Flexible pressure sensor and preparation method thereof

Abstract

The invention provides a flexible pressure sensor and a preparation method thereof. The sensor comprises a pressure sensitive layer and an electrode connected with the pressure sensitive layer. The pressure sensitive layer is a porous elastomer containing a conductive network material, and the conductive network material is a carbon nanomaterial. The sensor has high sensitivity, good stability and excellent flexibility, is suitable for the fields of medical monitoring, robot technology, wearable electronic equipment and the like, and meets the requirements for flexibility and adaptability in practical application.

Description

Technical Field

[0001] This invention relates to the field of flexible electronics and sensing technology, and in particular to a flexible pressure sensor and its fabrication method. Background Technology

[0002] Flexible pressure sensors, as key components that convert physical signals into electrical signals, have demonstrated significant application value in various fields such as medical monitoring, robotics, and wearable electronic devices. Although traditional silicon-based pressure sensors are favored for their high accuracy, their inherent rigid structure and brittle material properties make them difficult to meet the requirements for flexibility and adaptability in practical applications when facing dynamically curved surfaces. Summary of the Invention

[0003] This invention provides a flexible pressure sensor and its fabrication method, addressing the rigidity and brittleness limitations of traditional silicon-based pressure sensors in applications involving dynamically bent surfaces. The sensor of this invention exhibits high sensitivity, good stability, and excellent flexibility, making it suitable for applications such as medical monitoring, robotics, and wearable electronic devices, thus meeting the demands for flexibility and adaptability in practical applications.

[0004] The present invention provides a flexible pressure sensor, comprising a pressure-sensitive layer and an electrode connected to the pressure-sensitive layer; the pressure-sensitive layer is a porous elastomer containing a conductive network material, wherein the conductive network material is a carbon nanomaterial.

[0005] This invention provides a flexible pressure sensor, wherein the porous elastomer containing conductive network material is obtained by casting a sacrificial template coated with conductive network material into the elastomer material, and then etching the sacrificial template; the sacrificial template has a three-dimensional porous structure.

[0006] According to the present invention, a flexible pressure sensor is provided, wherein the carbon nanomaterial is reduced graphene oxide or carbon nanotubes.

[0007] According to the present invention, a flexible pressure sensor is provided, wherein the sacrificial template is made of nickel foam; the sacrificial template coated with conductive network material is specifically obtained by immersing the nickel foam in the carbon nanomaterial dispersion, and under ultrasonic assistance, wetting the carbon nanomaterial into the three-dimensional pore structure of the nickel foam, followed by drying.

[0008] According to the present invention, a flexible pressure sensor is provided, wherein the elastomer material is polydimethylsiloxane; the sacrificial template coated with conductive network material is obtained by casting the elastomer material into a sacrificial template, specifically by completely immersing nickel foam coated with carbon nanomaterials in a polydimethylsiloxane mixture, followed by vacuum drying and curing.

[0009] According to a flexible pressure sensor provided by the present invention, the sacrificial template is removed by a chemical etching reaction; the solution for the chemical etching reaction is hydrochloric acid or ferric chloride solution.

[0010] This invention also provides a method for fabricating a flexible pressure sensor, comprising: preparing a sacrificial template, wherein the sacrificial template has a three-dimensional porous structure; impregnating the sacrificial template with a conductive network material to obtain a first structure; based on the first structure, casting the sacrificial template impregnated with the conductive network material using an elastomer material to obtain a second structure; based on the second structure, post-etching the sacrificial template to obtain a pressure-sensitive layer; wherein the pressure-sensitive layer is a porous elastomer containing the conductive network material; and connecting electrodes on the pressure-sensitive layer to obtain a flexible pressure sensor.

