A fabric-based bifunctional graphene sensor and a preparation method and application thereof

Abstract

The application provides a fabric-based bifunctional graphene sensor and a preparation method and application thereof, and belongs to the technical field of flexible sensors.The preparation raw materials of the sensor include a polyimide precursor, a pore-forming agent and a temperature-sensitive material.The preparation raw materials of the polyimide precursor include 4,4'-diamino diphenyl ether, pyromellitic anhydride, N,N-dimethylacetamide, a catalyst and a dehydrating agent.The application has the advantages of simple process, laser-induced graphene technology, in-situ generation of a graphene sensitive layer on a precursor coating at normal temperature and pressure, no need of complex transfer or post-processing technology, no need of high-temperature vacuum equipment, high sensitivity of the prepared sensor, dual-function response of bending and temperature, good air permeability and suitability for long-term wearing health monitoring.

Description

Technical Field

[0001] This invention belongs to the field of flexible sensor technology, and particularly relates to a fabric-based bifunctional graphene sensor, its preparation method and application. Background Technology

[0002] With the rapid development of flexible electronics and smart wearable technology, flexible sensors that can conform to human skin and monitor various physiological signals in real time are showing broad application prospects in health monitoring, human-computer interaction, and smart healthcare. Among them, bending sensors can be used to monitor mechanical signals such as joint movement and muscle deformation, while temperature sensors can be used to monitor body surface temperature, local inflammation, and environmental thermal changes. However, existing flexible sensors generally suffer from insufficient sensitivity in responding to minute joint movements and changes in body surface temperature, making it difficult to meet the needs of high-precision real-time monitoring.

[0003] To address the technical challenge of insufficient sensitivity, researchers have turned their attention to graphene. Graphene, with its unique two-dimensional structure, high carrier mobility, excellent mechanical flexibility, and good conductivity, is considered an ideal sensitive material for constructing high-performance flexible sensors. However, graphene preparation typically relies on methods such as chemical vapor deposition or graphene oxide reduction, often requiring complex transfer or post-processing steps, which not only increases preparation costs but also hinders low-cost, customizable mass production. Against this backdrop, laser-induced graphene (LIG) technology has emerged as an ideal alternative. This technology allows for the in-situ formation of a three-dimensional porous graphene conductive network by directly irradiating carbon-containing precursors such as polyimide with a laser beam at room temperature and pressure. LIG technology eliminates the need for a vacuum environment, metal catalysts, and complex transfer processes, and can achieve patterned direct writing under computer control, offering advantages in both ease of preparation and customizability, providing a new direction for the integrated manufacturing of flexible sensors.

[0004] Chinese invention patent CN119845132A discloses a patterned laser-induced graphene strain sensor with optimized stress distribution. By embedding a laser-induced graphene dot-line patterned structure on a PDMS substrate, a strain sensor with high sensitivity is fabricated, verifying the application potential of LIG technology in the field of flexible sensing. However, such PDMS-based LIG sensors suffer from poor breathability. During prolonged close-fitting wear, sweat easily accumulates beneath the device, affecting signal stability, potentially causing skin inflammation, and reducing wearing comfort. This severely limits the widespread application of LIG sensors in wearable health monitoring. Therefore, there is an urgent need to develop a dual-function sensor that combines high sensitivity and good breathability. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a fabric-based bifunctional graphene sensor, its preparation method, and its application.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a fabric-based bifunctional graphene sensor, comprising the following steps: A polyimide precursor, a pore-forming agent, and a temperature-sensitive material are uniformly mixed to obtain a mixed slurry. The raw materials for preparing the polyimide precursor include 4,4'-diaminodiphenyl ether (ODA), pyromellitic phthalic anhydride (PMDA), N,N-dimethylacetamide (DMAc), a catalyst, and a dehydrating agent. The mixed slurry is coated onto the fabric according to a preset pattern using DIW 3D printing technology, and then subjected to thermosetting treatment; Laser induction is performed on the fabric according to the preset pattern to convert polyimide into a graphene sensitive layer in situ. Electrodes are fabricated on the graphene sensitive layer and then encapsulated to obtain the fabric-based bifunctional graphene sensor.

