Zwitterionic composite hydrogel adhesive and method of making same

Abstract

The application discloses a kind of zwitterionic composite hydrogel adhesive and preparation method thereof, the method uses one-pot copolymerization method, with MBAA and borax as crosslinking agent, preparation contains SBMA, PVA, THMA and AMPS zwitterionic polyelectrolyte hydrogel, with excellent adhesive property and biocompatibility, suitable for biological medicine field.The method polyvinyl alcohol enhances the physical properties of hydrogel due to its crosslinking site and hydrogen bond.SBMA cationic and anionic group improves the adhesive property, and the reaction monomer THMA provides hydrogen bond effect, further promotes adhesion, so that the prepared hydrogel adhesive exhibits excellent adhesive property and biocompatibility, suitable for wound dressing, drug release system and tissue engineering biological medicine applications.

Description

Technical Field

[0001] This invention belongs to the field of bioadhesive development technology, and relates to an amphoteric ion composite hydrogel adhesive and its preparation method. Background Technology

[0002] The research field of medical adhesives is broad and in-depth, aiming to continuously overcome the various limitations of traditional adhesives. For example, the cyanoacrylate-based adhesive disclosed in patent number CN202211429820.3, while performing well in some aspects, faces problems such as insufficient elasticity at the bonded joint, short shelf life, and easy solidification, which greatly limits its scope and effectiveness in practical applications. Similarly, the fibrin adhesive described in patent number CN202310060671.6, despite its advantages such as biocompatibility, also suffers from defects such as low bonding strength and low hardness, making it difficult to meet complex and ever-changing medical needs.

[0003] Against this backdrop, hydrogels, as unique semi-solid materials, are considered polymeric materials highly similar to human soft tissue due to their three-dimensional network structure and abundant hydrophilic groups. Among them, zwitterionic hydrogels, with their unique properties such as high ion density and ion sensitivity, have shown broad application prospects in flexible sensing, biomaterials, and medical engineering. However, despite the many advantages of zwitterionic hydrogels, their mechanical properties are relatively weak, and their adhesion needs improvement; their overall performance cannot yet fully meet the needs of practical applications. Furthermore, due to these limitations, the application scenarios of zwitterionic hydrogels are relatively limited, hindering their potential in broader medical fields. Therefore, how to further improve the mechanical properties and adhesion capabilities of zwitterionic hydrogels and broaden their application scenarios is a crucial issue that urgently needs to be addressed in the current research field of medical adhesives. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides an amphoteric ionic composite hydrogel adhesive and its preparation method, thereby solving the technical problems of poor mechanical properties and adhesion of amphoteric ionic hydrogels in the prior art.

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

[0006] A method for preparing a zwitterionic composite hydrogel adhesive includes the following steps:

[0007] S1: Dissolve the reactive monomers SBMA and AMPS in water, sonicate at room temperature to ensure complete dissolution, then add THMA, stir until homogeneous, add initiator and crosslinking agent, sonicate to dissolve, and obtain precursor solution;

[0008] S2: Add PVA aqueous solution to the precursor solution to carry out free radical polymerization reaction to obtain the zwitterionic composite hydrogel adhesive.

[0009] Preferably, the ratio of the reactive monomer SBMA to AMPS is (9~5):(1~5) by mass.

[0010] Preferably, the ratio of THMA to SBMA and AMPS by mass parts is 1:(9~5):(1~5).

[0011] Preferably, the ratio of PVA to SBMA and AMPS by mass is 20:(9~5):(1~5).

[0012] Preferably, the ratio of SBMA to AMPS and initiator by mass parts is (25~13):(2~13):1.

[0013] Preferably, the ratio of SBMA to AMPS and crosslinking agent by mass parts is (300~160):(30~160):1.

[0014] Preferably, the crosslinking agent is N,N'-methylenebisacrylamide and borax; the ratio of N,N'-methylenebisacrylamide to borax is (1~5):(1~10) by mass.

[0015] Preferably, the preparation process of the PVA aqueous solution is as follows: dissolve PVA in water and heat and stir at 90~100℃ for 5~8 hours to obtain the PVA aqueous solution.

