Ultra-fast preparation method of room-temperature self-agglutination and wide-temperature strain conductive eutectic gel, prepared gel and application

Abstract

The invention belongs to the technical field of intelligent soft materials, and discloses a method for ultra-rapidly preparing room-temperature self-agglutination and wide-temperature strain conductive eutectic gel, the prepared gel and application. The eutectic gel is composed of gelatin, LS-coated Ag, a polymer monomer, DES, a cross-linking agent, an initiator and water. Strain sensing related tests prove that the gel has excellent sensitivity and strain sensing performance, and has application potential in the fields of high and low temperature severe environment monitoring, human health monitoring and motion monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent soft materials, and particularly relates to a method for ultra-rapid preparation of a room-temperature self-polymerizing and wide-temperature strain-conductive eutectic gel, the prepared gel, and applications thereof. Background Art

[0002] Hydrogels are three-dimensional network structure materials composed of water and natural or synthetic polymer materials, with high water content, adjustable physical and chemical properties, and good biocompatibility, and are widely used in fields such as flexible electronics, environmental engineering, and biomedicine. Especially in the fields of flexible electronics and intelligent sensing, hydrogels are used in scenarios such as strain sensors and wearable devices due to their excellent mechanical properties and conductivity. However, the preparation of traditional hydrogels usually relies on external heat sources or ultraviolet light, and the process is complex and time-consuming. For example, the gelation of acrylamide-based hydrogels may take from several minutes to several hours, severely limiting their large-scale application. In addition, the strain sensing range and temperature adaptability of most conductive hydrogels are limited, and it is difficult to work stably in extreme environments.

[0003] In recent years, the rapid development of flexible electronics and intelligent sensing technologies has put forward higher requirements for hydrogels, especially rapid response and wide-temperature-range strain-conductive properties. Traditional conductive hydrogels usually need to add conductive fillers (such as carbon nanotubes, metal particles, etc.), which not only increases the cost but may also affect the mechanical properties of the materials. At the same time, the performance of existing hydrogels at extreme temperatures is insufficient, making it difficult to meet the application requirements in complex environments. Therefore, developing a hydrogel preparation method that does not require an external heat source, can self-polymerize rapidly, and has wide-temperature-range strain-conductive properties has important practical significance and application value. Summary of the Invention

[0004] In order to overcome the disadvantages and deficiencies existing in the prior art, the primary object of the present invention is to provide a method for ultra-rapid preparation of a room-temperature self-polymerizing and wide-temperature strain-conductive eutectic gel; this method constructs a gelatin-acrylic acid-sodium lignosulfonate@silver nanoparticles-deep eutectic solvent (GA-LS@Ag-DES) hydrogel through reasonable molecular design. The double-network structure composed of the polymer monomers acrylic acid (AA) and gelatin provides good mechanical properties for the eutectic gel and can also improve the adhesion performance. Sodium lignosulfonate@silver nanoparticles (LS@Ag) can improve the adhesion performance, photothermal conversion efficiency, and photothermal antibacterial ability of the gel system. The eutectic conductive agent can improve the antifreeze and water retention performance of the hydrogel and the strain-sensing conductive performance of human joint movement; the entire preparation process does not require an external heat source or ultraviolet irradiation, and the solution can form the required hydrogel in 3 s - 30 min.

[0005] Another object of the present invention is to provide a room-temperature self-polymerizing and wide-temperature strain-conductive eutectic gel prepared by the above method.

[0006] Another object of the present invention is to provide an application of the above room-temperature self-polymerizing and wide-temperature strain-conductive eutectic gel.

[0007] The object of the present invention is achieved by the following technical solutions: A method for ultra-rapidly preparing a room-temperature self-polymerizing and wide-temperature strain-conductive eutectic gel, comprising the following operating steps: (1) Dissolve lignin in an NaOH solution to obtain an aqueous lignin solution; add ammonia water to an AgNO 3 aqueous solution to obtain a solution containing [Ag(NH 3 ) 2 + complex; drop the aqueous lignin solution into the solution containing [Ag(NH 3 ) 2 + complex solution, stir and react under light-shielded conditions to generate a solution containing silver nanoparticles encapsulated by sodium lignosulfonate (LS@Ag); dialyze the obtained solution containing silver nanoparticles encapsulated by sodium lignosulfonate, and then freeze-dry to obtain a freeze-dried powder of silver nanoparticles encapsulated by sodium lignosulfonate; then prepare an aqueous solution of silver nanoparticles encapsulated by sodium lignosulfonate from the freeze-dried powder; (2) Add zinc chloride to ethylene glycol, stir and mix evenly in a water bath at 80 °C for 2 h to obtain a clear and transparent deep eutectic solvent, wherein the molar ratio of zinc chloride to ethylene glycol is 1:3; (3) Add gelatin to deionized water and place it in an oven for 5 min until the gelatin is completely dissolved to obtain a gelatin aqueous solution; (4) Using a one-pot mixing method, add the aqueous solution of silver nanoparticles encapsulated by sodium lignosulfonate obtained in step (1), the gelatin aqueous solution obtained in step (3), the polymer monomer, the crosslinking agent N,N'-methylenebisacrylamide, and the initiator to the deep eutectic solvent obtained in step (2), mix evenly to obtain a gel prepolymer solution, and the concentration of the deep eutectic solvent in the gel prepolymer solution is 30-35 wt%; fill the gel prepolymer solution into a mold, place it at room temperature for self-polymerization, and then place it in an oven for 1-2 h to obtain a room-temperature self-polymerizing and wide-temperature strain-conductive eutectic gel GA-LS@Ag-DES.

