Multifunctional ion-conducting high toughness hydrogel and preparation method and application thereof

Abstract

The application discloses a multifunctional ion conductive high-toughness hydrogel as well as a preparation method and application thereof, and belongs to the field of polymer hydrogels. The ion conductive hydrogel comprises a zwitterionic polymer and phytic acid; the ion conductive hydrogel has a double-network structure; zwitterionic monomers are polymerized with each other to form a first double-network structure; and the phytic acid and the zwitterionic polymer form a second double-crosslinked network through non-covalent interaction. The conductivity of the hydrogel can reach 2.44 S / m at the maximum, the strain coefficient (GF) can reach 9.7 at the maximum, and the conductivity is improved by two orders of magnitude compared with that of a polyzwitterionic hydrogel.

Description

Technical Field

[0001] This application relates to a multifunctional ion-conductive high-strength and tough hydrogel, its preparation method and application, belonging to the field of polymer hydrogels. Background Technology

[0002] In recent years, conductive hydrogels have seen significant development in wearable sensors, artificial muscles, and electronic skin due to their excellent mechanical properties and stability, high sensitivity, and stable conductivity. Converting mechanical signals from human activity into electrical signals relies on the electrical properties of conductive hydrogels. Among these, conductivity, as an important property for evaluating the electrical performance of flexible sensors, has received widespread attention and research.

[0003] Depending on the transfer medium, conductive hydrogels can be classified into electronically conductive hydrogels and ionically conductive hydrogels. The former improves conductivity by doping the system with conductive fillers (such as metal nanomaterials, conductive carbon or carbide / nitride nanomaterials, and graphene) or introducing conductive polymers (such as polypyrrole, polyaniline, and PEDOT). However, both the aggregation or random distribution of fillers and the hardness of the conductive polymer can lead to a decrease in gel ductility, resilience, and conductivity. Since these gels transmit electrical signals via electrons and holes, the electrical behavior of the system is easily affected by changes in the internal network structure. Under large strain, the internal network structure of the gel is easily damaged, and the system loses its conductivity. On the other hand, when electronically conductive hydrogels are applied to the detection of human physiological signals, they often exhibit poor biocompatibility. Furthermore, electronic conductors are often opaque, which also poses an obstacle to the fabrication and use of flexible and wearable devices. Ionically conductive hydrogels generally consist of three substrates: water, polymer, and ionic conductor. The water within the hydrogel provides a reliable pathway for the transport of ions within the system, while the polymers, linked by chemical or physical interactions, form a three-dimensional network structure, providing mechanical structural support for the hydrogel. Compared to electronically conductive hydrogels, flexible and wearable devices made from ionically conductive hydrogels exhibit a wider strain detection range, better conductivity, and demonstrate high transparency and good biocompatibility.

[0004] Despite significant progress and development in ion-conducting hydrogels, preparing hydrogels with ideal mechanical properties (such as tensile strength, extensibility, toughness, and resilience) and high electrical conductivity remains a challenge. To date, the preparation of conventional ion-conducting hydrogels mainly involves two steps: (1) preparing a traditional strong and tough hydrogel as a carrier material; and (2) loading an electrolyte into the hydrogel network by immersion in a high-concentration salt solution to improve the material's conductivity. However, immersion in the salt solution disrupts the internal network structure of the strong hydrogel, sacrificing the system's mechanical and adhesive properties while improving conductivity. Furthermore, the complex preparation process increases energy and time costs, resulting in substantial resource waste.

[0005] In biological applications, conductive hydrogel materials need to integrate high conductivity and good mechanical properties to enable them to be compatible with human tissues (such as skin, muscle, heart, or brain) for extended periods. Furthermore, other important parameters should be considered in practical applications, such as: when used as a flexible sensor, conductive hydrogels need to adhere to tissue surfaces; when used on traumatic skin surfaces or post-operatively, the material needs to possess antibacterial properties to prevent invasion and infection by pathogenic microorganisms; and it needs to have a certain degree of freeze resistance to meet the requirements of low-temperature applications.

