A lignin-based conductive eutectic gel, and a preparation method and application thereof

Abstract

The application discloses a lignin-based conductive eutectic gel and a preparation method and application thereof, and belongs to the technical field of intelligent soft materials.The lignin-based conductive eutectic gel comprises the following components in proportion by weight: 20-50 parts of polymerizable monomers, 0.01-0.2 parts of a crosslinking agent, 0.01-0.15 parts of sodium lignosulfonate, 3-6 parts of modified keratin, 0.1-1 parts of an initiator, 50-90 parts of a deep eutectic solvent and 50-100 parts of water; the polymerizable monomers are acrylic acid and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide; and the modified keratin is polyethylene glycol-based double-end crosslinking monomers and disulfide di(p-phenylene)di(2-methyl acrylate) grafted modified keratin.The lignin-based conductive eutectic gel has excellent strain sensing performance, can be used for monitoring the movement of different parts of a human body and personal health, and has excellent adhesion performance and can be stably combined with fitness equipment.

Description

Technical Field

[0001] This invention relates to the field of smart soft materials technology, specifically to a lignin-based conductive eutectic gel, its preparation method, and its application. Background Technology

[0002] Hydrogels are polymers with a three-dimensional network structure composed of hydrophilic segments, exhibiting outstanding conductivity, flexibility, biomimetic structure, biocompatibility, and responsiveness to electrical signals. Hydrogel-based sensors can convert chemical or biological signals into measurable electrical signals, showing broad application prospects in water treatment, environmental monitoring, biomedicine, and food safety. The application of hydrogels in flexible wearable sensors is constantly expanding, covering multiple fields such as strain, pressure, temperature, optical, and acoustic sensors. In recent years, flexible wearable sensing systems based on hydrogel materials have demonstrated unique research value in the development of intelligent fitness equipment due to their excellent biocompatibility and mechanical adaptability. By integrating flexible hydrogel sensors with exercise equipment, dynamic capture of human biomechanical parameters during exercise can be achieved, providing crucial data support for posture correction, training load optimization, and sports injury early warning. In particular, the construction of a pressure sensing network at the foot-machine interface can analyze the dynamic characteristics of foot pressure distribution during exercise in real time, which is of great significance for balance assessment—this parameter has been proven to be an important predictive indicator of strength training imbalance, the risk of equipment use in the elderly, and the recovery of motor function in rehabilitation patients. These data are primarily obtained through wearable pressure monitoring devices, which need to be capable of detecting changes in pressure information in real time, accurately, sensitively, and reliably. However, the polymer networks of current traditional conductive hydrogels generally suffer from poor mechanical properties, fragility, and poor environmental tolerance, which reduces the service life and application value of these materials. Summary of the Invention

[0003] To overcome the shortcomings of the existing technology, the present invention provides a lignin-based conductive eutectic gel, its preparation method and application. The conductive eutectic gel is a hydrogel network copolymerized from SBMA, modified keratin, acrylic acid, crosslinking agent and sodium lignin sulfonate, and a deep eutectic solvent is added for metal coordination to construct secondary dynamic crosslinking points outside the covalent network, thereby endowing the gel with excellent self-healing properties, energy dissipation ability and fatigue resistance.

[0004] The purpose of this invention is to provide a lignin-based conductive eutectic gel, its preparation method, and its applications.

[0005] This invention is achieved through the following technical solution:

[0006] A lignin-based conductive eutectic gel, comprising, by weight, the following components: 20-50 parts polymerizable monomer, 0.01-0.2 parts crosslinking agent, 0.01-0.15 parts sodium lignin sulfonate, 3-6 parts modified keratin, 0.1-1 parts initiator, 50-90 parts deep eutectic solvent, and 50-100 parts water; wherein the polymerizable monomer is acrylic acid and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA), and the modified keratin is polyethylene glycol-based bi-terminal crosslinking monomer and disulfide di(p-phenylene)di(2-methacrylate) grafted modified keratin.

[0007] In one specific embodiment, the polyethylene glycol-based dual-end crosslinking monomer is at least one of polyethylene glycol diacrylate or polyethylene glycol dimethacrylate, and the structural formula of the disulfide di(p-phenylene)di(2-methacrylate) is shown in Formula 1:

[0008]

[0009] In one specific embodiment, the preparation of the modified keratin includes the following steps:

[0010] S1. Pure keratin is extracted from feathers and hair using urea as a solvent and L-cysteine ​​as a reducing agent through a swelling-reduction method.

