A hydrogel-elastic hybrid flexible sensor based on double-sided interlocking structure and a preparation method thereof

Abstract

The application provides a hydrogel-elastic body hybrid flexible sensor based on a double-sided interlocking structure and a preparation method thereof, and belongs to the technical field of flexible strain sensors. The method comprises the following steps: preparing a porous TPU fiber membrane; performing oxygen plasma treatment on the porous TPU fiber membrane, immersing the porous TPU fiber membrane in a polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution, taking out the preformed hydrogel, and stacking the preformed hydrogel on the front side of the porous TPU fiber membrane and performing ultraviolet curing to form a first interlocking interface; coating a TPU solution on the back side of the porous TPU fiber membrane to form a dense TPU film layer, then stacking a preformed CNT / TPU composite membrane on the dense TPU film layer to form a second interlocking interface, and obtaining the hydrogel-elastic body hybrid flexible sensor based on the double-sided interlocking structure. The sensor has excellent interfacial toughness, high adhesion, a wide working strain range, high sensitivity and a fast response time.

Description

Technical Field

[0001] This invention belongs to the field of flexible strain sensor technology, specifically relating to a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure and its fabrication method. Background Technology

[0002] With the rapid development of wearable devices and soft robots, flexible strain sensors have shown broad application prospects in fields such as human motion monitoring, health detection, and human-computer interaction. Traditional elastomer-based sensors, while possessing high sensitivity, generally lack self-adhesion and are prone to detachment during dynamic use. Hydrogel-based sensors, while exhibiting good adhesion and biocompatibility, suffer from lower sensitivity, and the introduction of conductive fillers often sacrifices mechanical properties and flexibility. In existing technologies, it is difficult to simultaneously achieve high adhesion, high sensitivity, and strong interfacial bonding using a single material or simple layered structure. Therefore, developing a flexible strain sensor that combines strong adhesion, high sensitivity, a wide detection range, and excellent interfacial stability is of great significance. Summary of the Invention

[0003] This invention provides a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure and its preparation method. By constructing a hydrogel layer and a CNT / TPU composite membrane on both sides of a porous TPU fiber membrane, and utilizing physical interlocking and chemical bonding to synergistically enhance the interfacial bonding, a unified approach of high adhesion, high sensitivity, wide strain range, and excellent cycle stability is achieved, thereby effectively solving at least one of the technical problems involved in the background art.

[0004] To solve the above-mentioned technical problems, the present invention is implemented as follows: A method for fabricating a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure includes the following steps: Step S1: Prepare porous TPU fiber membranes using electrospinning with TPU solution; Step S2: The porous TPU fiber membrane is treated with oxygen plasma, then immersed in a polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution. After removal, the pre-formed hydrogel is stacked on the front side of the porous TPU fiber membrane and cured with ultraviolet light to form the first interlocking interface. Step S3: Coat the back of the porous TPU fiber membrane with TPU solution to form a dense TPU film layer. Then, stack the pre-formed CNT / TPU composite membrane on the dense TPU film layer to form a second interlocking interface, thus obtaining a hydrogel-elastomer hybrid flexible sensor with a double-sided interlocking structure.

[0005] As a preferred improvement, the TPU solution in steps S1 and S3 is prepared in the following manner: DMF and THF are mixed in a mass ratio of 1:1 to 1:2 to obtain a mixed solvent. A certain mass of TPU is dissolved in the mixed solvent to obtain a TPU solution with a concentration of 15-20 wt%.

[0006] As a preferred improvement, in step S2, the polyacrylate-N-hydroxysuccinimide hydrogel precursor solution is prepared in the following manner: Dissolve 1-4 mg of N-hydroxysuccinimide acrylate monomer and 5-9 mg of N,N'-methylenebisacrylamide crosslinking agent in 100-250 μL of photoinitiator I-1173. After the reaction is complete, a polyacrylic acid N-hydroxysuccinimide hydrogel precursor solution is obtained.