[0008] The pH value of the NaOH solution in step (1) is 9-12; the concentration of the aqueous lignin solution is 25-35 mg·mL -1 ; the concentration of the ammonia water is 4 mol / L - 6 mol / L; the concentration of the AgNO 3 aqueous solution is 15-25 mg·mL -1 ​​; The solution concentration of the complex containing [Ag(NH 3 ) 2 + is 0.01 - 0.06 mol / L; The volume ratio of the aqueous lignin solution to the solution of the complex containing [Ag(NH 3 ) 2 + is 1:1; The temperature of the stirring reaction is 20 - 40 °C, the time of the stirring reaction is 12 - 36 h, and the rotation speed of the stirring is 300 - 800 rpm; The time of dialysis is 1 - 2 weeks; The concentration of the aqueous solution of silver nanoparticles wrapped with sodium lignosulfonate is 5 - 15 mg·mL -1 .

[0009] In step (3), the temperature of the oven is 50 - 70 °C; In step (4), the polymer monomer is one of acrylamide and acrylic acid; The initiator is potassium persulfate or ammonium persulfate.

[0010] In step (4), the dosage of silver nanoparticles wrapped with sodium lignosulfonate in the aqueous solution of silver nanoparticles wrapped with sodium lignosulfonate is 0.05 - 0.15 wt% of the gel prepolymer solution; The dosage of the polymer monomer is 20 - 25 wt% of the gel prepolymer solution; The dosage of the crosslinking agent is 0.01 - 0.05 wt% of the gel prepolymer solution; The dosage of the initiator is 0.5 - 0.9 wt% of the gel prepolymer solution; The dosage of gelatin in the aqueous gelatin solution is 2 - 5 wt% of the gel prepolymer solution, preferably 2.30292 wt%.

[0011] In step (4), the mold is a square or rectangular polytetrafluoroethylene or silicone mold; Filling the prepolymer solution into the mold is to control the thickness of the finally obtained room-temperature self-polymerizing and wide-temperature strain conductive eutectic gel by controlling the addition amount of the prepolymer solution.

[0012] In step (4), the room temperature condition is 10 - 30 °C, and the time of placing under the room temperature condition is 3 s - 30 min; The temperature of the oven is set at 40 - 55 °C, and the time of placing in the oven is 1 - 2 h.

[0013] A room-temperature self-polymerizing and wide-temperature strain conductive eutectic gel prepared by the above method, and the conductivity of the eutectic gel is as high as 0.6 S / m, and stable electrical signals can be obtained in the range of -40 °C - 60 °C.

[0014] Application of the above room-temperature self-polymerizing and wide-temperature strain conductive eutectic gel as a conductor in a sensor.

[0015] Application of the above room-temperature self-polymerizing and wide-temperature strain conductive eutectic gel in realizing human motion monitoring in wearable devices, medical health monitoring devices or human-computer interaction devices.​​

[0016] Principle of the present invention: The present invention regulates the speed of free radical initiation by regulating the lignin phenol-quinone balance. The sodium lignosulfonate-coated silver nanoparticles obtained during the preparation process can generate more free radicals. Coupled with the zinc ions used in the preparation, which can complex with polymer monomers such as AA, the polymerization speed can be regulated, greatly accelerating the polymerization rate, and achieving an ultra-fast preparation at room temperature within 3 s - 30 min. Each raw material of the present invention is rationally matched and synergistically functions. The obtained eutectic gel has a stable structure, water is not easily volatilized, and various properties are stable and superior, with high conductivity and high sensitivity, and stable electrical signals can be obtained within a wide temperature range of -40°C - 60°C.

[0017] The present invention has the following advantages and beneficial effects compared with the prior art: (1) The present invention ultra-fast prepares a room-temperature self-polymerizing and wide-temperature strain-conductive eutectic gel. The conductive filler used is a eutectic conductive agent, which has excellent conductivity, stability, and durability; the finally prepared eutectic gel has a high conductivity of 0.6 S / m, and has a wide application temperature range, and stable electrical signals can be obtained at -40°C - 60°C.