[0006] Therefore, it is of great significance to explore a simple, low-cost and easy-to-process method to prepare multifunctional conductive hydrogels that match tissue properties and are stable. Summary of the Invention

[0007] According to a first aspect of this application, an ion-conductive hydrogel is provided. This ion-conductive, high-strength, and tough hydrogel utilizes the polymerization of zwitterionic monomers to form a first cross-linked network, and constructs a second cross-linked network through the addition of phytic acid. The first cross-linked network is formed through covalent bonds and electrostatic interactions between the zwitterionic monomers; the second cross-linked network is formed by hydrogen bonds and electrostatic interactions between phytic acid and the zwitterionic polymer. The selected zwitterionic polymer exhibits excellent adhesion, achieving adhesion to various material surfaces and demonstrating universal adhesion. The added phytic acid, while enhancing the gel network and improving adhesion, introduces a large number of free hydrogen ions into the system through phosphate ionization, endowing the hydrogel with excellent conductivity.

[0008] The ion-conductive, high-strength, and tough hydrogel obtained by this method exhibits excellent antibacterial properties. When applied to a wound, it interacts with the bacterial cell membrane, disrupting its structural integrity to achieve antibacterial effects, preventing further wound damage and bacterial invasion, reducing pain, and saving medical costs. The mechanical, adhesive, conductive, antibacterial, and antifreeze properties of this ion-conductive, high-strength, and tough hydrogel can be subjectively controlled by adjusting the relative content of phytic acid and zwitterionic structural units, as well as the reaction conditions.

[0009] This conductive hydrogel combines antibacterial properties, self-adhesion, high light transmittance, stress-strain sensing capabilities, and antifreeze properties, making it suitable for various flexible wearable devices and wound dressings. The conductive hydrogel forms a cross-linked network structure through the polymerization of zwitterionic monomers. The added phytic acid, on the one hand, provides freely moving ions within the gel through dissociation, imparting excellent conductivity; on the other hand, it enhances the gel's mechanical and adhesive properties through electrostatic interactions with zwitterionic groups and skin tissue surface groups. Furthermore, it kills bacteria through interaction with bacteria, achieving antibacterial effects; and it imparts excellent antifreeze properties through strong hydrogen bonding with water molecules. Those skilled in the art can independently determine the appropriate application within the scope defined in this application.

[0010] The ion-conductive, high-strength, and tough hydrogel consists of two functional components: the first component provides excellent mechanical properties and self-adhesive characteristics; the second component imparts antibacterial, antifreeze, and conductive properties to the hydrogel. The two components are bonded together through various non-covalent bonds to enhance the overall material properties, enabling the prepared hydrogel to integrate conductive sensing, antibacterial, antifreeze, and self-adhesive characteristics.

[0011] An ion-conducting hydrogel includes a zwitterionic polymer and phytic acid;

[0012] The ion-conductive hydrogel has a dual network structure;

[0013] zwitterionic monomers polymerize to form the first layer of network structure;

[0014] The phytic acid and the zwitterionic polymer form a second cross-linked network through non-covalent interactions.

[0015] Optionally, the ion-conductive hydrogel consists of a three-dimensional network structure and a continuous aqueous phase.

[0016] Optionally, the zwitterionic units are covalently bonded and electrostatically interact.

[0017] Optionally, the zwitterionic polymer forms dipole-dipole interactions and hydrogen bonding interactions with the tissue interface to achieve adhesion.

[0018] Optionally, the zwitterionic unit contains both cationic and anionic charges on the same macromolecular chain.

[0019] Optionally, the phytic acid dissociates into free hydrogen ions under acidic conditions.

[0020] Optionally, the phytic acid interacts with the groups of the zwitterionic unit through ionic and hydrogen bonding.

[0021] Optionally, the phosphate groups in the phytic acid form hydrogen bonds with water molecules.

[0022] Phytic acid disrupts the structural integrity of bacteria by interacting with the bacterial cell membrane.

[0023] Optionally, the zwitterionic monomer is selected from at least one of methacryloylethyl sulfobetaine, 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propionate, 2-((3-acrylamidopropyl)dimethylammonium)acetate, and 2-methacryloyloxyethyl phosphocholine.

[0024] Optionally, the water content in the ion-conductive hydrogel is 0.36 to 0.61%.

[0025] Optionally, the molar percentage of the zwitterionic polymer in the ion-conductive hydrogel is 0.67 to 0.95.

[0026] Optionally, the phytic acid in the ion-conductive hydrogel has a molar ratio of 0.04 to 0.33.

[0027] The zwitterionic monomers provide a polymer network structure after polymerization: on the one hand, the zwitterionic monomers can form a hydrogel network structure through free radical polymerization under the action of initiators and crosslinking agents; on the other hand, the zwitterionic units strengthen the network strength through electrostatic interactions.