[0007] As a preferred improvement, step S2 specifically includes the following steps: The porous TPU fiber membrane is plasma treated for 120-180 seconds, then immersed in a polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution for 10-15 minutes. After removal, the pre-formed hydrogel is stacked on the front side of the porous TPU fiber membrane and cured with ultraviolet light for 60-90 seconds to form the first interlocking interface.

[0008] As a preferred improvement, in step S3, the CNT / TPU composite membrane is prepared by depositing a CNT dispersion onto the surface of a porous TPU fiber membrane using a vacuum filtration method.

[0009] A hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure was prepared using the above-described method.

[0010] As a preferred improvement, it includes an adhesive layer, a bonding layer, and a sensing layer stacked sequentially, wherein: Pre-formed hydrogels serve as adhesive layers to provide strong adhesion to a variety of substrates; Porous TPU fiber membrane serves as a bonding layer, providing skeletal support; The CNT / TPU composite film serves as the sensing layer, responsible for sensing and converting strain signals. The adhesive layer and the bonding layer form a first interlocking interface through physical interlocking and chemical bonding, and the bonding layer and the sensing layer form a second interlocking interface through physical interlocking and chemical bonding.

[0011] As a preferred improvement, the adhesive layer has an interfacial toughness of not less than 138 for dry pigskin. The adhesion retention rate on wet skin is greater than 80%; the sensor has different sensitivity coefficients in three strain ranges: 0-100%, 100%-250%, and 250%-400%, and the sensitivity coefficient is not less than 130 in the 250-400% strain range.

[0012] One application of the sensor described above is in human motion monitoring, health signal detection, or intelligent grasping and recognition systems for soft robots.

[0013] Compared with the prior art, the present invention has the following beneficial effects: A porous TPU fiber membrane was prepared by electrospinning. One side of the TPU fiber membrane was impregnated with a hydrogel precursor solution and then laminated with the hydrogel. The other side was coated with a TPU solution and then laminated with a CNT / TPU composite membrane, forming a double-sided interlocking structure. This sensor exhibits excellent interfacial toughness, high adhesion, a wide operating strain range, high sensitivity, and a fast response time. The sensor can be directly attached to the skin or the surface of a soft robot to achieve real-time monitoring of signals such as human joint movement and muscle contraction, and can be used for machine learning-based object recognition and classification. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments 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, wherein: Figure 1 A flowchart illustrating a method for fabricating a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure, provided by the present invention. Figure 2 A schematic diagram of a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure provided by the present invention; Figure 3 express Figure 2 The diagram shows the sensor's state under tension, bending, and torsion. Figure 4 for Figure 2 The cross-sectional SEM image of the sensor shown; Figure 5 for Figure 2 A schematic diagram of the interface bonding mechanism of the sensor shown; Figure 6 The graph shows the adhesion performance test results of the sensor shown in Example 1 on different substrates; Figure 7 The graph shows the tensile strength test results of the sensor shown in Example 1 on different substrates; Figure 8 The strain-resistance response curve and cyclic stability test results of the sensor shown in Example 1 are shown below. Figure 9 This is a schematic diagram illustrating the application of the sensor shown in Example 1 in human joint motion monitoring; Figure 10 This is a schematic diagram of the system shown in Example 1, in which the sensor is integrated into a soft gripper for fruit identification. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] like Figures 1-4 As shown, this embodiment provides a method for fabricating a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure, comprising the following steps: Step S1: Prepare porous TPU fiber membranes using electrospinning with TPU solution; Step S2: The porous TPU fiber membrane is treated with oxygen plasma, then immersed in a polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution. After removal, the pre-formed hydrogel is stacked on the front side of the porous TPU fiber membrane and cured with ultraviolet light to form the first interlocking interface. Step S3: Coat the back of the porous TPU fiber membrane with TPU solution to form a dense TPU film layer. Then, stack the pre-formed CNT / TPU composite membrane on the dense TPU film layer to form a second interlocking interface, thus obtaining a hydrogel-elastomer hybrid flexible sensor with a double-sided interlocking structure.