[0016] Preferably, the free radical polymerization reaction is carried out at a temperature of 35-45°C for 10-15 hours.

[0017] A zwitterionic composite hydrogel adhesive is prepared by the above method; the tensile strength of the zwitterionic composite hydrogel adhesive is 0.07~0.14MPa, and the adhesion force is 20~33Kpa.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] This invention discloses a method for preparing a zwitterionic composite hydrogel adhesive. The method involves incorporating the anionic monomer 2-acrylamide-2-methylpropanesulfonate (AMPS) into a bilayer network of zwitterionic polymers ([2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propane)ammonium hydroxide, SBMA) and polyvinyl alcohol (PVA). During the reaction, N-[tris(hydroxymethyl)methyl]acrylamide (THMA) is added to provide hydrogen bonding to the polymer, thereby further promoting adhesion. The zwitterionic composite hydrogel adhesive is prepared in a one-pot process. Polyvinyl alcohol (PVA) has abundant crosslinking sites and multiple hydrogen bonds. Zwitterionic SBMA has both cationic and anionic groups and a high dipole moment. This strong dipole moment allows it to adhere to many surfaces through ion-dipole or dipole-dipole interactions. The chain-to-chain association between its polymers can provide physical crosslinking to enhance the mechanical properties of the hydrogel adhesive. The reactive monomer N-[tris(hydroxymethyl)methyl]acrylamide (THMA) provides hydrogen bonding to the polymer, thereby further promoting adhesion. The zwitterionic composite hydrogel adhesive of this invention is safe, simple, easy to operate, and inexpensive to prepare. This adhesive exhibits rapid gelation, is easy to operate, enables rapid bonding, and demonstrates high adhesion strength on the epidermis, making it suitable for applications such as bonding sensor materials, wound hemostasis, and adhesion. The PVA used in this invention possesses abundant crosslinking sites and multiple hydrogen bonds, which contribute to enhancing the hydrogel's performance. The reactive monomer SBMA has both cationic and anionic groups, maintaining overall electroneutrality. This strong dipole property allows for adhesion to various surfaces through ion-dipole or dipole-dipole interactions, and the association between its polymer chains provides physical crosslinking, thereby enhancing the mechanical properties of the water-based adhesive. AMPS, as an anionic monomer, can improve the system's conductivity. The zwitterionic composite hydrogel prepared by this invention has minimal impact on bioactive substances, thus exhibiting good bioactivity in tissue engineering and possessing broad application potential in the biomedical field.

[0020] Furthermore, based on mass fractions, the ratio of the reactive monomer SBMA to AMPS is (9~5):(1~5), which effectively ensures the adhesion performance of the hydrogel and improves its mechanical properties.

[0021] Furthermore, the ratio of THMA to SBMA and AMPS by mass is 1:(9~5):(1~5), which can improve the adhesion of the hydrogel.

[0022] Furthermore, based on mass fractions, the ratio of PVA to SBMA and AMPS is 20:(9~5):(1~5), which can improve the degree of network cross-linking.

[0023] Furthermore, based on mass fractions, the ratio of SBMA to AMPS and the initiator is (25~13):(2~13):1, effectively ensuring the full progress of the cross-linking reaction.

[0024] Furthermore, based on mass parts, the ratio of SBMA to AMPS and crosslinking agent is (300~160):(30~160):1, which allows the monomers to undergo a full crosslinking reaction.

[0025] Furthermore, the crosslinking agent is N,N'-methylenebisacrylamide and borax; the ratio of N,N'-methylenebisacrylamide to borax is (1~5):(1~10) by mass. N,N'-methylenebisacrylamide can form covalent bonds with monomer molecules during polymerization, thereby constructing a tight chemical crosslinking network. Borax can release borate ions in aqueous solution. These ions can form ionic crosslinks with functional groups (such as hydroxyl and carboxyl groups) on polymer chains, constructing an ionic crosslinking network. The two crosslinking agents work together to form a double crosslinking network structure, giving the hydrogel higher strength and stability. By adjusting the ratio of N,N'-methylenebisacrylamide to borax, the crosslinking density of the hydrogel can be controlled. A higher crosslinking density can improve the mechanical strength and wear resistance of the hydrogel, while a lower crosslinking density may give the hydrogel better flexibility and elasticity. This controllability allows the hydrogel to meet the needs of different application scenarios.

