Resistance-type flexible multifunctional sensor and preparation method and application thereof

Abstract

The invention provides a resistance-type flexible multifunctional sensor and a preparation method and application thereof. The sensor comprises a flexible fabric, a sensing layer attached to the surface of the flexible fabric and an electrode attached to the surface of the sensing layer. The sensing layer is of an intercalation structure formed by stacking and distributing graphene (GR), carbon nanoparticles (CNPs) and silicone rubber (SR). According to the resistive flexible multifunctional sensor and the preparation method and application thereof, the sensing layer of an intercalation structure formed by stacking and distributing the graphene, the carbon nanoparticles and the silicone rubber is adopted, measurement of pressure, strain and temperature can be achieved at the same time, and therefore the high-performance flexible multifunctional sensor is obtained; and a multi-mode sensing mode is expected to be provided for precise monitoring and somatosensory application.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular, to a resistive flexible multifunctional sensor, a preparation method thereof, and an application thereof. Background Art

[0002] Rigid sensors mainly use hard materials such as ceramics and metals. These materials endow them with excellent hardness, enabling them to maintain a stable physical form even in complex and harsh environments. However, in the field of wearables, the shortcomings of rigid sensors are fully exposed. Due to their hard materials, they have poor flexibility and bendability, and it is difficult to closely fit with the complex curved surfaces of the human body. When accurately monitoring human physiological parameters or motion states, poor fitting will lead to the inability to accurately perceive the subtle changes of the human body, and thus it is difficult to complete accurate measurements. In sharp contrast to rigid sensors, textile-based flexible sensors have significant characteristics such as skin-friendliness, breathability, and shape retention. Whether in a static or dynamic state, they can always maintain a good degree of fit, ensuring the accuracy of information collection from various parts of the human body. With these characteristics, textile-based flexible sensors have been widely used in fields such as wearable electronic devices, electronic skin, and health monitoring. However, the physiological state of the human body is extremely complex, covering numerous different dimensions of information. It is obviously limited to rely on a single signal to monitor the overall condition of the human body. Therefore, how to prepare a high-performance multifunctional sensor remains a daunting challenge. Summary of the Invention

[0003] Based on the technical problems existing in the background art, the present invention proposes a resistive flexible multifunctional sensor, a preparation method thereof, and an application thereof. By using a sensing layer with an intercalated structure in which graphene, carbon nanoparticles, and silicone rubber are stacked and distributed, it can simultaneously measure pressure, strain, and temperature, thereby obtaining a high-performance flexible multifunctional sensor, which is expected to provide a multimodal sensing mode for precision monitoring and somatosensory applications.

[0004] A resistive flexible multifunctional sensor proposed by the present invention includes a flexible fabric, a sensing layer attached to the surface of the flexible fabric, and an electrode attached to the surface of the sensing layer;

[0005] The sensing layer is an intercalated structure in which graphene (GR), carbon nanoparticles (CNPs), and silicone rubber (SR) are stacked and distributed.

[0006] In the present invention, the flexible fabric has soft elasticity, endowing the sensor with good flexibility and bending performance, meeting the requirements of wearable materials; the sensing layer is a GR / CNPs / SR stacked and distributed intercalated structure formed by the composite of GR, CNPs, and SR, endowing the obtained sensor with the ability to simultaneously sense pressure, strain, and temperature, and showing significant advantages of high sensitivity and fast response time.

[0007] Preferably, the flexible fabric is cotton fabric, wool fabric, silk fabric, linen fabric, chemical fiber fabric or blended fabric;

[0008] Preferably, the flexible fabric is Lycra cotton fabric.

[0009] In the present invention, the flexible fabric has significant characteristics such as skin-friendly property, breathability and shape retention property. After specifically selecting Lycra cotton fabric, since the surface of Lycra fabric contains a large number of functional groups such as hydroxyl groups that are easy to modify, the bonding strength between the sensing layer and the flexible fabric can be improved through surface modification.

[0010] Preferably, the mass ratio of the graphene, carbon nanoparticles and silicone rubber is 2:1 - 3:2 - 4, preferably 2:2:3.

[0011] Preferably, the electrode is a metal electrode.