[0011] S2. Using tris(2-carbonylethyl)phosphohydrochloride solution as a reducing agent, the disulfide bonds of keratin are reduced to thiol groups, and then polyethylene glycol-based double-ended crosslinking monomers, disulfide di(p-phenylene)di(2-methacrylate) and initiator are added for graft modification to obtain modified keratin.

[0012] In one specific embodiment, the amount of reducing solution added in step S2 is 80wt% to 100wt% of the keratin content, and the amount of polyethylene glycol-based double-ended crosslinking monomer and disulfide di(p-phenylene) di(2-methacrylate) added is 60wt% to 100wt% of the keratin content.

[0013] Keratin molecules are three-dimensional network proteins formed by various amino acids through disulfide bonds, peptide bonds, hydrogen bonds, etc. Their high degree of cross-linking makes keratin insoluble in water, salt solutions, dilute acids, or dilute alkalis, exhibiting extremely strong resistance. This invention uses polyethylene glycol-based bi-terminal cross-linked hydrophilic monomers to modify keratin, improving its solubility. Simultaneously, disulfide di(p-phenylene)di(2-methacrylate) is added to replenish the disulfide bonds reduced and consumed during keratin modification, maintaining the macromolecular structure and film-forming properties of keratin. Furthermore, the alkenyl groups not completely consumed in the modified keratin can be polymerized with polymerizable monomers, ensuring successful integration of the modified keratin and enhancing the cross-linking density of the hydrogel cross-linking network.

[0014] In one specific embodiment, the mass ratio of acrylic acid to [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide is (4-6):1, and the mass ratio of polyethylene glycol-based dual-end crosslinking monomer to disulfide di(p-phenylene)di(2-methacrylate) is (5-10):1.

[0015] In one specific embodiment, the initiator is selected from at least one of potassium persulfate, ammonium persulfate, and sodium sulfite; the crosslinking agent is at least one of N,N'-methylenebisacrylamide, bisacrylamide, polyethylene glycol diacrylate, or polyethylene glycol dimethacrylate; and the deep eutectic solvent is an ethylene glycol solution of ZnCl2 with a molar ratio of 1:(5-8).

[0016] Another objective of this invention is to protect a method for preparing a lignin-based conductive eutectic gel, comprising the following steps: mixing a polymerizable monomer, a crosslinking agent, sodium lignin sulfonate, modified keratin, an initiator, a deep eutectic solvent, and pure water to obtain a prepolymer solution; filling the prepolymer solution into a mold, ultrasonically stirring it vigorously, placing it in a vacuum drying oven, and heating it at 70–90°C for 30–60 min to obtain a lignin-based conductive eutectic gel.

[0017] Another object of the present invention is to protect the application of the lignin-based conductive eutectic gel in sensors, biomedicine and flexible electronics.

[0018] Specifically, the conductive eutectic gel monitors human movement by measuring changes in the peak value and shape of the electrical signal.

[0019] Beneficial effects

[0020] This invention provides a lignin-based conductive eutectic gel, its preparation method, and its application. The conductive eutectic gel is a hydrogel network copolymerized from SBMA, modified keratin, acrylic acid, a crosslinking agent, and sodium lignin sulfonate, with metal coordination achieved by adding a deep eutectic solvent. SBMA is an amphoteric monomer, with stable quaternary ammonium cations and sulfonate anions simultaneously on its chain segments. This inherent amphoteric characteristic forms a highly hydrated ionic network in the aqueous phase and can react with the partially deprotonated carboxylic acid groups of AA and Zn in the deep eutectic solvent. 2+ Ions, through interactions such as metal coordination bonds, significantly enhance the mechanical strength and resistance to volume expansion of the gel. The Zn provided by the deep eutectic solvent... 2+Ions can reversibly coordinate with the carboxyl, hydroxyl, and amide groups in modified keratin molecules, constructing secondary dynamic cross-linking points outside the covalent network, endowing the gel with excellent self-healing properties, energy dissipation capacity, and fatigue resistance. Modified keratin is rich in hydroxyl and amide groups, forming a dense hydrogen bond network between the polymer matrix and water molecules. These non-covalent interactions can break sequentially under external force loading and partially recombine after unloading, achieving good elastic recovery. The deep eutectic solvent not only improves the solubility of each precursor, ensuring uniform polymerization, but its high osmotic pressure characteristics also regulate the gel pore structure and water content, giving the material both excellent compressive stability and controllable environmental stability. Attached Figure Description