[0011] According to a method for preparing a flexible pressure sensor provided by the present invention, the preparation of the sacrificial template includes: ultrasonically cleaning and drying a nickel foam to obtain a pretreated nickel foam; the method of impregnating the sacrificial template with a conductive network material to obtain a first structure includes: immersing the pretreated nickel foam in a carbon nanomaterial dispersion, and under ultrasonic assistance, wetting the carbon nanomaterial into the three-dimensional pore structure of the nickel foam, and drying to obtain the first structure.

[0012] According to a method for preparing a flexible pressure sensor provided by the present invention, the second structure is obtained by casting a sacrificial template coated with conductive network material using an elastomer material based on the first structure, comprising: completely immersing a nickel foam coated with carbon nanomaterials in a polydimethylsiloxane mixture, and then vacuum drying and curing to obtain the second structure.

[0013] According to a method for fabricating a flexible pressure sensor provided by the present invention, the step of obtaining a pressure-sensitive layer by post-etching a sacrificial template based on the second structure includes: removing the sacrificial template by a chemical etching reaction based on the second structure to obtain the pressure-sensitive layer; the solution for the chemical etching reaction is hydrochloric acid or ferric chloride solution.

[0014] This invention provides a flexible pressure sensor and its fabrication method. The sensor has high sensitivity, good stability and excellent flexibility, and is suitable for medical monitoring, robotics and wearable electronic devices, meeting the needs for flexibility and adaptability in practical applications. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a cross-sectional schematic diagram of a flexible pressure sensor provided by the present invention.

[0017] Figure 2 This is a schematic diagram illustrating the principle of a method for fabricating a flexible pressure sensor provided by the present invention.

[0018] Figure 3 This is a schematic flowchart of a method for fabricating a flexible pressure sensor provided by the present invention.

[0019] Figure 4 This is a schematic diagram illustrating the specific process of a method for fabricating a flexible pressure sensor provided by the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] Flexible pressure sensors, as key components for converting physical signals into electrical signals, have significant application value in fields such as medical monitoring, robotics, and wearable electronics. While traditional silicon-based MEMS sensors offer high accuracy, their rigid structure and brittle materials make them difficult to adapt to dynamically curved surfaces.

[0022] Please refer to Figure 1 , Figure 1 This is a cross-sectional schematic diagram of a flexible pressure sensor provided by the present invention.

[0023] The present invention provides a flexible pressure sensor, including a pressure-sensitive layer and an electrode connected to the pressure-sensitive layer; the pressure-sensitive layer is a porous elastomer containing a conductive network material, and the conductive network material is a carbon nanomaterial.

[0024] In a preferred embodiment, the porous elastomer containing conductive network material is obtained by casting a sacrificial template coated with conductive network material into the elastomer material, and then etching the sacrificial template; the sacrificial template has a three-dimensional porous structure.

[0025] To address the technical problems existing in current technologies, this invention proposes a high-performance elastic conductive foam sensor fabricated using a sacrificial template etching method. This sensor exhibits high sensitivity, good stability, breathability, and wearing comfort, and can be widely applied in fields such as human-computer interaction, electronic skin, and wearable health monitoring. Specifically, a conductive network material is uniformly coated onto the surface of a sacrificial template using a dip-coating method to form a continuous and complete conductive network precursor. Subsequently, a biocompatible elastomer is used for casting and curing. Finally, the sacrificial template is removed by etching to form a pressure-sensitive layer. Electrodes are placed on both sides of the pressure-sensitive layer to obtain an elastic foam sensor with a three-dimensional interconnected porous structure and a highly uniform conductive network. This invention, by constructing conductive pathways before molding the porous elastomer, solves the key problems of uneven distribution and easy agglomeration of conductive fillers. While maintaining high conductivity, it significantly improves the mechanical stability and signal consistency of the device, and the resulting sensor exhibits superior fatigue resistance. Meanwhile, the present invention can adjust the shape and arrangement of the sacrificial template according to the needs, so as to achieve precise design of pore structure and sensing performance. The process is simple and low cost, and it is suitable for large-scale production. It has broad application prospects in medical and health fields such as pulse wave monitoring and respiratory waveform detection.