[0028] The zwitterionic monomers provide an environment rich in ionic components: on the one hand, the hydrogel itself is composed of a three-dimensional network structure and a continuous aqueous phase, which can provide a large number of channels for ion migration; on the other hand, the zwitterionic monomers contain both cationic and anionic charges on the same macromolecular chain, which can construct a network structure rich in charge units.

[0029] The zwitterionic units provide adhesive properties to the gel: they can form dipole-dipole interactions and hydrogen bonding interactions with the tissue interface to achieve adhesion, and have a certain degree of universal adhesion.

[0030] Phytic acid, acting as an ionic crosslinking agent, interacts with zwitterionic groups through ionic and hydrogen bonds, thereby enhancing the mechanical properties of the material.

[0031] The phytic acid dissociates to generate a large number of free hydrogen ions, which, through their interaction with the charged groups of the zwitterionic components, endow the hydrogel with high ionic conductivity.

[0032] Phytic acid enhances antifreeze performance: the abundant phosphate groups in phytic acid can form strong hydrogen bonds with water molecules, reducing water evaporation and crystallization in the system, thus achieving excellent antifreeze performance.

[0033] Phytic acid can achieve antibacterial effects by interacting with bacterial cell membranes and disrupting their structural integrity, thus preventing further damage to wounds and bacterial invasion, reducing pain, and saving medical costs.

[0034] Optionally, the molar percentage of the zwitterionic monomer polymer in the ion-conductive hydrogel is independently selected from any value of 0.67, 0.73, 0.79, 0.85, 0.91, 0.95 or any range between both.

[0035] Optionally, the molar percentage of phytic acid in the ion-conductive hydrogel is independently selected from any value of 0.04, 0.11, 0.18, 0.25, 0.31, 0.33 or a range between any two.

[0036] Optionally, the water content in the ion-conductive hydrogel is independently selected from any value or a range between 0.36, 0.38, 0.40, 0.42, 0.44, 0.46, 0.48, 0.50, 0.52, 0.54, 0.56, 0.58, 0.60, and 0.61.

[0037] According to a second aspect of this application, a method for preparing an ion-conductive hydrogel is provided. This method is simple and controllable, and can be achieved by free radical polymerization of zwitterionic monomers and phytic acid in the presence of a small amount of initiator and chemical crosslinking agent. It is quick to prepare, low in cost, and easy to put into large-scale industrial production.

[0038] A method for preparing an ion-conducting hydrogel includes the following steps:

[0039] S1. Stir the mixture containing zwitterionic monomers, phytic acid, initiator and chemical crosslinking agent to obtain a gel prepolymer solution;

[0040] S2. Inject the gel prepolymer into a mold and cure it under ultraviolet light or by heating to obtain an ion-conductive hydrogel.

[0041] Optionally, in step S1, the stirring speed is not less than 750 r / min.

[0042] Optionally, in step S1, the concentration of phytic acid is 0.1 mol / L to 1 mol / L.

[0043] Optionally, the concentration of phytic acid is independently selected from any value or a range between 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, and 1.0 mol / L.

[0044] Optionally, the phytic acid concentration is 0.6 mol / L.

[0045] Optionally, in step S1, the concentration of the zwitterionic monomer is 2.0 mol / L to 4.2 mol / L.

[0046] Optionally, the concentration of the zwitterionic monomer is independently selected from any value or a range between 2.0 mol / L, 3 mol / L, 3.2 mol / L, 3.4 mol / L, 3.6 mol / L, 3.8 mol / L, 4 mol / L, and 4.2 mol / L.

[0047] Optionally, the concentration of the zwitterionic monomer is 4 mol / L.

[0048] Optionally, in step S1, the initiator includes at least one of a photoinitiator and a thermal initiator.

[0049] Optionally, in step S1, the photoinitiator is selected from at least one of 2-hydroxy-2-methylphenylacetone, 2-oxoglutaric acid, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone.

[0050] Optionally, in step S1, the thermal initiator is selected from at least one of potassium persulfate, ammonium persulfate, and sodium persulfate.

[0051] Optionally, in step S1, the chemical crosslinking agent is selected from at least one of polyethylene glycol diacrylate, N,N-methylenebisacrylamide, polyethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, (meth)acrylate ethyleneoxy polyethylene glycol ester, and 6,6'-diamino-3,3'-methylenedibenzoic acid.

[0052] Optionally, the concentration of the initiator is 0.002 mol / L to 0.02 mol / L.