[0021] Figure 1 Infrared spectra of polymerizable monomers, modified keratin, and conductive cocrystal gel;

[0022] Figure 2 This is a surface morphology diagram of the conductive eutectic gel of Example 1;

[0023] Figure 3 The image shows the adhesion performance of the conductive eutectic gel of Example 1 to different substrates.

[0024] Figure 4 The images show the antifreeze and anti-drying effects of the conductive eutectic gel of Example 1 at room temperature and -20°C.

[0025] Figure 5 The graph shows the resistance change of the conductive eutectic gel in Example 1 under different strains and frequencies during cyclic stretching / releasing. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Unless otherwise specified, the experimental methods used in the embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0028] The raw materials used in the examples and comparative examples are described below:

[0029] Polymerizable monomer 1: Acrylic acid, 99%, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0030] Polymerizable monomer 2: [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide; 98%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0031] Crosslinking agent: N,N-methylenebisacrylamide, 2% solution, purchased from Sigma-Aldrich;

[0032] Sodium lignosulfonate: purchased from Shanghai Maclean Biochemical Technology Co., Ltd.;

[0033] Duck feathers: Hangzhou Yongfeng Down Products Co., Ltd.;

[0034] 4,4'-Dihydroxydiphenyl disulfide: 98%, purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0035] Methacrylamide chloride: 95%, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0036] Initiator: Ammonium persulfate, 99.99%, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0037] Deep eutectic solvent: Add 2g of zinc chloride to 5.47g of ethylene glycol, place in a 70-75℃ hot water bath and stir until dissolved to prepare a deep eutectic solvent with a molar ratio of ethylene glycol to zinc chloride of 6:1;

[0038] Polyethylene glycol-based double-ended crosslinking monomer: polyethylene glycol dimethacrylate; Mn700, Shanghai Maclean Biochemical Technology Co., Ltd.

[0039] Disulfide di(p-phenylene)di(2-methacrylate): Prepared in-house, the preparation method is as follows: Under anhydrous and oxygen-free nitrogen atmosphere, 0.1 mol of 4,4'-dihydroxydiphenyl disulfide and 0.2 mol of triethylamine were dissolved in chloroform, and 0.2 mol of methacryloyl chloride was added dropwise under ice bath conditions. The temperature was slowly raised to 80°C and stirred for 6 hours until the reaction was completed. After cooling, the mixture was quenched with ice water. The organic phase was washed with 5% NaHCO3 solution, then washed with water until neutral, concentrated under reduced pressure, and recrystallized with n-heptane / acetone mixed solvent to obtain disulfide di(p-phenylene)di(2-methacrylate).

[0040] Modified keratin 1: Homemade, preparation method as follows:

[0041] S1. Using duck feathers as raw material, wash and dry them, then pulverize them to 30 mesh using a pulverizer. Use an 8 mol / L urea solution as solvent (liquid ratio 1:30), add 10 wt.% L-cysteine ​​reducing agent (equivalent to the weight of the duck feathers), and adjust the pH of the system to 9 with a 5.0% sodium hydroxide solution. Weigh the pulverized duck feathers and add them to the prepared extraction solution. React at 85℃ for 7 hours to obtain a mixture. Centrifuge the obtained mixture and pour the solution into a dialysis bag for dialysis for 2-3 days until the pH of the keratin solution in the dialysis bag is neutral, obtaining a dialyzed keratin solution. Adjust the dialyzed keratin solution to approximately the isoelectric point of keratin (4.5-5.5) with a 1.0% acetic acid solution to precipitate the keratin. Collect the precipitated keratin and freeze-dry it to obtain a solid keratin powder.