[0018] (2) The conductive eutectic gel prepared by the present invention with room-temperature self-polymerization and wide-temperature strain sensing has high sensitivity, a wide strain monitoring range, a wide application temperature range, good cycle stability when used as a flexible sensor, and the conductive filler is green and non-toxic. The preparation process is simple and the cost is low, and it has great potential in the fields of high and low temperature harsh environment monitoring, human health monitoring, sports monitoring, etc.

[0019] (3) The eutectic gel of the present invention has the characteristic of room-temperature self-polymerization. It can self-polymerize into a gel within 3 s - 30 min after adding an initiator, which can achieve rapid preparation and also makes up for the defect of the long preparation time required by existing wide-temperature conductive materials. Description of the drawings

[0020] Figure 1 It is the infrared spectra of each raw material and product. Among them, A is the infrared spectrum of the deep eutectic solvent (DES) and its components, zinc chloride conductive agent (ZnCl 2 ) and ethylene glycol (EG); B is the infrared spectrum of gelatin (Gelatin), acrylic acid (AA) and their GA-LS@Ag-DES eutectic gel; C is the infrared spectrum of lignin (LS) and LS@Ag.

[0021] Figure 2 It is the fracture tensile curves of GA-LS@Ag-DES eutectic gels with different LS@Ag contents.

[0022] Figure 3The adhesion strength of the GA-LS@Ag-DES eutectic gel to different substrates.

[0023] Figure 4 The strain sensing sensitivity curve of the GA-LS@Ag-DES eutectic gel.

[0024] Figure 5 Examples of human motion monitoring signals, where A is the monitoring signal of the GA-LS@Ag-DES eutectic gel attached to the finger at different bending angles of the finger, and B is the monitoring signal of the GA-LS@Ag-DES eutectic gel attached to the wrist at different bending angles of the wrist.

[0025] Figure 6 The relative resistance change of the GA-LS@Ag-DES eutectic gel at different temperatures. Detailed implementation manners

[0026] The following further illustrates the technical solution of the present invention through specific implementation manners. The following examples are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0027] The preparation process of the super-fast preparation, wide-temperature strain sensing and highly sensitive conductive eutectic gel in the following examples is carried out according to the following operation steps: Step 1: Dissolve lignin in a NaOH solution with a pH value of 9 - 12 to obtain an aqueous lignin solution with a concentration of 25 - 35 mg·mL -1 ; Then, add NH 3 ·OH solution (4 - 6 mol / L) to an aqueous AgNO -1 solution with a concentration of 15 - 25 mg·mL 3 to obtain a solution containing a complex with a concentration of 0.01 - 0.06 mol / L [Ag(NH 3 ) 2 + ; Finally, drop the aqueous lignin solution into the solution containing the [Ag(NH 3 ) 2 + complex. The volume ratio of the aqueous lignin solution to the solution containing the [Ag(NH 3 ) 2 + complex is 1:1; Keep it in the dark and stir at a temperature of 20 - 40 °C at 300 - 800 rpm for 12 - 36 h to generate a solution containing LS@Ag (sodium lignosulfonate-coated silver nanoparticles); Dialyze the obtained solution containing LS@Ag for 1 - 2 weeks and then freeze-dry it to obtain LS@Ag freeze-dried powder; Then prepare the LS@Ag freeze-dried powder into an aqueous LS@Ag solution with a concentration of 5 - 15 mg·mLl -1 .​​​ Step 2: Add zinc chloride to ethylene glycol and stir in a water bath at 80 °C for 2 h to mix evenly, obtaining a clear and transparent deep eutectic solvent. The molar ratio of zinc chloride to ethylene glycol is 1:3; Step 3: Add gelatin to deionized water and place it in an oven at 50 - 70 °C for 5 min until all the gelatin is dissolved to obtain a gelatin aqueous solution; Step 4: Using a one-pot mixing method, add the LS@Ag aqueous solution obtained in Step 1, the gelatin aqueous solution obtained in Step 3, polymer monomers, crosslinking agents, and initiators to the deep eutectic solvent obtained in Step 2, and mix evenly to obtain a gel prepolymer solution. The amount of sodium lignosulfonate-coated silver nanoparticles in the LS@Ag aqueous solution is 0.05 - 0.15 wt% of the gel prepolymer solution, the amount of polymer monomers is 20 - 25 wt% of the gel prepolymer solution, the amount of crosslinking agent is 0.01 - 0.05 wt% of the gel prepolymer solution, the amount of initiator is 0.5 - 0.9 wt% of the gel prepolymer solution, and the amount of gelatin in the gelatin aqueous solution is 2 - 5 wt% of the gel prepolymer solution, preferably 2.30292 wt%; the concentration of the deep eutectic solvent in the gel prepolymer solution is 30 - 35 wt%; fill the gel prepolymer solution into a polytetrafluoroethylene or silica gel mold, control the thickness of the finally obtained gel patch by controlling the amount of prepolymer solution added, and place it at room temperature of 10 - 30 °C for 3 s - 30 min for self-polymerization to obtain a self-polymerized gel; Step 5: Place the obtained self-polymerized gel in an oven at 40 - 55 °C for 1 - 2 h to obtain a room-temperature self-polymerized and wide-temperature strain conductive eutectic gel (GA-LS@Ag-DES eutectic gel).