[0026] Furthermore, the preparation process of the PVA aqueous solution is as follows: PVA is dissolved in water and heated and stirred at 90~100℃ for 5~8 hours to obtain the PVA aqueous solution, which can improve the degree of cross-linking of the system.

[0027] Furthermore, the free radical polymerization reaction is carried out at a temperature of 35–45°C for 10–15 hours. Setting the reaction temperature within this range ensures a suitable reaction rate while avoiding side reactions and product degradation that may result from excessively high temperatures. This temperature range facilitates the complete dissolution and diffusion of monomer molecules, promoting chain growth and thus improving the efficiency of the polymerization reaction and the molecular weight of the product. The 10–15 hour reaction time ensures the polymerization reaction proceeds fully. During this period, monomer molecules can be fully converted into polymer chains, forming a stable cross-linked network structure. Simultaneously, the longer reaction time helps reduce the residue of unreacted monomers and byproducts, improving the purity and quality of the product. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 FTIR spectra of different reactive monomers and synthesized PSAT zwitterionic composite hydrogels;

[0030] Figure 2 The results of uniaxial tensile tests on the zwitterionic composite hydrogels prepared in Examples 1-3 of this invention are shown.

[0031] Figure 3 The adhesion test curves of the zwitterionic composite hydrogels prepared in Examples 1-3 of the present invention and the PST prepared in Comparative Example 1 are shown.

[0032] Figure 4 The antibacterial performance test results of the zwitterionic composite hydrogels prepared in Examples 1-3 of the present invention are shown, wherein (a) is a schematic diagram of the antibacterial zone of the hydrogel and (b) is a diagram of the diameter measurement of the antibacterial zone of the hydrogel.

[0033] Figure 5 The images show the hemolysis patterns of the zwitterionic composite hydrogels prepared in Examples 1-3 of this invention.

[0034] Figure 6 This is a schematic diagram illustrating hydrogel as a wound dressing. Detailed Implementation

[0035] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0036] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0037] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0038] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0039] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0040] This invention provides a method for preparing a zwitterionic composite hydrogel adhesive, comprising the following steps:

[0041] S1: Dissolve the reactive monomers SBMA and AMPS in water, sonicate at room temperature to ensure complete dissolution, then add THMA, stir until homogeneous, add initiator and crosslinking agent, sonicate to dissolve, and obtain precursor solution;

[0042] The ratio of the reactive monomers SBMA to AMPS, by mass parts, is (9~5):(1~5). The ratio of THMA to SBMA and AMPS is 1:(9~5):(1~5). The ratio of PVA to SBMA and AMPS is 20:(9~5):(1~5). The ratio of SBMA to AMPS and the initiator is (25~13):(2~13):1. The ratio of SBMA to AMPS and the crosslinking agent is (300~160):(30~160):1. The crosslinking agent is N,N'-methylenebisacrylamide and borax; the ratio of N,N'-methylenebisacrylamide to borax, by mass parts, is (1~5):(1~10).

[0043] S2: Add the PVA aqueous solution to the precursor solution and carry out a free radical polymerization reaction at 35~45℃ for 10~15h to obtain the zwitterionic composite hydrogel adhesive.

[0044] In step S2, the obtained polymer solution can be injected evenly into the glass plate mold using a 5mL syringe to ensure uniform distribution.

[0045] The preparation process of the PVA aqueous solution is as follows: PVA is dissolved in water and heated and stirred at 90~100℃ for 5~8 hours to obtain the PVA aqueous solution.

[0046] The present invention also discloses an amphoteric composite hydrogel adhesive prepared by the above method, wherein the tensile strength of the amphoteric composite hydrogel adhesive is 0.07~0.14MPa and the adhesion force is 20~33KPa.