[0017] It should be noted that the front and back sides are two sides of a porous TPU fiber membrane facing each other.

[0018] The TPU solutions in steps S1 and S3 are prepared as follows: DMF (N,N-dimethylformamide) and THF (tetrahydrofuran) are mixed in a mass ratio of 1:1 to 1:2 to obtain a mixed solvent. A certain mass of TPU (thermoplastic polyurethane elastomer) is dissolved in the mixed solvent to obtain a TPU solution with a concentration of 15-20wt%.

[0019] In step S1, the electrospinning process of the TPU solution can be carried out using conventional techniques in the field, and will not be described in detail in this embodiment.

[0020] In step S2, the polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution is prepared in the following manner: Dissolve 1-4 mg of N-hydroxysuccinimide acrylate monomer and 5-9 mg of N,N'-methylenebisacrylamide crosslinking agent in 100-250 μL of photoinitiator I-1173. After the reaction is complete, a polyacrylic acid N-hydroxysuccinimide hydrogel precursor solution is obtained.

[0021] Step S2 specifically includes the following steps: The porous TPU fiber membrane is plasma treated for 120-180 seconds, then immersed in a polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution for 10-15 minutes. After removal, the pre-formed hydrogel is stacked on the front side of the porous TPU fiber membrane and cured with ultraviolet light for 60-90 seconds to form the first interlocking interface.

[0022] Direct bonding of porous TPU fiber membranes to hydrogels suffers from insufficient adhesion. Therefore, this invention first immerses the porous TPU fiber membrane in a polyacrylic acid-N-hydroxysuccinimide hydrogel precursor solution with the same composition as the hydrogel. This allows the precursor solution to adhere to the surface of the porous TPU fiber membrane, and the precursor solution undergoes regrafting with the hydrogel, thereby increasing compatibility with the hydrogel and improving the interfacial bonding strength between the porous TPU fiber membrane and the hydrogel. Simultaneously, the precursor solution penetrates into the interior of the porous TPU fiber membrane during the immersion process, and after UV curing, it forms a mechanical interlock with the fibers, further enhancing the bonding ability.

[0023] In step S3, the CNT / TPU composite membrane is prepared by depositing a CNT dispersion onto the surface of a porous TPU fiber membrane using a vacuum filtration method.

[0024] The CNT / TPU composite film incorporates CNTs (carbon nanotubes) with good electrical conductivity, which can effectively perform the function of sensing and converting strain signals.

[0025] Before bonding the CNT / TPU composite membrane to the porous TPU fiber membrane, a layer of TPU solution was first applied. The TPU solution has the same composition as the CNT / TPU composite membrane and the porous TPU fiber membrane, and has good properties. It can improve the bonding ability between the CNT / TPU composite membrane and the porous TPU fiber membrane based on the grafting effect. At the same time, the TPU solution can also penetrate into the interior of the porous TPU fiber membrane, and after curing, it forms a mechanical interlock with the fibers, further strengthening the bonding ability.

[0026] This embodiment also provides a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure, which is fabricated using the above-described preparation method. Figure 2As shown, the fabricated hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure consists of three layers: an adhesion layer, a bonding layer, and a sensing layer. The pre-formed hydrogel, as an adhesive layer, is mainly composed of polyacrylic acid-N-hydroxysuccinimide ester, which is used to provide strong adhesion to a variety of substrates. Porous TPU fiber membrane serves as a bonding layer, providing skeletal support; The CNT / TPU composite film serves as the sensing layer, responsible for sensing and converting strain signals. The interface between adjacent layers is enhanced by physical interlocking and chemical bonding. Specifically, the adhesive layer and the bonding layer form a first interlocking interface through physical interlocking and chemical bonding, and the bonding layer and the sensing layer form a second interlocking interface through physical interlocking and chemical bonding.