[0007] Furthermore, the laser-induced laser power is 5.4-9W and the velocity is 190.5mm / s.

[0008] Furthermore, the heating procedure for the thermosetting treatment is as follows: holding at 100℃, 150℃ and 200℃ for 30 minutes each.

[0009] Furthermore, the method for preparing the polyimide precursor includes the following steps: 4,4'-diaminodiphenyl ether was added to N,N-dimethylacetamide and stirred until completely dissolved. Then, pyromellitic anhydride was added and reacted for 2-3 hours. A mixture of catalyst and dehydrating agent was then added and the reaction was continued for 3-5 minutes to obtain the polyimide precursor (ODA-PMDA type).

[0010] Furthermore, the catalyst comprises one of 3,5-dimethylpyridine, pyridine, or triethylamine, and the dehydrating agent comprises one of propionic anhydride, acetic anhydride, or benzoic anhydride.

[0011] Furthermore, the molar ratio of the 4,4'-diaminodiphenyl ether to pyromellitic anhydride is (0.95~1.05):1.

[0012] Furthermore, the pore-forming agent includes one or more of polystyrene microspheres and polymethyl methacrylate microspheres.

[0013] Furthermore, the temperature-sensitive material includes one or more of manganese dioxide, nickel oxide, and cobalt tetroxide.

[0014] Further, by weight, the mixed slurry comprises 20-40 parts of polyimide precursor, 1-5 parts of pore-forming agent, and 1-5 parts of temperature-sensitive material; even further, the mixed slurry comprises 30 parts of polyimide precursor, 2.53 parts of pore-forming agent, and 3.61 parts of temperature-sensitive material.

[0015] The present invention also provides a fabric-based bifunctional graphene sensor, which is prepared according to the above preparation method.

[0016] The present invention also provides an application of the above-mentioned fabric-based bifunctional graphene sensor in wearable health monitoring, smart textiles and human motion detection devices.

[0017] This invention utilizes a laser-induced graphene system, with polyimide as a precursor, and incorporates pore-forming agents and temperature-sensitive materials for functional design. Laser-induced graphene technology can form a two-scale porous conductive network in situ at room temperature and pressure, while also possessing intrinsic temperature-sensitive response characteristics. It eliminates the need for complex transfer or post-processing steps, fundamentally avoiding the structural damage and performance degradation problems caused by the transfer process in traditional graphene sensors. Furthermore, the inherent porous structure of the fabric substrate endows the device with excellent breathability and long-term wear comfort.

[0018] Through the precise material selection and structural design described above, the shortcomings of existing laser-induced graphene sensors, such as insufficient sensitivity, limited functionality, and poor air permeability, are effectively overcome. In this invention, the polyimide precursor synthesis monomers are limited to 4,4'-diaminodiphenyl ether and pyromellitic anhydride, both of which are rigid monomers containing aromatic rings. The polyimide backbone obtained by condensation polymerization is rich in conjugated aromatic structures. During laser induction, the aromatic rings are easily thermally decomposed, carbonized, and rearranged into sp... 2 The hybrid carbon network facilitates the formation of LIGs with high graphitization and low defect density. Simultaneously, the ODA-PMDA type polyimide exhibits excellent thermal stability, with a residual carbon rate of 50%-60% after high-temperature carbonization, ensuring uniform thickness and controllable pore structure of the laser-induced graphene layer, thus constructing a continuous three-dimensional conductive network. Furthermore, the polyimide solution possesses suitable viscosity and wettability, enabling uniform coating onto the fabric surface and penetration into the fiber gaps. Even after laser induction, it maintains tight adhesion to the substrate, preventing signal instability and ensuring good cyclic stability of the sensor. The pore-forming agent volatilizes under laser irradiation to form macropores, which, together with the micropores formed by the pyrolysis of polyimide, constitute a two-scale porous structure, generating a greater resistance response under strain. Simultaneously, the added nickel oxide nanoparticles, acting as a thermosensitive material, endow the sensor with intrinsic thermosensitive properties, significantly enhancing its sensitivity to temperature changes.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects: (1) The process of this invention is simple. It uses laser-induced graphene technology to generate graphene sensitive layers directly on the precursor coating at room temperature and pressure. It does not require complex transfer or post-processing processes, nor does it require high-temperature vacuum equipment. The process is simple and suitable for large-scale production.