[0042] S2. Prepare a 50 mmol / L reducing agent stock solution by dissolving tris(2-carbonylethyl) phosphate hydrochloride in an ethanol-water solution with a volume ratio of 1:1. Weigh 0.5 g of keratin and add it to the reducing agent stock solution, which is equivalent to 80 wt% of the keratin mass. Adjust the pH to 7 with a Na2CO3 / NaHCO3 buffer solution (pH > 9) and reduce at 20 °C for 4 h.

[0043] S3. Under nitrogen protection, an initiator equivalent to 5 wt% of the keratin weight and polyethylene glycol-based double-ended crosslinking monomer and disulfide di(p-phenylene)di(2-methacrylate) equivalent to 60 wt% of the keratin weight were added to the reduced keratin. The mass ratio of polyethylene glycol-based double-ended crosslinking monomer to disulfide di(p-phenylene)di(2-methacrylate) was 10:1. The pH of the system was adjusted to 7, and the reduced keratin was grafted at 20°C for 4 hours to obtain modified keratin. The reaction solution was centrifuged and the solution was poured into a dialysis bag for dialysis for 2-3 days to obtain modified keratin solution 1.

[0044] Modified keratin 2: self-made. The preparation method is different from that of modified keratin 1 in that the mass ratio of polyethylene glycol-based double-ended crosslinking monomer and disulfide di(p-phenylene) di(2-methacrylate) is 5:1.

[0045] Modified keratin 3: Homemade, the preparation method is the same as that of modified keratin 1, except that polyethylene glycol-based double-ended crosslinking monomers are not added;

[0046] Modified keratin 4: Homemade, the preparation method is the same as that of modified keratin 1, except that disulfide di(p-phenylene) di(2-methacrylate) is not added;

[0047] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this invention are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0048] Examples and Comparative Examples

[0049] A lignin-based conductive eutectic gel, the weight proportions of which are shown in Table 1, is prepared as follows:

[0050] 1) Mix polymerizable monomers, crosslinking agents, sodium lignosulfonate, modified keratin, initiator, deep eutectic solvent and pure water to obtain a prepolymer solution; defoam by ultrasonication for 10 min, fill the prepolymer solution into a mold, stir vigorously by ultrasonication, place in a vacuum drying oven, and heat at 70°C for 30 min to obtain a lignin-based conductive eutectic gel.

[0051] Table 1. Lignin-based conductive eutectic gels (parts by weight)

[0052]

[0053]

[0054] The lignin-based conductive eutectic gels prepared in the examples and comparative examples were subjected to the following performance tests, and the results are shown in the figure and table 2, respectively.

[0055] 1. Infrared Spectroscopy: Raw materials and conductive eutectic gel were mixed with potassium bromide at a ratio of 1:50 to prepare a pellet. An Avatar 380 spectrometer was used for this test. Before testing, a blank background was scanned, followed by the placement of the pellet for measurement. The scanning range was 500-4000 cm⁻¹. -1 The result is as follows Figure 1 As shown.

[0056] 2. Surface Microstructure: The surface microstructure of the conductive eutectic gel obtained in Example 1 was examined using field emission scanning electron microscopy (SEM). The conductive eutectic gel was frozen in liquid nitrogen and fractured, then dried in a freeze dryer. Finally, the surface microstructure of the eutectic gel was observed under a field emission scanning electron microscope (SEM). The results are as follows: Figure 2 As shown.

[0057] 3. Tensile strength and elongation at break: A universal testing machine was used to test the tensile strength and tensile properties of the eutectic conductive eutectic gel. The two ends of the eutectic gel were neatly clamped on the tensile testing machine, the tensile speed was set to 50 mm / min, and the stress-strain curves were recorded in real time until the eutectic gel broke.

[0058] 4. Compression performance: Conductive eutectic gel with a diameter of 20 mm and a thickness of 3 mm was prepared. The compression performance of the conductive eutectic gel was tested using a universal testing machine. The eutectic gel was neatly placed on the compression fixture of the tensile testing machine. The compression conditions were set to a compression speed of 20 mm / min and a compression rate of 90%. The stress and strain curves were recorded in real time during the process.

[0059] 5. Conductivity: A 5mm wide conductive copper foil was neatly attached to both ends of the conductive eutectic gel. The sensor was then connected to the electrochemical workstation using conductive copper tape. The impedance information of the conductive eutectic gel at different AC frequencies was recorded in real time. Finally, the conductivity σ was calculated using the following formula. Where σ is the conductivity, L is the length, S is the cross-sectional area, and R is the material resistance.