[0053] Optionally, the concentration of the initiator is independently selected from any value or a range between any two of 0.002 mol / L, 0.004 mol / L, 0.006 mol / L, 0.008 mol / L, 0.009 mol / L, 0.010 mol / L, 0.011 mol / L, 0.012 mol / L, 0.013 mol / L, 0.014 mol / L, 0.015 mol / L, 0.016 mol / L, 0.018 mol / L, and 0.02 mol / L.

[0054] Optionally, the concentration of the initiator is 0.012 mol / L.

[0055] Optionally, in step S1, the concentration of the chemical crosslinking agent is 0.002 mol / L to 0.02 mol / L.

[0056] Optionally, the concentration of the chemical crosslinking agent is independently selected from any value or a range between 0.002 mol / L, 0.004 mol / L, 0.006 mol / L, 0.008 mol / L, 0.009 mol / L, 0.010 mol / L, 0.011 mol / L, 0.012 mol / L, 0.013 mol / L, 0.014 mol / L, 0.015 mol / L, 0.016 mol / L, 0.018 mol / L, and 0.02 mol / L.

[0057] Optionally, the concentration of the crosslinking agent is 0.012 mol / L.

[0058] Optionally, in step S2, the UV curing conditions are as follows:

[0059] The time is 10 min to 45 min.

[0060] Optionally, in step S2, the wavelength of the ultraviolet light is 200nm to 420nm.

[0061] Optionally, in step S2, the heating conditions are as follows:

[0062] The temperature is 55℃~85℃;

[0063] The time is from 18:00 to 24:00.

[0064] Optionally, the conditions for UV curing (free radical polymerization) are: curing for 20 minutes under UV light at a wavelength of 365 nm in the presence of a crosslinking agent and a photoinitiator.

[0065] Optionally, the heating (free radical polymerization) conditions are as follows: in the presence of a crosslinking agent and a thermal initiator, the water bath temperature is 65°C, and the water bath polymerization lasts for 20 hours.

[0066] Optionally, the following steps are included:

[0067] A1. Dissolve the zwitterionic monomer uniformly in water to obtain a zwitterionic monomer dispersion;

[0068] A2. Add the mixture containing phytic acid, crosslinking agent and initiator to the zwitterionic monomer dispersion, and mix to obtain a gel prepolymer solution;

[0069] A3. The gel prepolymer is injected into a molding mold, and a free radical polymerization reaction is carried out to obtain an ion-conductive hydrogel.

[0070] According to a third aspect of this application, an application of an ion-conducting hydrogel is provided.

[0071] Applications of the ion-conducting hydrogels described above and / or the ion-conducting hydrogels prepared by the methods described above in flexible wearable devices and wound dressings.

[0072] The flexible wearable devices include fields such as limb motion monitoring, stress and strain distribution monitoring, human tissue motion detection, and artificial intelligence.

[0073] According to one embodiment of this application, the preparation method of the phytic acid composite zwitterionic polymer hydrogel includes at least the following steps:

[0074] (1) The zwitterionic monomer is fully dissolved in water by ultrasound and stirring, and the molar concentration of the zwitterionic monomer added is 4 mol / L.

[0075] (2) Add phytic acid to the aqueous solution of the zwitterionic monomer prepared above, mix, then add 0.012 mol / L of crosslinking agent and 0.012 mol / L of initiator, mix evenly until the solution is clear, and obtain the gel prepolymer solution.

[0076] (3) The gel prepolymer obtained in step (2) is injected into the molding mold and subjected to free radical polymerization to obtain the multifunctional ion-conductive high-strength and tough hydrogel.

[0077] The beneficial effects that this application can produce include:

[0078] 1) The multifunctional ion-conductive high-strength and tough hydrogel provided in this application uses zwitterionic polymers to construct the main network of the gel. The zwitterionic polymers selected have excellent adhesion and can adhere to different material surfaces, showing universality of adhesion. At the same time, the addition of phytic acid can enhance the adhesion ability of the hydrogel while imparting conductivity, thus achieving a comprehensive improvement in conductivity and adhesion. Its adhesion strength on the surface of pigskin can reach up to 21.5 kPa, which is 1 times higher. In the visible light range (780-400 nm), it can achieve a visible light transmittance of more than 90%. It can withstand a low temperature of -50℃.