[0026] Flexible pressure sensors can also be encapsulated, such as with TPU (Thermoplastic Polyurethane) or PDMS (Polydimethylsiloxane).

[0027] The electrodes can be made by bonding electrode sheets with conductive silver paste. The electrode material can also be one or more combinations of gold, platinum, nickel, indium, carbon nanotubes, graphene, or silver nanowires; the electrode can be led out by printing or physical cutting.

[0028] The core of this invention lies in the pressure-sensitive layer made of foam-like PDMS elastomer containing carbon nanomaterials. The sensor of this invention achieves a high signal-to-noise ratio response to minute pressure fluctuations; it possesses excellent mechanical durability, capable of withstanding long-term repeated pressing and bending; the overall device has good breathability and skin affinity, improving comfort during long-term wear; and scalable manufacturing is achieved through low-cost solution processing and template methods.

[0029] In a preferred embodiment, the carbon nanomaterial is reduced graphene oxide or carbon nanotubes.

[0030] In a preferred embodiment, the sacrificial template is made of nickel foam; the sacrificial template coated with conductive network material is specifically obtained by immersing nickel foam in a carbon nanomaterial dispersion, allowing the carbon nanomaterial to wet the three-dimensional pore structure of the nickel foam under ultrasonic assistance, and then drying it.

[0031] In a preferred embodiment, the elastomer material is polydimethylsiloxane; the sacrificial template coated with conductive network material is obtained by casting the elastomer material into a sacrificial template by completely immersing nickel foam coated with carbon nanomaterials in a polydimethylsiloxane mixture, followed by vacuum drying and curing.

[0032] In a preferred embodiment, the sacrificial template is specifically removed by a chemical etching reaction; the solution for the chemical etching reaction is hydrochloric acid or ferric chloride solution.

[0033] Please refer to Figure 2 , Figure 2 This is a schematic diagram illustrating the principle of a method for fabricating a flexible pressure sensor provided by the present invention.

[0034] In this embodiment, the fabrication process of the flexible piezoresistive sensor is as follows: Preparation of carbon nanomaterial-nickel foam composites: Nickel foam acts as a three-dimensional sacrificial template for the growth of multilayer carbon nanomaterials during the preparation process. The microstructure of the nickel foam is characterized by a framework width distribution within... Between, and possess The pretreated nickel foam is immersed in a carbon nanomaterial dispersion (e.g., an aqueous solution of graphene oxide) of a certain concentration, and the dispersion is fully wetted into the three-dimensional pore structure of the nickel foam under ultrasonic assistance. After removal, it is dried, and the "immersion-drying" process can be repeated multiple times as needed to increase the loading of carbon nanomaterials. Subsequently, an appropriate reduction method can be selected according to actual needs, such as heat treatment under an inert atmosphere, or solution chemical reduction (e.g., treatment with hydrogen iodide HI solution), to partially reduce the graphene oxide and firmly attach it to the surface of the nickel foam skeleton, finally obtaining a nickel foam composite material modified with carbon nanomaterials.

[0035] PDMS Material Infusion: Thoroughly mix the PDMS base agent and curing agent at a mass ratio of 10:1, stir, and let stand to remove air bubbles. Then, completely immerse the pretreated composite foam material in the mixture and evacuate to ensure the PDMS fully replaces the air in the nickel foam. After removal, place it on a flat surface and allow it to air dry at room temperature. Once the PDMS has initially cured and set, use a precision cutter or scissors to cut it to the required size and shape. Finally, place it in an oven... Heat for 2 hours to complete curing.

[0036] Nickel foam etching: The surface of the PDMS / carbon nanomaterial composite foam is lightly polished to break the dense encapsulation layer and expose the internal nickel framework. It is then immersed in a solution of hydrochloric acid (HCl) or ferric chloride (HCl) of a certain concentration. In the solution, the nickel metal template was removed by chemical etching reaction, and finally the carbon nanomaterial-PDMS semi-embedded three-dimensional porous network structure was obtained.

