An amphiphilic polymer and its preparation method and application

Abstract

The application discloses an amphiphilic polymer and a preparation method and application thereof, and a structure formula of the polymer is shown in the following formula: wherein n is 70-636, and R is a saturated aliphatic alkyl group; the polymer has a folded chain structure and is obtained by a Michael addition reaction of a double bond with a sulfide and an amino group; and the application further discloses an application of the amphiphilic polymer in improving the mechanical properties of a hydrogel. The polymer has both a hydrophilic group and a hydrophobic group, and can be self-assembled into a regular and ordered folded chain structure. After the polymer is introduced into the hydrogel system, the strength, stiffness and toughness of the hydrogel are greatly improved.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to an amphiphilic polymer, its preparation method, and its applications. Background Technology

[0002] Hydrogels are a class of highly hydrophilic three-dimensional network gels. Due to the presence of cross-linked networks, hydrogels can swell rapidly and retain a large amount of water without dissolving. The amount of water absorbed is closely related to the degree of cross-linking of the hydrogel. Generally, the higher the degree of cross-linking, the lower the water absorption. Therefore, the degree of cross-linking can be controlled to obtain hydrogels with water content ranging from a few percent to as high as 99%. Because of this characteristic, the aggregated state of hydrogels is neither completely solid nor completely liquid; that is, hydrogels exhibit both the behavior of solids that can maintain their shape and volume under certain conditions and the liquid behavior of solutes that can diffuse or permeate from the hydrogel.

[0003] In hydrogel networks, water molecules are tightly bound to the hydrophilic groups of polymer chains, resulting in highly malleable materials with excellent hydrothermal properties and biocompatibility. This makes hydrogels promising for applications in flexible electronics, soft robotics, and tissue engineering. However, due to their non-uniform network and high water content, hydrogels generally exhibit less than ideal strength and toughness, limiting their applications. For example, many bio-hydrogels found in animals, such as muscle, heart valves, cartilage, and tendons, require extremely high mechanical properties, including exceptional toughness, strength, elasticity, adhesion, and fatigue resistance. These mechanical properties are crucial for the various applications of hydrogels.

[0004] The poor mechanical properties of traditional hydrogels are due to several inherent characteristics. Firstly, there is the inhomogeneity of polymer density distribution and chain length within the polymer network between crosslinking points. Therefore, hydrogels are susceptible to stress concentration under load, leading to cracking. Secondly, the lack of an energy dissipation mechanism results in poor rubber toughness, leading to low resistance to crack propagation. Furthermore, traditional hydrogels typically contain abundant water, and the low solids content further contributes to their weak mechanical properties.

[0005] Key mechanical properties of hydrogels include: toughness—resistance to defect propagation, characterized by fracture energy Γ; stiffness—elastic modulus E; and strength—fracture strain ε. For a simple polymer network material, these mechanical properties are interrelated and conflicting. Increases in elastic modulus and strength lead to decreased deformability and toughness. Furthermore, strengthening or toughening hydrogels often reduces their tensile strength, further limiting their applications.

[0006] One of the main obstacles to the practical application of hydrogels is their low mechanical strength and toughness. Since 2000, significant breakthroughs have been made in improving the mechanical strength and toughness of hydrogels, leading to substantial progress in the research of soft materials and a deeper understanding of their failure mechanisms. Currently, commonly used strategies for reinforcing and toughening hydrogels include: fiber / fabric reinforcement, designing dual-network reinforcement, introducing supramolecular interactions for reinforcement, solvent displacement reinforcement, and designing well-structured hydrogels. While these methods make it possible to simultaneously improve the strength and toughness of hydrogels, these strategies often have one or more limitations, such as complex synthesis processes, limited reinforcement, and lack of versatility. Therefore, preparing hydrogels with both strength and toughness remains a significant challenge.

[0007] Therefore, developing a general strategy for preparing hydrogels that combine strength and toughness is of great practical value. Summary of the Invention

[0008] The technical problem to be solved by this invention is how to simultaneously improve the strength and toughness of hydrogels.

[0009] The present invention solves the above-mentioned technical problems through the following technical means:

[0010] An amphiphilic polymer has one of the following structural formulas:

[0011]

[0012] Where n is 70-636 and R is a saturated aliphatic alkyl group.

[0013] Preferably, n = 70-266.