[0079] 2) The multifunctional ion-conductive high-strength and tough hydrogel provided in this application utilizes the polymerization of zwitterionic monomers to form a first polymer network. The added phytic acid enhances the polymer structure of the gel network through hydrogen bonding and electrostatic interactions, thereby improving various mechanical properties. The maximum elongation at break can reach 422%, and the maximum tensile strength can reach 333 kPa, which is 3 times higher than the group without phytic acid. The maximum compressive strength can reach 4.22 MPa, which is 2 times higher than the group without phytic acid. At the same time, the addition of phytic acid and the ionization of phosphate introduce a large number of freely moving ions into the system, further enhancing the conductivity of the hydrogel. Its conductivity can reach a maximum of 2.44 S / m, and the strain coefficient (GF) can reach a maximum of 9.7, which is two orders of magnitude higher than the control group of zwitterionic hydrogels.

[0080] 3) The multifunctional ion-conductive high-strength and tough hydrogel provided in this application has excellent antibacterial properties. When applied to a wound, it can interact with the bacterial cell membrane to disrupt its structural integrity, thereby achieving antibacterial effects, preventing further damage to the wound and bacterial invasion, reducing pain, and saving medical costs.

[0081] 4) The multifunctional ion-conductive high-strength and tough hydrogel provided in this application has a simple and controllable preparation method. It can be achieved by free radical polymerization of zwitterionic monomers and phytic acid in the presence of a small amount of initiator and chemical crosslinking agent. It is quick to produce, low in cost, and easy to put into large-scale industrial production.

[0082] 5) The mechanical properties, adhesive properties, electrical properties, antibacterial properties and antifreeze properties of the multifunctional ion-conductive high-strength and tough hydrogel provided in this application can be subjectively controlled by adjusting the relative content of phytic acid and zwitterionic monomer structural units and the reaction conditions. Attached Figure Description

[0083] Figure 1 This is a schematic diagram of the tensile properties of the ion-conductive high-strength and high-toughness hydrogel of this application.

[0084] Figure 2This is a schematic diagram of the compression properties of the ion-conductive high-strength and tough hydrogel of this application.

[0085] Figure 3 This is a schematic diagram of the adhesion properties of the ion-conductive high-strength and tough hydrogel of this application.

[0086] Figure 4 This is a schematic diagram of the conductivity of the ion-conductive high-strength and tough hydrogel of this application.

[0087] Figure 5 This is a schematic diagram showing the relative resistance change rate and strain coefficient (GF) changes of the ion-conductive high-strength and tough hydrogel of this application.

[0088] Figure 6 This is the transmittance spectrum of the ion-conductive high-strength and tough hydrogel of this application in the visible light range.

[0089] Figure 7 This is a schematic diagram of the antibacterial properties of the ion-conductive high-strength and tough hydrogel of this application, where a represents Escherichia coli and b represents Staphylococcus aureus.

[0090] Figure 8 The thermal property reaction curves of the ion-conductive high-strength and tough hydrogel of this application are shown. Detailed Implementation

[0091] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0092] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.

[0093] The analysis method in the embodiments of this application is as follows:

[0094] The conductivity of the hydrogel was tested using a four-probe tester (Jiangsu Jingge).

[0095] The mechanical and adhesive properties of the hydrogel were tested using a universal testing machine (Sansitaijie).

[0096] The thermal properties of the hydrogel were determined using a differential scanning calorimeter (DSC) of TA Instruments DSC2500.

[0097] The inhibition zone experiment was used to study the antibacterial effect of hydrogels on Gram-positive bacteria (such as Staphylococcus aureus) and Gram-negative bacteria (such as Escherichia coli).

[0098] Example 1

[0099] (1) The 4 mol / L methacryloyl ethyl sulfobetaine (SBMA) monomer was fully dissolved in water by ultrasonication and stirring (750 r / min).

[0100] (2) Add phytic acid with a molar concentration of 0.1, 0.2, 0.4, 0.6, 0.8, or 1.0 mol / L to the aqueous solution of the zwitterionic monomer prepared above. After mixing, add 0.012 mol / L polyethylene glycol diacrylate and 0.012 mol / L 2-hydroxy-2-methylphenylacetone. Mix until the solution is clear to obtain a gel prepolymer solution.

[0101] (3) The gel prepolymer obtained in step (2) is injected into the molding mold and cured for 20 minutes under ultraviolet light with a wavelength of 365nm to obtain the multifunctional ion-conductive high-strength and tough hydrogel, which are named "SP-1, SP-2, SP-4, SP-6, SP-8, SP-10" respectively.

