Conductive hydrogel with self-repairing and anti-freezing functions and preparation method thereof

Abstract

The present application relates to the technical field of conductive hydrogel, and discloses a hydrogel with self-repairing and anti-freezing functions and a preparation method thereof.The preparation method comprises the following steps: constructing a crosslinking network by using an amino-rich water-soluble polymer and a crosslinking agent containing a dynamic disulfide bond; and introducing a conductive polymer to make the supramolecular interaction between the multi-component system affect the continuity of the conductive network, so as to solve the problems of the traditional pure conductive polymer hydrogel, such as large brittleness of mechanical properties, easy breaking under stress, and the molecular chain design problem of being difficult to simultaneously achieve high conductivity and high tensile flexibility.The preparation method adds the crosslinking agent containing the dynamic disulfide bond and the inorganic salt with hygroscopicity and solubility, utilizes the dynamic reversible characteristics of the disulfide bond and the ion-water dipole interaction, so that the flexible sensing hydrogel can be quickly self-repaired and keep high sensitivity conductive sensing under the condition of frequent tensile damage or low-temperature freezing environment, and the long-term service stability of the device is ensured.

Description

Technical Field

[0001] This invention relates to the field of conductive hydrogel technology, and in particular to a hydrogel with self-healing and antifreeze functions and its preparation method. Background Technology

[0002] With the rapid development of cutting-edge concepts such as the "Internet of Everything" and personalized medicine, the research and development of human-computer interaction technology and health monitoring equipment is transforming towards flexibility, shape preservation, and comfort. Developing flexible electronic materials that combine mechanical flexibility with high conductivity, and achieving long-term stable extraction of complex physiological signals from the human body, is an effective way to promote the widespread adoption of wearable devices. Conductive hydrogels are a highly representative core material in the field of flexible sensing. Due to their porous network structure similar to biological soft tissue, excellent flexibility, and highly tunable electrical properties, they have received widespread attention in cutting-edge fields such as artificial intelligence, electronic skin, and medical monitoring. The three-dimensional polymer network of conductive hydrogels can accommodate a large amount of water and ions. When subjected to external stress (such as stretching, bending, and compression), the conductive pathways within the network can undergo corresponding configurational changes, thereby converting mechanical deformation into measurable electrical signal output.

[0003] Currently, traditional conductive hydrogels are diverse, but they often have stringent environmental requirements for stable sensing performance, typically requiring room temperature and a sealed environment to achieve good signal monitoring. This limitation significantly restricts their application in complex environments, especially those with long-term exposure to air or extremely cold conditions. In open environments, moisture evaporation and freezing at low temperatures severely interfere with the synergy between the polymer network and the conductive medium, leading to a sharp deterioration in mechanical properties or even complete loss of sensing function. This is mainly because moisture loss or phase transitions can damage the cross-linked network of the hydrogel, block electron transport paths, or impede the effective dissipation of strain energy. On the one hand, from the perspective of moisture evaporation, long-term exposure to air causes a large amount of solvent to evaporate from the hydrogel, disrupting the originally flexible arrangement of polymer chains. This causes the hydrogel to shrink, harden, and become brittle, unable to buffer mechanical stress according to the expected deformation path, ultimately preventing effective tensile elongation and significantly reducing its mechanical flexibility. On the other hand, at the low-temperature freezing level, water molecules form ice crystals below zero degrees Celsius. These rigid ice crystals not only pierce and destroy the polymer network skeleton that originally maintains the three-dimensional structure, causing the hydrogel to lose its elastic response to external stress; at the same time, the freezing process greatly restricts the transport of free ions, severely blocks the formation of continuous conductive networks, further reduces conductivity, and in severe cases directly leads to the complete failure of electrical signal response. Summary of the Invention

[0004] In view of this, the main objective of the present invention is to provide a hydrogel with self-healing and antifreeze functions and a method for preparing the same, thereby solving the problems in the prior art.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows: This invention discloses a method for preparing a conductive hydrogel with self-healing and antifreeze functions, comprising the following steps: S1. Pretreatment: The conductive polymer aqueous solution is mixed with the secondary dopant, and the mixture is heated for doping and then cooled to obtain mixture A. S2. Prepare a premixed solution by adding deionized water to a water-soluble polymer rich in amino groups; mix until the water-soluble polymer rich in amino groups is completely dissolved to form a mixture B. S3. Slowly add mixture A dropwise into mixture B, mix, and then add an inorganic salt that is hygroscopic and easily soluble to form mixture C.

