Super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material and preparation method and application thereof
By combining string fibers with multi-arm hydrophilic polymers, metal ion coordination, and self-assembled peptide fibers in a hydrogel design, the conflict between high strength and high toughness of hydrogel materials under high-frequency mechanical loads was resolved, achieving rapid recovery and fatigue resistance, and exhibiting excellent mechanical properties.
Patent Information
- Application Number
- CN202211219403.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-09-30
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2042-09-30
AI Technical Summary
Existing hydrogel materials struggle to achieve both high strength and high toughness under high-frequency mechanical loads, and their recovery time is long, resulting in a lack of fatigue resistance.
A hydrogel is formed by copolymerizing string fibers and multi-arm hydrophilic polymers through double bonds, which, combined with metal ion coordination and self-assembled polypeptide fibers, forms an energy dissipation and rapid recovery mechanism.
The hydrogel material exhibits high mechanical strength, ultra-high toughness, rapid recovery, and fatigue resistance, with a fracture stress of 4.1 MPa, fracture energy of 25.3 kJ m⁻², fatigue threshold of 451 J m⁻², and second-level mechanical property recovery.
Smart Images
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of new materials, in particular to a super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material and a preparation method and application thereof. BACKGROUND
[0002] As part of our musculoskeletal system, many connective tissues such as muscle, cartilage and tendon, continuously bear dynamic mechanical loads in regular motion. In multiple mechanical cycles, mechanical properties can be recovered within seconds, showing significant mechanical stability and reliability. For example, our articular cartilage can bear more than 40% compression and 6 times body weight at a frequency of 0.5 Hz without showing significant mechanical fatigue. Inspired by the mechanical properties of human load-bearing tissues, great efforts have been made in the field of biomimetic hydrogels with such properties, expecting that the gel materials can function under high-frequency mechanical loading. A key design principle of tough hydrogels is to use sacrificial bonds / networks to dissipate energy, such as hydrophobic interactions, ion pairs, hydrogen bonds, coordination interactions, host-guest interactions and microcrystals. Although these methods can greatly improve the toughness of hydrogel materials, they often cannot simultaneously improve their mechanical strength, because strength and toughness are mutually exclusive mechanical properties. In addition, although these weak interactions are completely reversible at the molecular level, macroscopic hydrogels require a longer time scale to recover, because the reorganization of these dynamic bonds in the hydrogel network overcomes a large entropic energy barrier. In addition, since the sacrificial bonds / networks are broken before the hydrogel breaks, these hydrogels lack a mechanism to prevent fatigue under cyclic loading.
[0003] In biological tissues in nature, load-bearing tissues exhibit a complex hierarchical structure across different scales, which means that a complex multi-level structure is an effective strategy for building synthetic hydrogels with excellent mechanical properties. Recently, some experts and scholars have introduced layered structures into hydrogels through freeze casting and additional processing, which can effectively improve both strength and toughness. However, these methods often require harsh conditions, which are not suitable for biological applications. In addition, these hydrogels often have difficulty in quickly recovering their mechanical properties after removing the load, because without special external conditions, the layered structure cannot change. In natural load-bearing materials, the hierarchical structure is formed through complex self-assembly over millions of years of evolution, with nanoscale structures and molecular-level interactions working together to simultaneously build high strength, high toughness, fast recovery and fatigue resistance of the material. The network in these natural load-bearing materials is built by complex self-assembled nanoscale structures. The destruction of these assembled fiber structures can help unload mechanical loads and provide hidden length to enhance ductility.
[0004] Inspired by the structure of biological networks, the present application proposes a new type of super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material. The hydrogel is mainly composed of string-like fibers cross-linked with each other. The obtained hydrogel exhibits excellent mechanical properties, including high mechanical strength (breaking stress of about 4.1 MPa), super high toughness (breaking energy of about 25.3 kJ m -2 ), excellent fatigue resistance (fatigue threshold of about 451 J m -2 ) and mechanical property recovery speed of seconds. This design provides a new way for synthesizing hydrogels to solve the conflict between high strength and high toughness. Due to its unique structure and excellent mechanical properties, the hydrogel can be applied to soft robots, artificial skin, flexible sensor devices, artificial tendons and cartilage repair, etc. SUMMARY
[0005] The problem to be solved by the present application is to propose an innovative solution to the conflict between toughness and strength in hydrogel materials, which is a disadvantage of the existing materials.
[0006] To solve the above problems, the present application adopts the following scheme: a super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material, characterized in that the hydrogel material is a string fiber cross-linked with a double bond copolymerized multi-arm hydrophilic polymer; and the metal ions are stably coordinated on the polypeptide of the string fiber; the string fiber is a self-assembled double bond modified polypeptide polymerization unsaturated bond monomer; and the multi-arm hydrophilic polymer is a hydrophilic cross-linking molecule with an unsaturated bond at the end.
[0007] Further, the super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material is characterized in that the metal ions are copper ions or zinc ions; and the multi-arm hydrophilic polymer is a methylene bisacrylamide molecule or a four-arm polyethylene glycol molecule modified with a double bond at the end.