[0102] The prepared multifunctional ion-conductive high-strength and tough hydrogels exhibit different mechanical properties, adhesive properties, antibacterial properties and conductive properties due to differences in ion concentration.

[0103] Example 2

[0104] The preparation method is the same as in Example 2, except that the zwitterionic monomer of methacryloyl ethyl sulfobetaine (SBMA) is replaced by 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propionate (CBMA) with a molar concentration of 4 mol / L. The hydrogel prepared is named CP-x (x represents different contents of phytic acid) hydrogel using the same method as above.

[0105] The CP series hydrogels prepared by this method exhibit similar trends in mechanical properties, antibacterial properties, and electrical conductivity as the SP series hydrogels prepared in Example 1.

[0106] Example 3

[0107] (1) The monomer of 4 mol / L methacryloyl ethyl sulfobetaine (SBMA) was fully dissolved in water by ultrasound and stirring.

[0108] (2) Add 0.1 mol / L phytic acid to the aqueous solution of the zwitterionic monomer prepared above, mix, then add 0.012 mol / L polyethylene glycol diacrylate and 0.012 mol / L ammonium persulfate, mix evenly until the solution is clear, and obtain the gel prepolymer solution.

[0109] (3) Inject the gel prepolymer obtained in step (2) into the molding mold and polymerize it in a water bath at a temperature of 65°C for 20 hours.

[0110] The hydrogel prepared according to the above method has almost the same mechanical and electrical properties as the SP series hydrogel obtained in Example 1.

[0111] Comparative Example 1

[0112] (1) The monomer of 4 mol / L methacryloyl sulfonate betaine (SBMA) was fully dissolved in water by ultrasonication and stirring at 750 r / min.

[0113] (2) Add 0.012 mol / L polyethylene glycol diacrylate and 0.012 mol / L 2-hydroxy-2-methylphenylacetone to the aqueous solution of the zwitterionic monomer prepared above without adding phytic acid, and mix well until the solution is clear to obtain the gel prepolymer solution.

[0114] (3) The gel prepolymer obtained in step (2) is injected into the molding mold and cured for 20 minutes under ultraviolet light with a wavelength of 365nm to obtain the multifunctional ion-conductive high-strength and tough hydrogel, named "SP-0".

[0115] Similarly, the hydrogels prepared by the above method were characterized for a series of mechanical properties, adhesive properties, electrical conductivity, antibacterial properties and antifreeze properties, and the results were summarized.

[0116] Comparative Example 2

[0117] MP hydrogels were prepared by combining the cationic monomer methacryloyloxyethyltrimethylammonium chloride (MTAC) with phytic acid, as follows:

[0118] (1) The 4 mol / L methacryloyloxyethyltrimethylammonium chloride (MTAC) monomer was fully dissolved in water by ultrasonication and stirring at 750 r / min.

[0119] (2) Add phytic acid with a molar concentration of 0.6 mol / L, N,N'-methylenebisacrylamide with a molar concentration of 0.012 mol / L and 2-hydroxy-2-methylphenylacetone with a molar concentration of 0.012 mol / L to the monomer aqueous solution prepared above, mix evenly until the solution is clear, and obtain the gel prepolymer solution.

[0120] (3) The gel prepolymer obtained in step (2) is injected into the molding mold and cured under ultraviolet light at a wavelength of 365nm for 60 minutes to form a hydrogel, which is named "MP-6".

[0121] Comparative Example 3

[0122] AP hydrogels were prepared by combining the anionic monomer 2-acrylamido-2-methylpropanesulfonic acid (AMPS) with phytic acid, as follows:

[0123] (1) Dissolve 4 mol / L 2-acrylamido-2-methylpropanesulfonic acid (AMPS) monomer in water by ultrasonication and stirring at 750 r / min.

[0124] (2) Add phytic acid with a molar concentration of 0.6 mol / L, polyethylene glycol diacrylate with a molar concentration of 0.012 mol / L and 2-hydroxy-2-methylphenylacetone with a molar concentration of 0.012 mol / L to the monomer aqueous solution prepared above, mix evenly until the solution is clear, and obtain gel prepolymer solution.

[0125] (3) The gel prepolymer obtained in step (2) is injected into the molding mold and cured for 20 minutes under ultraviolet light with a wavelength of 365nm to form a hydrogel, which is named "AP-6".