[0012] The present invention also provides a preparation method of the above-mentioned resistive flexible multifunctional sensor, which includes the following steps:

[0013] S1. Disperse graphene, carbon nanoparticles and silicone rubber in an organic solvent to obtain a conductive solution;

[0014] S2. Immerse the flexible fabric in the conductive solution, take it out and dry it to obtain a sensing layer attached to the surface of the flexible fabric;

[0015] S3. Paste the electrode on both sides of the sensing layer with conductive silver paste, which can effectively reduce the contact resistance between the electrode and the flexible fabric, to obtain an electrode attached to the surface of the sensing layer, that is, the sensor is obtained.

[0016] In the present invention, graphene, carbon nanoparticles and silicone rubber are composite materials with high conductivity and sensitive to temperature. When they are compounded and an intercalated structure with GR / CNPs / SR stacked distribution is formed on the fabric surface through the impregnation and drying process, relying on such material and structure basis, the obtained sensor exhibits significant advantages such as high sensitivity and fast response time.

[0017] Preferably, in step S1, the conductive solution is obtained by first dispersing graphene and carbon nanoparticles in an organic solvent, and then adding silicone rubber and heating and stirring to dissolve;

[0018] Preferably, the organic solvent is naphtha, the heating and stirring temperature is 80 - 120 °C, and the time is 20 - 60 min;

[0019] Preferably, the concentration of the conductive solution is 0.5 - 5 wt%.

[0020] Preferably, in step S2, before dipping the flexible fabric into the conductive solution, surface modification of the flexible fabric is further included.

[0021] Preferably, the surface modification is to immerse the flexible fabric in an amino silane coupling agent solution, take it out and dry it to obtain a modified flexible fabric;

[0022] Preferably, the amino silane coupling agent is γ-aminopropyltriethoxysilane (APTES) or γ-aminopropyltrimethoxysilane;

[0023] Preferably, the concentration of the amino silane coupling agent solution is 0.5-2 wt%.

[0024] In the present invention, the flexible fabric is pre-impregnated in the amino silane coupling agent solution. On the one hand, the siloxane groups at one end of the amino silane coupling agent can undergo a condensation reaction with the hydroxyl groups on the surface of the flexible fabric to form a stable chemical bond structure, and more active groups are connected to the surface of the flexible fabric; on the other hand, the amino groups at the other end of the amino silane coupling agent can interact with inorganic carbonaceous fillers such as GR and CNPs. Thus, it helps to build a solid bridge between the organic flexible fabric and the inorganic carbon-based conductive material, thereby promoting the interfacial adhesion between the sensing layer and the flexible fabric and making the sensor structure more firmly constructed.

[0025] Preferably, in step S2, the dipping temperature is 10-30 °C and the time is 20-60 min.

[0026] The present invention also proposes an application of the above-mentioned sensor or the sensor prepared by the above-mentioned preparation method in wearable devices, electronic skin or health monitoring.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] (1) The present invention uses a GR / CNPs / SR composite material with high conductivity and temperature sensitivity, and adopts a simple dipping process to immerse the composite material into the flexible fabric. The sensor constructed in this way can not only achieve sensing responses in multiple working modes, but also effectively avoid the use of additional sensing device components.

[0029] (2) In order to further improve the mechanical properties of the obtained sensor and strengthen the adhesion between components, the present invention introduces an amino silane coupling agent to connect the organic fabric fibers and the inorganic carbonaceous fillers through it. The synergistic effect generated by the mutual cooperation of these components endows the sensor with excellent capabilities of detecting pressure, strain and temperature. Such flexible multifunctional sensors are expected to provide multi-modal sensing modes for precision monitoring and somatosensory applications.

[0030] (3) The monitoring of human physiological health involves information in different dimensions. Relying solely on a single signal to reflect human health indicators may lead to errors. The sensor described in the present invention has the ability to sense pressure, tensile strain, and temperature, and can collect human physiological information from multiple dimensions, greatly improving the accuracy and comprehensiveness of the monitoring of human health status. Description of the Drawings

[0031] Figure 1 It is a schematic diagram of the preparation process of the sensor described in the embodiment of the present invention;

[0032] Figure 2 It is a schematic diagram of the overall structure of the sensor described in the embodiment of the present invention;

[0033] Figure 3 It is a physical diagram of the sensor obtained before and after omitting step (1) in the embodiment of the present invention: the left figure is the physical diagram of the sensor obtained before omitting step (1) in the embodiment, and the right figure is the physical diagram of the sensor obtained after omitting step (1) in the embodiment;