[0008] Further, the super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material is characterized in that the self-assembled double bond modified polypeptide is a nanoscale fiber formed by self-assembly of ACLT-GK11 polypeptide through an unsaturated bond, wherein the sequence of the ACLT-GK11 polypeptide is acrylic acid-glycine-histidine-valine-histidine-threonine-histidine-arginine-valine-leucine-histidine-lysine; and the unsaturated bond monomer is acrylamide or acrylic acid.
[0009] Further, the preparation method of the super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material is characterized in that: unsaturated bond monomers, ACLT-GK11 polypeptides and multi-arm hydrophilic polymers are dissolved in deoxygenated ultrapure water at a mass ratio of 45:12:10, uniformly mixed, and a double bond polymerization initiator ammonium persulfate with a concentration of 6 mg / mL is added to obtain a hydrogel precursor solution; the hydrogel precursor solution is placed at 25 DEG C for 2 hours to complete self-assembly of the polypeptides, that is, the single-end unsaturated bond ACLT-GK11 polypeptides are firstly self-assembled to form self-assembled double bond modified polypeptides, and the self-assembled double bond modified polypeptides and the unsaturated bond monomers are one-step polymerized to form string fibers; then, the hydrogel precursor solution is subjected to ultraviolet light irradiation for 4 hours, and the string fibers are crosslinked to the multi-arm hydrophilic polymers through covalent bonds to obtain a primary hydrogel material; the obtained primary hydrogel material is immersed in a 50-fold volume of a buffer solution containing metal ions for more than 24 hours to complete ion coordination of the string fibers and swelling of the overall hydrogel, and a super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material is obtained.
[0010] Further, the preparation method is characterized in that: the buffer solution containing metal ions is a Tris-HCl buffer solution with a concentration of 1M and a pH of 7.6, the metal ions are copper ions or zinc ions, and the concentration of the metal ions is 200mM; the multi-arm hydrophilic polymer is a double bond modified four-arm polyethylene glycol polymer with a molecular weight of 20kDa, and the unsaturated bond monomer is acrylamide.
[0011] An application of a super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material in a flexible electronic device.
[0012] An application of a super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material in a soft robot.
[0013] An application of a super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material in biological medicine, medical devices or tissue engineering.
[0014] The technical effects of the present application are as follows: 1. Compared with traditional double-network hydrogels, the hydrogel material in the present application integrates the hidden length and energy dissipation network in the hydrogel polymer network into the same network, realizes the integration of mechanical strength and toughness, and the breaking strength reaches 4.1MPa, the toughness reaches 40MJ / m 3 , the breaking toughness reaches 25kJ / m 2 , and the breaking toughness reaches 2 times that of rubber.
[0015] 2. Compared with the traditional hydrogel fast recovery mechanism, the hydrogel material in the application mainly relies on small range of string fiber dissociation and combination to carry out fast energy dissipation and mechanical property recovery; because of the synergy of polypeptide assembly and ion coordination, the molecular level and assembly level have fast combination kinetics, so that the fast recovery of the hydrogel is realized. The mechanical property of the hydrogel in the application can be recovered by 100% in a few seconds.
[0016] 4. Compared with the traditional hydrogel material, the hydrogel material in the application relies on self-assembly polypeptide fiber dissociation and dissociation of metal ion coordination to carry out energy dissipation, and the fatigue threshold of the hydrogel in the application reaches 451J / m 2 , which is 40 times of the rubber fatigue threshold.
[0017] 5. Compared with the traditional hydrogel material, the hydrogel adhesive material in the application integrates high toughness, high strength, fast recovery and excellent fatigue resistance, while the traditional hydrogel material can only achieve relatively high properties in some of the characteristics, and it is difficult to balance all aspects. BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 Network diagram of super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material.
[0019] Figure 2 String fiber diagram of self-assembly and ion coordination synergy.
[0020] Figure 3 Microstructure of string fiber of self-assembly and ion coordination synergy.
[0021] Figure 4 Photo of compression resistance and fast recovery property of super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material.
[0022] Figure 5 Super-tough and super-strong mechanical property characterization of super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material.
[0023] Figure 6 Fast recovery mechanical property characterization of super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material.
[0024] Figure 7 Fatigue resistance property characterization of super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material. DETAILED DESCRIPTION
[0025] The application will be further described in detail below with reference to the drawings.