[0006] S4: During the gelation process, place the beaker containing the mixture C in an ice-water bath and stir vigorously. At the same time, add the crosslinking agent containing dynamic disulfide bonds in small amounts several times. After mixing, place the mixture in a vacuum drying oven and dry for 8-12 hours.

[0007] In a preferred embodiment, the conductive polymer is an intrinsically conductive polymer with good water dispersibility: one of polyaniline, polypyrrole, and PEDOT:PSS. The secondary dopant is selected from ethylene glycol, N,N-dimethylformamide, methanol, and dimethyl sulfoxide. The amino-rich polymer is selected from chitosan, polyallylamine, polyamide-amine dendritic polymer, or polyethyleneimine. The inorganic salt that is hygroscopic and easily soluble is selected from one of CaCl2, LiBr, ZnCl2 or LiCl; The crosslinking agent containing dynamic disulfide bonds is selected from 3,3'-dithiodipropionic acid or thioctic acid. In a preferred embodiment, the conductive polymer is PEDOT:PSS; The secondary dopant is dimethyl sulfoxide; The amino-rich polymer is polyethyleneimine; The hygroscopic and easily soluble inorganic salt is LiCl; The crosslinking agent containing dynamic disulfide bonds is thioctic acid powder.

[0008] In a preferred embodiment, the volume ratio of PEDOT:PSS aqueous solution to dimethyl sulfoxide in mixture A is 10:0.5; The PEDOT content in the PEDOT:PSS aqueous solution is 0.286-0.371 wt%, and the PSS content is 0.714-0.929 wt%.

[0009] In a preferred embodiment, the mass ratio of polyethyleneimine to deionized water in the mixture B is 1:(6.5-8.5); The mass ratio of mixture A, mixture B, LiCl and lipoic acid in mixture C is (0.8-1.2):(7.5-9.5):(0.03-0.05):(0.15-0.25).

[0010] In a preferred embodiment, the mass ratio of mixture A, mixture B, LiCl and lipoic acid in mixture C is 1:8.758:0.042:0.2.

[0011] In a preferred embodiment, the mixing conditions in S1 are: acoustic field resonance for 20-40 minutes, and acceleration controlled at 55-65 m / s². 2 The doping conditions were: heating in a 60 ℃ oven for 1 h; The mixing conditions in S2 are: acoustic field resonance for 5-10 minutes, and acceleration of 55-65 m / s². 2 Continue until the polyethyleneimine is completely dissolved.

[0012] In a preferred embodiment, the mixing conditions in S3 are as follows: after slowly dripping mixture B into mixture A, the acoustic field resonates for 90-120 minutes, and the acceleration is 55-65 m / s². 2 After adding LiCl, the acoustic field resonated for 10-30 minutes, with an acceleration of 55-65 m / s². 2 , until completely dissolved.

[0013] In a preferred embodiment, the operation steps in S4 are as follows: place the beaker containing the mixture C in an ice-water bath, stir vigorously at a speed of 1100-1300 rpm, add thioctic acid powder in small amounts several times over 8-10 minutes, the thioctic acid powder can be added in 3-10 portions, and after adding the thioctic acid, continue stirring in the ice bath for 3-10 minutes.

[0014] In a preferred embodiment, the mixing conditions in S4 are: acoustic field resonance for 90-120 min, and acceleration of 65-75 m / s². 2 .