[0034] Figure 4 It is a diagram showing the influence of SR on the dispersion effect of GR and CNPs in the naphtha system in the embodiment of the present invention;

[0035] Figure 5 It is an SEM diagram of the modified Lycra cotton fabric and the sensing layer described in the embodiment of the present invention at different resolutions: (a) and (b) are SEM diagrams of the modified Lycra cotton fabric at different resolutions, and (c) and (d) are SEM diagrams of the sensing layer at different resolutions;

[0036] Figure 6 It is a diagram of the sensing mechanism of the sensor described in the embodiment of the present invention for sensing pressure;

[0037] Figure 7 It is an experimental verification diagram of the pressure sensitivity of the sensor described in the embodiment of the present invention;

[0038] Figure 8 It is a response curve diagram of the sensor described in the embodiment of the present invention for sensing different pressure intensities;

[0039] Figure 9 It is a response curve diagram of the sensor described in the embodiment of the present invention for sensing different compression frequencies;

[0040] Figure 10 It is a diagram of the sensing mechanism of the sensor described in the embodiment of the present invention for sensing strain;

[0041] Figure 11 It is an experimental verification diagram of the tensile strain sensitivity of the sensor described in the embodiment of the present invention;

[0042] Figure 12The response curve graph of the tensile hysteresis of the sensor described in the embodiment of the present invention;

[0043] Figure 13 The curve graph of the stretching response time sensed by the sensor described in the embodiment of the present invention;

[0044] Figure 14 The sensing mechanism diagram of the sensor affected by temperature described in the embodiment of the present invention;

[0045] Figure 15 The experimental verification graph of the temperature sensitivity of the sensor described in the embodiment of the present invention;

[0046] Figure 16 The response curve graph of the temperature sensing per unit time of the sensor described in the embodiment of the present invention;

[0047] Figure 17 The comparison graph of the pressure, tensile strain and temperature sensitivities of the sensors obtained by separately adding GR or CNPs in step (2) of the embodiment of the present invention: (a) is the comparison graph of pressure sensitivity, (b) is the comparison graph of tensile strain sensitivity, and (c) is the comparison graph of temperature sensitivity;

[0048] Figure 18 The comparison graph of the pressure, tensile strain and temperature sensitivities of the sensors obtained by adding GR and CNPs with different ratios in step (2) of the embodiment of the present invention: (a) is the comparison graph of pressure sensitivity, (b) is the comparison graph of tensile strain sensitivity, and (c) is the comparison graph of temperature sensitivity. Detailed implementation manners

[0049] Next, the technical solutions of the present invention will be described in detail through specific embodiments. However, it should be clearly stated that these embodiments are used for illustrative purposes only and are not construed as limiting the scope of the present invention.

[0050] APTES was purchased from Shanghai Macklin Biochemical Technology Co., Ltd. (China); Lycra cotton fabric (95% cotton and 5% spandex) was purchased from Weifang Qiaomi Cloth Workshop Co., Ltd. (China); GR with a purity > 98%, 1 - 3 layers, monolayer rate > 80%, D50: 7 - 12μm, D90: 11 - 15μm, was purchased from Shenzhen Hongdachang Evolution Co., Ltd. (China); CNPs was purchased from Suzhou Carbon Feng Technology (China); SR was purchased from Sichuan Zhonghao Chenguang Chemical Research Institute Co., Ltd.; Conductive silver paste (YC - 02) was purchased from Nanjing Hangshuo Electronic Technology Co., Ltd.; The copper foil has a thickness of 0.1mm ± 0.005 and is from 3J Tape (Dongguan) Co. (China).