[0027] The adhesive layer has an interfacial toughness of not less than 138 for dry pigskin. The adhesion retention rate on wet skin is greater than 80%; the sensor has different sensitivity coefficients in three strain ranges: 0-100%, 100%-250%, and 250%-400%, and the sensitivity coefficient is not less than 130 in the 250-400% strain range.

[0028] like Figure 3 As shown, the fabricated sensor can adapt to various conditions such as stretching, bending, and torsion, exhibiting good flexibility; Figure 4 As shown, the SEM image of the sensor reveals a distinct three-layer structure. The hydrogel in the adhesive layer is fused and regrafted with the hydrogel network in the bonding layer (derived from the impregnated precursor solution). Meanwhile, the upper end of the bonding layer retains a fibrous structure, which can be bonded to the fibers of the sensing layer.

[0029] The interface bonding principle of the sensor prepared by this invention is as follows: Figure 5 As shown, a double-sided interlocking structure (first interlocking interface, second interlocking interface) is formed, which is compared with the single-interface bonding strength of directly bonding the hydrogel and the fiber membrane (146). The bonding strength was increased by 3.2 times compared to the single-interface bonding strength of directly bonding the hydrogel and the TPU dense film (21). ), which increased by 22.3 times.

[0030] This embodiment also provides an application of the sensor as described above, applied to human motion monitoring, health signal detection, or intelligent grasping and recognition systems for soft robots.

[0031] The sensor prepared by this invention can be directly attached to the skin or the surface of a soft robot to realize real-time monitoring of signals such as human joint movement and muscle contraction, and can be used for object recognition and classification based on machine learning.

[0032] Example 1 This embodiment provides a method for fabricating a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure, comprising the following steps: (1) A certain mass of TPU was dissolved in a mixed solvent of DMF and THF in a mass ratio of 1:1 to obtain a 20wt% TPU solution. The porous TPU fiber membrane was prepared by electrospinning at a temperature of 25℃ and a humidity of 60%. (2) Dissolve 1 mg of N-hydroxysuccinimide acrylate monomer and 9 g of N,N'-methylenebisacrylamide crosslinking agent in 250 μL of photoinitiator I-1173. After the reaction is complete, PAAc-NHS (polyacrylic acid-N-hydroxysuccinimide ester) hydrogel precursor solution is obtained. (3) Take a porous TPU fiber membrane and treat it with oxygen plasma for 120 seconds, then immerse it in PAAc-NHS hydrogel precursor solution for 10 minutes. After taking it out, stack it with the pre-formed hydrogel layer and cure it with ultraviolet light for 60 seconds. Coat the side of the porous TPU fiber membrane without hydrogel layer with 20wt% TPU solution to form a dense TPU film layer. (4) The CNT dispersion is deposited onto another porous TPU fiber membrane by vacuum filtration, and after drying, it is composited onto the surface of the dense TPU film layer in step (3) to obtain a double-sided interlocked sensor.

[0033] Performance testing was conducted on the sensor: the interface toughness was 468.5. The adhesion strength to dry pigskin is 138.33. It has a sensitivity coefficient of up to 131 in the strain range of 0–400%, a response time of 100ms, and an adhesion retention rate of over 85% on wet skin.

[0034] Example 2 (1) A certain mass of TPU was dissolved in a mixed solvent of DMF and THF in a mass ratio of 1:1 to obtain a 20wt% TPU solution. The porous TPU fiber membrane was prepared by electrospinning at a temperature of 25℃ and a humidity of 60%. (2) Dissolve 4 mg of N-hydroxysuccinimide acrylate monomer and 5 mg of N,N'-methylenebisacrylamide crosslinking agent in 100 μL of photoinitiator I-1173. After the reaction is complete, PAAc-NHS (polyacrylic acid-N-hydroxysuccinimide ester) hydrogel precursor solution is obtained. (3) Take a porous TPU fiber membrane and treat it with oxygen plasma for 180 seconds, then immerse it in PAAc-NHS hydrogel precursor solution for 15 minutes. After taking it out, stack it with the pre-formed hydrogel layer and cure it with ultraviolet light for 90 seconds. Coat the side of the porous TPU fiber membrane without hydrogel layer with 20wt% TPU solution to form a dense TPU film layer. (4) The CNT dispersion is deposited onto another porous TPU fiber membrane by vacuum filtration, and after drying, it is composited onto the surface of the dense TPU film layer in step (3) to obtain a double-sided interlocked sensor.