[0047] In a further preferred embodiment, the present invention provides a method for preparing a zwitterionic composite hydrogel adhesive, comprising the following steps:

[0048] Step 1: Dissolve 20 parts of PVA in 180 ml of deionized water and heat and stir at 90~100℃ for 5 hours to obtain 10 wt% PVA solution A, which is reserved for later use.

[0049] Step 2: Dissolve the reactants SBMA and AMPS in 6 parts of deionized water and sonicate at room temperature for 5 min to form an aqueous solution. Then add 1 part of THMA to the solution. After the solution is fully mixed, add 0.4 parts of initiator APS, 15-25 μL of crosslinking agent MBAA, and 10-20 μL of borax. Sonicate in a water bath for 10 min to obtain precursor solution B.

[0050] Step 3: Mix 3 portions of PVA solution and precursor solution B, and stir for 10-15 minutes. Then, inject the mixture into a reaction vessel consisting of a pair of glass plates spaced 2 mm apart. In an oven at 35-45°C, proceed with free radical polymerization for 10-15 hours to obtain a zwitterionic polymeric hydrogel adhesive.

[0051] The initiator is ammonium persulfate, and the crosslinking agent is N,N'-methylenebisacrylamide and borax; the contents of the initiator and the crosslinking agent are 0.4 parts and 15~25 μL (mass concentration of 2%), respectively.

[0052] This invention prepares a hydrogel via a one-pot method by incorporating the anionic monomer 2-acrylamide-2-methylpropanesulfonate (AMPS) into a bilayer network of zwitterionic polymeric monomer (SBMA) and polyvinyl alcohol (PVA). PVA possesses abundant crosslinking sites and multiple hydrogen bonds. The zwitterionic monomer [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) has both cationic and anionic groups and a high dipole moment. This strong dipole moment allows for adhesion to surfaces through ion-dipole or dipole-dipole interactions, and the chain-to-chain association between polymers provides physical crosslinking to enhance the mechanical properties of the water-based adhesive. The reactive monomer N-[tris(hydroxymethyl)methyl]acrylamide (THMA) provides hydrogen bonding to the polymer, further promoting adhesion. The mechanical and adhesive properties of the zwitterionic composite hydrogel adhesive are mainly achieved through the ratio of reactive monomers SBMA and AMPS. In this invention, the selected polyvinyl alcohol (PVA) has abundant crosslinking sites. The zwitterionic [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA) possesses strong dipolarity and can provide physical crosslinking through interchain association, enhancing mechanical properties. Simultaneously, the cationic quaternary ammonium group imparts certain antibacterial properties to the adhesive. The reactive monomer N-[tris(hydroxymethyl)methyl]acrylamide (THMA) can provide triple hydrogen bonds and load-sharing effects, thereby improving adhesion. 2-Acrylamido-2-methylpropanesulfonic acid (AMPS), as an anionic monomer, exhibits ionic synergistic effects with the zwitterionic group, promoting ion migration and improving conductivity.

[0053] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0054] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0055] Example 1

[0056] A method for preparing a zwitterionic composite hydrogel adhesive includes the following steps:

[0057] Step 1: First, weigh 20 parts of polyvinyl alcohol (PVA) and dissolve it in 180 parts of deionized water. This process is carried out under heating conditions of 90°C and stirring continuously for 5 hours to ensure that the PVA is completely dissolved and forms a uniform 10wt% PVA solution A for subsequent use.

[0058] Step 2: Weigh 9 parts of the reactant monomer [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonylpropyl)ammonium hydroxide (SBMA) and 1 part of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and dissolve them in 6 parts of deionized water. At room temperature, sonicate for 5 minutes to ensure complete dissolution of the reactant monomers and the formation of a homogeneous aqueous solution. Then, add 1 part of N-[tris(hydroxymethyl)methyl]acrylamide (THMA) and mix thoroughly. Next, add 0.4 parts of initiator APS, 15 µL of crosslinking agent N,N'-methylenebisacrylamide (MBAA), and 10 µL of borax. Place the solution in a water bath and sonicate for 10 minutes to ensure complete reaction of all components, obtaining precursor solution B.