[0051] Embodiment

[0052] Figure 1 The schematic diagram of the preparation process of the sensor described in the embodiment of the present invention, referring toFigure 1 It can be seen that this embodiment proposes a preparation method for a resistive flexible multifunctional sensor, specifically including:

[0053] (1) Add APTES to absolute ethanol, magnetically stir for 20 min and then disperse evenly to obtain an APTES solution with a concentration of 1 wt%. After cutting the Lycra cotton fabric into a size of 1×3 cm, immerse it in the APTES solution for 30 min, take it out, and dry it at 50 °C to obtain a modified Lycra cotton fabric;

[0054] (2) Add 0.13 g of GR and 0.13 g of CNPs to 20 mL of naphtha, ultrasonically and magnetically stir for 30 min, then add 0.20 g of SR, heat to 100 °C and keep stirring magnetically for 50 min to obtain a GR / CNPs / SR composite solution. Immerse the modified Lycra cotton fabric in the GR / CNPs / SR composite solution for 30 min, take it out, and dry it at 50 °C to obtain a sensing layer attached to the surface of the modified Lycra cotton fabric;

[0055] (3) Cut the copper foil into a size of 1.5×20 cm, evenly coat the surface with a silver glue solution, fold it in half and then paste it on both sides of the sensing layer to obtain an electrode attached to the surface of the sensing layer, that is, the sensor is obtained.

[0056] Figure 2 is a schematic diagram of the overall structure of the sensor according to the embodiment of the present invention. Referring to Figure 2 It can be seen that the sensor includes a modified Lycra cotton fabric 2 and a sensing layer attached to the surface of the modified Lycra cotton fabric 2. The sensing layer includes an upper surface dense conductive layer 1 and a lower surface dense conductive layer 3

[0057] In the present invention, using GR / CNPs / SR as the solute and naphtha as the organic solvent, after ultrasonic dispersion and sufficient stirring, a uniform conductive solution is formed. Then, through the impregnation process, GR / CNPs / SR can form a stable intercalated structure in the Lycra cotton fabric, and stack and disperse with each other to form a sensing layer.

[0058] Figure 3 is a physical diagram of the sensor before and after omitting step (1) in the embodiment of the present invention. It is used as a reference for the situation of the conductive material attached to the surface of the flexible fabric before and after modification with APTES. The left figure is a schematic diagram of the uniform distribution of the conductive material on the fabric surface after the modified flexible fabric is impregnated with the conductive material, and the right figure is a schematic diagram of the non-uniform distribution of a small amount of the conductive material on the fabric surface after the unmodified flexible fabric is impregnated with the conductive material. From Figure 3 it can be seen that the modified Lycra cotton fabric obtained after modification with the APTES solution has a better impregnation effect on GR / CNPs / SR.

[0059] Figure 4This is the diagram showing the influence of SR on the dispersion effect of GR and CNPs in the naphtha system in the embodiments of the present invention. Refer to Figure 4 It can be seen that the sedimentation rate of the carbon-based materials in the conductive solution doped with SR has been significantly improved. SR plays an important role as an adhesive in the GR / CNPs / SR composite solution, and can effectively promote the uniform dispersion of the GR / CNPs composite nanomaterials in the naphtha solvent. During the dispersion process, SR molecules surround and wrap the GR / CNPs composite nanomaterials through physical or chemical actions, reducing their agglomeration phenomenon and ensuring their uniform distribution in naphtha; this uniform dispersion not only facilitates the subsequent processes, but also significantly enhances the stability of the finally formed carbon-based conductive fabric, enabling it to better maintain the consistency and reliability of performance in practical applications.

[0060] Figure 5 This is the SEM diagram of the modified Lycra cotton fabric and the sensing layer in the embodiments of the present invention at different resolutions. Refer to Figure 5 (a) It can be seen that in the modified Lycra cotton fabric, the arrangement of adjacent fibers is not tight, which helps to immerse as much composite conductive material into the fibers as possible. Refer to Figure 5 (b) It can be seen that the fiber surface is not completely smooth, but has some uneven peaks and valleys. This uneven structure not only enhances the adhesion between the conductive filler and the fiber, but also provides a broader distribution point for the conductive filler. Refer to Figure 5 (c) It can be seen that GR / CNPs / SR are stacked on top of each other and cover the fabric substrate, forming a dense and permeable network. Refer to Figure 5 (d) It can be seen that CNPs and GR form an obvious intercalation structure. The formation of this structure can not only reduce the interlayer resistance of graphene, but also inhibit the agglomeration of GR.