[0015] In a preferred embodiment, the drying conditions in S4 are as follows: in a vacuum drying oven at 60 ℃, the vacuum is drawn to -0.08 to -0.1 MPa, and the drying time is 8 to 12 hours.

[0016] The present invention also discloses a hydrogel with self-healing and antifreeze functions, which is prepared by the above-mentioned method for preparing a conductive hydrogel with self-healing and antifreeze functions.

[0017] The present invention provides a hydrogel with self-healing and antifreeze functions and its preparation method, which has the following beneficial effects: The preparation method of this invention involves constructing a crosslinked network using a water-soluble polymer rich in amino groups and a crosslinking agent containing dynamic disulfide bonds. By introducing a conductive polymer, the influence of supramolecular interactions between the multi-component system on the continuity of the conductive network is mitigated, thus solving the problems of high brittleness and easy breakage under stress in traditional pure conductive polymer hydrogels. By adjusting the amount of crosslinking agent containing dynamic disulfide bonds and the amount of conductive polymer added, the molecular chain design problem of simultaneously achieving high conductivity and high tensile flexibility can be solved.

[0018] The preparation method of the present invention adds a crosslinking agent containing dynamic disulfide bonds and an inorganic salt with hygroscopicity and easy solubility. By utilizing the dynamic reversible characteristics of disulfide bonds and ion-water dipole interaction, the flexible sensing hydrogel can quickly self-repair and maintain high-sensitivity conductive sensing even when subjected to frequent tensile damage or in low-temperature freezing environments, thus ensuring the long-term service stability of the device.

[0019] The hygroscopic and easily soluble inorganic salts not only provide ion transport channels, but more importantly, they inhibit the evaporation of water and significantly lower the freezing point of water by utilizing the hygroscopic properties of inorganic salts. This allows the hydrogel sensor to maintain good mechanical properties and stable, highly sensitive electrical signal output even in harsh environments such as extreme cold (freezing) and long-term exposure (drying). Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A mapping diagram of a hydrogel prepared according to an embodiment of the present disclosure of a conductive hydrogel with self-healing and antifreeze functions. Figure 2Fourier transform infrared (FTIR) spectrum of a hydrogel prepared according to an embodiment of the present disclosure of a conductive hydrogel with self-healing and antifreeze functions. Figure 3 This is an experimental diagram of the electrochemical impedance (EIS) gradient of a hydrogel prepared according to the method for preparing a self-healing and antifreeze conductive hydrogel according to this disclosure. Detailed Implementation

[0022] The following detailed description, in conjunction with the accompanying drawings and embodiments of the present invention, provides a further explanation of a hydrogel with self-healing and antifreeze functions and its preparation method.

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] The terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0026] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0027] according to Figures 1-3 As shown, this application discloses a method for preparing a conductive hydrogel with self-healing and antifreeze functions, comprising the following steps: S1. Pretreatment: Mix an aqueous solution of an intrinsically conductive polymer with good water dispersibility with a secondary dopant, and obtain mixture A by heating and cooling. S2. Prepare a premixed solution by adding deionized water to a water-soluble polymer rich in amino groups; mix until the water-soluble polymer rich in amino groups is completely dissolved to form a mixture B; deionized water serves as the reaction medium and the dispersed phase of the hydrogel.

[0028] S3. Slowly add mixture A dropwise to mixture B, mix, and then add an inorganic salt that is hygroscopic and easily soluble, forming mixture C. The hygroscopic and easily soluble inorganic salt, upon dissolution, generates positive and negative ions, providing an ionic conductivity pathway. Furthermore, its strong hydration effect allows it to form a strong ion-dipole interaction with water molecules, lowering the freezing point of water and inhibiting water evaporation.

[0029] S4: During the gelation process, place the beaker containing the mixture C in an ice-water bath and stir vigorously. At the same time, add the crosslinking agent containing dynamic disulfide bonds in small amounts several times. After mixing, place the mixture in a vacuum drying oven and dry for 8-12 hours.