[0028] Example 1 This example provides a preparation method of GA-LS@Ag-DES eutectic gel, including the following operation steps: Step 1: Dissolve lignin in a NaOH solution with a pH value of 10 to obtain a lignin aqueous solution of 30 mg·mL -1 ; then, add NH 3 ·OH solution (5 mol / L) to a 20 mg·mL -1 AgNO 3 aqueous solution to obtain a solution containing a complex with a concentration of 0.059 mol / L [Ag(NH 3 ) 2 + ; finally, drop the lignin aqueous solution into the solution containing [Ag(NH 3 ) 2 + complex. The lignin aqueous solution and the solution containing [Ag(NH 3 ) 2 ​​+ The volume ratio of the complex solution is 1:1; under light-shielded conditions, at a temperature of 30 °C, stir the reaction at 600 rpm for 24 h to generate a solution containing LS@Ag (sodium lignosulfonate-coated silver nanoparticles); dialyze the obtained solution containing LS@Ag for 2 weeks and then freeze-dry it to obtain LS@Ag lyophilized powder; then prepare an aqueous solution of LS@Ag with a concentration of 10 mg·mL -1 of LS@Ag; Step 2: Add zinc chloride (ZnCl 2 ) to ethylene glycol (EG) and stir in a water bath at 80 °C for 2 h to mix evenly to obtain a clear and transparent deep eutectic solvent. The molar ratio of zinc chloride to ethylene glycol is 1:3; Step 3: Add gelatin to deionized water and place it in an oven at 50 °C for 5 min until the gelatin is completely dissolved to obtain a gelatin aqueous solution; Step 4: Using a one-pot mixing method, add the LS@Ag aqueous solution obtained in Step 1, the gelatin aqueous solution obtained in Step 3, the polymer monomer acrylic acid (AA), the crosslinking agent N,N'-methylenebisacrylamide (BIS), and the initiator ammonium persulfate (APS) to the deep eutectic solvent obtained in Step 2. According to the different amounts of the LS@Ag aqueous solution added, add 0.7 mL, 0.9 mL, 1.1 mL, and 1.3 mL of different amounts of the LS@Ag aqueous solution respectively, and mix evenly to obtain four gel prepolymer solutions with different ratios (LS@Ag accounts for 0.08060 wt%, 0.10363 wt%, 0.12666 wt%, and 0.14969 wt% of the total mass of the gel prepolymer solution respectively), which are named LS@Ag 0.7 、LS@Ag 0.9 、LS@Ag 1.1 、LS@Ag 1.3 respectively. Adjust the total mass of the four gel prepolymer solutions with different ratios to 8.6846 g by controlling the amount of the gelatin aqueous solution added. At the same time, the gelatin concentration in the gelatin aqueous solution in Step 2 is different, and the concentration of gelatin in the final gel prepolymer solution is 2.30292 wt%; the polymer monomer acrylic acid (AA) accounts for 24.20376 wt% of the total mass of the gel prepolymer solution, the crosslinking agent N,N'-methylenebisacrylamide (BIS) accounts for 0.04145 wt% of the total mass of the gel prepolymer solution, the initiator ammonium persulfate (APS) accounts for 0.82905 wt% of the total mass of the gel prepolymer solution, and the concentration of the deep eutectic solvent in the gel prepolymer solution is 33.05 wt%; fill the gel prepolymer solutions into polytetrafluoroethylene molds respectively, control the thickness of the final obtained gel patches by controlling the amount of the gel prepolymer solution added, and self-polymerize at room temperature for 3 s - 30 min to obtain four self-polymerized gels with different ratios; ​Step 5: The obtained self-polymerized gels were placed in a 45°C oven for 1 h to obtain four room temperature self-polymerized and wide temperature strain conductive eutectic gels (GA-LS@Ag-DES eutectic gels) with different proportions, named LS@Ag 0.7 Eutectic gel, LS@Ag 0.9 Eutectic gel, LS@Ag 1.1 Eutectic gel, LS@Ag 1.3 Eutectic gel.