[0014] Preferably, the amphiphilic polymer has a weight-average molecular weight (Mw) of 30,000 to 270,000; and R in the structural formula is -(CH2). 10 - or -(CH2)6-.

[0015] Preferably, the amphiphilic polymer is an amphiphilic diene monomer. With alkyl monomers containing disulfide groups Or alkyl monomers containing diamine groups It is obtained by Michael addition reaction, where R is a saturated aliphatic alkyl group.

[0016] The present invention also proposes a method for preparing the aforementioned amphiphilic polymer, comprising: preparing an amphiphilic diene monomer... The amphiphilic polymer is obtained by Michael addition reaction with an alkyl monomer containing a disulfide group or an alkyl monomer containing a diamine group; wherein the alkyl monomer containing the disulfide group has the following structural formula: The structural formula of the alkyl monomer containing the diamine group is: R is a saturated aliphatic alkyl group.

[0017] This method has the advantages of simple preparation and mild reaction conditions.

[0018] Preferably, the molar ratio of the amphiphilic diene monomer, the alkyl monomer containing a disulfide group, or the alkyl monomer containing a diamine group is 1 to 1.2:1. The molecular weight of the amphiphilic polymer can be controlled by the feed ratio.

[0019] Preferably, the reaction temperature of the amphiphilic diene monomer with the alkyl monomer containing a disulfide group is room temperature, and the reaction time is 24 h; the reaction temperature of the amphiphilic diene monomer with the alkyl monomer containing a diamine group is 70-80 °C, and the reaction time is 24 h; the alkyl monomer containing a disulfide group is 1,10-decanedithiol; the alkyl monomer containing a diamine group is N,N'-dimethyl-1,6-hexanediamine; and the initial concentration of the amphiphilic diene monomer in the system is between 20 mg / mL and 100 mg / mL.

[0020] If the monomer concentration is too high, the resulting amphiphilic polymer will have an excessively large molecular weight and high viscosity after the vigorous Michael addition reaction. If the monomer concentration is too low, the chain radicals will have difficulty capturing the monomer during the chain growth stage, resulting in a smaller molecular weight and a wider molecular weight distribution in the amphiphilic polymer. Therefore, the concentration of the amphiphilic diene monomer should be controlled within a suitable range to obtain an amphiphilic polymer with appropriate molecular weight and molecular weight distribution.

[0021] Preferably, the ratio of the amphiphilic diene monomer to the solvent used in the reaction is 3g:40mL.

[0022] Preferably, the solvent used in the reaction is DMF.

[0023] In the technical solution of the present invention, by dissolving an amphiphilic diene monomer and a long alkyl chain monomer containing thioether or amino in DMF, due to the Michael addition reaction between the two double bonds of the amphiphilic diene monomer provided by the present invention and the thioether or amino, a polymer with a tendency to folded chains is obtained, which simultaneously has hydrophilic and hydrophobic groups.

[0024] Preferably, the catalyst used in the Michael addition reaction is one or a mixture of organic bases such as tetramethylguanidine, triethylamine, and 1,8-diazabicycloundec-7-ene, and the molar ratio of the amphiphilic diene monomer to the organic base is 1:0.2.

[0025] The present invention also proposes an application of the amphiphilic polymer in the preparation of hydrogels.

[0026] Preferably, the hydrogel is a polyacrylamide hydrogel.

[0027] The present invention also proposes a high-strength and high-toughness hydrogel, which is prepared from raw materials including the aforementioned amphiphilic polymer and hydrogel monomer.

[0028] Because amphiphilic polymers have double bonds at both ends, they can be introduced into hydrogel systems through simple polymerization reactions. Based on the tendency of amphiphilic polymers to form folded chains during the molecular structure design stage, they form a regular and ordered folded structure under static conditions, serving as physical cross-linking points and enhancing the strength of the hydrogel. When subjected to external forces, the regular phase structure formed by the folded chains absorbs a large amount of energy to unfold and stretch its own folded chain structure, greatly increasing the chain length between cross-linking points. Simultaneously, due to the strong interactions between structural units—hydrogen bonds and π-π stacking interactions—the folded chains serve as effective energy dissipation sites. Therefore, the introduction of amphiphilic polymers can achieve multiple improvements in the strength, stiffness, and toughness of hydrogels.