[0059] Step 3: Finally, thoroughly mix 3 portions of PVA solution and precursor solution B, stirring for 10 minutes to ensure homogeneity. Then, inject the mixture into a reaction plate consisting of a pair of glass plates spaced 2 mm apart. Place the reaction plate in an oven at 35-45°C and allow it to undergo free radical polymerization for 10 hours to obtain the desired zwitterionic polymeric hydrogel adhesive. This hydrogel adhesive exhibits excellent adhesive properties and biocompatibility in various applications. The synthesized zwitterionic composite hydrogel can be designated as PS5A5T.

[0060] Example 2

[0061] Based on mass fractions, the difference from Example 1 is that the ratio of SBMA to AMPS is 7:3, and the synthesized zwitterionic composite hydrogel can be represented as PS7A3T.

[0062] Example 3

[0063] Based on mass fractions, the difference from Example 1 is that the ratio of SBMA to AMPS is 9:1, and the synthesized zwitterionic composite hydrogel can be represented as PS9A1T.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 1 is that AMPS was not added, and the mass ratio of PVA, SBMA and THMA was 8:6:5. The resulting sample was labeled PST.

[0066] Figure 1The figures show FTIR spectra of different reactants and the synthesized PSAT zwitterionic composite hydrogel. As can be seen from the figures, the broad peak of the stretching vibration of the hydroxyl group (OH) is located at 3400 cm⁻¹. −1 The OH tensile vibration peaks of THMA, SBMA, and PVA are 3431 cm⁻¹, respectively. −1 3564 cm −1 and 3400 cm −1 After hydrogel synthesis, the OH stretching vibrations of the PSAT hydrogel shifted to lower wavenumbers (3000 cm⁻¹). −1 The formation of hydrogen bonds within or between molecules leads to a decrease in the mechanical constants of chemical bonds, resulting in a low wavenumber shift in vibrational frequencies. The shift of the OH absorption band to a lower wavenumber indicates that strong hydrogen bonds formed between THMA, SBMA, and PVA after hydrogel synthesis. Furthermore, at 1193 cm⁻¹... −1 The weakening of the characteristic peak of the sulfonic acid group at the SBMA structure indicates that the negatively charged -SO group in the SBMA structure... 3 - Group protonation.

[0067] Figure 2 The figures show the uniaxial tensile test results of the zwitterionic composite hydrogels prepared in Examples 1-3 of this invention. As shown in the figures, the tensile strength of the PS9A1T hydrogel is 0.13 MPa, and the fracture strain is 385%. With changes in the mass ratio of SBMA to AMPS, the degree of cross-linking in the hydrogel network changes. The increase in negatively charged AMPS monomers in the system partially shields the dipole-dipole interactions in SBMA. Therefore, the PS5A5T hydrogel becomes softer and more tensile, with a tensile strength of 0.06 MPa and a fracture strain of 470%.

[0068] Figure 3 This figure shows the adhesion test curves of the zwitterionic composite hydrogels prepared in Examples 1-3 of this invention and the PST prepared in Comparative Example 1. The figure illustrates the adhesion performance test results of the PSAT zwitterionic composite hydrogel adhesives with different ratios, reflecting the differences in adhesion strength and stability among the samples, providing a basis for optimizing the adhesive formulation. As can be seen from the figure, the adhesion strength varies with the ratio of SBMA to AMPS. The stability and strong adhesion of the PSAT hydrogel to different substrates can be attributed to the multiple covalent / non-covalent interactions of the hydrogel, such as hydrogen bonds, borate ester bonds, and ionic interactions. The positive and negative charges of the zwitterions generate extremely high dipole moments, which gives the zwitterionic hydrogel excellent adhesion. The introduction of the three hydroxyl groups of THMA into the system can form high-density hydrogen bonds, increasing the toughness of the interface. With the intervention of the anionic monomer, the –SO4 of AMPS… 3– Groups can interact with –N in the SBMA network. + (R)3 Interactions, but as the overall concentration of AMPS increases, the –SO4 on the surface of the PSAT hydrogel... 3– Increasing the number of functional groups alters the electrostatic state of the hydrogel system, leading to a decrease in its adhesive strength. This indicates that the adhesive properties of polyanionic hydrogels are closely related to the electrostatic state of the hydrogel and the substrate.