[0020] (2) This invention achieves dual-function integration, enabling the sensor to sense both bending deformation and temperature changes, overcoming the shortcomings of traditional graphene sensors with only one function. This invention realizes the simultaneous implementation of bending sensing and temperature sensing functions on the same device, and the two do not interfere with each other and can be independently decoupled: bending strain mainly causes the resistance change of the two-scale porous structure, while temperature change mainly depends on the resistance-temperature characteristics of the temperature-sensitive material. The two have different response mechanisms, and the contributions of bending and temperature to the total resistance change can be separated by simple signal processing (such as linear superposition or polynomial fitting), thereby realizing synchronous and crosstalk-free monitoring of joint movement and body surface temperature.

[0021] (3) The graphene sensor prepared by this invention has a bending sensitivity of 51.6 and a temperature coefficient of resistance of -0.158%·℃. -1 It can effectively monitor deformation and temperature changes.

[0022] (4) The present invention uses fabric as a base, which has good breathability. The DIW 3D printing technology retains the breathability and flexibility of the fabric base, avoiding the stuffy feeling when wearing it for a long time and ensuring wearing comfort. Attached Figure Description

[0023] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The results are the thermal stability test results of the polyimide precursor in Example 1; Figure 2 The images are SEM images of the graphene layer in Example 1 at different magnifications ((a) is 20 μm, (b) is 2 μm). Figure 3 The following are schematic diagrams of the air permeability test of the sensors prepared in Example 1 and Comparative Example 1, where (a) is a schematic diagram of the sample in Comparative Example 1, (b) is a schematic diagram of the sample in Example 1, (c) is an air permeability test of the sample in Comparative Example 1, and (d) is an air permeability test of the sample in Example 1. Figure 4 The bending performance test results of the fabric-based bifunctional graphene sensors in Examples 1-3 are shown below. Figure 5 The temperature response test results of the fabric-based bifunctional graphene sensors in Examples 1-3 are shown. Figure 6The results of the cycle stability test of the fabric-based bifunctional graphene sensor in Example 1 are shown. Figure 7 The results of the application test of the fabric-based bifunctional graphene sensor in Example 1 are as follows; Figure 8 This is a flowchart illustrating the fabrication process of the fabric-based bifunctional graphene sensor of the present invention. Detailed Implementation

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0026] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0027] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0028] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0029] This invention provides a method for fabricating a fabric-based bifunctional graphene sensor. The fabrication flowchart is shown below. Figure 8 Specifically, it includes the following steps: The polyimide precursor, pore-forming agent and temperature-sensitive material are uniformly mixed to obtain a mixed slurry. The raw materials for preparing the polyimide precursor include 4,4'-diaminodiphenyl ether (ODA), pyromellitic phthalic anhydride (PMDA), N,N-dimethylacetamide (DMAc), catalyst and dehydrating agent. The mixed slurry is coated onto the fabric according to a preset pattern using DIW 3D printing technology, and then subjected to thermosetting treatment; Laser-induced polyimide is converted into a graphene sensitive layer in situ by laser induction on the fabric according to a preset pattern. Electrodes are fabricated on the graphene sensitive layer and then encapsulated to obtain a fabric-based bifunctional graphene sensor.

[0030] In a preferred embodiment of the present invention, the laser-induced laser power is 5.4-9W and the speed is 190.5mm / s.

[0031] In a preferred embodiment of the present invention, the heating procedure for the thermosetting treatment is as follows: holding at 100°C, 150°C and 200°C for 30 minutes each.