[0029] The present invention also proposes a method for preparing the high-strength and high-toughness hydrogel, comprising using the amphiphilic polymer and hydrogel monomer as raw materials to carry out a photo-initiated polymerization reaction to obtain the high-strength and high-toughness hydrogel.

[0030] The amphiphilic polymer has double bonds at both ends. After being uniformly mixed with hydrogel monomers and photoinitiators at the molecular level, it undergoes photo-initiated polymerization to obtain a hydrogel based on the amphiphilic polymer. The hydrogel obtained by uniformly mixing the amphiphilic polymer prepared in this invention with hydrogel monomers and then undergoing photo-initiated polymerization exhibits significantly improved strength and toughness.

[0031] A class of amphiphilic polymers was designed and synthesized at the molecular level and introduced into hydrogel systems to enhance the mechanical properties of hydrogels. Furthermore, the reinforcing and toughening effects of these amphiphilic polymers can be controlled by manipulating the polymer's structure and molecular weight.

[0032] Preferably, the molar ratio of the amphiphilic polymer to the hydrogel monomer is 1:2000 to 20000; the molar ratio of the photoinitiator to the hydrogel monomer is 7:10000; and the hydrogel monomer is acrylamide.

[0033] Preferably, the molar ratio of the amphiphilic polymer to the hydrogel monomer is (0.005% to 0.05%):1. If the molar ratio of the added amphiphilic polymer is too high, the polymer will be difficult to disperse, and the constructed hydrogel will exhibit obvious inhomogeneity. If the molar ratio of the added amphiphilic polymer is too low, the hydrogel's reinforcing and toughening effect may be insignificant.

[0034] Preferably, during the reaction, the solid content of the mixed reaction solution formed by the amphiphilic polymer and the hydrogel monomer is 408 mg / mL to 568.9 mg / mL.

[0035] Preferably, the conditions for the photo-initiated polymerization reaction are: room temperature and 20 min.

[0036] Preferably, the preparation method of the high-strength, high-toughness hydrogel includes the following steps:

[0037] (1) Dissolution of amphiphilic polymer: Using DMF or water as solvent, weigh the amphiphilic polymer and add it to the solvent, then heat and stir at 60-70℃ for 3 hours.

[0038] (2) Mix the amphiphilic polymer solution with the hydrogel monomer AM according to the molar ratio of amphiphilic polymer to hydrogel monomer AM of 0.005% to 0.05%:1, add a photoinitiator, and irradiate with a 395nm excitation light source for 20 minutes to obtain the high-strength and high-toughness hydrogel.

[0039] Preferably, the method for preparing the amphiphilic diene monomer includes the following steps: 3,5-diaminobenzoic acid... With acryloyl chloride A nucleophilic substitution reaction occurs, yielding the product;

[0040] Preferably, the molar ratio of 3,5-diaminobenzoic acid to acryloyl chloride is 1:2 to 2.2; by controlling the molar amount of acryloyl chloride to be two times or more than twice that of 3,5-diaminobenzoic acid, two hydrogen atoms on two primary amines can be replaced, thereby obtaining an amphiphilic diene monomer.

[0041] Preferably, the conditions for the nucleophilic substitution reaction are: a temperature of 0–5°C and a time of 2–4 h.

[0042] The amphiphilic diene monomer can be obtained solely through a nucleophilic substitution reaction, which has advantages such as a short process flow, mild reaction conditions, and ease of industrial production. The specific reaction equation is shown below:

[0043]

[0044] This amphiphilic diene monomer possesses both hydrophilic and hydrophobic groups. The two olefinic groups can undergo Michael addition reactions with thioethers and amino groups containing long alkyl chains, increasing the hydrophobic effect of the system and enabling the preparation of amphiphilic polymers that exhibit folded chain behavior in hydrogel systems. Due to the hydrophilic-hydrophobic interactions of the structural units, the π-π stacking interactions of the benzene rings, and the hydrogen bonding interactions within the system, the basic conditions for assembly are met, leading to a tendency for this amphiphilic polymer to fold into regular, ordered folded chains.

[0045] Preferably, the 3,5-diaminobenzoic acid is first added to ethyl acetate and potassium hydroxide solution and stirred to mix. Then, acryloyl chloride is dissolved in ethyl acetate and slowly added dropwise to the mixed solution under an ice-water bath at 0-5°C.

[0046] Preferably, the molar ratio of 3,5-diaminobenzoic acid to potassium hydroxide is 1:2 to 2.2.