[0061] Figure 6 This is the diagram showing the sensing mechanism of the sensor for sensing pressure in the embodiments of the present invention. Figure 6The dual-component mechanism of the pressure-sensitive unit in the sensor sensing layer is presented, including the gap structure between the fabric fiber and the GR / CNPs / SR composite conductive material, and the interlaced structure of the overlapping distribution characteristics of the conductive filler. The pressure-sensitive mechanism described in this study includes the deformation of the micrometer-level gaps between the fibers and the nanometer-level gaps inside the composite conductive material. Specifically, the pressure required for the micrometer-level gaps is much lower than that for the nanometer-level gaps. When in a low-pressure environment, the gaps between the fibers can be compressed rapidly, and the contact area of ​​the composite conductive material increases rapidly; as the pressure continues to increase, the compression process of the gaps between the fibers gradually approaches the saturation state; at the same time, with the gradual reduction of the gaps between the GR and CNPs layers, the resistance continues to decrease; until the end of the high-pressure state, only the overall structure composed of the fabric, GR and CNPs itself is deformed, and the change in the resistance of the piezoresistive sensor with the increase in pressure is minimal.

[0062] The present invention can prepare an interlaced structure with overlapping distribution characteristics by adding CNPs into GR. In this process, CNPs not only effectively alleviate the agglomeration phenomenon of GR, but also further increase the interlayer distance of GR, providing a structural basis for optimizing sensor performance. Figure 6 It also presents the dynamic changes of the intercalation structure under different stretching conditions: as the stretching degree increases, the intercalation structure gradually collapses, causing the sensor's sensitivity to pressure to decrease.

[0063] Figure 7 This is an experimental verification diagram of the pressure sensitivity of the sensor according to the embodiment of the present invention. Figure 7 It is essentially the sensitivity curve of the sensor when it is subjected to a pressure of 0-660 kPa, where the sensitivity is represented by S, S = (ΔR / R 0 )×100% / ΔP, ΔR=R 0 -R P The sensor sensitivity is mainly divided into three stages: the first stage is from 0kPa to 20kPa, and the sensitivity is about 0.7223kPa -1 ; The second stage is between 20kPa and 200kPa, with a sensitivity of about 0.1787kPa -1 ; The third stage is between 200kPa and 660kPa, with a sensitivity of about 0.0033kPa -1 This result shows that the sensor of the present invention has good sensitivity in a small pressure range, which is consistent with Figure 6 The micron-scale gaps between the fabric fibers presented are best compressed and matched.

[0064] Figure 7A comparative analysis of the pressure sensitivity of the unstretched sensor and the pressure sensitivity at 20%, 40%, and 60% stretch is also presented. The results clearly show that the sensor has the highest sensitivity under zero tension conditions, which is consistent with the Figure 6 This corresponds to the mechanism explanation.

[0065] Figure 8 is a response curve diagram of the sensor according to the embodiment of the present invention sensing different pressure strengths, Figure 8 The essence is to explain the cyclic response characteristics of the resistance change of the sensor when it is stretched to different strain conditions and corresponds to different pressures. The specific experimental operation process is as follows: first, the sensor is stretched from the initial 0% to 20%, 40% and 60% in sequence, and then the corresponding detection work is carried out for the resistance signal under different pressure conditions of 66.7kPa, 133.3kPa and 333.3kPa. Through the analysis of the experimental data, it can be seen that the resistance value of the sensor shows a trend of decreasing with increasing pressure. It is particularly noteworthy that the phenomenon of the above resistance value changing with pressure is most prominent when it is not stretched.

[0066] Figure 9 is a response curve diagram of the sensor according to the embodiment of the present invention sensing different compression frequencies, Figure 9 The essence is to explain the cyclic response characteristics of the resistance change rate of the sensor when it is stretched to different strain conditions and corresponding to the application of different frequency pressures. The specific experimental operation process is detailed as follows: First, the sensor is stretched from the initial 0% to 20%, 40% and 60% in a predetermined order; then, under the conditions of 0.05Hz, 0.1Hz and 0.2Hz, the resistance signal generated when a constant pressure is applied to the sensor is tested accordingly. Through the analysis of the experimental data, it can be seen that the change in the resistance value of the sensor shows a trend of accelerating with the continuous increase in frequency. It is particularly important to point out that when the sensor is not stretched, the above-mentioned phenomenon of resistance value changing with frequency is particularly significant.

[0067] Figure 8 and Figure 9 The experimental results may be attributed to the gradual separation between GR and CNPs with the gradual increase in strain, which in turn leads to the reduction of the distance between GR layers and the collapse of the intercalation structure. In this case, the contact area between the conductive fillers shows a gradual decrease, and the conductive network is also damaged, resulting in the interruption of the original complete conductive path, which in turn affects the overall performance of the sensor.

