Hydrogel based on microgel enhanced non-covalent crosslinking and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, and particularly discloses hydrogel based on microgel reinforced non-covalent crosslinking and a preparation method of the hydrogel. The hydrogel is prepared from the following raw materials: phenylboronic acid-based microspheres, acrylamide and an initiator A; the phenylboronic acid-based microspheres are prepared from the following raw materials: ethyl 2-(2-methoxyethoxy) acrylate, methacrylic acid, ethylene glycol dimethacrylate, 3-acrylamide phenylboronic acid, an emulsifier and an initiator B; the non-covalent cross-linked hydrogel with excellent mechanical properties is prepared by taking the phenylboronic acid-based microspheres as a cross-linking agent, the mechanical properties of the non-covalent cross-linked hydrogel can be regulated and controlled by the proportion of the phenylboronic acid-based microspheres and the pH value of a system, and the prepared hydrogel realizes high tensile strength, high stretch rate and low hysteresis and has excellent fatigue resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a hydrogel based on microgel-enhanced non-covalent cross-linking and a preparation method thereof. Background Art

[0002] Hydrogels, due to their softness, biocompatibility, and water content, have broad applications in biomedical engineering, soft robotics, biosensors, and bioelectronics. These applications require hydrogels to possess excellent mechanical properties, including high fracture toughness, low hysteresis, and superior fatigue resistance. Conventional covalently cross-linked hydrogels suffer from low toughness and high hysteresis, limiting their stability and reliability in practical applications.

[0003] Existing mechanical enhancement strategies utilize interactions between microgels and polymer matrices, including chain entanglement, hydrogen bonding, ionic interactions, and chemical bonds. Microgels are cross-linked polymer particles with sizes ranging from a few nanometers to a few micrometers. Due to their unique microstructure and material properties, they can enhance the mechanical properties of hydrogels. Currently, microgels enhance the mechanical properties of hydrogels mainly through chain entanglement. Systems dominated by entanglement exhibit significant hysteresis in irreversible chain disentanglement and microgel fracture, which limits the fatigue resistance of hydrogels under cyclic loading. Physical cross-linking methods that rely on a single dynamic interaction (such as chain entanglement or ionic bonding) often trade off between high strength and low hysteresis. Design principles for controlling cooperative energy dissipation mechanisms remain underexplored, especially for systems combining multiple dynamic bonds without chemical cross-linkers.

[0004] Therefore, it is necessary to provide a hydrogel based on microgel-enhanced non-covalent cross-linking and a preparation method thereof to improve the tensile strength, elongation and low hysteresis of the hydrogel. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a hydrogel based on microgel-enhanced non-covalent cross-linking and a preparation method thereof, so as to improve the tensile strength, elongation and low hysteresis of the hydrogel.

[0006] The first aspect of the present invention provides a hydrogel based on microgel-enhanced non-covalent cross-linking.

[0007] Specifically, the raw materials of the hydrogel include phenylboronic acid-based microspheres, acrylamide, and initiator A;

[0008] The raw materials of the phenylboronic acid-based microspheres include 2-(2-methoxyethoxy)ethyl acrylate, methacrylic acid, ethylene glycol dimethacrylate, 3-acrylamidephenylboric acid, an emulsifier, and an initiator B.

[0009] Preferably, the raw materials of the hydrogel include, by weight, 0.1 to 10 parts of phenylboronic acid microspheres, 20 to 40 parts of acrylamide, and 0.05 to 0.1 parts of initiator A.

[0010] Further preferably, the raw materials of the hydrogel include, by weight, 0.5-10 parts of phenylboronic acid-based microspheres, 25-40 parts of acrylamide, and 0.06-0.1 parts of initiator A.

[0011] More preferably, the raw materials of the hydrogel include, by weight, 0.5-8 parts of phenylboronic acid microspheres, 25-35 parts of acrylamide, and 0.08-0.1 parts of initiator A.

[0012] Preferably, the raw materials of the phenylboronic acid-based microspheres include, by weight, 10 to 15 parts of 2-(2-methoxyethoxy)ethyl acrylate, 1 to 5 parts of methacrylic acid, 0.1 to 1 part of ethylene glycol dimethacrylate, 0.1 to 1 part of 3-acrylamidephenylboric acid, 0.1 to 1 part of emulsifier, and 0.01 to 0.1 part of initiator B.

[0013] Further preferably, the raw materials of the phenylboronic acid-based microspheres include, by weight, 12 to 15 parts of 2-(2-methoxyethoxy)ethyl acrylate, 1 to 3 parts of methacrylic acid, 0.1 to 0.5 parts of ethylene glycol dimethacrylate, 0.1 to 0.5 parts of 3-acrylamidephenylboric acid, 0.1 to 0.5 parts of emulsifier, and 0.01 to 0.08 parts of initiator B.