[0035] Performance testing was conducted on the sensor: the interface toughness was 451.6. The adhesion strength to dry pigskin is 126.89. It has a sensitivity coefficient of up to 126 and a response time of 100ms in the strain range of 0–400%; the adhesion retention rate on wet skin is also over 85%.

[0036] Comparative Example 1 This embodiment provides a method for fabricating a hydrogel-elastomer hybrid flexible sensor based on a single-sided interlocking structure, comprising the following steps: (1) A certain mass of TPU was dissolved in a mixed solvent of DMF and THF in a mass ratio of 1:1 to obtain a 20wt% TPU solution. The porous TPU fiber membrane was prepared by electrospinning at a temperature of 25℃ and a humidity of 60%. (2) Dissolve 1 mg of N-hydroxysuccinimide acrylate monomer and 9 g of N,N'-methylenebisacrylamide crosslinking agent in 250 μL of photoinitiator I-1173. After the reaction is complete, PAAc-NHS (polyacrylic acid-N-hydroxysuccinimide ester) hydrogel precursor solution is obtained. (3) The CNT dispersion was deposited onto the porous TPU fiber membrane by vacuum filtration, and then immersed in the PAAc-NHS hydrogel precursor solution for 10 minutes. After removal, it was stacked with the pre-formed hydrogel layer and cured under ultraviolet light for 60 seconds.

[0037] Performance testing was conducted on the sensor: the interface toughness was 412.6. The adhesion strength to dry pigskin is 124.87. The sensitivity coefficient is only 38.62 in the strain range of 0–400%.

[0038] Comparative Example 2 This embodiment provides a method for fabricating a hydrogel-based flexible sensor, including the following steps: (1) Dissolve 1 mg of N-hydroxysuccinimide acrylate monomer and 9 g of N,N'-methylenebisacrylamide crosslinking agent in 250 μL of photoinitiator I-1173. After the reaction is complete, PAAc-NHS (polyacrylic acid-N-hydroxysuccinimide ester) hydrogel precursor solution is obtained. (2) Pour the PAAc-NHS hydrogel precursor solution into a mold and solidify for 25 minutes to make a flexible sensor based on hydrogel.

[0039] Performance testing of the sensor revealed that its sensitivity coefficient was only 4.16 within the strain range of 0–400%, indicating very low sensitivity.

[0040] As can be seen from Examples 1-2 and Comparative Examples 1-2, the hydrogel-elastomer hybrid flexible sensor with double-sided interlocking structure obtained by the present invention has achieved a significant improvement in sensitivity coefficient in the strain range of 0–400% compared with the single-sided interlocking structure hydrogel-elastomer hybrid flexible sensor and hydrogel flexible sensor. It also has good interfacial toughness, adhesion strength, adhesion retention rate and short response time.

[0041] Furthermore, the hydrogel-elastomer hybrid flexible sensor with a double-sided interlocking structure obtained in Example 1 was subjected to multiple performance tests, and the test results are as follows: Figures 6-10 As shown: like Figure 6 As shown, the sensor exhibits good adhesion to soft substrates such as PE, pigskin, PA6, and PET; Figure 7 As shown, the sensor exhibits good adhesion to hard substrates such as glass, metal, wood, and silicon; for example... Figure 8 As shown, the fabricated sensor exhibits higher sensitivity and better cycling stability compared to hydrogel-based sensors; Figure 9 As shown, the sensor is attached to joints such as the wrist, elbow, and knee to monitor bending movements in real time, with stable signals and good repeatability; Figure 10 As shown, the sensor is integrated into the surface of the gripper of the soft robot. By grasping the strain signals generated by fruits of different sizes, and combining them with the KNN algorithm, the fruit is classified with an accuracy rate of 97%.

