Preparation of metal / conductive polymer composite gel stretchable electrode material and multi-mode wearable sensing application

Abstract

The invention discloses preparation of a metal / conductive polymer composite gel stretchable electrode material and multi-mode wearable sensing application, and particularly relates to the field of electrochemical materials. Comprising PAA (polyacrylic acid) / PEDOT (poly (3, 4-ethylenedioxythiophene)): PSS (poly (3, 4-ethylenedioxythiophene): polystyrolsulfon acid) / M composite gel, the PAA / PEDOT: PSS / M composite gel is prepared from the following raw materials: an acrylic monomer, PEDOT: PSS and metal M aerogel; the acrylic monomer is polymerized to obtain polyacrylic acid, a chain of the polyacrylic acid and a chain of PEDOT: PSS are intertwined and interwoven to form a three-dimensional net-shaped covalent bond structure, and the metal M aerogel is located in the net-shaped covalent bond structure. The stretchable electrode material has excellent electrochemical performance, mechanical performance and conductivity, and can be directly used as a stretchable electrode for electrochemical sensing test and strain sensing test.

Description

Technical Field

[0001] This application relates to the field of electrochemical materials, and in particular to the preparation of a metal / conductive polymer composite gel stretchable electrode material and its multimodal wearable sensing applications. Background Technology

[0002] With the increasing demand for health monitoring, the research and application of wearable devices have developed rapidly. Wearable sensors based on electrochemical principles have been widely used to monitor human biochemical signals due to their rapid response, high selectivity, high sensitivity, and ease of miniaturization. However, traditional electrochemical sensors mainly rely on rigid electrodes, which are difficult to meet the requirements of wearable devices for tolerance to skin deformation. In contrast, flexible electrochemical sensors have become an ideal solution due to their unique advantages such as stretchability, conformal fit to the skin, good biocompatibility, and wearability comfort. The key to developing high-performance flexible wearable electrochemical sensors lies in constructing an efficient and flexible electrochemical sensing interface. Therefore, developing flexible electrode sensing materials with superior electrochemical performance and excellent flexibility is the core challenge currently faced.

[0003] In flexible electrochemical sensing, the sensitive electrode material not only needs to possess high sensitivity, selectivity, and stability similar to traditional rigid sensitive electrode materials, but also needs to maintain structural and signal stability under wearable conditions such as bending, twisting, and stretching. Metal aerogels with unique network structures have shown great application potential in the construction of flexible sensors as excellent flexible electrochemical sensitive electrode materials. However, their pure metal framework still lacks sufficient flexibility to withstand frequent stretching and bending deformations in daily life, and modifications onto flexible substrates can lead to detachment during use, thus limiting their further physiological applications. Summary of the Invention

[0004] The main objective of this application is to provide a method for preparing a metal / conductive polymer composite gel stretchable electrode material and its application in multimodal wearable sensing, aiming to solve the problem of poor flexibility in existing flexible sensors.

[0005] To achieve the above objectives, this application provides a metal / conductive polymer composite gel stretchable electrode material, comprising a PAA / PEDOT:PSS / M composite gel; the raw materials of the PAA / PEDOT:PSS / M composite gel include acrylic monomer, PEDOT:PSS and metal M aerogel; wherein, the mass ratio of acrylic monomer, PEDOT:PSS and metal M aerogel is 1:(1-4):(0.005-0.04); the acrylic monomer is polymerized to obtain polyacrylic acid, and the chains of polyacrylic acid and PEDOT:PSS are intertwined to form a three-dimensional network covalent bond structure, and the metal M aerogel is located inside the network covalent bond structure.

[0006] Optionally, the M in the metal M aerogel is one or a combination of two of gold, platinum, palladium, copper and nickel.

[0007] Optionally, the preparation method of metal M aerogel includes: adding a reducing agent to a metal chloride to obtain a metal M hydrogel; and freeze-drying the metal M hydrogel to obtain a metal M aerogel.

[0008] Optionally, the molar ratio of metal chloride to reducing agent is 1:(1-25).

[0009] Optionally, the metal chloride includes one or a mixture of two of chloroauric acid, chloroplatinic acid, palladium chloride, copper chloride, and nickel chloride; the reducing agent is NaBH4.