[0014] More preferably, the raw materials of the phenylboronic acid-based microspheres include, by weight, 12 to 13 parts of 2-(2-methoxyethoxy)ethyl acrylate, 2 to 3 parts of methacrylic acid, 0.2 to 0.3 parts of ethylene glycol dimethacrylate, 0.4 to 0.5 parts of 3-acrylamidephenylboric acid, 0.4 to 0.5 parts of emulsifier, and 0.03 to 0.05 parts of initiator B.

[0015] Preferably, the initiator A comprises ammonium persulfate and N,N,N',N'-tetramethylethylenediamine.

[0016] Preferably, the emulsifier comprises sodium lauryl sulfate.

[0017] Preferably, the initiator B comprises ammonium persulfate.

[0018] The second aspect of the present invention provides a method for preparing a hydrogel based on microgel-enhanced non-covalent cross-linking.

[0019] Specifically, the method for preparing the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0020] (1) mixing ethyl 2-(2-methoxyethoxy)acrylate, methacrylic acid, ethylene glycol dimethacrylate, and 3-acrylamide phenylboronic acid to prepare a comonomer solution;

[0021] (2) adding the comonomer solution to water containing an emulsifier and an initiator B, mechanically stirring, and cooling under an inert gas atmosphere to obtain a microsphere dispersion;

[0022] (3) dialyzing the microsphere dispersion in water to obtain phenylboronic acid-based microspheres;

[0023] (4) After acrylamide and phenylboronic acid-based microspheres are dissolved and dispersed in water, initiator A is added, the pH value is adjusted, and polymerization is performed to obtain a hydrogel based on microgel-enhanced non-covalent cross-linking.

[0024] Preferably, in step (2), the temperature of the mechanical stirring is 75-85° C., and the time is 55-65 min.

[0025] Further preferably, in step (2), the temperature of the mechanical stirring is 80-85° C., and the time is 55-60 min.

[0026] More preferably, in step (2), the temperature of the mechanical stirring is 80° C. and the time is 60 min.

[0027] Preferably, in step (3), the dialysis duration is 5 to 10 days.

[0028] More preferably, in step (3), the dialysis duration is 6 to 8 days.

[0029] More preferably, in step (3), the dialysis duration is 7 days.

[0030] Preferably, in step (4), the pH value is 5.0 to 7.5.

[0031] Further preferably, in step (4), the pH value is 5.0 to 7.4.

[0032] More preferably, in step (4), the pH value is 5.2 to 7.4.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention uses phenylboronic acid-based microspheres as a cross-linking agent to prepare a non-covalently cross-linked hydrogel with excellent mechanical properties. The mechanical properties of the hydrogel can be regulated by the proportion of phenylboronic acid-based microspheres and the pH value of the system. The prepared hydrogel achieves high tensile strength, elongation, low hysteresis, and excellent fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The particle size and pH responsiveness of the phenylboronic acid-based microspheres in Example 1. DETAILED DESCRIPTION

[0036] In order to make the technical solution of the present invention more clearly understood by those skilled in the art, the following examples are given for illustration. It should be noted that the following examples do not limit the scope of protection claimed by the present invention.

[0037] Unless otherwise specified, the raw materials, reagents, or devices used in the following examples can be obtained from conventional commercial sources or by existing known methods.

[0038] Example 1

[0039] Phenylboronic acid-based microspheres are composed of the following raw materials:

[0040] Table 1 Raw material composition of phenylboronic acid microspheres

[0041]

[0042]

[0043] The preparation method of phenylboronic acid-based microspheres comprises the following steps:

[0044] (1) mixing ethyl 2-(2-methoxyethoxy)acrylate, methacrylic acid, ethylene glycol dimethacrylate, and 3-acrylamide phenylboronic acid to prepare a comonomer solution;

[0045] (2) adding the comonomer solution to water containing sodium lauryl sulfate and ammonium persulfate, mechanically stirring at 80° C. for 60 min under an inert gas atmosphere, and cooling to room temperature to obtain a microsphere dispersion;

[0046] (3) The microsphere dispersion was dialyzed in water for 7 days to obtain phenylboronic acid-based microspheres.