[0037] Finally, conductive silver paste is used to draw out electrodes on both sides.

[0038] The sensing mechanism of the sensor of this invention is as follows: In the initial state, the carbon nanomaterial network has limited contact points and a small contact area, with a large number of nanoscale gaps, resulting in high contact resistance and tunneling resistance, and an overall high resistance level. In the low-pressure region, the three-dimensional porous structure undergoes local elastic collapse, significantly increasing the number of effective contacts and the contact area, causing a significant decrease in contact resistance; simultaneously, the nanoscale gaps are rapidly compressed, exponentially reducing the tunneling resistance. The superposition of these two factors leads to a sharp decrease in relative resistance, exhibiting extremely high sensitivity. In the medium- and high-pressure regions, the conductive network gradually densifies, and new seepage channels are continuously formed. The equivalent conductivity is approximately power-law related to the pressure; the growth of the number of contacts slows down, but new conductive paths continue to be established. The resistance change exhibits a linear or weakly nonlinear response to pressure, forming a wide detection range; as the pressure further increases, the network tends to compact, the contribution of newly added contact points and tunneling channels becomes saturated, some microstructures may undergo microcracks or rearrangements, the change in conductive paths weakens, the rate of change in resistance decreases, and finally, a plateau or sublinear trend is observed.

[0039] The beneficial effects of this invention are as follows: Ultra-high sensitivity: This invention constructs a low-modulus hollow porous framework structure based on three-dimensional sacrificial template replication technology. Utilizing the properties imparted by the nickel foam template... The large-pore open microstructure significantly reduces the equivalent elastic modulus of the sensitive layer. Under low pressure (e.g., 0–1 kPa), the high-porosity framework is prone to elastic buckling and local collapse. This macroscopic deformation is directly coupled to the microscopic conductive interface, prompting the carbon nanomaterial network semi-embedded in the pore walls to undergo large-area physical contact and reconstructing of permeation channels. This mechanism transforms minute mechanical stress into a nonlinear surge in the effective contact area of ​​the conductive network, leading to an exponential decrease in contact resistance and tunneling resistance. This enables high signal-to-noise ratio capture and extremely low detection limit for weak physiological signals (such as pulse waves), significantly improving the piezoresistive response sensitivity of the device.

[0040] Exceptional Stability and Durability: This invention employs an in-situ solidification and anchoring semi-embedded interface construction process. By pre-assembling a continuous carbon nanomaterial layer on the surface of a nickel framework and utilizing the wetting and solidification process of a liquid PDMS precursor, in-situ physical anchoring of the conductive material on the surface of the elastomer pore walls is achieved. The semi-embedded structure of this invention forms a robust "matrix-filler" heterogeneous interface, effectively suppressing interface slippage and microcrack propagation caused by modulus mismatch during cyclic loading. Simultaneously, the sacrificial template method accurately replicates the topologically continuous three-dimensional interconnected network of the nickel foam, avoiding the risk of conductive pathway breakage or aggregation. This defined geometry combined with a robust interface ensures that the sensor's resistance baseline and response characteristics remain highly consistent under long-term repeated compression, bending, and torsional deformation, exhibiting extremely low hysteresis error and excellent mechanical fatigue resistance.

[0041] Excellent flexibility and comfort: This invention uses PDMS as a flexible substrate and retains a three-dimensional porous skeleton structure, making the device lightweight, soft and breathable, and able to fit closely to the skin surface, significantly improving wearing comfort and biocompatibility.

[0042] Simple process and low cost: The present invention can complete the preparation of the sensor through only dip coating, casting and etching processes. The process is simple and easy to control, the raw material cost is low, and it is suitable for large-scale production and commercial application.