[0010] To achieve the above objectives, this application also provides a method for preparing a metal / conductive polymer composite gel stretchable electrode material, comprising: adding PEDOT:PSS to an acrylic monomer to obtain a dispersion; adding metal M aerogel to the dispersion to obtain a mixed solution; adding an oxidant and a crosslinking agent to the mixed solution, and injecting it into a mold and heating it at a temperature of 30-80℃ for 4-20 min to obtain a PAA / PEDOT:PSS / M composite gel.

[0011] Optionally, the crosslinking agent is N,N'-methylenebisacrylamide, and the oxidizing agent is ammonium persulfate; the mass ratio of acrylic monomer, crosslinking agent and oxidizing agent is 1:(0.001-0.01):(0.01-0.05).

[0012] To achieve the above objectives, this application also provides an application of a metal / conductive polymer composite gel stretchable electrode material in a flexible wearable sensor.

[0013] Optionally, it can be used to monitor physiological and biochemical indicators of the human body.

[0014] Optionally, biochemical indicators include the concentrations of Glu, L-dopa, AA, or UA in human sweat; physiological indicators include human movement signals.

[0015] Compared with the prior art, the beneficial effects of this application are as follows: The metal / conductive polymer composite gel stretchable electrode material of this invention possesses a three-dimensional interpenetrating cross-linked structure and extensive intermolecular interactions, giving it high elasticity and stretchability. The three-dimensional interconnected porous structure can promote electron conduction and ion / molecular diffusion. It exhibits excellent electrochemical, mechanical, and electrical properties and can be directly used as a stretchable electrode for electrochemical sensing and strain sensing tests. By integrating stretchable electrode materials of various metals into a flexible sensing array, physiological and biochemical indicators can be monitored in real time simultaneously.

[0016] The method for preparing the metal / conductive polymer composite gel stretchable electrode material of the present invention is simple, low-cost, and does not require complex equipment. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a metal / conductive polymer composite gel stretchable electrode material according to this application; Figure 2 Scanning electron microscope, transmission electron microscope, and TEM-EDS mappings of the stretchable electrode material obtained in Example 1; Figure 3 These are test images of the electrochemical and mechanical properties of the stretchable electrode material obtained in Example 1; Figure 4 The graph shows the test results of the stretchable electrode material obtained in Example 1 on different sweat metabolic components; Figure 5 The graph shows the electrochemical sensing performance of the stretchable electrode material obtained in Example 1. Figure 6 The strain sensing performance test diagram of the stretchable electrode material obtained in Example 1 is shown. Figure 7 This is a schematic diagram of a multimodal flexible sensing array made of the stretchable electrode material obtained in Example 1 and its sensing principle.

[0018] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0020] The first embodiment of the present invention provides a metal / conductive polymer composite gel stretchable electrode material, such as... Figure 1 As shown, it includes PAA / PEDOT:PSS / M composite gel; the raw materials of PAA / PEDOT:PSS / M composite gel include acrylic monomer, PEDOT:PSS and metal M aerogel; wherein, the acrylic monomer is polymerized to obtain polyacrylic acid, and the chains of polyacrylic acid and PEDOT:PSS are intertwined to form a three-dimensional network covalent bond structure, and the metal M aerogel is located inside the network structure.

[0021] Specifically, under the action of an oxidant, the double bonds of acrylic monomers break and form new free radicals, which further undergo cross-linking reactions with cross-linking agents, forming chemical bonds between polymer chains and connecting them to form a three-dimensional network structure of polyacrylic acid. At the same time, the carboxylic acid bonds in polyacrylic acid and the sulfonic acid bonds in PEDOT:PSS are combined through hydrogen bonding to form a three-dimensional network covalent bond structure. The metal M aerogel forms coordination bonds with the cross-linking agent and PEDOT:PSS, so that the metal M aerogel is located inside the three-dimensional network covalent bond structure.

[0022] For example, the M in the metal M aerogel is one or a combination of two of gold, platinum, palladium, copper and nickel.