[0047] The advantages of this invention are:

[0048] (1) This invention provides an amphiphilic diene monomer that simultaneously possesses hydrophilic groups, hydrophobic groups, hydrogen bonding interactions, and π-π stacking interactions of the benzene ring, satisfying the basic conditions for assembly. The two olefinic groups can be converted into long alkyl chain structures through Michael addition reactions, increasing the hydrophilic and hydrophobic effects of the system and enabling it to achieve folded chain behavior in hydrogel systems.

[0049] (2) The present invention provides a method for preparing an amphiphilic polymer, which is obtained by Michael addition of the above-obtained amphiphilic diene monomer and a long alkyl chain monomer containing disulfide or di-secondary amine.

[0050] (3) This invention also provides a method for preparing a high-strength, high-toughness hydrogel, by introducing the aforementioned amphiphilic polymer into the hydrogel system. The amphiphilic polymer has double bonds at both ends. After being uniformly mixed with the hydrogel monomer and photoinitiator at the molecular level, photo-initiated polymerization is performed to obtain a hydrogel based on the amphiphilic polymer. The hydrogel obtained by uniformly mixing the amphiphilic polymer prepared by this invention with the hydrogel monomer and then performing photo-initiated polymerization exhibits significantly improved strength, stiffness, and toughness. Attached Figure Description

[0051] Figure 1 The 1H NMR spectrum of the amphiphilic diene monomer DBA prepared in Example 1 of this invention;

[0052] Figure 2 The 1H NMR spectrum of the amphiphilic polymer PDBASH prepared in Example 1 of this invention;

[0053] Figure 3 The 1H NMR spectrum of the amphiphilic polymer PDBANH prepared in Example 1 of this invention;

[0054] Figure 4 The stress-strain curve of the amphiphilic polymer prepared in Example 1 of this invention;

[0055] Figure 5The mechanical property test diagrams are for PAAM+x%PDBASH–nW (n = 3, 5, and 10 respectively) hydrogels constructed from amphiphilic polymers prepared in Examples 2-7, 14-19, and 26-29 of this invention. Figure 5 (ac) represents the stress-strain curve of PAAM+x%PDBASH–nW (n is 3, 5, and 10 respectively). Figure 5 (df) is the curve of the fracture energy change of PAAM+x%PDBASH–nW (n is 3, 5, 10 respectively); Figure 5 (gi) is the curve showing the change in elastic modulus of PAAM+x%PDBASH–nW (gi in the figure represents 3, 5, and 10 respectively);

[0056] Figure 6 The mechanical property test diagrams are for PAAM+x%PDBANH–nW (n = 3, 5, and 10 respectively) hydrogels constructed from amphiphilic polymers prepared in Examples 8-13, 20-25, and 30-33 of this invention. Figure 6 (ac) represents the stress-strain curve of PAAM+x%PDBANH–nW (n is 3, 5, and 10 respectively); Figure 6 (df) is the curve of the fracture energy change of PAAM+x%PDBANH–nW (n is 3, 5, 10 respectively); Figure 6 (gi) is the curve of the change in elastic modulus of PAAM+x%PDBANH–nW (gi in the figure represents n as 3, 5, and 10 respectively);

[0057] Figure 7 Electron micrograph of the DBA self-assembly forming a two-dimensional structure;

[0058] Figure 8 Electron microscopy images of the two-dimensional structures formed by the self-assembly of the amphiphilic polymer PDBANH with molecular weights of 3W, 5W, and 10W (from top to bottom) prepared in Example 1 of this invention. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0060] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0061] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0062] The molecular weights mentioned below are weight-average molecular weights (Mw).

[0063] Example 1

[0064] 1) Synthesis of amphiphilic diene monomers

[0065] Weigh 3,5-diaminobenzoic acid (3.043 g, 0.02 mol) into a round-bottom flask, add 100 mL of ethyl acetate and 200 mL of KOH aqueous solution (concentration 11.8 mg / mL), and stir to dissolve. Add acryloyl chloride (3.801 g, 0.042 mol) to 20 mL of ethyl acetate, and slowly add it dropwise through a dropping funnel to the round-bottom flask under ice bath conditions of 0–5 °C. After the addition is complete, allow the reaction to proceed for 4 h. After the reaction is complete, adjust the pH to acidic with dilute hydrochloric acid (1 M), resulting in a purplish-gray turbid precipitate. Filter and wash with water to obtain the amphiphilic diene monomer DBA, whose structural formula is [insert structural formula here]. 1H NMR spectrum as follows Figure 1 As shown;