[0029] Experimental results: Fourier transform infrared spectrometer was used to analyze the pure substances of each component and LS@Ag 0.9 The eutectic gel was tested. Figure 1 As shown in A, for pure EG, at 3363 cm -1 The peak at 2944 cm represents the -OH stretching vibration; -1 and 2880cm -1 The peak at -CH 2 Symmetric and asymmetric stretching vibrations; 1086 cm -1 and 1041 cm -1 The peaks at 883 cm are the stretching vibration peaks of CC and CO; -1 The peak at -CH 2 Swinging bending vibration; when ZnCl 2 When mixed with EG at a molar ratio of 1:3 to form DES, EG has a peak at 3363 cm -1 The absorption band at 3245 cm-1 broadens and shifts downward to 3245 cm-1. -1 This transformation may be due to the transfer of oxygen electrons to hydrogen bonds, resulting in a change in vibrational state, indicating that EG binds to ZnCl 2 A hydrogen bond structure is formed between -CH 2 From 883cm -1 Down to 879 cm -1 , and it is also proved that EG and ZnCl 2 A hydrogen bond structure is formed between them.

[0030] FTIR spectra of gelatin, acrylic acid monomer (AA) and eutectic gel Figure 1 As shown in B. For gelatin, the characteristic peak is at 3285cm -1 The 1633 cm -1 The peak at 3510 cm represents the stretching vibration of the carbonyl (C=O) in the amide group of the gelatin molecule. -1 and 3070 cm -1 It is attributed to the stretching vibration of -OH and -CH. The peak appears at 1724 cm -1 and 1702 cm-1 They are respectively attributed to the vibrations of C=C and C=O. The peak is at 1432 cm -1 is due to the O-H bending vibration. Compared with the two monomers, the infrared spectrum of the GA-LS@Ag-DES eutectic gel shows that a broad peak of -OH appears at around 3308 cm -1 in the spectrum. The broad peak of -OH appears at around 3308 cm, and the peak at 1713 cm -1 attributed to the double bond of C=C disappears, proving that the C=C double bond polymerizes to form more saturated C-C bonds.

[0031] The FTIR spectra of LS and LS@Ag are as shown in Figure 1 C. In the spectrum of LS, a broad peak characteristic of phenolic hydroxyl appears at 3394 cm -1 , while in the spectrum of LS@Ag, the peaks belonging to phenolic hydroxyl (~3349 cm -1 and ~1248 cm -1 ) weaken, indicating that they are oxidized.

[0032] Comparative Example 1 This example provides a preparation method of GA-LS@Ag-DES eutectic gel. The addition amount of LS@Ag aqueous solution is selected to be 0.9 mL, that is, LS@Ag accounts for 0.10363 wt% of the total mass of the gel prepolymer solution. Other steps are the same as in Example 1, except that the total mass of the gel prepolymer solution obtained in step (4) is adjusted by the addition amount of gelatin aqueous solution to be 8.1846 g, 8.6846 g, and 9.1846 g respectively, where gelatin accounts for 2.44361 wt%, 2.30292 wt%, and 2.17756 wt% of the total mass of the gel prepolymer solution respectively. Finally, three ratios of GA-LS@Ag-DES eutectic gels are prepared and named G 2.44361wt% A-LS@Ag 0.9 eutectic gel, G 2.30292wt% A-LS@Ag 0.9 eutectic gel, G 2.17756wt% A-LS@Ag 0.9 eutectic gel.

[0033] The initial length of the eutectic gel is controlled to be 20 mm. The eutectic gel is parallel to the steel ruler, and the above three ratios of eutectic gels are pulled by hand at a relatively uniform speed. The scale at which the eutectic gel breaks is recorded by means of photography.

[0034] Experimental results: The elongation at break of the G 2.44361wt% A-LS@Ag 00.9 eutectic gel is 650 - 750%, and the elongation at break of the G 2.30292wt% A-LS@Ag 0.9 eutectic gel is 1200 - 1300%. The elongation at break of the G 2.17756wt%A-LS@Ag 0.9 The elongation at break of the eutectic gel is 750 - 850%. It is confirmed that the G prepared by adding 2.30292 wt% of gelatin based on the total mass of the prepolymer solution 2.30292wt% A-LS@Ag 0.9 The elongation at break of the eutectic gel with this proportion is the best. Therefore, in the subsequent research of the present invention, the scheme of adding 2.30292 wt% of gelatin based on the total mass of the gel prepolymer solution is selected.

[0035] Comparative Example 2 This example provides a preparation method of GA-LS@Ag-DES eutectic gel. The addition amount of the LS@Ag aqueous solution is selected to be 0.9 mL, that is, LS@Ag accounts for 0.10363 wt% of the total mass of the gel prepolymer solution. Other steps are the same as in Example 1, except that the crosslinking agent added in step (iv) is replaced from N,N'-methylenebisacrylamide (BIS) to polyethylene glycol diacrylate (PEGDA), obtaining two kinds of GA-LS@Ag-DES eutectic gels, which are respectively named GA PEGDA -LS@Ag 0.9 eutectic gel and GA BIS -LS@Ag 0.9 eutectic gel.