[0043] The following describes the fabrication method of the flexible pressure sensor provided by the present invention. The fabrication method of the flexible pressure sensor described below can be referred to in correspondence with the flexible pressure sensor described above.

[0044] Please refer to Figure 3 , Figure 3 This is a schematic flowchart illustrating a method for fabricating a flexible pressure sensor provided by the present invention.

[0045] This invention also provides a method for fabricating a flexible pressure sensor, comprising: 301: Prepare the sacrificial template, which is a three-dimensional porous structure; 302: The sacrificial template is dipped in conductive network material to obtain the first structure; 303: Based on the first structure, a second structure is obtained by casting a sacrificial template coated with conductive network material using an elastomer material; 304: Based on the second structure, a pressure-sensitive layer is obtained by post-etching a sacrificial template; the pressure-sensitive layer is a porous elastomer containing a conductive network material; electrodes are connected to the pressure-sensitive layer to obtain a flexible pressure sensor.

[0046] As a preferred embodiment, preparing a sacrificial template includes: ultrasonically cleaning and drying a nickel foam to obtain a pretreated nickel foam; and impregnating the sacrificial template with a conductive network material to obtain a first structure, which includes: immersing the pretreated nickel foam in a carbon nanomaterial dispersion, using ultrasound to wet the carbon nanomaterial into the three-dimensional pore structure of the nickel foam, and drying to obtain the first structure.

[0047] As a preferred embodiment, based on the first structure, a second structure is obtained by casting a sacrificial template coated with conductive network material using an elastomer material, including: completely immersing a nickel foam coated with carbon nanomaterials in a polydimethylsiloxane mixture, followed by vacuum drying and curing to obtain the second structure.

[0048] As a preferred embodiment, based on the second structure, a pressure-sensitive layer is obtained by post-etching a sacrificial template, including: based on the second structure, removing the sacrificial template by a chemical etching reaction to obtain the pressure-sensitive layer; the solution for the chemical etching reaction is hydrochloric acid or ferric chloride solution.

[0049] Please refer to Figure 4 , Figure 4 This is a schematic diagram illustrating the specific process of a method for fabricating a flexible pressure sensor provided by the present invention.

[0050] Example 1 In this embodiment, the method for fabricating the flexible pressure sensor includes: Nickel foam pretreatment: Take a piece of foam approximately [size missing] Nickel foam (area density approximately) The solution was sequentially placed in acetone, 1M hydrochloric acid solution, and deionized water, and ultrasonically cleaned for 10 minutes in each solution. It was then rinsed with anhydrous ethanol and placed in... The nickel foam was dried in a vacuum oven for 1 hour to obtain the pretreated nickel foam.

[0051] Carbon nanomaterial impregnation and reduction: Prepare a 2 mg / mL GO (graphene oxide) aqueous dispersion. Completely immerse the nickel foam in the dispersion and ultrasonically agitate in a water bath for 20 minutes to allow the liquid to fully penetrate the pores. A short-term low-vacuum treatment can be used to enhance penetration. Remove and allow to air dry for 10-15 minutes; repeat the impregnation process twice. Anneal the GO-loaded foam in a vacuum tube furnace at a temperature of [temperature missing]. The reaction was kept at a constant temperature for 30 minutes to reduce GO to rGO and allow it to adhere firmly. After the reaction was complete, the mixture was rinsed several times with deionized water until neutral. The first structure was obtained by drying in a vacuum oven for 1 hour.

[0052] PDMS Infusion and Curing: Mix PDMS base agent and curing agent at a ratio of 10:1 and stir for 5 minutes until homogeneous. Degas under vacuum for 10 minutes. Immerse rGO-nickel foam into the degassed PDMS and apply vacuum for 5-10 minutes to ensure penetration. Allow to stand at room temperature for 30 minutes for initial curing, then... Curing in an oven for 1.5 hours until fully cured yields the second structure.