[0066] 2) Synthesis of amphiphilic polymers

[0067] Weigh 3 g (0.012 mol) of the amphiphilic diene monomer DBA into a round-bottom flask, dissolve it in 40 mL of DMF, then add 2.4769 g (0.012 mol) of 1,10-decanedithiol and 0.2764 g (0.0024 mol) and stir to mix. React at room temperature for 24 h. After the reaction is complete, precipitate in water to obtain a brown solid precipitate. Wash with water and freeze-dry to obtain the amphiphilic polymer PDBASH with a yield of 72% and a molecular weight of 27W. The 1H NMR spectrum is shown below. Figure 2 As shown, the polymer PDBASH structure is n is 636.

[0068] Weigh 3 g (0.012 mol) of the amphiphilic diene monomer DBA into a round-bottom flask, dissolve it in 40 mL of DMF, then add N,N'-dimethyl-1,6-hexanediamine (1.755 g, 0.012 mol) and tetramethylguanidine (0.2764 g, 0.0024 mol), stir and mix, and react at 75 °C for 24 h. After the reaction is complete, precipitate in water to obtain a brown solid precipitate. Wash with water and freeze-dry to obtain the amphiphilic polymer PDBANH, with a yield of 65% and a molecular weight of 23W. The 1H NMR spectrum is shown below. Figure 3 As shown, the polymer PDBANH has the following structural formula: n is 611.

[0069] The molecular weight of the amphiphilic polymer can also be controlled by adjusting the feed ratio to obtain amphiphilic polymers with molecular weights of 30,000 (W), 50,000 (W), and 100,000 (W).

[0070]

[0071] Following the method described in 2) above for synthesizing the amphiphilic polymer, only the amount of the amphiphilic diene monomer DBA was adjusted to (20 g, 0.08 mol), and the amount of 1,10-decanedithiol was adjusted to (16.038 g, 0.0777 mol). The remaining steps were the same as in 2), resulting in an amphiphilic polymer PDBASH with n = 71 and a molecular weight of 3W.

[0072] The only difference is that the amount of the amphiphilic diene monomer DBA in step 2) is adjusted to (20 g, 0.08 mol) and the amount of 1,10-decanedithiol is adjusted to (16.224 g, 0.0786 mol). All other steps are the same as in step 2), and an amphiphilic polymer PDBASH with n = 118 and molecular weight = 5 W is obtained.

[0073] The only difference between step 2) is that the amount of the amphiphilic diene monomer DBA is adjusted to (20 g, 0.08 mol) and the amount of 1,10-decanedithiol is adjusted to (16.368 g, 0.0793 mol), while the other steps are the same as in step 2), to obtain an amphiphilic polymer PDBASH with n = 235 and molecular weight = 10 W.

[0074] The only difference in step 2) was the adjustment of the amount of the amphiphilic diene monomer DBA to (20 g, 0.08 mol) and the amount of N,N'-dimethyl-1,6-hexanediamine to (11.252 g, 0.0780 mol). All other steps remained the same as in step 2), yielding the amphiphilic polymer PDBANH with n = 80 and a molecular weight of 3 W. Its electron micrograph is shown below. Figure 8 As shown;

[0075] The only difference in step 2) was the adjustment of the amount of the amphiphilic diene monomer DBA to (20 g, 0.08 mol) and the amount of N,N'-dimethyl-1,6-hexanediamine to (11.368 g, 0.0788 mol). All other steps remained the same as in step 2), yielding the amphiphilic polymer PDBANH with n = 133 and a molecular weight of 5 W. Its electron micrograph is shown below. Figure 8 As shown;

[0076] The only difference was that the amount of the amphiphilic diene monomer DBA in step 2) was adjusted to (20 g, 0.08 mol) and the amount of N,N'-dimethyl-1,6-hexanediamine was adjusted to (11.454 g, 0.0794 mol). All other steps were the same as in step 2), yielding the amphiphilic polymer PDBANH with n = 266 and a molecular weight of 10 W. Its electron micrograph is shown below. Figure 8 As shown;

[0077] Weigh 150.0 mg of the prepared amphiphilic polymers PDBASH and PDBANH and place them on a polytetrafluoroethylene film. Press the upper and lower plates together at 100°C for 5 minutes. Place the hot-pressed amphiphilic polymers PDBASH and PDBANH into a manual hydraulic punching machine, cut them into dumbbell-shaped strips, and clamp them in a universal tensile testing machine for mechanical property testing. Figure 4 The results showed that the amphiphilic polymers PDBASH and PDBANH have strong mechanical properties.