[0032] In a preferred embodiment of the present invention, the method for preparing the polyimide precursor includes the following steps: 4,4'-Diaminodiphenyl ether is added to N,N-dimethylacetamide and stirred until completely dissolved. Then, pyromellitic anhydride is added and reacted for 2-3 hours. Next, a mixture of catalyst and dehydrating agent is added and the reaction continues for 3-5 minutes to obtain a polyimide precursor (the polyimide precursor referred to in this invention refers to a polyamic acid system that has undergone partial imidization or contains imidizing agents). The catalyst includes one of 3,5-dimethylpyridine, pyridine, or triethylamine (preferably 3,5-dimethylpyridine), and the dehydrating agent includes one of propionic anhydride, acetic anhydride, or benzoic anhydride (preferably propionic anhydride). The molar ratio of 4,4'-diaminodiphenyl ether to pyromellitic anhydride is (0.95~1.05):1, preferably 0.98:1.

[0033] For example, in this embodiment of the invention, the method for preparing the polyimide precursor includes the following steps: At room temperature, 7.64 g (0.0382 mol) of ODA was added to a beaker containing 64 mL of DMAc. After the ODA was completely dissolved, 8.5 g (0.0390 mol) of PMDA was slowly added. After reacting for 2 hours, a polyamic acid solution was obtained. Subsequently, 0.75 mL of 3,5-dimethylpyridine and 1 mL of propionic anhydride were mixed thoroughly and added to the polyamic acid solution. The mixture was stirred for 5 minutes to obtain a polyimide precursor (ODA-PMDA type). The structural formula of this polyimide precursor is as follows: , where n is a positive integer.

[0034] In a preferred embodiment of the present invention, the pore-forming agent includes one or more of polystyrene microspheres and polymethyl methacrylate microspheres; preferably, the pore-forming agent is polystyrene microspheres.

[0035] In a preferred embodiment of the present invention, the temperature-sensitive material includes one or more of manganese dioxide, nickel oxide, and cobalt tetroxide; the preferred temperature-sensitive material is nickel oxide, and the nickel oxide used in the embodiments of the present invention is nickel oxide nanoparticles with a particle size range of 50 nm.

[0036] In a preferred embodiment of the present invention, the mixed slurry comprises, by weight, 20-40 parts of polyimide precursor, 1-5 parts of pore-forming agent and 1-5 parts of temperature-sensitive material; the preferred mixed slurry comprises 30 parts of polyimide precursor, 2.53 parts of pore-forming agent and 3.61 parts of temperature-sensitive material.

[0037] This invention also provides a fabric-based bifunctional graphene sensor, prepared according to the above-described preparation method.

[0038] This invention also provides an application of the above-mentioned fabric-based bifunctional graphene sensor in wearable health monitoring, smart textiles, and human motion detection devices.

[0039] All raw materials used in the embodiments of this invention were purchased commercially.

[0040] In this embodiment of the invention, room temperature refers to 25±2℃.

[0041] The fabric used in this embodiment of the invention is spandex.

[0042] The technical solution of the present invention will be further illustrated by the following embodiments.

[0043] Example 1 (1) At room temperature, 7.64 g of ODA was added to a beaker containing 64 mL of DMAc. After the ODA was completely dissolved, 8.5 g of PMDA was slowly added. After reacting for 2 h, a polyamic acid solution was obtained. Then, 0.75 mL of 3,5-dimethylpyridine and 1 mL of propionic anhydride were mixed evenly and added to the polyamic acid solution. After stirring for 5 min, a polyimide precursor was obtained. (2) Mix 30g of the polyimide precursor obtained in step (1), 2.53g of polystyrene microspheres and 3.61g of nickel oxide nanoparticles evenly to obtain a mixed slurry; (3) The mixed slurry is coated onto the fabric according to the preset pattern using DIW 3D printing technology, and then heat curing is performed (the heating program is: keep warm at 100℃, 150℃ and 200℃ for 30 minutes each). (4) Laser induction is performed on the fabric according to the preset pattern. The laser power is set to 5.4W and the speed is 190.5mm / s, so that the polyimide is converted into the graphene sensitive layer in situ. (5) Copper tape is attached to the graphene layer as an electrode and conductive silver paste is coated to reduce the contact resistance. Finally, the entire device is encapsulated with polyimide (PI) tape to obtain a fabric-based bifunctional graphene sensor, denoted as NiO / LIPG-1.

[0044] Example 2 Same as Example 1, except that the laser power is set to 6W, and the resulting fabric-based bifunctional graphene sensor is denoted as NiO / LIPG-2.