[0053] Nickel template etching and post-treatment: Lightly sand the surface with fine sandpaper to expose part of the nickel skeleton. Immerse in 2M hydrochloric acid solution at room temperature or... React in a water bath for 5-10 minutes, then rinse repeatedly with deionized water after etching. Dry in a vacuum oven for 1-2 hours. Then, cure the conductive silver paste to form copper wires for 2 hours.

[0054] Example 2 In this embodiment, the method for fabricating the flexible pressure sensor includes: Nickel foam pretreatment: Take a piece of foam approximately [size missing] Nickel foam (area density approximately) The solution was sequentially placed in acetone, 1M hydrochloric acid solution, and deionized water, and ultrasonically cleaned for 10 minutes in each solution. It was then rinsed with anhydrous ethanol and placed in... The nickel foam was dried in a vacuum oven for 1 hour to obtain the pretreated nickel foam.

[0055] Carbon nanomaterial impregnation and reduction: Prepare a 4 mg / mL GO aqueous dispersion. Completely immerse the nickel foam in the dispersion and ultrasonically agitate in a water bath for 30 minutes to allow the liquid to fully penetrate the pores. A short-term low-vacuum assisted process for 5 minutes can be used to improve penetration. Remove and allow to air dry for 10-15 minutes. Repeat the impregnation process three times. Anneal the GO-loaded foam in a vacuum tube furnace at a temperature of [temperature missing]. The reaction was kept at a constant temperature for 30 minutes to reduce GO to rGO and allow it to adhere firmly. After the reaction was complete, the mixture was rinsed several times with deionized water until neutral. Dry in a vacuum oven for 1 hour.

[0056] PDMS Infusion and Curing: Mix PDMS base agent and curing agent at a ratio of 10:1 and stir for 5 minutes until homogeneous. Degas under vacuum for 10 minutes. Immerse rGO-nickel foam into the degassed PDMS and apply vacuum for 5-10 minutes to ensure penetration. Allow to stand at room temperature for 30 minutes for initial curing, then... Cur in an oven for 1.5 hours until fully cured.

[0057] Nickel template etching and post-treatment: Lightly sand the surface with fine sandpaper to expose part of the nickel skeleton. Immerse in 1M... The solution was reacted at room temperature for 6 hours, with the solution changed once during the process. After etching, the solution was rinsed multiple times with deionized water. Dry in a vacuum oven for 1-2 hours. The etching is gentle, which helps maintain the microporous structure. Conductive silver paste can be applied to lead out copper wires and cured for 2 hours.

[0058] Example 3 In this embodiment, the method for fabricating the flexible pressure sensor includes: Nickel foam pretreatment: Take a piece of foam approximately [size missing] Nickel foam (area density approximately) The solution was sequentially placed in acetone, 1M hydrochloric acid solution, and deionized water, and ultrasonically cleaned for 10 minutes in each solution. It was then rinsed with anhydrous ethanol and placed in... The nickel foam was dried in a vacuum oven for 1 hour to obtain the pretreated nickel foam.

[0059] Carbon nanomaterial dip-coating and reduction: Prepare a 3 mg / mL multi-walled carbon nanotube (MWCNT) dispersion using NMP (N-Methyl-2-Pyrrolidone) as the solvent. Immerse the nickel foam and dispersion in a beaker and agitate in an ultrasonic water bath for 20 minutes to allow the liquid to fully penetrate the pores. A short period of low vacuum assistance for 5 minutes can be used to improve the penetration effect. Remove and allow to air dry for 10-15 minutes. Repeat the dip-coating process twice.

[0060] PDMS Infusion and Curing: Mix PDMS base agent and curing agent at a ratio of 10:1 and stir for 5 minutes until homogeneous. Degas under vacuum for 10 minutes. Immerse rGO-nickel foam into the degassed PDMS and apply vacuum for 5-10 minutes to ensure penetration. Allow to stand at room temperature for 30 minutes for initial curing, then... Cur in an oven for 1.5 hours until fully cured.