[0023] In this embodiment, a metal M aerogel is used as the matrix, and a dynamically cross-linked conductive polymer gel is introduced to form a three-dimensional interpenetrating network structure. This protects the metal M aerogel within the large pore structure of the hydrogel. Furthermore, the composite gel contains hydrogen bonds and extensive intermolecular interactions, resulting in a dual gel structure with excellent flexibility and fatigue resistance. The three-dimensional interconnected pore structure promotes electron conduction and ion / molecule diffusion, and the three-dimensional structure provides good structural stability. Specifically, the conductive polymer PEDOT:PSS exhibits excellent conductivity and electrochemical activity, while polyacrylic acid possesses excellent mechanical properties. The acrylic monomer forms a conductive hydrogel with PEDOT:PSS, and this hydrogel, combined with the metal M aerogel, yields a PAA / PEDOT:PSS / M composite gel, which possesses excellent electrochemical, mechanical, and conductive properties.

[0024] Furthermore, the preparation method of metal M aerogel includes: adding a reducing agent to a metal chloride to obtain a metal M hydrogel; and freeze-drying the metal M hydrogel to obtain a metal M aerogel. The molar ratio of metal chloride to reducing agent is 1:(1-25). The metal chloride includes one or a mixture of two of chloroauric acid, chloroplatinic acid, palladium chloride, copper chloride, and nickel chloride; the reducing agent is NaBH4.

[0025] In this embodiment, metal M aerogel is prepared by a one-step reduction method, which is simple to operate and easy to implement.

[0026] The second embodiment of the present invention provides a method for preparing a metal / conductive polymer composite gel stretchable electrode material, specifically including the following steps: Step S1: PEDOT:PSS is added to the acrylic monomer to obtain a dispersion; wherein, PEDOT:PSS is a PEDOT:PSS suspension with a solid content of 1%-1.3% and Clevios pH 1000 (Heraeus).

[0027] Step S2: Add metal M aerogel to the dispersion to obtain a mixed solution; Step S3: Add oxidant and crosslinking agent to the mixed solution, and inject it into a mold. Heat at 30-80℃ for 4-20 min to obtain a stretchable electrode material. Heating the mixture in the mold promotes gelation. The mass ratio of acrylic monomer, PEDOT:PSS, and metal M aerogel is 1:(1-4):(0.005-0.04), and the mass ratio of acrylic monomer, crosslinking agent, and oxidant is 1:(0.001-0.01):(0.01-0.05). The crosslinking agent is N,N'-methylenebisacrylamide, and the oxidant is ammonium persulfate.

[0028] In this embodiment, under the action of an oxidant, the double bonds of the acrylic monomer and the crosslinking agent are broken, resulting in a polymerization reaction to obtain polyacrylic acid. The carboxylic acid bond of polyacrylic acid and the sulfonic acid bond of PEDOT:PSS are combined through hydrogen bonds to form a three-dimensional network covalent bond structure. The metal M aerogel forms coordination bonds with the crosslinking agent and PEDOT:PSS, so that the metal M aerogel is located in the pores of the covalent bond structure.

[0029] A third embodiment of the present invention provides an application of a metal / conductive polymer composite gel stretchable electrode material in a flexible wearable sensor. Specifically, it is used to monitor physiological and biochemical indicators of the human body. Biochemical indicators include the concentrations of Glu, L-dopa, AA, or UA in human sweat, while physiological indicators include human motion signals.

[0030] Example 1 Step 1: Add 50 mL of ultrapure water to a 150 mL Erlenmeyer flask, then add 59.1 μL of 10 wt% HAuCl4 solution and 50 μL of 0.1 M NiCl2 solution, and stir thoroughly for 2 min. Quickly add 0.6 mL of NaBH4 solution (volume concentration of 33 mg / mL), and the solution turns black instantly. After stirring at room temperature for 2 min, allow it to mature in the dark for 12 h to obtain Au3Ni1 hydrogel. After washing 10 times with ultrapure water, obtain Au3Ni1 aerogel by freeze-drying. Step 2: Dissolve 200 μL of acrylic monomer in 754 μL of ultrapure water, add 400 μL of PEDOT:PSS suspension and 9 mg of Au3Ni1 aerogel, and sonicate to mix evenly under ultrasonic power of 100 W to obtain a mixed solution; add 1 mg of N,N'-methylenebisacrylamide and 6 mg of ammonium persulfate to the mixed solution, mix thoroughly, and pour into a rectangular glass mold. After sealing the glass mold, place it in an 80 ℃ oven and let it stand for 20 min to form a gel, thus obtaining PAA / PEDOT:PSS / Au3Ni1 (PP / Au3Ni1) composite gel stretchable electrode material.