[0068] Figure 10 This is the sensing mechanism diagram of the sensor for sensing strain in the embodiments of the present invention. Figure 10 Essentially, it is the stretching mechanism of the sensor. When the sensor is subjected to tensile strain, the originally intertwined fabric fibers will unfold from the initial curled state, and this process changes the original morphological structure of the fabric fibers. Subsequently, continuous sliding phenomena begin to occur between the GR sheets, and initial cracks will appear in the dense conductive layer formed on their surfaces. When the deformation of the fabric fibers and the sliding of the GR sheets reach a certain extent, if a higher-intensity tensile strain is further applied, the GR layers will be disconnected from each other. At this time, the number of effective conductive channels inside the sensor significantly decreases, bringing a relatively serious negative effect on the conductive performance and overall working efficiency of the sensor. To solve this phenomenon, doped CNPs / SR is used as a conductive bridge to connect the dispersed GR network under high-tensile conditions and inhibit the damage of the conductive network.

[0069] Figure 11 This is the experimental verification diagram of the tensile strain sensitivity of the sensor in the embodiments of the present invention. Figure 11 Essentially, it is the sensitivity curve of the sensor under a strain range of 120%. The sensitivity is represented by the gauge factor (GF), and GF = (ΔR / R 0 )×100% / ε, where ΔR = R ε -R 0 , and ε represents the strain. By fitting the curve between the relative resistance change and the strain, the entire sensing process is divided into two stages. When the strain is 0 - 95%, the GF value is 17.97, and when the strain is 95 - 120%, the GF value is 40.37.

[0070] Figure 12 This is the response curve diagram of the tensile hysteresis of the sensor in the embodiments of the present invention. Figure 12 Essentially, it presents the hysteresis characteristics of the sensor measured through multiple stretching and releasing cycles. The strain resistance curve after stretching 120% shows that the hysteresis of the sensor is not obvious, and the maximum hysteresis error is only 7.24%.

[0071] Figure 13 This is the curve diagram of the sensing response time of the sensor for sensing stretching in the embodiments of the present invention. Figure 13 Essentially, it is the test result of the real-time response of the sensor under strains of 5%, 60%, and 120%, indicating that the sensor has the characteristic of rapid response to stretchable strain and can quickly respond to external stimulus information in actual application scenarios.

[0072] Figure 14 This is the sensing mechanism diagram of the sensor affected by temperature in the embodiments of the present invention. Figure 14Shown is the temperature-sensitive mechanism of the sensor sensing layer, which mainly covers the SR thermal expansion squeezing CNPs and the entropy thermal motion of GR. They each play a unique and crucial role in the temperature-sensitive characteristics and jointly constitute the basis for the sensing layer to respond to temperature changes.

[0073] SR has the characteristic of a high coefficient of thermal expansion; when the ambient temperature rises, SR will rapidly expand, compressing the remaining space within the conductive network. Due to the compression of this space, the distance between adjacent CBs is gradually shortened. After that, with the continuous reduction of this distance, it will promote the formation of a more effective conduction path in the conductive network. And as this process continues, it will ultimately cause the temperature coefficient of resistance (TCR) of the CB and SR system to show a negative value.

[0074] The graphene selected in this invention is a mixture composed of single-layer and multi-layer graphene, and the content of multi-layer graphene is approximately 20%. The presence of multi-layer graphene causes an overlap between the valence band and the conduction band, thereby making it present a semi-metallic state. Compared with single-layer graphene, in addition to the top and bottom channels, there are also interlayer channels for carriers to migrate at this time. Compared with single-layer graphene, the influence of temperature on the electron thermal motion rate within the sandwich structure is very significant, that is to say, the influence degree of temperature on the conductivity of multi-layer doped graphene is more obvious than that on single-layer graphene.

[0075] Figure 15 It is the experimental verification diagram of the temperature sensitivity of the sensor described in the embodiment of the present invention. Figure 15 It is essentially the response curve diagram of the temperature sensitivity of the sensor, where the temperature coefficient is represented by TCR, TCR=(ΔR / R 0 )×100% / ΔT, ΔR = R T -R 0 . By fitting the curve between the relative resistance change and temperature, in the full range of 23 - 70 °C, the value of TCR is -1.1868 °C -1 .