[0047] Example 2

[0048] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0049] Table 2 Raw material composition of microgel-enhanced non-covalent cross-linked hydrogels

[0050] raw material parts by mass Acrylamide 25 Phenylboronic acid-based microspheres 0.5 N,N,N',N'-Tetramethylethylenediamine 0.04 Ammonium persulfate 0.04 Deionized water 74.5

[0051] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0052] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 7.4, and a hydrogel based on microgel-enhanced non-covalent cross-linking was prepared after polymerization.

[0053] Example 3

[0054] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0055] Table 3 Raw material composition of microgel-enhanced non-covalent cross-linked hydrogels

[0056]

[0057]

[0058] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0059] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 7.4, and a hydrogel based on microgel-enhanced non-covalent cross-linking was prepared after polymerization.

[0060] Example 4

[0061] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0062] Table 4 Raw material composition of microgel-enhanced non-covalent cross-linked hydrogels

[0063] raw material parts by mass Acrylamide 25 Phenylboronic acid-based microspheres 4 N,N,N',N'-Tetramethylethylenediamine 0.04 Ammonium persulfate 0.04 Deionized water 71

[0064] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0065] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 7.4, and a hydrogel based on microgel-enhanced non-covalent cross-linking was prepared after polymerization.

[0066] Example 5

[0067] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0068] Table 5 Raw material composition of microgel-enhanced non-covalent cross-linked hydrogels

[0069]

[0070]

[0071] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0072] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 7.4, and a hydrogel based on microgel-enhanced non-covalent cross-linking was prepared after polymerization.

[0073] Example 6

[0074] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0075] Table 6 Raw material composition of microgel-enhanced non-covalent cross-linked hydrogels

[0076] raw material parts by mass Acrylamide 35 Phenylboronic acid-based microspheres 4 N,N,N',N'-Tetramethylethylenediamine 0.04 Ammonium persulfate 0.04 Deionized water 61

[0077] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0078] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 5.2, and a hydrogel based on microgel-enhanced non-covalent cross-linking was prepared after polymerization.

[0079] Example 7

[0080] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0081] Table 7 Raw material composition of microgel-enhanced non-covalent cross-linked hydrogels

[0082]

[0083]

[0084] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0085] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 6.0, and a microgel-enhanced non-covalent cross-linked hydrogel was obtained after polymerization.

[0086] Example 8

[0087] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0088] Table 8 Raw material composition of microgel-enhanced non-covalent cross-linked hydrogels

[0089] raw material parts by mass Acrylamide 35 Phenylboronic acid-based microspheres 4 N,N,N',N'-Tetramethylethylenediamine 0.04 Ammonium persulfate 0.04 Deionized water 61

[0090] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0091] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 6.2, and a hydrogel based on microgel-enhanced non-covalent cross-linking was obtained after polymerization.

[0092] Example 9

[0093] Microgel-enhanced non-covalent cross-linked hydrogels are composed of the following raw materials:

[0094] Table 9 Raw material composition of microgel-enhanced non-covalently cross-linked hydrogels

[0095]

[0096]

[0097] The preparation method of the hydrogel based on microgel-enhanced non-covalent cross-linking comprises the following steps:

[0098] After acrylamide and the phenylboronic acid-based microspheres prepared in Example 1 were dissolved and dispersed in water, N,N,N',N'-tetramethylethylenediamine and ammonium persulfate were added, the pH value was adjusted to 7.4, and a hydrogel based on microgel-enhanced non-covalent cross-linking was prepared after polymerization.

[0099] Comparative Example 1

[0100] Covalently cross-linked hydrogels are composed of the following raw materials:

[0101] Table 10 Raw material composition of covalently cross-linked hydrogel

[0102] raw material parts by mass Acrylamide 35 N,N′-methylenebisacrylamide 0.05 N,N,N',N'-Tetramethylethylenediamine 0.04 Ammonium persulfate 0.04 Deionized water 64

[0103] The preparation method of the covalently cross-linked hydrogel comprises the following steps:

[0104] Acrylamide, N,N′-methylenebisacrylamide, N,N,N′,N′-tetramethylethylenediamine and ammonium persulfate are mixed to prepare a covalently cross-linked hydrogel.

[0105] Performance testing:

[0106] 1. Particle size and pH responsiveness of phenylboronic acid-based microspheres in Example 1.

[0107] Depend on Figure 1It can be seen that the small-sized (less than 200 nm) macromolecular cross-linking agent prepared by the present invention has pH responsiveness, and its size increases with increasing pH.

[0108] 2. Tensile performance test.

[0109] Table 11 Tensile properties of hydrogels from Examples 2 to 5

[0110]

[0111]

[0112] As shown in Table 11, the elongation at break, tensile stress and mechanical strength of the non-covalently cross-linked hydrogel prepared by cross-linking using the phenylboronic acid-based microsphere cross-linker of the present invention can be controlled by the proportion of the phenylboronic acid-based microspheres.