[0030] The preparation method of this invention involves constructing a crosslinked network using a water-soluble polymer rich in amino groups and a crosslinking agent containing dynamic disulfide bonds. By introducing a conductive polymer, the influence of supramolecular interactions between the multi-component system on the continuity of the conductive network is mitigated, thus solving the problems of high brittleness and easy breakage under stress in traditional pure conductive polymer hydrogels. By adjusting the amount of crosslinking agent containing dynamic disulfide bonds and the amount of conductive polymer added, the molecular chain design problem of simultaneously achieving high conductivity and high tensile flexibility can be solved.

[0031] The preparation method of the present invention adds a crosslinking agent containing dynamic disulfide bonds and an inorganic salt with hygroscopicity and easy solubility. By utilizing the dynamic reversible characteristics of disulfide bonds and ion-water dipole interaction, the flexible sensing hydrogel can quickly self-repair and maintain high-sensitivity conductive sensing even when subjected to frequent tensile damage or in low-temperature freezing environments, thus ensuring the long-term service stability of the device.

[0032] The hygroscopic and easily soluble inorganic salts not only provide ion transport channels, but more importantly, they inhibit the evaporation of water and significantly lower the freezing point of water by utilizing the hygroscopic properties of inorganic salts. This allows the hydrogel sensor to maintain good mechanical properties and stable, highly sensitive electrical signal output even in harsh environments such as extreme cold (freezing) and long-term exposure (drying).

[0033] The conductive polymer selected is an intrinsically conductive polymer with good water dispersibility: one of polyaniline (PANI), polypyrrole (PPy), and PEDOT:PSS. These polymers have good water dispersibility and their function is to construct a three-dimensional continuous conductive network. PEDOT:PSS is preferred.

[0034] Secondary dopants can be selected from ethylene glycol (EG), N,N-dimethylformamide (DMF), methanol, and dimethyl sulfoxide (DMSO), with dimethyl sulfoxide (DMSO) being preferred. The principle of using DMSO for secondary doping and heating of PEDOT:PSS is to promote the rearrangement and partial removal of the insulating PSS shell, improving the microcrystallineity and connectivity of the PEDOT core. Its advantage lies in significantly increasing the intrinsic conductivity of the conductive filler.

[0035] Amino-rich polymers serve as the flexible polymer backbone, such as chitosan, polyallylamine (PAA), polyamide-amine dendritic polymers (PAMAM), or polyethyleneimine (PEI). Their role is to facilitate proton transfer with carboxyl groups and provide a crosslinking network; polyethyleneimine (PEI) is preferred. As a flexible polymer backbone for hydrogels, polyethyleneimine (PEI) contains abundant first, second, and third amino groups, providing numerous crosslinking sites and imparting mechanical support to the hydrogel structure.

[0036] The hygroscopic and readily soluble inorganic salt can be selected from CaCl2 (calcium chloride), LiBr (lithium bromide), ZnCl2 (zinc chloride), or LiCl (lithium chloride); its function is to utilize the ion-dipole interaction of strong hydrated ions to break ice crystal condensation and retain moisture, with LiCl (lithium chloride) being preferred. Free Li... + and Cl - Provides an ion-conducting pathway.

[0037] Crosslinking agents containing dynamic disulfide bonds can be 3,3'-dithiodipropionic acid (DTDPA) or lipoic acid (TA), whose function is to achieve dynamic repair through their disulfide bonds. Lipoic acid (TA) powder is preferred. Both of these substances contain dynamically reversible disulfide bonds (-SS-), and theoretically, when the gel network is damaged by external stress, they can achieve self-repair of the structure through the breaking and recombination of disulfide bonds. This invention preferably uses lipoic acid (TA) powder, which contains not only disulfide bonds but also carboxyl groups. The carboxyl groups can undergo proton transfer with the amino group of PEI to form electrostatic interactions and hydrogen bonds.