[0076] Figure 16 It is the response curve diagram of the temperature perception per unit time of the sensor described in the embodiment of the present invention. Figure 16 It is essentially the response curve diagram of the temperature perception per unit time of the sensor, indicating that the sensor has a stable thermal response.

[0077] Figure 17 It is the comparison diagram of the pressure, tensile strain and temperature sensitivity of the sensors obtained by separately adding GR or CNPs in step (2) of the embodiment of the present invention. Refer to Figure 17It can be seen that the synergistic effect of GR and CNPs significantly improves the sensitivity and stability of the sensing layer, and this phenomenon is attributed to the outstanding intercalation structure of GR and CNPs.

[0078] Figure 18 This is a comparison chart of the pressure, tensile strain, and temperature sensitivities of the sensors obtained by adding different ratios of GR and CNPs in step (2) of the embodiment of the present invention. Refer to Figure 17 It can be seen that when GR:CNPs = 1:1, the obtained sensor has the highest sensitivity and the most stable performance. This may be because at this ratio, the conductive network of the sensing layer is the most uniform, without excessive aggregation and stacking of GR, nor excessive CNPs with a smaller specific surface area weakening the conductivity.

[0079] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its inventive concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A resistive flexible multifunctional sensor, characterized in that: It comprises a flexible fabric, a sensing layer attached to the surface of the flexible fabric, and an electrode attached to the surface of the sensing layer; The sensing layer is an intercalation structure in which graphene, carbon nanoparticles and silicone rubber are stacked and distributed.

2. The resistive flexible multifunctional sensor according to claim 1, characterized in that: The flexible fabric is cotton fabric, wool fabric, silk fabric, linen fabric, chemical fiber fabric or blended fabric; Preferably, the flexible fabric is Lycra cotton fabric.

3. The resistive flexible multifunctional sensor according to claim 1 or 2, characterized in that: The mass ratio of the graphene, carbon nanoparticles and silicone rubber is 2:1-3:2-4, preferably 2:2:

3.

4. The resistive flexible multifunctional sensor according to any one of claims 1 to 3, characterized in that: The electrode is a metal electrode.

5. A method for preparing the resistive flexible multifunctional sensor according to any one of claims 1 to 4, characterized in that: The steps include: S1, dispersing graphene, carbon nanoparticles and silicone rubber in an organic solvent to obtain a conductive solution; S2, immersing the flexible fabric in the conductive solution, taking it out and drying it, thereby obtaining a sensing layer attached to the surface of the flexible fabric; S3. Paste electrodes on both sides of the sensing layer using conductive silver paste to obtain electrodes attached to the surface of the sensing layer, that is, to obtain the sensor.

6. The method for preparing the resistive flexible multifunctional sensor according to claim 5, characterized in that: In step S1, the conductive solution is obtained by first dispersing graphene and carbon nanoparticles in an organic solvent, and then adding silicone rubber to the solvent and heating and stirring to dissolve the solvent; Preferably, the organic solvent is naphtha, the heating and stirring temperature is 80-120°C, and the time is 20-60min; Preferably, the concentration of the conductive solution is 0.5-5wt%.

7. The method for preparing the resistive flexible multifunctional sensor according to claim 5 or 6, characterized in that: In step S2, before immersing the flexible fabric in the conductive solution, the flexible fabric is further subjected to surface modification.

8. The method for preparing the resistive flexible multifunctional sensor according to claim 7, characterized in that: The surface modification is to immerse the flexible fabric in an aminosilane coupling agent solution, take it out and dry it, so as to obtain a modified flexible fabric; Preferably, the aminosilane coupling agent is γ-aminopropyltriethoxysilane or γ-aminopropyltrimethoxysilane; Preferably, the concentration of the aminosilane coupling agent solution is 0.5-2 wt %.

9. The method for preparing the resistive flexible multifunctional sensor according to any one of claims 5 to 8, characterized in that: In step S2, the immersion temperature is 10-30°C and the time is 20-60 minutes.

10. Use of the sensor according to any one of claims 1 to 4 or the sensor prepared by the preparation method according to any one of claims 5 to 9 in wearable devices, electronic skin or health monitoring.

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