[0113] Table 12 Tensile properties of hydrogels in Examples 6 to 9 and Comparative Example 1

[0114] project Example 6 Example 7 Example 8 Example 9 Comparative Example 1 Young's modulus (kPa) 120.09 86.28 79.31 91.76 89 Elongation at break (%) 1583.32 2508.43 2658.11 2372.23 491 Maximum tensile stress (kPa) 163.95 283.85 411.91 452.13 222 <![CDATA[Tensile strength (kJ / m 3 )]]> 2342.17 4290.04 4289.56 4075.73 864.18

[0115] As shown in Table 12, the tensile properties of the non-covalently cross-linked hydrogel prepared using the phenylboronic acid-based microsphere cross-linking agent of the present invention can be regulated by the pH value of the system. Compared with the traditional hydrogel cross-linked with a commercial covalent cross-linking agent in Comparative Example 1, the non-covalently cross-linked hydrogel of the present invention has obvious advantages in elongation at break, tensile stress, and mechanical strength.

[0116] 3. Fatigue resistance test.

[0117] Table 13 Fatigue resistance of hydrogels in Example 9 after 200 cycles of compression

[0118] Number of cycles Hysteresis rate (%) 1 -0.34618 10 0.618216 20 0.69147 50 1.175594 100 1.371402 150 2.166452 200 1.86659

[0119] As can be seen from Table 13, the non-covalently cross-linked hydrogel prepared by cross-linking using the phenylboronic acid-based microsphere cross-linking agent of the present invention has a low hysteresis rate and excellent anti-fatigue performance.

[0120] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions derived from modifications, equivalent substitutions, improvements, etc. made by those skilled in the art based on the concepts of the present invention through logical analysis, reasoning, or limited experimentation on the basis of the prior art shall be within the scope of protection defined by the claims.

Claims

1. A hydrogel based on microgel-enhanced non-covalent cross-linking, characterized in that: The raw materials of the hydrogel include phenylboronic acid microspheres, acrylamide, and initiator A; The raw materials of the phenylboronic acid-based microspheres include 2-(2-methoxyethoxy)ethyl acrylate, methacrylic acid, ethylene glycol dimethacrylate, 3-acrylamidephenylboric acid, an emulsifier, and an initiator B.

2. The hydrogel according to claim 1, wherein The raw materials of the hydrogel include, by weight, 0.1 to 10 parts of phenylboronic acid microspheres, 20 to 40 parts of acrylamide, and 0.05 to 0.1 parts of initiator A.

3. The hydrogel according to claim 1, wherein The raw materials of the phenylboronic acid-based microspheres include, by weight, 10 to 15 parts of 2-(2-methoxyethoxy)ethyl acrylate, 1 to 5 parts of methacrylic acid, 0.1 to 1 part of ethylene glycol dimethacrylate, 0.1 to 1 part of 3-acrylamidephenylboric acid, 0.1 to 1 part of emulsifier, and 0.01 to 0.1 part of initiator B.

4. The hydrogel according to claim 1, wherein The initiator A includes ammonium persulfate and N,N,N',N'-tetramethylethylenediamine.

5. The hydrogel according to claim 1, wherein The emulsifier includes sodium lauryl sulfate.

6. The hydrogel according to claim 1, wherein The initiator B includes ammonium persulfate.

7. The method for preparing a hydrogel based on microgel-enhanced non-covalent cross-linking according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) mixing ethyl 2-(2-methoxyethoxy)acrylate, methacrylic acid, ethylene glycol dimethacrylate, and 3-acrylamide phenylboronic acid to prepare a comonomer solution; (2) adding the comonomer solution to water containing an emulsifier and an initiator B, mechanically stirring, and cooling under an inert gas atmosphere to obtain a microsphere dispersion; (3) dialyzing the microsphere dispersion in water to obtain phenylboronic acid-based microspheres; (4) After acrylamide and phenylboronic acid-based microspheres are dissolved and dispersed in water, initiator A is added, the pH value is adjusted, and polymerization is performed to obtain a hydrogel based on microgel-enhanced non-covalent cross-linking.

8. The preparation method according to claim 7, characterized in that In step (2), the temperature of the mechanical stirring is 75 to 85° C., and the time is 55 to 65 minutes.

9. The preparation method according to claim 7, characterized in that In step (3), the dialysis duration is 5 to 10 days.

10. The preparation method according to claim 7, characterized in that In step (4), the pH value is 5.0 to 7.5.

Images