[0045] Example 3 Same as Example 1, except that the laser power was set to 9W, and the resulting fabric-based bifunctional graphene sensor was denoted as NiO / LIPG-3.

[0046] Comparative Example 1 Same as Example 1, except that in step (3), the mixed slurry is applied to the fabric using a 1000μm scraper, and the rest of the steps are the same as in Example 1.

[0047] Performance testing 1. Thermal stability test The polyimide precursor prepared in Example 1 was tested using a thermogravimetric analyzer at a temperature range of 30-800°C and a heating rate of 10°C / min. The test atmosphere was nitrogen. Figure 1 The results of the thermal stability test of the polyimide precursor in Example 1 show that it has excellent thermal stability, and the residual carbon rate after high-temperature carbonization can reach 50%-60%.

[0048] 2. Morphology of porous graphene The morphology of the graphene layer prepared in Example 1 (i.e., the laser-induced graphene sensitive layer) was observed using a scanning electron microscope. Figure 2 The SEM images of the graphene layer in Example 1 at different magnifications ((a) is 20 μm, (b) is 2 μm) show that a dual-scale porous structure was formed.

[0049] 3. Breathability test The air permeability of sensors prepared by the scraping method in Comparative Example 1 and the DIW 3D printing method in Example 1 was tested respectively. The sample to be tested was placed over the mouth of a bottle containing water and nitrogen. The amount of gas passing through the sample was determined by the bubbles generated by the nitrogen, thereby evaluating the air permeability of the sample.

[0050] Figure 3The diagrams show the air permeability tests of the sensors prepared in Example 1 and Comparative Example 1, where (a) is a schematic diagram of the sample in Comparative Example 1, (b) is a schematic diagram of the sample in Example 1, (c) shows the air permeability test results of the sample in Comparative Example 1, and (d) shows the air permeability test results of the sample in Example 1. It can be seen that the air permeability of the DIW 3D printed sample is superior to that of the blade coating method.

[0051] 4. Bending response test The fabric-based bifunctional graphene sensors of Examples 1-3 were subjected to bending tests using a flexible electronic testing instrument, and their electrical signals were recorded in real time by a high-frequency data acquisition system. The sensing performance of the sensors was characterized by the change in relative resistance (ΔR / R0), and its calculation formula is shown in Equation (1): (1); In the formula, R0 is the initial resistance of the sensor, R is the resistance after strain is applied, and ΔR is the change in resistance.

[0052] Sensor sensitivity is expressed as the strain gauge sensitivity coefficient, and its calculation formula is shown in equation (2): (2); In the formula, ε = h / 2r, where ε is the applied strain, h is the sample thickness, and r is the bending radius of the sensor.

[0053] 5. Temperature response test The sensor was tested using a programmed temperature-increasing oven, and the changes in the electrical signal of the sensor during the temperature rise from 25℃ to 50℃ were recorded in real time using a data acquisition system. The sensitivity of the sensor is expressed by the temperature coefficient of resistance, and its calculation formula is shown in equation (3): (3); In the formula, ΔT represents the temperature change.

[0054] The bending and temperature response test results of the fabric-based bifunctional graphene sensors in Examples 1-3 are shown below. Figure 4 and Figure 5 .Depend on Figure 4 and Figure 5 It can be seen that as the power increases, the bending sensitivity of the sensor first increases and then decreases, while the temperature coefficient continues to decrease. Considering the combined bending and temperature sensing performance, Example 1 exhibits the best overall performance.

[0055] The results of the bending response and temperature response tests are detailed in Table 1 (the percentages in the table represent strain rates).

[0056] Table 1 6. Cyclic stability test The sensor prepared in Example 1 was subjected to 3000 bending-release tests under a strain of 2.2%, and the changes in electrical signals were recorded in real time. Figure 6 The results of the cyclic stability test of the fabric-based bifunctional graphene sensor in Example 1 show that after 3000 cycles of bending, the resistance change rate of the sensor did not show significant shift or attenuation, and the signal response remained highly consistent, indicating that it has excellent cyclic stability.