[0038] 3,3'-Dithiodipropionic acid (DTDPA) or lipoic acid (TA) contains not only disulfide bonds but also carboxyl groups. The carboxyl groups can undergo proton transfer with amino groups in amino-rich polymers to form electrostatic interactions and hydrogen bonds.

[0039] The dynamic cross-linked network based on PEI / TA utilizes the electrostatic complexation and hydrogen bonding between the carboxyl groups of TA and the amino groups of PEI, as well as the dynamic disulfide bonds of TA itself, to endow the hydrogel with excellent tensile flexibility, self-healing ability and multi-substrate adhesion. At the same time, the flexible network effectively encapsulates and supports the rigid conductive network of PEDOT:PSS, achieving a perfect compatibility between "high conductivity" and "high tensile strength".

[0040] The volume ratio of PEDOT:PSS aqueous solution to DMSO in mixture A is 10:0.5; The PEDOT content in the PSS aqueous solution is 0.286-0.371 wt%, and the PSS content is 0.714-0.929 wt%.

[0041] The mass ratio of PEI to deionized water in mixture B is 1:(6.5-8.5); preferably, the mass ratio of PEI to deionized water in mixture B is 1:7.758 g.

[0042] The mass ratio of mixture A, mixture B, LiCl and TA in mixture C is (0.8-1.2):(7.5-9.5):(0.03-0.05):(0.15-0.25).

[0043] The preferred mass ratio of mixture A, mixture B, LiCl and TA in mixture C is 1:8.758:0.042:0.2.

[0044] The mixing conditions in S1 are: acoustic field resonance for 20-40 minutes, and acceleration controlled at 55-65 m / s². 2 The doping conditions were: heating in a 60 ℃ oven for 1 h.

[0045] The mixing conditions in S2 are: acoustic field resonance for 5-10 minutes, and acceleration of 55-65 m / s². 2 Continue until PEI is completely dissolved.

[0046] The mixing conditions in S3 are as follows: after slowly adding mixture B dropwise to mixture A, the acoustic field resonates for 90-120 minutes, and the acceleration is 55-65 m / s². 2 After adding LiCl, the acoustic field resonated for 10-30 minutes, with an acceleration of 55-65 m / s². 2 , until completely dissolved.

[0047] The operating steps in S4 are as follows: Place the beaker containing the mixture C in an ice-water bath and stir vigorously at a speed of 1100-1300 rpm. Add TA powder in small amounts several times over 8-10 minutes. After adding TA, continue stirring in the ice bath for 3-10 minutes.

[0048] The method of introducing TA using an ice-water bath and slow feeding is based on the principle that the carboxyl group of TA and the amino group of PEI have an extremely fast acid-base reaction and electrostatic complexation rate, which easily leads to local instantaneous gelation at room temperature, resulting in uneven cross-linking network. The ice-water bath reduces the rate of molecular thermal motion and acid-base reaction, which has the advantage of ensuring a uniform and dense distribution of the cross-linking network throughout the system.

[0049] The mixing conditions in S4 are: acoustic field resonance for 90-120 minutes, and acceleration of 65-75 m / s². 2 .

[0050] The drying conditions for S4 are as follows: in a vacuum drying oven at 60 ℃, evacuate to -0.08 to -0.1 MPa and dry for 8 to 12 hours.

[0051] The present invention also discloses a hydrogel with self-healing and antifreeze functions, which is prepared by any of the above-mentioned methods for preparing conductive hydrogels with self-healing and antifreeze functions.

[0052] Example 1 Step 1: Take 0.5 ml of DMSO and add 10 ml of pH 1000 (PEDOT:PSS) stock solution. Incubate the sound field for 30 minutes, controlling the acceleration at 60 m / s². 2 The mixture was heated and mixed in a 60 °C oven for 1 h; after being removed, it was allowed to cool naturally to room temperature (about 25 °C) to obtain mixture A.