[0036] Control the initial length of the eutectic gel to be 20 mm. The eutectic gel is parallel to the steel ruler, and the eutectic gels with the above three proportions are pulled by hand at a relatively uniform speed. The scale at which the eutectic gel breaks is recorded by means of photography.

[0037] Experimental results: The elongation at break of the GA PEGDA -LS@Ag 0.9 eutectic gel is 600 - 650%, and the elongation at break of the GA BIS -LS@Ag 0.9 eutectic gel is 1200 - 1300%. It is confirmed that the elongation at break of the eutectic gel with the above-added PEGDA crosslinking agent is not as good as that of the LS@Ag eutectic gel prepared by adding the BIS crosslinking agent 0.9 The elongation at break of the eutectic gel is good. Using the slightly rigid BIS as the crosslinking agent has a better effect than using the relatively flexible PEGDA.

[0038] Example 2 This example provides a method for evaluating the fracture tensile strength of GA-LS@Ag-DES eutectic gel, which specifically includes the following steps: Use a universal testing machine to detect the four different proportions of GA-LS@Ag-DES eutectic gels obtained in Example 1 (LS@Ag 0.7 eutectic gel, LS@Ag 0.9 eutectic gel, LS@Ag1.1 Eutectic gel, LS@Ag 1.3 The fracture tensile properties of the eutectic gel). The two ends of the eutectic gel were regularly clamped on a tensile machine, the tensile speed was set at 50 mm / min, and the stress-strain curve during this process was recorded in real time until the eutectic gel was broken.

[0039] Experimental results: As Figure 2 shown, LS@Ag 0.7 The tensile strength of the eutectic gel is 155 KPa, and the elongation at break is 951%; LS@Ag 0.9 The tensile strength of the eutectic gel is 176 KPa, and the elongation at break is 1470%; LS@Ag 1.1 The tensile strength of the eutectic gel is 154 KPa, and the elongation at break is 1400%; LS@Ag 1.3 The tensile strength of the eutectic gel is 166 KPa, and the elongation at break is 1230%; It is confirmed that LS@Ag 0.9 The eutectic gel of the prepared GA-LS@Ag-DES has the best elongation at break and tensile strength in terms of proportion.

[0040] Example 3 This example provides a method for evaluating the adhesion performance of GA-LS@Ag-DES eutectic gel to different materials, including the following steps specifically: Step A: Prepare GA-LS@Ag-DES: Other steps are the same as those for the preparation of LS@Ag 0.9 eutectic gel in Example 1, except that the GA-LS@Ag-DES prepolymer solution obtained in Step 4 was filled into a silica gel mold with a length of (40 mm) × width of (20 mm) × height of (2 mm) to obtain a 2-mm-thick GA-LS@Ag-DES eutectic gel.

[0041] Step B: Select 4 different adhesion substrates, including: wood, metal, glass, and plastic. Cut them all into a size of length (70 mm) × width (30 mm). Then, lay the eutectic gel prepared in Step A flat on one of the cut substrates along the wide-edge and long-edge, length-to-length and width-to-width, and then cover the other side of the eutectic gel with the same substrate starting from the other wide edge, and avoid air bubbles between the material paste surfaces. Then, clamp the two long ends of the adhered substrate on a tensile machine, set the tensile speed at 100 mm / min, and record the mechanical curve during this process in real time until the two substrates are completely separated. Each substrate is tested in parallel three times.

[0042] Experimental results: As Figure 3As shown, the adhesion strengths of the GA-LS@Ag-DES eutectic gel to four substrates, namely wood, metal, glass, and plastic, reached 23.1, 20.2, 17.7, and 14.3 kPa, respectively. The reason for the excellent adhesion of the eutectic gel is that the eutectic gel has many quinone, catechol, amino, and carboxylic acid groups, which can produce hydrophobic, electrostatic, hydrogen bond, π-π, and cation-π interactions with the interface, synergistically promoting the strong cohesion and adhesion strength of the eutectic gel. This excellent adhesion performance enables the GA-LS@Ag-DES eutectic gel to form good conformal contact with different materials, which is beneficial to the capture of electrical signals.

[0043] Example 4 This example provides an evaluation method for the strain sensing of the GA-LS@Ag-DES eutectic gel, including the following steps specifically: Step A 1 : Prepare the GA-LS@Ag-DES eutectic gel, and the steps are the same as those for LS@Ag in Example 1 0.9 Preparation of the eutectic gel.