[0031] The SEM and TEM images of the PAA / PEDOT:PSS / Au3Ni1 composite gel stretchable electrode material obtained in this embodiment are shown below. Figure 2 From SEM and TEM images, it can be found that... Figure 2 A and Figure 2 B indicates that the composite gel has a three-dimensional porous structure. Figure 2 C indicates that the nanonetwork structure of the metal M aerogel remains intact within this structure; therefore, the composite gel exhibits a three-dimensional cross-linked porous network structure. Figure 2 Further analysis of the D-side and line scans reveals that PEDOT:PSS is encapsulated in the outer layer of Au3Ni1 aerogel, indicating that the composite gel has a dual gel structure. This structure is conducive to promoting electron conduction and ion / molecule diffusion, thereby enabling multimodal sensing of physiological and biochemical signals.

[0032] Example 2 Step 1: Add 50 mL of ultrapure water to a 150 mL Erlenmeyer flask, then add 61.4 μL of 10 wt% H2PtCl4 solution and 50 μL of 0.1 M NiCl2 solution, and stir thoroughly for 2 min; quickly add 0.6 mL of NaBH4 solution (33 mg / mL), the solution turns black instantly, stir at room temperature for 2 min, and then age in the dark for 12 h to obtain Pt3Ni1 hydrogel; after washing 10 times with ultrapure water, obtain Pt3Ni1 aerogel by freeze drying.

[0033] Step 2: Dissolve 200 μL of acrylic monomer in 754 μL of ultrapure water, then add 400 μL of PEDOT:PSS suspension and 9 mg of Pt3Ni1 aerogel. Mix the solutions by ultrasonication at 100 W to obtain a mixed solution. Add 1 mg of N,N'-methylenebisacrylamide and 6 mg of ammonium persulfate to the mixed solution, mix thoroughly, and pour into a rectangular glass mold. After sealing the glass mold, place it in an 80℃ oven and let it stand for 20 min to form a gel, thus obtaining the PAA / PEDOT:PSS / Pt3Ni1 (PP / Pt3Ni1) composite gel stretchable electrode material.

[0034] Example 3 Step 1: Add 144.25 mL of ultrapure water to a 250 mL Erlenmeyer flask, add 174 μL of 10 wt% HAuCl4 solution, and stir thoroughly for 3 min; add 3.48 mL of 1 wt% sodium citrate solution, and after stirring thoroughly for 1 min, quickly add 2.09 mL of a mixed solution (the mixed solution contains 1.74 mL of 1 wt% sodium citrate solution and 0.35 mL of 0.15 M NaBH4 solution); keep the reaction solution at room temperature for 2 h to obtain a wine-red Au nanoparticle solution, let it stand and mature overnight, and then obtain an Au nanoparticle solution concentrated to 8.5 mg / mL by ultrafiltration and centrifugation; take 1 mL of Au nanoparticle solution, add 106 μL of 1.2 mg / mL dopamine solution, shake for 5 min, let stand overnight to obtain Au hydrogel, wash 10 times with ultrapure water, and obtain Au aerogel by freeze drying.

[0035] Step 2: Dissolve 200 μL of acrylic monomer in 754 μL of ultrapure water, then add 400 μL of PEDOT:PSS suspension and 9 mg of Au aerogel. Mix the solutions by ultrasonication at 100 W to obtain a mixed solution. Add 1 mg of N,N'-methylenebisacrylamide and 6 mg of ammonium persulfate to the mixed solution, mix thoroughly, and pour into a rectangular glass mold. After sealing the glass mold, place it in an 80 ℃ oven and let it stand for 20 min to form a gel, thus obtaining the PAA / PEDOT:PSS / Au (PP / Au) composite gel stretchable electrode material.

[0036] Comparative Example 1 200 μL of acrylic monomer was dissolved in 754 μL of ultrapure water, and then 400 μL of PEDOT:PSS suspension was added. The mixture was ultrasonically mixed at 100 W. 1 mg of N,N'-methylenebisacrylamide and 6 mg of ammonium persulfate were added and mixed thoroughly. The solution was injected into a self-made cuboid glass mold. After sealing the mold, it was placed in an 80 ℃ oven and allowed to stand for 20 min to form a gel, thus obtaining PAA / PEDOT:PSS (PP) hydrogel.