[0053] Step 2: Weigh 1 g of PEI and add it to a clean glass beaker, then add 7.791 g of deionized water; perform acoustic resonance for 8 minutes with an acceleration of 60 m / s². 2 Continue until PEI is completely dissolved to form a clear and transparent solution, thus forming mixture B; Step 3: Accurately weigh 1g of mixture A and slowly add it dropwise to mixture B. Incubate the sound field for 100 minutes with an acceleration of 60 m / s². 2 To ensure the formation of a uniform black dispersion without significant agglomeration, weigh 0.042 g of LiCl and add it to the dispersion. Incubate the mixture under acoustic resonance for 20 min at an acceleration of 60 m / s². 2 , and mix to form mixture C.

[0054] Step 4: Gelation process. Place the beaker containing the premixed solution in an ice-water bath; start vigorous stirring at 1200 rpm; add 0.167 g of TA powder in 6 portions over 9 minutes; after adding all TA, continue stirring in the ice bath for 5 minutes; then perform acoustic resonance for 100 minutes with an acceleration of 70 m / s². 2 Immediately pour the mixture into the mold, place the mold in a 60 ℃ vacuum drying oven, evacuate to -0.09 MPa, and dry for 10 hours to form the final product.

[0055] The mass of each component in this embodiment is as follows: Mixture A is 1 g, the mass ratio of TA to PEI is 1:6, deionized water is 7.791 g, PEI is 1 g, LiCl is 0.042 g, the addition amount is moderate; TA powder is 0.167 g.

[0056] Example 2 The preparation steps in this embodiment are the same as in Example 1. The mass of each component is as follows: the amount of mixture A is 1 g, the mass ratio of TA to PEI is 1:5, the amount of deionized water is 7.758 g, the amount of PEI is 1 g, the amount of LiCl is 0.042 g, and the amount added is at a high level; the mass of TA powder is 0.200 g.

[0057] Example 3 The preparation steps in this embodiment are the same as in Example 1. The mass of each component is as follows: Mixture A is 1 g, the mass ratio of TA to PEI is 1:4, deionized water is 7.750 g, PEI is 1 g, LiCl is 0 g, and TA powder is 0.250 g. This group serves as a control without inorganic salts to highlight the role of LiCl in antifreeze and water retention properties.

[0058] Example 4 The preparation steps in this embodiment are the same as in Example 1. The mass of each component is as follows: the amount of mixture A is 2g, the mass ratio of TA to PEI is 1:6, the amount of deionized water is 6.791g, the amount of PEI is 1g, the amount of LiCl is 0.042g, and the amount added is at a high level; the mass of TA powder is 0.167g.

[0059] Example 5 The preparation steps in this embodiment are the same as in Example 1. The mass of each component is as follows: 2 g of mixture A, and the mass ratio of TA to PEI is 1:5. 6.800 g of deionized water, 1 g of PEI, 0 g of LiCl, and 0.200 g of TA powder.

[0060] The mass of each component in the above embodiments is shown in Table 1.

[0061] Table 1. Mass of each component in Examples 1-5

[0062] Figure 1 This is a mapping image of a hydrogel prepared according to an embodiment of the conductive hydrogel with self-healing and antifreeze functions, specifically a mapping image of a hydrogel prepared according to embodiment 2. Figure 1 As can be seen from the image, energy-dispersive X-ray spectroscopy (EDS) elemental mapping (scale bar 10 μm) of the composite hydrogel clearly shows that the five characteristic elements—carbon (C), nitrogen (N), oxygen (O), sulfur (S), and chlorine (Cl)—are all highly dense and uniformly distributed in the hydrogel matrix. There are no obvious blank areas or abnormally enriched bright patches in the image, which directly proves that the multi-component system achieved molecular-level uniform mixing during gelation, and that the components have excellent compatibility with each other, without any macroscopic or microscopic phase separation.

[0063] Figure 2 The image shown is a Fourier transform infrared (FTIR) spectrum of a hydrogel prepared according to an embodiment of this disclosure of a conductive hydrogel with self-healing and antifreeze functions, specifically a Fourier transform infrared (FTIR) spectrum of a hydrogel prepared according to embodiment 2. Figure 2 As can be seen from the spectrum, the absorption peak positions of each characteristic functional group are clearly displayed, confirming the strong interaction between the components and the successful construction of the multiple non-covalent cross-linked network.