[0060] 6. Adhesion Properties: A conductive eutectic gel with a length of 40 mm × width of 40 mm × thickness of 2 mm was prepared. Eight different adhesion substrates were selected, including glass, wood, plastic, PTFE, metal, silicone, ceramic, and skin. The prepared conductive eutectic gel was then smoothly adhered to one of the substrates, and glass was then adhered to the other side of the eutectic gel, avoiding air bubbles between the material bonding surfaces. Optical images of the gel adhering to different substrates were recorded, such as... Figure 3 As shown.

[0061] 7. Freeze-thaw resistance: Conductive eutectic gels with a length of 50 mm × width of 10 mm × thickness of 2 mm were prepared and incubated at -20℃ for 24 h. The freeze-thaw resistance of the gel was determined by observing whether crystallization occurred and by comparing its flexibility with that under room temperature conditions. Simultaneously, the conductive eutectic gels were placed under open room temperature conditions, and the mass change at 0 h and 72 h was compared to test the drying resistance of the eutectic gels. The results are as follows: Figure 4 As shown.

[0062] 8. Strain Sensing Performance: A universal testing machine and a multimeter were used together to test the strain sensing performance of the conductive eutectic gel sensor. A 5mm wide conductive copper tape was neatly attached to both ends of the conductive eutectic gel. The gel, along with the attached conductive copper tape, was then clamped onto a tensile testing machine, with the conductive copper tape extended. The sensor was then connected to the multimeter using the conductive copper tape. The tensile testing machine subjected the sensor to cyclic stretching / releasing at different strains and frequencies, and the resistance change signal of the sensor was recorded in real time during this process. Figure 5 As shown.

[0063] Table 2 Performance test results of conductive eutectic gel

[0064]

[0065] From the appendix Figure 1As can be seen in the SBMA spectrum, the peak appears at 1722 cm⁻¹. -1 Attributable to the stretching vibration of C=O on the ester carbonyl group, the peak occurs at 1185 cm⁻¹. -1 and 1045cm -1 Attributable to the vibration of the sulfonic acid group, the peak appears at 1643 cm⁻¹. -1 This is attributed to the C=C vibration. In the spectrum of modified keratin, the peak appears at 3292 cm⁻¹. -1 Attributable to the stretching vibrations of NH on the amide group and the stretching vibrations of CO-NH, the peak occurs at 2958 cm⁻¹. -1 The stretching vibrations, attributed to CH2, peak at 1652 cm⁻¹. -1 Attributable to the stretching vibration of C=O on the amide group, the peak occurs at 1528 cm⁻¹. -1 It belongs to the NH bending vibration and CN stretching vibration, with the peak value appearing at 1041 cm. -1 This is attributed to the stretching vibration of COC. In the AA spectrum, the peak is at 3502 cm⁻¹. -1 and 3072cm -1 The stretching vibrations attributed to -OH and -CH peak at 1630 cm⁻¹. -1 and 1704cm -1 These vibrations are attributed to C=C and C=O vibrations, respectively. In the conductive eutectic gel, the peak of the C=C vibration is significantly reduced, and the characteristic groups of the three monomers are present, proving that SBMA, AA, and modified keratin have been successfully copolymerized.

[0066] From the appendix Figure 2 It can be seen that the conductive eutectic gel has a porous structure, which provides excellent channels for ion transport and further provides a good foundation for the conductivity of the conductive eutectic gel.

[0067] From the appendix Figure 3 As can be seen, conductive eutectic gels can adhere to the surfaces of various substrates at room temperature and withstand a certain weight without peeling off, such as plastics, glass, wood, and skin. This is based on the fact that the abundant carboxyl, amino, and hydroxyl groups on the surface of the hydrogel can interact with the physical interactions between materials through hydrogen bonds, ion-dipole interactions, and metal complexation. The excellent adhesion properties provide a foundation for the stable acquisition of sensing electrical signals.