[0078] Examples 2-33

[0079] Preparation of amphiphilic polymer hydrogels

[0080] Using DMF or water as a solvent, weigh out the amphiphilic polymer PDBASH / PDBANH and add it to DMF or water. Heat and stir at 60-70°C for 3 hours until fully dissolved. Weigh the dissolved PDBASH / PDBANH solution according to the molar ratio of amphiphilic polymer to acrylamide (AM, 800 mg) of 0.005%-0.05%:1 and add it to a test tube containing acrylamide. Balance the solution to 2 mL with DMF or water to ensure the same concentration in each example. Then add 100 μL of the photoinitiator 2-hydroxy-2-methylphenylacetone solution (HMPP). The concentration of HMPP in the 2-hydroxy-2-methylphenylacetone solution is 13 mg / mL, and the molar ratio of photoinitiator to AM is 7:10000. After mixing thoroughly, transfer the reaction solution to a polytetrafluoroethylene mold and irradiate it with a 395 nm ultraviolet lamp at room temperature for 20 min to obtain a high-strength, high-toughness hydrogel, i.e., the amphiphilic polymer hydrogel.

[0081] The specific formulations for preparing hydrogels according to Examples 2-13 above are shown in Tables 1 and 2.

[0082] Table 1. Specific Formulation of PAAM+x%PDBASH-3W Hydrogel

[0083]

[0084] Table 2. Specific Formulation of PAAM+x%PDBANH-3W Hydrogel

[0085]

[0086] The specific formulations for preparing hydrogels in Examples 14-25 are shown in Tables 3 and 4.

[0087] Table 3. Specific Formulation of PAAM+x%PDBASH-5W Hydrogel

[0088]

[0089] Table 4. Specific Formulation of PAAM+x%PDBANH-5W Hydrogel

[0090]

[0091] The specific formulations for preparing hydrogels in Examples 26-33 are shown in Tables 5 and 6;

[0092] Table 5. Specific Formulation of PAAM+x%PDBASH-10W Hydrogel

[0093]

[0094] Table 6. Specific Formulation of PAAM+x%PDBANH-10W Hydrogel

[0095]

[0096] In the preparation process of the above hydrogel, when the molar ratio of the amphiphilic polymer doping to the AM molar ratio is x%:1 = 0.1%:1, the reaction solution is dark gray, which affects the photopolymerization effect and makes it impossible to obtain a gel through photopolymerization.

[0097] Hydrogel mechanical property testing

[0098] The hydrogel was placed in a manual hydraulic punching machine, cut and pressed into dumbbell-shaped strips, and then clamped in a universal tensile testing machine for mechanical property testing.

[0099] like Figure 5As shown, the strength of polyacrylamide (PAAM) hydrogels (PAAM + x% PDBASH – nW (n = 3, 5, 10) constructed with the introduction of amphiphilic PDBASH polymers is significantly improved, and the strength of the hydrogel gradually increases with the increase of the amount of amphiphilic PDBASH polymer. Among them, the strength of PAAM hydrogel with 0.05% monomer molar amount of PDBASH-3W is 46.8 times higher than that of PAAM + 0.02% BIS hydrogel crosslinked by the traditional chemical crosslinking agent BIS. However, due to the relatively hydrophobic molecular structure of PDBASH polymer, there is poor solubility during the construction of PAAM hydrogel, so the introduction of PDBASH polymer has no significant effect on the improvement of fracture strain and toughness of PAAM hydrogel. However, the mechanical properties of PAAM + x% PDBASH – nW (n = 3, 5, 10) hydrogels still show molecular weight dependence, and the strength and stiffness increase with the increase of the molecular weight of the introduced amphiphilic polymer.