[0069] Figure 4 The figures show the antibacterial performance test results of the zwitterionic composite hydrogels prepared in Examples 1-3 of this invention. (a) is a schematic diagram of the hydrogel's antibacterial zone, and (b) is a diagram showing the measured diameter of the hydrogel's antibacterial zone. This figure presents the performance of PSAT zwitterionic composite hydrogel adhesives with different ratios in the antibacterial performance test, evaluates their inhibitory effect on various bacteria, and verifies their antibacterial potential in biomedical materials. As shown in the figure, the zwitterionic composite hydrogels prepared in this invention have a strong inhibitory effect on both types of bacterial colonies. The cationic quaternary ammonium groups attract the anionic portion of the bacterial membrane through strong Coulomb attraction, which can kill a large number of bacteria. Simultaneously, the presence of sulfonic acid groups in AMPS in the system may lower the pH value of the hydrogel surface or damage the bacterial membrane. Therefore, the antibacterial ability may be attributed to the synergistic effect between the zwitterionic SBMA and the sulfonic acid group in AMPS. However, excessive AMPS carries a large amount of negative charge, thus shielding some of the positive charge of the zwitterionic ions, reducing the attraction of the hydrogel to the bacterial membrane, and ultimately leading to a decrease in antibacterial performance.

[0070] Figure 5 This figure shows the hemolysis diagrams of the zwitterionic composite hydrogels prepared in Examples 1-3 of this invention. The diagram illustrates the blood compatibility test results of different ratios of PSAT zwitterionic composite hydrogel adhesives, demonstrating their influence on blood components and providing important reference for their application in the biomedical field. As shown in the figure, the supernatant of all hydrogel groups is almost colorless, similar to the PBS solution control group, contrasting with the bright red solution of the positive control group. Quantitative test results show that the hemolysis rate of all hydrogel groups is less than 5%, proving that the prepared hydrogels have good blood compatibility.

[0071] Figure 6 This diagram illustrates the use of hydrogel as a wound dressing. As shown in the diagram, the hydrogel adhesive can adhere well to the wound defect in mice, completely adhering to the skin and exhibiting antibacterial and skin-growth-promoting effects.

[0072] Example 4

[0073] A method for preparing a zwitterionic composite hydrogel adhesive includes the following steps:

[0074] S1: Dissolve the reactive monomers SBMA and AMPS in water, sonicate at room temperature to ensure complete dissolution, then add THMA, stir until homogeneous, add initiator and crosslinking agent, sonicate to dissolve, and obtain precursor solution;

[0075] S2: Dissolve PVA in water and heat and stir at 90°C for 8 hours to obtain the PVA aqueous solution; add the PVA aqueous solution to the precursor solution and carry out free radical polymerization at 35°C for 15 hours to obtain the zwitterionic composite hydrogel adhesive.

[0076] In the above preparation process, the ratio of the reactive monomers SBMA to AMPS is 9:1 by mass. The ratio of THMA to SBMA and AMPS is 1:9:1. The ratio of PVA to SBMA and AMPS is 20:9:1. The ratio of SBMA to AMPS and the initiator is 20:2:1. The ratio of SBMA to AMPS and the crosslinking agent is 280:30:1. The crosslinking agent is N,N'-methylenebisacrylamide and borax; the ratio of N,N'-methylenebisacrylamide to borax is 1:1 by mass.

[0077] The zwitterionic composite hydrogel adhesive prepared in this embodiment has a tensile strength of 0.07 MPa and an adhesion force of 20 kPa.

[0078] Example 5

[0079] A method for preparing a zwitterionic composite hydrogel adhesive includes the following steps:

[0080] S1: Dissolve the reactive monomers SBMA and AMPS in water, sonicate at room temperature to ensure complete dissolution, then add THMA, stir until homogeneous, add initiator and crosslinking agent, sonicate to dissolve, and obtain precursor solution;

[0081] S2: Dissolve PVA in water and heat and stir at 100°C for 5 hours to obtain the PVA aqueous solution; add the PVA aqueous solution to the precursor solution and carry out free radical polymerization at 45°C for 10 hours to obtain the zwitterionic composite hydrogel adhesive.