[0126] The tensile mechanical properties of the MP-6 and AP-6 hydrogels prepared above were tested using a universal testing machine (Sansitaijie), repeated three times. The tensile stress of MP-6 hydrogel was 9.8 kPa and the elongation at break was 380.6%; the tensile stress of AP-6 hydrogel was 17.0 kPa and the elongation at break was 183.6%, neither of which meets the requirements for the fabrication of flexible sensors. Comparing the performance of the SP series hydrogels, it can be seen that the mechanical strength of hydrogels prepared from cationic or anionic monomers is much lower than that of hydrogels prepared from zwitterionic monomers under the same preparation conditions.

[0127] Comparative Example 4

[0128] The monomer of 4 mol / L methacryloyl sulfonate betaine (SBMA) was mixed with an aqueous solution by stirring only, with the stirring speed set to 750 r / min.

[0129] After stirring for 10 minutes, it was found that methacrylsulfonic acid betaine did not form a homogeneous liquid system, some monomers were difficult to dissolve, and some monomers had undergone self-polymerization in the solution, making it impossible to continue subsequent experimental operations.

[0130] Analysis example 1

[0131] The mechanical properties of the SP and CP hydrogels prepared in Examples 1, 2, and 3, as well as the SP-0 hydrogel of Comparative Example 1, were tested using a universal testing machine (Sansitaijie). These tests included tensile and compressive property tests. For the tensile test: the hydrogels were prepared into dumbbell-shaped specimens of the same size, and their tensile properties were tested at a crosshead speed of 100 mm / min until fracture. Figure 1 As shown. For the compression test: the hydrogel was cut into cylinders of uniform size and thickness and compressed at a rate of 10% strain per minute until 90% strain was reached, as shown. Figure 2 As shown.

[0132] The mechanical property test results of the two types show that the multifunctional ion-conductive high-strength and tough hydrogel prepared by this method can reach a maximum tensile strength of 333 kPa, a maximum elongation at break of 422%, and a maximum compressive strength of 4.22 MPa, indicating that the hydrogel prepared by this method has excellent mechanical properties.

[0133] Analysis example 2

[0134] The adhesion properties of SP and CP hydrogels on pigskin surface were measured using an lap shear test with a multi-functional testing machine. The experimental results are as follows: Figure 3 As shown, the hydrogel prepared by the above method has a maximum adhesion strength of 21.5 kPa on the surface of pigskin. Simultaneously, tests revealed that the prepared hydrogel can adhere to various materials such as rubber, glass, plastic, and metal, indicating that the hydrogel prepared by zwitterionic bonding has universal adhesion properties.

[0135] Analysis example 3

[0136] The SP hydrogel prepared by the above method was cut into rectangular samples of uniform size and thickness. The resistivity of the SP hydrogel was measured using a four-probe resistivity meter, and the conductivity of the material was calculated. Figure 4 As shown, the hydrogel has a maximum conductivity of 2.44 S / m, which is two orders of magnitude higher than that of zwitterionic hydrogels. Furthermore, the conductivity of the hydrogel first increases and then decreases with the increase of phytic acid content.

[0137] Analysis example 4

[0138] The SP hydrogel prepared by the above method was cut into rectangular samples of uniform size and thickness (50mm*40mm*1.8mm). The SP hydrogel was tested using an electrochemical workstation in constant voltage mode to obtain the relationship between the relative resistivity change rate (ΔR / R0) and its tensile strain. The strain coefficient (GF) is an important parameter for evaluating the sensitivity of strain sensors and can be defined as the ratio of the relative resistivity change rate to the strain. Figure 5 As shown, the resistance change rate of the hydrogel exhibits a nonlinear monotonically increasing trend with increasing strain, while its strain coefficient GF shows a linear monotonically increasing trend, with GF reaching a maximum of 9.7.

[0139] Considering the combined mechanical and electrical properties of the hydrogel, it can be found that the hydrogel prepared by the above method meets the requirements for fabricating flexible and wearable devices.

[0140] Analysis example 5

[0141] SP-6 hydrogels with a concentration of 0.6 mol / L and a thickness of 1 mm were prepared using the method described above. The transmittance spectrum of the hydrogel material was characterized using a UV-Vis spectrophotometer, and the transmittance of air was measured as a baseline, with the wavelength range selected as 800-400 nm.