[0100] Based on the reinforcing and toughening results of hydrogels constructed with amphiphilic PDBASH polymers, the molecular structure of the amphiphilic polymer was designed and adjusted. Through a Michael addition reaction with the protonable monomer N,N'-dimethyl-1,6-hexanediamine, the amphiphilic polymer PDBANH was obtained. PAAM hydrogels were constructed by adding different molar amounts of the amphiphilic polymer PDBANH, and their mechanical properties were tested. Figure 6 The results showed that the PAAM hydrogels (PAAM+x%PDBANH–nW (n = 3, 5, 10) constructed with the amphiphilic polymer PDBANH exhibited significantly improved strength, stiffness, and toughness. Furthermore, the strength, stiffness, and toughness increased with increasing PDBANH content. Specifically, the PAAM hydrogel with 0.03% PDBANH-5W polymer showed a 28.3-fold increase in strength, a 10-fold increase in fracture strain, and a 261.7-fold increase in toughness compared to the PAAM+0.02% BIS hydrogel crosslinked with the traditional chemical crosslinking agent BIS. The mechanical properties of the PAAM+x%PDBANH–nW (n = 3, 5, 10) hydrogels increased with increasing molecular weight of the introduced amphiphilic polymer.

[0101] Weigh 3 g (0.012 mol) of the amphiphilic diene monomer DBA and 0.48 g (0.012 mol) of NaOH into a round-bottom flask, add 40 mL of water and dissolve completely; add potassium persulfate (0.032 g, 0.0001 mol), and polymerize at 70 °C for 8 h. After the reaction is complete, dialyze the reaction solution for 48 h, freeze-dry, and DBA self-assembles into a two-dimensional structure, as shown in the electron micrograph. Figure 7As shown, the amphiphilic diene monomer DBA possesses hydrophilic-hydrophobic interactions, π-π stacking interactions of the benzene ring, and hydrogen bonding interactions within the system, endowing it with the ability to self-assemble in the aqueous phase and providing impetus for the folding of amphiphilic polymers.

[0102] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An amphiphilic polymer, characterized in that: Its structural formula is one of the following: Where n is 70-636 and R is a saturated aliphatic alkyl group.

2. The amphiphilic polymer according to claim 1, characterized in that: n＝70-266。 3. The amphiphilic polymer according to claim 1 or 2, characterized in that: Its weight-average molecular weight is 30,000-270,000; R in the structural formula is -(CH2). 10 - or -(CH2)6-.

4. A method for preparing an amphiphilic polymer as described in any one of claims 1-3, characterized in that: Including amphiphilic diene monomers The amphiphilic polymer is obtained by Michael addition reaction with an alkyl monomer containing a disulfide group or an alkyl monomer containing a diamine group; wherein the alkyl monomer containing the disulfide group has the following structural formula: The structural formula of the alkyl monomer containing the diamine group is: R is a saturated aliphatic alkyl group.

5. The method for preparing the amphiphilic polymer according to claim 4, characterized in that: The molar ratio of the amphiphilic diene monomer, the alkyl monomer containing a disulfide group, or the alkyl monomer containing a di-secondary amine group is 1 to 1.2:

1.

6. The method for preparing the amphiphilic polymer according to claim 4, characterized in that: The amphiphilic diene monomer reacts with an alkyl monomer containing a disulfide group at room temperature for 24 hours; the amphiphilic diene monomer reacts with an alkyl monomer containing a diamine group at 70–80 °C for 24 hours; the alkyl monomer containing the disulfide group is 1,10-decanedithiol; the alkyl monomer containing the diamine group is N,N'-dimethyl-1,6-hexanediamine; the initial concentration of the amphiphilic diene monomer in the system is between 20 mg / mL and 100 mg / mL.

7. The use of an amphiphilic polymer as described in any one of claims 1-3 in the preparation of hydrogels.

8. A high-strength, high-toughness hydrogel, characterized in that: It is prepared using raw materials comprising the amphiphilic polymer and hydrogel monomer as described in any one of claims 1-3.

9. A method for preparing a high-strength, high-toughness hydrogel as described in claim 8, characterized in that: The high-strength, high-toughness hydrogel is obtained by photo-initiated polymerization of amphiphilic polymers and hydrogel monomers.

10. The method for preparing the high-strength, high-toughness hydrogel according to claim 9, characterized in that: The molar ratio of the amphiphilic polymer to the hydrogel monomer is 1:2000-20000; the molar ratio of the photoinitiator to the hydrogel monomer is 7:10000; and the hydrogel monomer is acrylamide.

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