[0082] In the above preparation process, the ratio of the reactive monomers SBMA to AMPS is 5:5 by mass. The ratio of THMA to SBMA and AMPS is 1:5:5. The ratio of PVA to SBMA and AMPS is 20:5:5. The ratio of SBMA to AMPS and the initiator is 13:13:1. The ratio of SBMA to AMPS and the crosslinking agent is 160:160:1. The crosslinking agent is N,N'-methylenebisacrylamide and borax; the ratio of N,N'-methylenebisacrylamide to borax is 2:5 by mass.

[0083] The zwitterionic composite hydrogel adhesive prepared in this embodiment has a tensile strength of 0.13 MPa and an adhesion force of 33 kPa.

[0084] Example 6

[0085] A method for preparing a zwitterionic composite hydrogel adhesive includes the following steps:

[0086] S1: Dissolve the reactive monomers SBMA and AMPS in water, sonicate at room temperature to ensure complete dissolution, then add THMA, stir until homogeneous, add initiator and crosslinking agent, sonicate to dissolve, and obtain precursor solution;

[0087] S2: Dissolve PVA in water and heat and stir at 95°C for 6 hours to obtain the PVA aqueous solution; add the PVA aqueous solution to the precursor solution and carry out free radical polymerization at 40°C for 12 hours to obtain the zwitterionic composite hydrogel adhesive.

[0088] In the above preparation process, the ratio of the reactive monomers SBMA to AMPS is 8:3 by mass. The ratio of THMA to SBMA and AMPS is 1:8:3. The ratio of PVA to SBMA and AMPS is 20:8:3. The ratio of SBMA to AMPS and the initiator is 17:6:1. The ratio of SBMA to AMPS and the crosslinking agent is 240:90:1. The crosslinking agent is N,N'-methylenebisacrylamide and borax; the ratio of N,N'-methylenebisacrylamide to borax is 3:7 by mass.

[0089] The zwitterionic composite hydrogel adhesive prepared in this embodiment has a tensile strength of 0.14 MPa and an adhesion force of 25 kPa.

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a zwitterionic composite hydrogel adhesive, characterized in that, Includes the following steps: S1: Dissolve the reactive monomers SBMA and AMPS in water, sonicate at room temperature to ensure complete dissolution, then add THMA, stir until homogeneous, add initiator and crosslinking agent, sonicate to dissolve, and obtain precursor solution; S2: Add PVA aqueous solution to the precursor solution to carry out free radical polymerization reaction to obtain the zwitterionic composite hydrogel adhesive; The ratio of THMA to SBMA and AMPS by mass parts is 1:(9~5):(1~5); The crosslinking agent is N,N'-methylenebisacrylamide and borax; the ratio of N,N'-methylenebisacrylamide to borax is (1~5):(1~10) by mass. The preparation process of the PVA aqueous solution is as follows: PVA is dissolved in water and heated and stirred at 90~100℃ for 5~8 hours to obtain the PVA aqueous solution.

2. The method for preparing a zwitterionic composite hydrogel adhesive according to claim 1, characterized in that, The ratio of PVA to SBMA and AMPS by mass parts is 20:(9~5):(1~5).

3. The method for preparing a zwitterionic composite hydrogel adhesive according to claim 1, characterized in that, The ratio of SBMA to AMPS and initiator by mass fraction is (25~13):(2~13):

1.

4. The method for preparing a zwitterionic composite hydrogel adhesive according to claim 1, characterized in that, The ratio of SBMA to AMPS and crosslinking agent by mass parts is (300~160):(30~160):

1.

5. The method for preparing a zwitterionic composite hydrogel adhesive according to claim 1, characterized in that, The free radical polymerization reaction is carried out at a temperature of 35-45°C for 10-15 hours.

6. A zwitterionic composite hydrogel adhesive, characterized in that, The amphoteric composite hydrogel adhesive is prepared by the method described in any one of claims 1 to 5; the tensile strength of the amphoteric composite hydrogel adhesive is 0.07 to 0.14 MPa, and the adhesion force is 20 to 33 kPa.

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