[0057] 7. Application To verify the actual application performance of the device: the sensor prepared in Example 1 was attached to the surface of a glove and heated from room temperature to 50°C in an electric heating environment, and the relative resistance change rate of the sensor was recorded. Figure 7 The application test results of the fabric-based bifunctional graphene sensor in Example 1 show that heating to 50°C significantly reduces the rate of change of resistance, and the signal can be restored to the initial fluctuation range after cooling back to room temperature. The temperature response is reversible and meets the actual needs of wearable temperature measurement.

[0058] In summary, the fabric-based bifunctional graphene sensor provided in this invention has multiple advantages: First, it integrates bending and temperature sensing functions, enabling the sensor to respond to bending deformation and temperature changes, overcoming the limitation of traditional devices having only one function. Second, by designing a dual-scale porous structure and introducing nickel oxide nanoparticles, the sensor's response to bending and temperature is significantly improved, thereby enhancing its overall sensitivity. The bending sensitivity reaches 51.6 (strain rate 1%-1.6%), and the temperature coefficient of resistance reaches -0.158 %·℃. -1 Furthermore, the DIW 3D printing technology preserves the breathability and flexibility of the fabric base, ensuring long-term wearing comfort.

[0059] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a fabric-based bifunctional graphene sensor, characterized in that, Includes the following steps: A polyimide precursor, a pore-forming agent and a temperature-sensitive material are uniformly mixed to obtain a mixed slurry. The raw materials for preparing the polyimide precursor include 4,4'-diaminodiphenyl ether, pyromellitic anhydride, N,N-dimethylacetamide, a catalyst and a dehydrating agent. The mixed slurry is coated onto the fabric according to a preset pattern using DIW 3D printing technology, and then subjected to thermosetting treatment; Laser induction is performed on the fabric according to the preset pattern to convert polyimide into a graphene sensitive layer in situ. Electrodes are fabricated on the graphene sensitive layer and then encapsulated to obtain the fabric-based bifunctional graphene sensor.

2. The method for preparing the fabric-based bifunctional graphene sensor according to claim 1, characterized in that, The laser-induced laser power is 5.4-9W, and the velocity is 190.5mm / s.

3. The method for preparing the fabric-based bifunctional graphene sensor according to claim 1, characterized in that, The heating procedure for the thermosetting process is as follows: hold at 100℃, 150℃ and 200℃ for 30 minutes each.

4. The method for preparing the fabric-based bifunctional graphene sensor according to claim 1, characterized in that, The method for preparing the polyimide precursor includes the following steps: 4,4'-diaminodiphenyl ether was added to N,N-dimethylacetamide and stirred until completely dissolved. Then, pyromellitic anhydride was added and reacted for 2-3 hours. A mixture of catalyst and dehydrating agent was then added and the reaction was continued for 3-5 minutes to obtain the polyimide precursor.

5. The method for preparing the fabric-based bifunctional graphene sensor according to claim 4, characterized in that, The catalyst comprises one of 3,5-dimethylpyridine, pyridine, or triethylamine, and the dehydrating agent comprises one of propionic anhydride, acetic anhydride, or benzoic anhydride. The molar ratio of 4,4'-diaminodiphenyl ether to pyromellitic anhydride is (0.95~1.05):

1.

6. The method for preparing the fabric-based bifunctional graphene sensor according to claim 1, characterized in that, The pore-forming agent includes one or more of polystyrene microspheres and polymethyl methacrylate microspheres.

7. The method for preparing the fabric-based bifunctional graphene sensor according to claim 1, characterized in that, The temperature-sensitive material includes one or more of manganese dioxide, nickel oxide, and cobalt tetroxide.

8. The method for preparing the fabric-based bifunctional graphene sensor according to claim 1, characterized in that, The mixed slurry comprises, by weight, 20-40 parts of polyimide precursor, 1-5 parts of pore-forming agent, and 1-5 parts of temperature-sensitive material.

9. A fabric-based bifunctional graphene sensor, characterized in that, It is prepared according to any one of claims 1 to 8.

10. The application of the fabric-based bifunctional graphene sensor as described in claim 9 in wearable health monitoring, smart textiles, and human motion detection devices.

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