[0064] In the spectrum, 3361.2 cm -1 The broadened characteristic peak at 1552 cm⁻¹ (overlapping of OH and NH) confirms the existence of a rich hydrogen bond network within the system. Most importantly, the peak at 1552 cm⁻¹... -1 and 1408.9 cm -1 Carboxylate ions (-COO) appeared in pairs at the site. - The stretching vibration peak indicates that the carboxyl group of lipoic acid successfully neutralized the amino group of PEI, forming a dense electrostatic complex network (-COO). - With -NH3 + This is key to giving the material high tensile strength and self-healing ability. Furthermore, 2934.9 cm -1 2833.8 cm -1 With 1286.1 cm -1 The absorption peaks further verified the integrity of the carbon chain and the CN flexible framework.

[0065] Finally, 816.4 cm -1 The clear presentation of the characteristic peak of the CS ring in PEDOT strongly confirms that the rigid conductive polymer PEDOT:PSS has been uniformly and stably embedded in the aforementioned flexible network. The cross-linking and composite at the microscopic level provide solid evidence for the hydrogel of this invention to achieve both high conductivity and high flexibility on a macroscopic scale.

[0066] The electrochemical impedance spectroscopy (EIS) gradient experimental diagram of the hydrogel prepared according to the self-healing and antifreeze function conductive hydrogel preparation method of this disclosure is shown below. Figure 3 It can be seen that the intercept of the curve in the high-frequency region of the X-axis (Z') represents the bulk resistance (Rb) of the hydrogel. The smaller the intercept, the smaller the charge transport resistance inside the hydrogel, and the better the overall conductivity. The test results show that the bulk resistance of each sample, from smallest to largest, is: Example 2 < Example 4 < Example 3 < Example 1 < Example 5. This result profoundly reveals the synergistic mechanism of the ion-electron dual conductivity network in the system of this invention: 1. Extremely low impedance dominated by ion channels: The bulk resistivity of the samples with high LiCl content (samples obtained in Examples 2 and 4) is as low as below 15 Ω, which is far superior to that of the medium salt (sample obtained in Example 1) and the salt-free group (Examples 3 and 5). This confirms that the free ions dissociated from LiCl construct a high-speed "ion-conducting" pathway in the water molecule channel, which produces a significant synergistic effect with electronic conduction.

[0067] 2. Conductive Polymer Concentration Threshold: The conductive polymer concentration in this application does not conform to the conventional understanding that "the more conductive agent, the better." Comparison with samples of the same salt concentration revealed that the conductivity of samples from Examples 2 and 3 was superior to that of samples from Examples 4 and 5. The bulk resistivity of the sample from Example 2 was 5 Ω, that of the sample from Example 3 was 120 Ω, that of the sample from Example 4 was 15 Ω, and that of the sample from Example 5 was 360 Ω. This demonstrates at the microscopic level that excessive rigid polymer macromolecules will aggregate, compressing the free volume of the flexible network and generating steric hindrance, thereby blocking the rapid migration of ions.

[0068] Impedance experiments confirmed that the optimal solution for overall conductivity in Example 2 was a mixture of 1g of sample solution A, a TA to PEI mass ratio of 1:5, and 0.042g of high-salt LiCl. This invention effectively overcomes the steric hindrance effect caused by the blind stacking of conductive fillers by precisely controlling the component ratios, achieving a perfect balance between microscopic compatibility and macroscopic high conductivity.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A method for preparing a conductive hydrogel with self-healing and antifreeze functions, characterized in that, Includes the following steps: S1. Pretreatment: The conductive polymer aqueous solution is mixed with the secondary dopant, and the mixture is heated for doping and then cooled to obtain mixture A. S2. Prepare a premixed solution by adding deionized water to the amino-rich polymer; mix until the amino-rich water-soluble polymer dissolves to form mixture B. S3. Slowly add mixture A dropwise into mixture B, mix, then add an inorganic salt that is hygroscopic and easily soluble, and mix to form mixture C; S4: During the gelation process, the beaker containing the mixture C is stirred vigorously, and a crosslinking agent containing dynamic disulfide bonds is added in small amounts several times. After mixing, the mixture is placed in a vacuum drying oven and dried for 8-12 hours.

2. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 1, characterized in that, The conductive polymer is selected from an intrinsically conductive polymer with good water dispersibility: one of polyaniline, polypyrrole, and PEDOT:PSS. The secondary dopant is selected from ethylene glycol, N,N-dimethylformamide, methanol, and dimethyl sulfoxide. The amino-rich polymer is selected from chitosan, polyallylamine, polyamide-amine dendritic polymer, or polyethyleneimine. The inorganic salt that is hygroscopic and easily soluble is selected from one of CaCl2, LiBr, ZnCl2 or LiCl; The crosslinking agent containing dynamic disulfide bonds is selected from 3,3'-dithiodipropionic acid or thioctic acid.

3. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 2, characterized in that, The conductive polymer is PEDOT:PSS; The secondary dopant is dimethyl sulfoxide; The amino-rich polymer is polyethyleneimine; The hygroscopic and easily soluble inorganic salt is LiCl; The crosslinking agent containing dynamic disulfide bonds is thioctic acid powder.

4. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 3, characterized in that, The volume ratio of PEDOT:PSS aqueous solution to dimethyl sulfoxide in the mixture A is 10:0.5; The PEDOT content in the PEDOT:PSS aqueous solution was 0.286-0.371 wt%, and the PSS content was 0.714-0.929 wt%. The mass ratio of polyethyleneimine to deionized water in the mixture B is 1:(6.5-8.5); The mass ratio of mixture A, mixture B, LiCl and lipoic acid in mixture C is (0.8-1.2):(7.5-9.5):(0.03-0.05):(0.15-0.25).

5. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 4, characterized in that, The mass ratio of mixture A, mixture B, LiCl and lipoic acid in mixture C is 1:8.758:0.042:0.

2.

6. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 4, characterized in that, The mixing conditions in S1 are: acoustic field resonance for 20-40 minutes, and acceleration controlled at 55-65 m / s². 2 The doping conditions were: heating in a 60 ℃ oven for 1 h; The mixing conditions in S2 are: acoustic field resonance for 5-10 minutes, and acceleration of 55-65 m / s². 2 Continue until the polyethyleneimine is completely dissolved.

7. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 4, characterized in that, The mixing conditions in S3 are as follows: after slowly dripping mixture B into mixture A, the acoustic field resonates for 90-120 minutes, and the acceleration is 55-65 m / s². 2 After adding LiCl, the acoustic field resonated for 10-30 minutes, with an acceleration of 55-65 m / s². 2 , until completely dissolved.

8. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 4, characterized in that, The operation steps in S4 are as follows: place the beaker containing the mixture C in an ice-water bath, stir vigorously, and control the stirring speed at 1100-1300 rpm. Add thioctic acid powder in small amounts several times over 8-10 minutes. After adding the thioctic acid, continue stirring in the ice bath for 3-10 minutes. The mixing conditions in S4 are: acoustic field resonance for 90-120 min, and acceleration of 65-75 m / s². 2 .

9. The method for preparing a conductive hydrogel with self-healing and antifreeze functions according to claim 4, characterized in that, The drying conditions in S4 are as follows: in a vacuum drying oven at 60 ℃, the vacuum is drawn to -0.08 to -0.1 MPa, and the drying time is 8 to 12 hours.

10. A hydrogel with self-healing and antifreeze functions, characterized in that: It is prepared by the method for preparing conductive hydrogels with self-healing and antifreeze functions as described in any one of claims 1-9.

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