[0061] Nickel template etching and post-treatment: Lightly sand the surface with fine sandpaper to expose part of the nickel skeleton. Immerse in 2M hydrochloric acid solution at room temperature or... React in a water bath for 5-10 minutes. After etching, gradient ethanol dehydration can be performed. (30 minutes each). Then place on Dry in a vacuum oven for 1-2 hours to protect the microporous structure. Then, cure the conductive silver paste to form copper wires for 2 hours.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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; and these 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.

Claims

1. A flexible pressure sensor, characterized in that, Includes a pressure-sensitive layer and electrodes connected to the pressure-sensitive layer; The pressure-sensitive layer is a porous elastomer containing a conductive network material, which is a carbon nanomaterial.

2. The flexible pressure sensor according to claim 1, characterized in that, The porous elastomer containing conductive network material is obtained by casting a sacrificial template coated with conductive network material into an elastomer material, followed by etching the sacrificial template; the sacrificial template has a three-dimensional porous structure.

3. The flexible pressure sensor according to claim 2, characterized in that, The carbon nanomaterial is reduced graphene oxide or carbon nanotubes.

4. The flexible pressure sensor according to claim 2, characterized in that, The sacrificial template is made of nickel foam; the sacrificial template coated with conductive network material is specifically obtained by immersing the nickel foam in the carbon nanomaterial dispersion, allowing the carbon nanomaterial to wet the three-dimensional pore structure of the nickel foam under ultrasonic assistance, and then drying it.

5. The flexible pressure sensor according to claim 4, characterized in that, The elastomer material is polydimethylsiloxane; the sacrificial template coated with conductive network material is obtained by casting the elastomer material into a sacrificial template, specifically by completely immersing nickel foam coated with carbon nanomaterials in a polydimethylsiloxane mixture, followed by vacuum drying and curing.

6. The flexible pressure sensor according to any one of claims 2 to 5, characterized in that, The sacrificial template is removed by a chemical etching reaction; the solution for the chemical etching reaction is hydrochloric acid or ferric chloride solution.

7. A method for fabricating a flexible pressure sensor, characterized in that, include: Prepare a sacrificial template, which is a three-dimensional porous structure; The sacrificial template is dipped in conductive network material to obtain the first structure; Based on the first structure, a second structure is obtained by casting a sacrificial template coated with conductive network material using an elastomer material; Based on the second structure, a pressure-sensitive layer is obtained by post-etching a sacrificial template; the pressure-sensitive layer is a porous elastomer containing a conductive network material. Electrodes are connected to the pressure-sensitive layer to obtain a flexible pressure sensor.

8. The method for fabricating a flexible pressure sensor according to claim 7, characterized in that, The prepared sacrifice template includes: The nickel foam is ultrasonically cleaned and dried to obtain pretreated nickel foam. The step of impregnating the sacrificial template with a conductive network material to obtain a first structure includes: The pretreated nickel foam is immersed in a carbon nanomaterial dispersion, and the carbon nanomaterial is impregnated into the three-dimensional pore structure of the nickel foam under ultrasonic assistance. After drying, the first structure is obtained.

9. The method for fabricating a flexible pressure sensor according to claim 8, characterized in that, Based on the first structure, a second structure is obtained by casting the sacrificial template coated with conductive network material using an elastomer material, comprising: The nickel foam coated with carbon nanomaterials was completely immersed in a polydimethylsiloxane mixture, and then vacuum dried and cured to obtain the second structure.

10. The method for manufacturing a flexible pressure sensor according to any one of claims 7 to 9, characterized in that, The pressure-sensitive layer, obtained by post-etching a sacrificial template based on the second structure, includes: Based on the second structure, the sacrificial template is removed by a chemical etching reaction to obtain a pressure-sensitive layer; the solution for the chemical etching reaction is hydrochloric acid or ferric chloride solution.

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