[0068] From the appendix Figure 4 It can be seen that the conductive eutectic gel placed in a -20℃ environment does not exhibit crystallization and maintains the same flexibility as in a normal temperature environment, confirming that the eutectic gel has excellent antifreeze properties. Furthermore, the eutectic gel did not show significant mass change after being placed in an open environment for 72 hours, confirming that the eutectic gel has excellent anti-drying properties.

[0069] From the appendix Figure 5It can be seen that when the eutectic gel sensor is subjected to cyclic stretching / release and compression / release under different strains using a universal testing machine, the peak value and peak shape of the electrical signal generated under the same strain conditions are similar, which confirms that the sensing performance of the conductive eutectic gel has excellent stability, which is a very important performance characteristic for flexible sensor devices.

[0070] As can be seen from Table 2, conductive eutectic gel has good mechanical and electrical properties, which can provide a basis for monitoring changes in electrical signals during various human movements.

[0071] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A lignin-based conductive eutectic gel, characterized in that, By weight, the raw materials include the following components: 20-50 parts of polymerizable monomer, 0.01-0.2 parts of crosslinking agent, 0.01-0.15 parts of sodium lignosulfonate, 3-6 parts of modified keratin, 0.1-1 parts of initiator, 50-90 parts of deep eutectic solvent, and 50-100 parts of water; wherein the polymerizable monomer is acrylic acid and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide, and the modified keratin is polyethylene glycol-based double-end crosslinking monomer and disulfide di(p-phenylene)di(2-methacrylate) grafted modified keratin.

2. The lignin-based conductive eutectic gel of claim 1, wherein, The polyethylene glycol-based dual-end crosslinking monomer is at least one of polyethylene glycol diacrylate or polyethylene glycol dimethacrylate, and the structural formula of the disulfide di(p-phenylene)di(2-methacrylate) is shown in Formula 1: Formula 1.

3. The lignin-based conductive eutectic gel of claim 1, wherein, The preparation of the modified keratin includes the following steps: S1. Pure keratin is extracted from feathers and hair using urea as a solvent and L-cysteine ​​as a reducing agent through a swelling-reduction method. S2. Using tris(2-carbonylethyl)phosphohydrochloride solution as a reducing agent, the disulfide bonds of keratin are reduced to thiol groups, and then polyethylene glycol-based double-ended crosslinking monomers, disulfide di(p-phenylene)di(2-methacrylate) and initiator are added for graft modification to obtain modified keratin.

4. The lignin-based conductive eutectic gel of claim 3, wherein, The amount of reducing solution added in step S2 is 80wt%~100wt% of keratin, and the amount of polyethylene glycol-based double-ended crosslinking monomer and disulfide di(p-phenylene) di(2-methacrylate) added is 60wt%~100wt% of keratin.

5. The lignin-based conductive eutectic gel of claim 1, wherein, The mass ratio of acrylic acid to [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propionic)ammonium hydroxide is (4~6):1, and the mass ratio of polyethylene glycol-based double-end crosslinking monomer to disulfide di(p-phenylene)di(2-methacrylate) is (5~10):

1.

6. The lignin-based conductive eutectic gel of claim 1, wherein, The initiator is selected from at least one of potassium persulfate, ammonium persulfate, and sodium sulfite; the crosslinking agent is at least one of N,N'-methylenebisacrylamide, bisacrylamide, polyethylene glycol diacrylate, or polyethylene glycol dimethacrylate; the deep eutectic solvent is an ethylene glycol solution of ZnCl2 with a molar ratio of 1:(5~8).

7. The method for preparing lignin-based conductive eutectic gel as described in claim 1, characterized in that, The process includes the following steps: mixing polymerizable monomers, crosslinking agents, sodium lignosulfonate, modified keratin, initiators, deep eutectic solvents, and pure water to obtain a prepolymer solution; filling the prepolymer solution into a mold, ultrasonically stirring it, placing it in a vacuum drying oven, and heating it at 70~90℃ for 30~60 min to obtain a lignin-based conductive eutectic gel.

8. The application of the lignin-based conductive eutectic gel as described in any one of claims 1 to 7 for non-disease diagnostic and therapeutic purposes in sensors, biomedicine, and flexible electronics.

9. Use according to claim 8, wherein the compound is ###0002### The conductive eutectic gel monitors human movement by measuring changes in the peak value and shape of electrical signals.

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