Repeat steps (1) to (3) to assemble the second composite layer.

[0060] (5) Select the porous material 1 and fully immerse it in the second ion solution to obtain the soaked porous material.

[0061] (6) The soaked porous material is sandwiched between the first composite layer and the second composite layer, thermally bonded to form a whole, and then completely wrapped with PDMS to obtain the flexible pressure sensor.

[0062] In the above step (2): the nickel cloth electrode is an uncoated high-purity nickel cloth.

[0063] In step (3) above, the first ionic solution used for screen-printing the ion membrane layer is prepared by the following steps: 2 g of thermoplastic polyurethane elastomer particles (TPU) are added to 5 ml of N,N-dimethylformamide, magnetic beads are added, heated to 100 degrees Celsius, and magnetically stirred at this temperature for 30 minutes. During the stirring process, 1 ml of ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) is added dropwise, and after magnetic stirring for a period of time, 0.1 g of carbon nanotubes is added and magnetic stirring is continued for 2 hours to fully dissolve the solution. The addition of carbon nanotubes and the like effectively increases the stiffness of TPU and reduces hysteresis. In addition, it can significantly prevent the loss of material in the ion membrane when the sensor is under pressure.

[0064] In step (5), the second ionic solution is prepared by adding the ionic liquid to deionized water and mixing them. The mass ratio of the ionic liquid to the deionized water is 1:10.

[0065] In step (6), the entire sensor is first thermally bonded and then wrapped with PDMS.

[0066] The porous material 1 is made of polyurethane sponge.

[0067] The flexible pressure sensor of this invention achieves double-layer ion enhancement by screen-printing an ion membrane layer on the electrode and sandwiching a porous polyurethane sponge soaked in ionic liquid between them. This effectively improves the sensor's sensitivity and detection range, especially ensuring high sensitivity even in deeper underwater environments. The resulting flexible pressure sensor has a total thickness of no more than 0.5 mm and can measure water depths of 0-400 meters. It has a minimum detection limit of 0.2 grams and a response time of 20 milliseconds.

[0068] Example 4

[0069] The preparation method is the same as that of Example 3. The difference is:

[0070] In step (2): the nickel cloth electrode is a platinum-plated high-purity nickel cloth to further improve the service life of the nickel cloth electrode in water.

[0071] In step (3), the first ionic solution used for screen-printing the ion membrane layer is prepared by the following steps: 2 g of thermoplastic polyurethane elastomer particles (TPU) are added to 4 ml of N,N-dimethylformamide, magnetic beads are added, and the mixture is heated to 120 degrees Celsius and magnetically stirred at this temperature for 40 minutes. During the stirring process, 1.2 ml of ionic liquid (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) is added dropwise. After magnetic stirring for a period of time, 0.2 g of hexagonal boron nitride is added and magnetic stirring is continued for 3 hours to fully dissolve the mixture.

[0072] Example 5

[0073] The preparation method is the same as that of Example 3, except that:

[0074] In step (5), when preparing the second ionic solution, the mass ratio of the ionic liquid to the deionized water is adjusted to 1:5, the mass ratio of the ionic liquid to the deionized water is adjusted to 1:15, and the mass ratio of the ionic liquid to the deionized water is adjusted to 1:20.

[0075] like Figure 4 As shown, the porous polyurethane sponge soaked in a mixed solution of deionized water and ionic liquid in different concentration ratios was tested, and it was found that a concentration ratio of 1:10 made the flexible pressure sensor perform best.

[0076] In the above embodiment, the nickel cloth electrode can be cut into different shapes by a small UV laser cutting machine, such as circle, rectangle, triangle, etc. Of course, the porous polyurethane sponge can also be cut into a shape compatible with the nickel cloth electrode by a small UV laser cutting machine.

[0077] The flexible pressure sensor of the present invention is an ionization-type pressure sensor (also known as a supercapacitive sensor). Its principle is the double-layer effect formed by ion-sensitive materials with high ion density and electrodes. Under pressure load, the contact area and spacing (on the order of nanometers) between the sensitive material and the electrodes change, causing the interface capacitance to change. Compared with traditional capacitive sensors, the ionization-type sensor based on the double layer of the present invention increases the capacitance value by more than 1,000 times, which can greatly improve the sensitivity and detection range of the sensor. In addition, the electrostatic interference carried by the device itself during the signal acquisition process can affect the sensor sensitivity. Ionization-type sensors have the advantages of high signal-to-noise ratio and reduced parasitic noise and environmental electromagnetic field interference.

[0078] The present invention incorporates a porous polyurethane sponge into the sensor, effectively increasing the range of water depth detection and preventing the flexible sensor from being squeezed when submerged in water, resulting in a loss of functionality due to the lack of a compression space. Furthermore, soaking the porous polyurethane sponge in an ionic liquid and screen-printing an ion membrane on the electrodes can enhance the sensitivity of the flexible sensor, ensuring high sensitivity even at greater depths underwater.

[0079] The performance test of the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor obtained in the present invention was carried out, and the results are as follows: Figure 5-Figure 9 shown.

[0080] like Figure 5 As shown in the figure, the lowest detection limit of the flexible pressure sensor is 0.2 grams, which means that the sensor is extremely sensitive and can capture tiny pressure changes to achieve high-precision measurement. Figure 6 As shown in Figure 2, the response time of the flexible pressure sensor is 20 milliseconds, and it can even detect tiny vibration signals underwater. Figure 7 As shown in Figure 2, the flexible pressure sensor was subjected to 4650 long-term cycles at a pressure of 1 MPa and maintained consistency and stability. Figure 8 As shown, the flexible pressure sensor was tested under a simulated underwater pressure of 0-5MPa, indicating that the flexible pressure sensor can measure data at a water depth of 0-400 meters and can further transmit the data to the device through a Bluetooth module.