[0037] Comparative Example 2 Step 1: Add 50 mL of ultrapure water to a 150 mL Erlenmeyer flask, then add 59.1 μL of 10 wt% HAuCl4 solution and 50 μL of 0.1 M NiCl2 solution, and stir thoroughly for 2 min; quickly add 0.6 mL of NaBH4 solution (33 mg / mL), the solution turns black instantly, stir at room temperature for 2 min, and then age in the dark for 12 h to obtain Au3Ni1 hydrogel; after washing 10 times with ultrapure water, obtain Au3Ni1 aerogel by freeze-drying.

[0038] Step 2: Dissolve 200 μL of acrylic monomer in 754 μL of ultrapure water, then add 400 μL of PEDOT:PSS suspension and sonicate until homogeneous. Add 1 mg of N,N'-methylenebisacrylamide and 6 mg of ammonium persulfate and mix thoroughly. Pour the solution into a self-made cuboid glass mold, seal the mold, and place it in an 80 ℃ oven for 20 min to form a gel, thus obtaining PAA / PEDOT:PSS hydrogel. Step 3: Au3Ni1 aerogel is dispersed in ultrapure water at a concentration of 6.6 mg / mL. After being ultrasonically dispersed evenly, it is modified on the surface of PAA / PEDOT:PSS hydrogel according to the ratio to obtain Au3Ni1 aerogel modified PAA / PEDOT:PSS (Au3Ni1 modified-PP) hydrogel stretchable electrode material.

[0039] The electrode materials obtained in Examples 1-3 and Comparative Examples 1-2 were subjected to performance tests. The test process and results are as follows.

[0040] Electrochemical performance testing: The composite gels prepared in Examples 1-3 and Comparative Examples 1-2 were cut into stretchable electrodes of 7 mm × 3 mm × 1 mm. A platinum sheet electrode was used to clamp the stretchable composite gel electrode as the working electrode, an Ag / AgCl electrode as the reference electrode, and a platinum wire electrode as the counter electrode. 0.1 M KCl and 5 mM [Fe(CN)6] were prepared. 3 / 4-The mixed solution was used as an electrochemical redox probe, and electrochemical tests were performed using a CHI660E electrochemical workstation. The main tests included cyclic voltammetry (CV) curves before and after simple mechanical deformation and repeated stretching, based on the peak-to-peak potential difference (ΔE). p The electrochemical performance of the material was investigated using the electrochemical active area (ECSA) obtained from the Randles-Sevcik equation. The test results are shown in [Figure number missing]. Figure 3 .

[0041] The CV test images of the PP / Au3Ni1 composite gel obtained in Example 1 before and after repeated stretching are shown below. Figure 3 A, the CV test images of the Au3Ni1modified-PP hydrogel stretchable electrode material obtained in Comparative Example 2 before and after repeated stretching are shown in Figure 1. Figure 3 B. As can be seen from the figure, the interpeak potential difference (ΔE) between the composite gel obtained in Example 1 and Comparative Example 2 before and after repeated stretching is... p The change graphs for the electrochemical active area (ECSA) and the electrochemical active area (ECSA) are shown below. Figure 3 C, after repeated stretching 200 times, compared with Au3Ni1 aerogel, the ΔE of the composite gel is... p The changes in both PP / Au3Ni1 and ECSA were small (<10%), indicating that the PP / Au3Ni1 composite gel has relatively stable flexible electrochemical properties and can be used to construct efficient and stable flexible electrochemical sensing interfaces.

[0042] Mechanical property testing: The composite gels prepared in Examples 1-3 were cut into stretchable electrodes of 50 mm × 10 mm × 3 mm. The mechanical properties of the composite gels were measured using an Instron-5900 electronic universal testing machine, primarily testing stress-strain curves and loading-unloading curves. The mechanical properties of the material were investigated based on elongation at break, Young's modulus, and hysteresis loop area. The test results are shown in [Figure number missing]. Figure 3 DF.