[0044] Step B 1 : Connect the universal testing machine and the multimeter to detect the strain sensing performance of the GA-LS@Ag-DES eutectic gel sensor obtained in Step A 1 Paste a 5-mm-wide conductive copper tape neatly around both ends of the eutectic gel, then clamp it together with the wound conductive copper tape on the tensile machine. At the same time, extend the conductive copper tape, and then connect the sensor to the multimeter through the conductive copper tape. Then, use the tensile machine to stretch / release the sensor with different strains, and record the resistance change signal of the sensor in real time during this process.

[0045] Experimental results: As Figure 4 shown, when the eutectic gel sensor is stretched / released with different strains using the universal testing machine, the sensing sensitivities (GF) of the eutectic gel sensor reach 3.43 (0 - 200%), 8.45 (200 - 600%), and 15.22 (600 - 1000%), respectively, which confirms the high sensitivity and wide sensing range of the GA-LS@Ag-DES eutectic gel sensor, and can realize the monitoring of the electrical signal changes of various human movements.

[0046] Example 5 This example provides an evaluation method for the strain sensing of the GA-LS@Ag-DES eutectic gel, including the following steps specifically: Step A 2 : Prepare the GA-LS@Ag-DES eutectic gel, and the steps are the same as those for LS@Ag in Example 1 0.9 Preparation of the eutectic gel.

[0047] Step B 2 :Use a multimeter to test step A 2 The strain sensing performance of the obtained GA-LS@Ag-DES eutectic gel sensor at different human joints. Conductive copper glue with a width of 5 mm was regularly pasted on both ends of the eutectic gel, and then attached to different human joints. The sensor was connected to a multimeter with the help of the extended conductive copper tape, and the resistance change signal of the sensor during different bending angles of different joints was recorded in real time.

[0048] Experimental results: Figure 5 As shown in Figure A, the strain sensor installed on the wrist can clearly distinguish the forward and backward bending state and bending angle of the wrist joint, and maintain a stable and repetitive relative resistance response. Figure 5 As shown in Figure B, as the bending angle of the finger increases, the relative change in resistance also gradually increases. When the bending angle of the finger is fixed at a certain value, the relative change in resistance also keeps pace with the movement state, maintaining the original value unchanged. This confirms that the GA-LS@Ag-DES eutectic gel sensor can monitor the changes in electrical signals of human body movements.

[0049] Example 6 This embodiment provides a method for evaluating the wide temperature conductivity of GA-LS@Ag-DES eutectic gel, which includes the following steps: Step A 3 : Preparation of GA-LS@Ag-DES eutectic gel, the steps are the same as those of LS@Ag in Example 1 0.9 Preparation of eutectic gel.

[0050] Step B 3 :Use the universal testing machine and multimeter to test step A 3 The wide temperature conductivity of the obtained GA-LS@Ag-DES eutectic gel sensor. A circle of 5 mm wide conductive copper tape was regularly pasted on both ends of the GA-LS@Ag-DES eutectic gel, and then it was clamped on the tensile machine together with the wrapped conductive copper tape. At the same time, the conductive copper tape was extended, and then the sensor was connected to the multimeter with the conductive copper tape. The GA-LS@Ag-DES eutectic gel wrapped with conductive copper glue was placed in a digital display low temperature box, and the extended part of the conductive copper tape was placed outside the box. The sensor was connected to the electrochemical workstation with the help of the conductive copper tape. After the temperature dropped to the required temperature, it was kept warm for 15 minutes, and then the sensor was stretched / released with a strain of 200% using a tensile machine, and the resistance change signal of the sensor during the process was recorded in real time.

[0051] Experimental results: Figure 6The relative resistance also changes correspondingly at different temperatures shown in A and B. It decreases when the temperature rises from 25°C to 60°C (ε = 200%), and increases when the temperature drops from 25°C to -40°C (ε = 200%). Moreover, the signal remains stable, indicating that the GA-LS@Ag-DES eutectic gel sensor has sensitive response capabilities at both high and low temperatures. The above results illustrate that the GA-LS@Ag-DES eutectic gel sensor has excellent environmental compatibility and can perform real-time health monitoring even under extreme environmental temperatures.