[0081] Figure 9 This is a performance comparison chart of the double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor made in an embodiment of the present invention and existing flexible pressure sensors. In the figure, reference 1 is a capacitive pressure sensor inspired by the biologically inspired KAPOK structure, with a wide detection range and high sensitivity, with a maximum sensitivity of 2.38kPa -1 , response range 10kPa; Reference 2 is a rugged, self-repairing, high-sensitivity pressure sensor based on plug-in type, with a maximum sensitivity of 0.125kPa -1 , response range 700kPa. Figure 9 As shown, by comparing the flexible pressure sensor with the existing conventional flexible pressure sensor, it can be seen that the sensitivity and the pressure range that the flexible pressure sensor can withstand are better than those of the existing conventional flexible pressure sensors, especially the pressure range that it can withstand is particularly outstanding, thereby verifying that the flexible pressure sensor of the present invention has the characteristics of high sensitivity and high range.

[0082] Figure 10This graph shows the sensitivity of a double-layer, ion-enhanced, high-range, high-linearity fabric-based flexible pressure sensor fabricated according to an embodiment of the present invention. The three stages in the graph demonstrate extremely high linearity, reaching as high as 0.999. High linearity translates to greater stability and better prediction of subsequent readings at specific depths.

[0083] Parts not described in the above methods can be achieved by adopting or drawing on existing technologies.

[0084] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any improvements, equivalent substitutions, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A double-layer ion-enhanced, high-range, high-linearity fabric-based flexible pressure sensor, characterized by: The invention comprises a first composite layer and a second composite layer, wherein a porous material is provided between the first composite layer and the second composite layer; The first composite layer and the second composite layer are symmetrically arranged on both sides of the porous material; The first composite layer includes, from the outside to the inside, a flexible substrate, a nickel cloth electrode, and an ion membrane layer. The flexible substrate is made by thermally bonding a fabric and a TPU film, with the fabric on the outside. The ion membrane layer is formed by screen-printing the first ion solution onto the nickel cloth electrode. The first ionic solution is prepared by the following steps: adding thermoplastic polyurethane elastomer particles to N,N-dimethylformamide, heating and stirring, and dropwise adding ionic liquid, and then adding carbon nanotubes, hexagonal boron nitride or silicon dioxide and fully dissolving them to obtain the first ionic solution; Thermally bonding the first composite layer, the porous material, and the second composite layer, and then wrapping the outsides of the first composite layer and the second composite layer with PDMS to obtain the flexible pressure sensor; The porous material is fully immersed in a second ionic solution and then sandwiched between the first composite layer and the second composite layer; the second ionic solution is prepared by the following steps: adding an ionic liquid to deionized water and mixing well; The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt; the porous material is polyurethane sponge; A gold layer is pre-sputtered on one side of the screen-printed ion membrane layer of the nickel cloth electrode.

2. The double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to claim 1, characterized in that: The flexible pressure sensor has a total thickness of no more than 0.5 mm and is capable of measuring water depths of 0-400 meters.

3. The method for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to any one of claims 1-2, characterized in that The following steps are involved: (1) Thermally bonding the fabric and TPU film to obtain a flexible substrate; (2) Assembling a nickel cloth electrode on the flexible substrate and on the side of the TPU film; (3) sputtering a gold layer on the surface of the nickel cloth electrode, and then screen-printing an ion membrane layer to assemble the first composite layer; (4) Repeat steps (1) to (3) to assemble a second composite layer; (5) Selecting a porous material and fully immersing it in a second ion solution to obtain a soaked porous material; (6) sandwiching the soaked porous material between the first composite layer and the second composite layer, thermally bonding them to form a whole, and then completely wrapping them with PDMS to obtain the flexible pressure sensor; In step (3), the first ion solution used for screen-printing the ion membrane layer is prepared by the following steps: adding thermoplastic polyurethane elastomer particles to N,N-dimethylformamide, heating and stirring, and dropping ionic liquid, and then adding carbon nanotubes, hexagonal boron nitride or silicon dioxide, stirring and dissolving them thoroughly to obtain; In step (5), the second ionic solution is prepared by the following steps: adding the ionic liquid to deionized water and mixing well.

4. The method for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to claim 3, characterized in that: In step (2): the nickel cloth electrode is an unplated high-purity nickel cloth or a gold-plated, platinum-plated, copper-plated, or silver-plated high-purity nickel cloth.

5. The method for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to claim 3, characterized in that: In step (3): based on 2 g of thermoplastic polyurethane elastomer particles, the amount of N,N-dimethylformamide is 3-6 ml, the amount of ionic liquid is 0.8-1.2 ml, and the amount of carbon nanotubes, hexagonal boron nitride or silicon dioxide is 0.1-0.3 g; Control the heating and stirring temperature to 90-120°C, the heating and stirring time to 30-45 minutes; and the sufficient stirring and dissolving time to 2-3 hours.

6. The method for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to claim 3, characterized in that: The ionic liquid is 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, the mass ratio of the ionic liquid to deionized water in the second ionic solution is 1:5-1:20; and the porous material is polyurethane sponge.

7. The method for preparing a double-layer ion-enhanced high-range and high-linearity fabric-based flexible pressure sensor according to claim 3, characterized in that: The flexible pressure sensor has a total thickness of no more than 0.5 mm and is capable of measuring water depths of 0-400 meters. The minimum detection line is 0.2Pa and the response time is 20 milliseconds.

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