[0042] This invention successfully integrates the strong adhesion of hydrogels and the high sensitivity of elastomer composites through a double-sided interlocking structure design, and produces a high-performance flexible strain sensor suitable for wearable monitoring and intelligent sensing of soft robots, which has important application prospects.

[0043] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of the present invention.

Claims

1. A method for fabricating a hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure, characterized in that, Includes the following steps: Step S1: Prepare porous TPU fiber membranes using electrospinning with TPU solution; Step S2: The porous TPU fiber membrane is treated with oxygen plasma, then immersed in a polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution. After removal, the pre-formed hydrogel is stacked on the front side of the porous TPU fiber membrane and cured with ultraviolet light to form the first interlocking interface. Step S3: Coat the back of the porous TPU fiber membrane with TPU solution to form a dense TPU film layer. Then, stack the pre-formed CNT / TPU composite membrane on the dense TPU film layer to form a second interlocking interface, thus obtaining a hydrogel-elastomer hybrid flexible sensor with a double-sided interlocking structure.

2. The preparation method according to claim 1, characterized in that, The TPU solutions in steps S1 and S3 are prepared as follows: DMF and THF are mixed in a mass ratio of 1:1 to 1:2 to obtain a mixed solvent. A certain mass of TPU is dissolved in the mixed solvent to obtain a TPU solution with a concentration of 15-20 wt%.

3. The preparation method according to claim 1, characterized in that, In step S2, the polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution is prepared in the following manner: Dissolve 1-4 mg of N-hydroxysuccinimide acrylate monomer and 5-9 mg of N,N'-methylenebisacrylamide crosslinking agent in 100-250 μL of photoinitiator I-1173. After the reaction is complete, a polyacrylic acid N-hydroxysuccinimide hydrogel precursor solution is obtained.

4. The preparation method according to claim 3, characterized in that, Step S2 specifically includes the following steps: The porous TPU fiber membrane is plasma treated for 120-180 seconds, then immersed in a polyacrylic acid-N-hydroxysuccinimide ester hydrogel precursor solution for 10-15 minutes. After removal, the pre-formed hydrogel is stacked on the front side of the porous TPU fiber membrane and cured with ultraviolet light for 60-90 seconds to form the first interlocking interface.

5. The preparation method according to claim 1, characterized in that, In step S3, the CNT / TPU composite membrane is prepared by depositing a CNT dispersion onto the surface of a porous TPU fiber membrane using a vacuum filtration method.

6. A hydrogel-elastomer hybrid flexible sensor based on a double-sided interlocking structure, characterized in that, It is prepared by the preparation method described in any one of claims 1-5.

7. The hydrogel-elastomer hybrid flexible sensor according to claim 6, characterized in that, It includes an adhesive layer, a bonding layer, and a sensing layer stacked sequentially, wherein: Pre-formed hydrogels serve as adhesive layers to provide strong adhesion to a variety of substrates; Porous TPU fiber membrane serves as a bonding layer, providing skeletal support; The CNT / TPU composite film serves as the sensing layer, responsible for sensing and converting strain signals. The adhesive layer and the bonding layer form a first interlocking interface through physical interlocking and chemical bonding, and the bonding layer and the sensing layer form a second interlocking interface through physical interlocking and chemical bonding.

8. The sensor according to claim 7, characterized in that, The adhesive layer has an interfacial toughness of not less than 138 for dry pigskin. The adhesion retention rate on wet skin is greater than 80%; the sensor has different sensitivity coefficients in three strain ranges: 0-100%, 100%-250%, and 250%-400%, and the sensitivity coefficient is not less than 130 in the 250-400% strain range.

9. An application of the sensor as described in any one of claims 6-8, characterized in that, It is applied to human motion monitoring, health signal detection, or intelligent grasping and recognition systems for soft robots.

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