[0043] from Figure 3 As can be seen from D, the elongation at break of the PP / Au3Ni1 composite gel obtained in Example 1 is 85% of that of the PP hydrogel obtained in Comparative Example 1, indicating that it still has good stretchability after composite formation. Stress loading-unloading cycle curves can reflect the energy dissipation and fatigue resistance of materials, such as... Figure 3 As shown in Figure E, the stress-strain curves of the PP / Au3Ni1 composite gel obtained in Example 1, after 100 loading-unloading cycles at a constant strain of 150%, show a high degree of overlap. Furthermore, from... Figure 3As can be seen from F, compared with the PP hydrogel of Comparative Example 1, the hysteresis loop area of ​​the PP / Au3Ni1 composite gel obtained in Example 1 is smaller, indicating that its fatigue resistance is superior. Therefore, this PP / Au3Ni1 composite gel has excellent electrochemical and mechanical properties, and is expected to be applied in wearable sensors for daily use.

[0044] Electrochemical sensing performance testing: Five μL of the composite gel precursor solution prepared in Examples 1-3 was used to modify a glassy carbon electrode. The glassy carbon electrode was then placed at 80 °C and allowed to stand for 20 min before being removed. The composite gel-modified glassy carbon electrode was used as the working electrode, the Ag / AgCl electrode as the reference electrode, and the platinum wire electrode as the counter electrode. A 0.1 M PBS solution (pH=7.4) was prepared as the electrolyte. Electrochemical tests were performed using a CHI660E electrochemical workstation, mainly measuring cyclic voltammetry (CV) and chronoamperometric curves (it).

[0045] The composite gels obtained in Examples 1-3 were tested in 0.1 M PBS (pH=7.4) for the response of sweat metabolic components, such as glucose, L-dopa, ascorbic acid (AA), and uric acid (UA). The CV test chromatograms are shown in the figure. Figure 4 , Figure 4 A represents the test results of the PP / Pt3Ni1 composite gel obtained in Example 2 on glucose. Figure 4 B represents the L-dopa test results of the PP / Au composite gel obtained in Example 3. Figure 4 CD represents the test results of the PP / Au3Ni1 composite gel obtained in Example 1 for AA and UA. As can be seen from the figure, the electrochemical response in the CV curve shows that introducing the PAA / PEDOT:PSS gel into different metal M aerogels enables the monitoring of multiple sweat metabolites. Therefore, it can be demonstrated that by changing different metal M aerogels, the composite gel of this embodiment can be used for the monitoring of multiple sweat metabolites.

[0046] Urea (UA) is an important indicator for diagnosing gout. Detecting UA concentration in sweat can provide warnings and guidance regarding people's lifestyle and dietary habits. Therefore, the response of the PP / Au3Ni1 composite gel obtained in Example 1 to different concentrations of UA was tested. Different concentrations of UA were added to 0.1 M PBS solution (pH=7.4), and an iterative testing (it) test was performed to achieve continuous monitoring of UA by the composite gel. The results are as follows: Figure 5 AB, from Figure 5 As can be seen from Figure A, the oxidation current gradually increases in a step-like manner with the increase of UA concentration; within the concentration range of 5 μM-8 mM, R...2 The correlation coefficient is 0.999, indicating a good linear correlation. (See...) Figure 5 B. To examine the anti-interference ability of this composite gel for UA detection, it was tested against common interfering substances in sweat (Glu, Lac, Urea, NaCl, KCl, and AA), such as... Figure 5 As shown in CD, the current signal generated after adding UA is much higher than the current response of the six interfering substances mentioned above. Therefore, the UA sensor based on this composite gel has a wide response range, low detection limit, and excellent selectivity.

[0047] Stress-strain sensing performance testing: The composite gels prepared in Examples 1-3 were cut into stretchable electrodes of 50 mm × 10 mm × 3 mm. The sensing performance of the composite gels was measured using a general mechanical testing instrument combined with a digital source meter (TH1992B). A sensor with a typical "sandwich" structure was fabricated using 3M tape as the elastic substrate and encapsulant. It was stably connected to the digital source meter using copper conductive tape and wires. The corresponding output voltage and current under different strains were measured, and the changes in resistance signals during human wrist, elbow, and knee movements were monitored.