[0052] The above embodiments are preferred embodiments of the present invention. However, the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A method for ultra-fast preparation of room temperature self-polymerization and wide temperature strain conductive eutectic gel, characterized in that The steps include: (1) Dissolve lignin in NaOH solution to obtain a lignin aqueous solution; add ammonia water to the AgNO3 aqueous solution to obtain a solution containing [Ag(NH3)2] + The lignin aqueous solution is added dropwise to the solution containing [Ag(NH3)2] + The solution of the complex is stirred and reacted under light-proof conditions to generate a solution containing silver nanoparticles wrapped with sodium lignin sulfonate; the obtained solution containing silver nanoparticles wrapped with sodium lignin sulfonate is dialyzed and then freeze-dried to obtain a lyophilized powder of silver nanoparticles wrapped with sodium lignin sulfonate; and the lyophilized powder is prepared into an aqueous solution of silver nanoparticles wrapped with sodium lignin sulfonate; (2) adding zinc chloride to ethylene glycol and stirring in a hot water bath at 80°C for 2 h to obtain a clear and transparent deep eutectic solvent, wherein the molar ratio of zinc chloride to ethylene glycol is 1:3; (3) Add deionized water to gelatin and place in an oven for 5 minutes until the gelatin is completely dissolved to obtain a gelatin aqueous solution; (4) Using a one-pot mixing method, the sodium lignin sulfonate solution encapsulating silver nanoparticles obtained in step (1), the gelatin solution obtained in step (3), the polymer monomer, the crosslinking agent N,N'-methylenebisacrylamide and the initiator are added to the deep eutectic solvent obtained in step (2), and the mixture is evenly mixed to obtain a gel prepolymer solution, wherein the concentration of the deep eutectic solvent in the gel prepolymer solution is 30-35 wt %. The gel prepolymer solution is filled into a mold, and allowed to self-polymerize at room temperature, and then placed in an oven for 1-2 hours to obtain a room temperature self-polymerizing and wide temperature strain conductive eutectic gel GA-LS@Ag-DES.

2. The method for ultra-fast preparation of room temperature self-polymerization and wide temperature strain conductive eutectic gel according to claim 1, characterized in that: The pH value of the NaOH solution in step (1) is 9-12; the concentration of the lignin aqueous solution is 25-35 mg·mL -1 ; The concentration of the ammonia water is 4mol / L-6mol / L; The concentration of the AgNO3 aqueous solution is 15-25mg·mL -1 ; The containing [Ag(NH3)2] + The solution concentration of the complex is 0.01-0.06 mol / L; the lignin aqueous solution contains [Ag(NH3)2] + The volume ratio of the complex solution is 1:1; the stirring reaction temperature is 20-40°C, the stirring reaction time is 12-36 h, and the stirring speed is 300-800 rpm; the dialysis time is 1-2 weeks; the concentration of the sodium lignin sulfonate-encapsulated silver nanoparticles aqueous solution is 5-15 mg·mL -1 .

3. The method for ultra-fast preparation of room temperature self-polymerization and wide temperature strain conductive eutectic gel according to claim 1, characterized in that: In step (3), the temperature of the oven is 50-70° C.; in step (4), the polymer monomer is one of acrylamide and acrylic acid; and the initiator is potassium persulfate or ammonium persulfate.

4. The method for ultra-fast preparation of room temperature self-polymerization and wide temperature strain conductive eutectic gel according to claim 1, characterized in that: In step (4), the amount of sodium lignin sulfonate-encapsulated silver nanoparticles in the sodium lignin sulfonate-encapsulated silver nanoparticles aqueous solution is 0.05-0.15 wt% of the gel prepolymer solution; the amount of the polymer monomer is 20-25 wt% of the gel prepolymer solution; the amount of the cross-linking agent is 0.01-0.05 wt% of the gel prepolymer solution; the amount of the initiator is 0.5-0.9 wt% of the gel prepolymer solution; and the amount of gelatin in the gelatin aqueous solution is 2-5 wt% of the gel prepolymer solution.

5. The method for ultra-fast preparation of room temperature self-polymerization and wide temperature strain conductive eutectic gel according to claim 1, characterized in that: The amount of gelatin in the gelatin aqueous solution is 2.30292wt% of the total mass of the gel prepolymer solution.

6. The method for ultra-fast preparation of room temperature self-polymerization and wide temperature strain conductive eutectic gel according to claim 1, characterized in that: The mold in step (4) is a square or rectangular polytetrafluoroethylene or silicone mold; the filling of the prepolymer liquid into the mold is performed by controlling the amount of prepolymer liquid added to control the thickness of the ultimately obtained room temperature self-polymerizing and wide temperature strain conductive eutectic gel.

7. The method for ultra-fast preparation of room temperature self-polymerization and wide temperature strain conductive eutectic gel according to claim 1, characterized in that: In step (4), the room temperature condition is 10-30°C, and the time of placing in the room temperature condition is 3s-30min; the temperature of the oven is set to 40-55°C, and the time of placing in the oven is 1-2h.

8. A room temperature self-polymerizing and wide temperature strain conductive eutectic gel prepared by the method according to any one of claims 1 to 7, characterized in that: The conductivity of the eutectic gel is as high as 0.6S / m, and a stable electrical signal can be obtained in the range of -40℃-60℃.

9. Use of the room temperature self-polymerizing and wide temperature strain conductive eutectic gel according to claim 8 as a conductor in a sensor.

10. Application of the room temperature self-polymerizing and wide temperature strain conductive eutectic gel according to claim 8 in wearable devices, medical health monitoring devices or human-computer interaction devices to realize human motion monitoring.

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