[0142] like Figure 6 As shown, SP-6 hydrogel exhibits excellent light transmittance in the visible light range (780-400nm), achieving a visible light transmittance of over 90%. When applied to health monitoring, it facilitates the accurate location of attachment points on tissues and allows for real-time observation of tissue surface conditions.

[0143] Analysis example 6

[0144] The SP hydrogel prepared by the above method was cut into cylindrical shapes with a diameter of 10 mm and a thickness of 1.8 mm using a circular cutter. The hydrogel was placed in an agar plate coated with the same concentration of Escherichia coli and incubated at 37°C for 18 hours. The diameter of the inhibition zone was observed and the difference between the diameter of the inhibition zone and the diameter of the gel sample was recorded. The inhibition zone experiment for Staphylococcus aureus was performed in the same manner, and the results are as follows. Figure 7 As shown.

[0145] The results of the inhibition zone experiment show that the multifunctional ion-conductive high-strength and tough hydrogel prepared by this method has excellent antibacterial properties against both Gram-positive and Gram-negative bacteria. The implantable device prepared by this method can effectively reduce the harm of pathogenic microorganisms to human health.

[0146] Analysis example 7

[0147] The SP-0, SP-2, SP-4, SP-6, SP-8, and SP-10 hydrogels prepared by the above method were used sequentially, and their thermal properties were measured using differential scanning calorimetry (DSC). Approximately 20 mg of crucible test sample was weighed, and an empty crucible of the same material was selected as a test reference. The hydrogels were cooled from 30°C to -90°C at a rate of -2°C / min.

[0148] like Figure 8 As shown, during the cooling process from 30℃ to -90℃, the phytic acid content in the system increases, which enhances the strong hydrogen bonding with water, and the antifreeze ability of SP hydrogel gradually improves. When the phytic acid content in the system reaches 1 mol / L (SP-10), no obvious exothermic peak appears during the entire heating process, indicating that the material has excellent low-temperature antifreeze performance.

[0149] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing an ion-conducting hydrogel, characterized in that, Includes the following steps: S1. Stir the mixture containing zwitterionic monomer, phytic acid, initiator and chemical crosslinking agent to obtain a gel prepolymer solution; wherein the concentration of the zwitterionic monomer is 2.0 mol / L ~ 4.2 mol / L and the concentration of the phytic acid is 0.2 mol / L ~ 1 mol / L; Step S1 specifically includes: A1. Dissolve the zwitterionic monomer in water by ultrasonication and stirring to obtain a zwitterionic monomer dispersion. A2. Add the mixture containing phytic acid, crosslinking agent and initiator to the zwitterionic monomer dispersion, and mix to obtain a gel prepolymer solution; The zwitterionic monomer is selected from at least one of methacryloylethyl sulfobetaine, 3-[[2-(methacryloyloxy)ethyl]dimethylammonium]propionate, 2-((3-acrylamidopropyl)dimethylammonium)acetate, and 2-methacryloyloxyethyl phosphocholine; The chemical crosslinking agent is selected from at least one of polyethylene glycol diacrylate, N,N-methylenebisacrylamide, polyethylene glycol dimethacrylate, and polyethylene dimethacrylate; S2. Inject the gel prepolymer liquid into a mold, and perform free radical polymerization reaction by UV curing or heating to obtain an ion-conductive hydrogel.

2. The preparation method according to claim 1, characterized in that, In step S1, the stirring speed shall not be less than 750 r / min; In step S1, the initiator includes at least one of a photoinitiator and a thermal initiator; In step S1, the photoinitiator is selected from at least one of 2-hydroxy-2-methylphenylacetone, 2-oxoglutaric acid, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone; In step S1, the thermal initiator is selected from at least one of potassium persulfate, ammonium persulfate, and sodium persulfate.

3. The preparation method according to claim 1, characterized in that, The concentration of the initiator is 0.002 mol / L ~ 0.02 mol / L; In step S1, the concentration of the chemical crosslinking agent is 0.002 mol / L ~ 0.02 mol / L.

4. The preparation method according to claim 1, characterized in that, In step S2, the UV curing conditions are as follows: The time is 10 min to 45 min; In step S2, the wavelength of the ultraviolet light is 200 nm ~ 420 nm.

5. The preparation method according to claim 1, characterized in that, In step S2, the heating conditions are as follows: The temperature ranges from 55°C to 85°C. The time period is 18 h to 24 h.

6. The application of the ion-conductive hydrogel obtained by the preparation method according to any one of claims 1 to 5 in flexible wearable devices and wound dressings.

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