[0048] The relative resistance of conductive hydrogels changes with strain. The strain sensing performance test results of the PP / Au3Ni1 composite gel obtained in Example 1 are shown in [reference needed]. Figure 6 ,from Figure 6 As can be seen from A, the PP / Au3Ni1 composite gel can reliably and stably detect continuous signals under different strains; Figure 6 Figure BC shows the resistance signal changes of the PP / Au3Ni1 composite gel sensor prepared in Example 1 when installed on different parts of the human body (finger joints, wrist, arm, and knee joints). As can be seen from the figures, the sensor can monitor various complex movements, including finger joint bending, wrist rotation, arm bending, and knee joint movement. Therefore, this composite gel sensor has a fast response and strain sensitivity, enabling real-time monitoring of human movement.

[0049] Managing human health requires analyzing various physiological and biochemical indicators, such as stress and sweat metabolites. Only by monitoring and comprehensively analyzing multiple indicators can we provide a more accurate basis for human health monitoring. Therefore, designing multimodal flexible wearable sensors for simultaneously monitoring physiological and biochemical indicators is of great significance. Figure 7 This is a schematic diagram of a multimodal flexible sensing array composed of various PAA / PEDOT:PSS / M composite gels prepared using this invention, and the sensing principle. Figure 7As shown, sensitive materials with different sensing functions (sweat metabolites, strain) are all integrated into a flexible sensing array. Then, a flexible wearable sensor is constructed by combining a sensor array (working electrode WE, reference electrode CE, counter electrode RE), signal processing circuit, wireless transmission module and microfluidic sweat collection device to realize real-time monitoring of physiological and biochemical indicators.

[0050] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A metal / conductive polymer composite gel stretchable electrode material, characterized in that, Including PAA / PEDOT:PSS / M composite gel; The raw materials for the PAA / PEDOT:PSS / M composite gel include acrylic monomers, PEDOT:PSS, and metal M aerogel. The mass ratio of the acrylic monomer, PEDOT:PSS, and metal M aerogel is 1:(1-4):(0.005-0.04). The acrylic monomer is polymerized to obtain polyacrylic acid. The chains of polyacrylic acid and PEDOT:PSS are intertwined to form a three-dimensional network covalent bond structure, and the metal M aerogel is located inside this network covalent bond structure.

2. The metal / conductive polymer composite gel stretchable electrode material according to claim 1, characterized in that, The M in the metal M aerogel is one or a combination of two of gold, platinum, palladium, copper and nickel.

3. The metal / conductive polymer composite gel stretchable electrode material according to claim 1, characterized in that, The preparation method of the metal M aerogel includes: A reducing agent is added to a metal chloride to obtain a metal M hydrogel; The metal M hydrogel was freeze-dried to obtain metal M aerogel.

4. The metal / conductive polymer composite gel stretchable electrode material according to claim 3, characterized in that, The molar ratio of the metal chloride to the reducing agent is 1:(1-25).

5. The metal / conductive polymer composite gel stretchable electrode material according to claim 4, characterized in that, The metal chloride includes one or a mixture of two of chloroauric acid, chloroplatinic acid, palladium chloride, copper chloride, and nickel chloride; the reducing agent is NaBH4.

6. A method for preparing the metal / conductive polymer composite gel stretchable electrode material according to claim 1, characterized in that, include: PEDOT:PSS was added to the acrylic monomer to obtain a dispersion; Metal M aerogel was added to the dispersion to obtain a mixed solution; An oxidant and a crosslinking agent are added to the mixed solution, and the solution is injected into a mold and heated at 30-80°C for 4-20 minutes to obtain a PAA / PEDOT:PSS / M composite gel.

7. The metal / conductive polymer composite gel stretchable electrode material according to claim 6, characterized in that, The crosslinking agent is N,N'-methylenebisacrylamide, and the oxidizing agent is ammonium persulfate; The mass ratio of the acrylic monomer, crosslinking agent, and oxidant is 1:(0.001-0.01):(0.01-0.05).

8. The application of the metal / conductive polymer composite gel stretchable electrode material of claim 1 in a flexible wearable sensor.

9. The application of the metal / conductive polymer composite gel stretchable electrode material according to claim 8 in flexible wearable sensors, characterized in that, It is used to monitor physiological and biochemical indicators of the human body.

10. The application of the metal / conductive polymer composite gel stretchable electrode material according to claim 9 in flexible wearable sensors, characterized in that, The biochemical indicators include the concentrations of Glu, L-dopa, AA, or UA in human sweat; the physiological indicators include human movement signals.

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