[0026] An ultra-strong, ultra-tough, fast-recovery and fatigue-resistant hydrogel material is formed by cross-linking of string fibers and multi-arm hydrophilic polymers; the cross-linking mode of the string fibers and the multi-arm hydrophilic polymers is double bond copolymerization, and the small-range disassembly and coordination dissociation of the string fibers form the energy dissipation mechanism and the fast-recovery characteristics of the hydrogel Figure 1 a and Figure 1 b); in the present application, the string fiber structure in the hydrogel material is obtained by one-step polymerization of self-assembled double bond modified polypeptides and acrylamide, the polypeptides are self-assembled to form a fiber structure, the acrylamide forms a random polymer chain combined at the end of the polypeptide to form a hidden length of the self-assembled fiber Figure 2 。
[0027] Further, a typical preparation method of an ultra-strong, ultra-tough, fast-recovery and fatigue-resistant hydrogel material, acrylamide, ACLT-GK11 polypeptide and end double bond modified four-arm polyethylene glycol polymer are dissolved in deoxygenated ultrapure water at a mass ratio of 45:12:10, mixed uniformly, and a double bond polymerization initiator ammonium persulfate is added at a concentration of 6 mg / mL to obtain a hydrogel precursor solution; the hydrogel precursor solution is placed at 25℃ for 2 hours to complete the self-assembly of the polypeptide; after the precursor solution is irradiated with ultraviolet light for 4 hours, an ultra-strong, ultra-tough, fast-recovery and fatigue-resistant hydrogel material is obtained; the obtained hydrogel material is immersed in a buffer solution containing metal ions with a volume of 50 times for more than 24 hours to complete the ion coordination of the string fibers and the swelling of the whole hydrogel.
[0028] Further, in the typical preparation method of the ultra-strong, ultra-tough, fast-recovery and fatigue-resistant hydrogel material, the buffer solution containing metal ions is Tris-HCl buffer solution with a concentration of 1M, pH of 7.6 and metal ion concentration of 200mM; the end double bond modified four-arm polyethylene glycol polymer has a molecular weight of 20kDa.
[0029] The performance of the present application is tested in the following examples.
[0030] Example 1 Verification of the microstructure of the string fiber with self-assembly and ion coordination synergy in the present application
[0031] In the present application, for the string fiber, that is, the self-assembled polypeptide fiber side is installed with a polyacrylamide polymer as a hidden length through double bond polymerization, and the polypeptide itself can also be assembled with copper ions, and the preparation method is described above, and the double bond modified polypeptide and acrylamide are formed by one-step polymerization. In order to verify the structure of the string fiber involved in the present application, the self-assembled polypeptide fiber alone and the self-assembled polypeptide fiber combined with copper ions are respectively detected by atomic force microscope scanning, as shown in Figure 3a shows that the microstructure of the polypeptide is in the form of nanofiber, and the fiber height is uniformly distributed in 1-2 nm before and after the combination of ions, and after the combination of ions, the microstructure is more entangled; as shown in Figure 3 b, the microstructure after the copolymerization of acrylamide and the double bond modified polypeptide is very obvious, and the microstructure is still in the form of nanofiber after the copolymerization, but the height of the fiber is obviously improved, which indicates that the acrylamide macromolecule exists in the form of a hidden length on the side of the polypeptide fiber, thereby improving the average height of the fiber, which is consistent with the string fiber structure proposed in the schematic Figure 2 diagram of the present application. Therefore, the special microstructure of the string fiber in the present application is verified.
[0032] Example 2: The intuitive image of the compression resistance and rapid recovery properties of the hydrogel material in the present application.
[0033] The hydrogel material in the present application as a whole presents a transparent blue gel form (s-Pep / Cu 2+ ), as shown in Figure 4 a bottom, and here also shows the hydrogel without adding polypeptide (PAM) and the hydrogel adding polypeptide but not ion coordination (s-Pep) as a control, it can be seen that for the hydrogel without adding polypeptide, the compression limit is less than 70%, and it is broken after being compressed to 70% deformation; for the hydrogel adding polypeptide but not ion coordination, the compression limit is less than 90%, and it is broken after being compressed to 90% deformation; and for the super strong, super tough, rapid recovery and fatigue resistant hydrogel material in the present application, the compression limit is higher than 90%, and after being compressed to 90%, it still does not break, and after the stress is released, it quickly recovers to the original form. As shown in Figure 4 b, for the super strong, super tough, rapid recovery and fatigue resistant hydrogel material in the present application, it is very difficult to cut the material even using a blade to cut it directly; as shown in Figure 4 c, the hydrogel material in the present application can be stretched to 23 times of its own length without breaking, proving its excellent tensile resistance. This example intuitively shows the super strong and super tough properties and excellent tensile resistance of the hydrogel material in the present application.
[0034] Example 3: Strength and toughness mechanical property test of the hydrogel material in the present application.
[0035] In order to verify the strength and toughness of the hydrogel material in the present application, the standard mechanical property test is carried out on the material, and the hydrogel without adding polypeptide (PAM) and the hydrogel adding polypeptide but not ion coordination (s-Pep) are used as controls. As shown in Figure 5 a, the hydrogel material (s-Pep / Cu 2+), showing tensile fracture strength over 4 MPa, tensile fracture length over 23 times of the original length, toughness up to 40 MJ / m 2 , far higher than the control group, showing the ultra-high strength and toughness of the hydrogel material in the application, and the toughness and fracture strength of the hydrogel can be further increased to more than 50 MJ / m 2 Figure 5 b). The hydrogel material shows obvious energy dissipation characteristics, and the energy dissipation increases with the increase of deformation, which is consistent with the toughness enhancement mechanism ( Figure 5 c). Further, according to the standard fracture toughness test method, the hydrogel material in the application shows a fracture toughness of up to 25 kJ / m 2 , which is 2 times higher than the fracture toughness of rubber material ( Figure 5 d). This embodiment shows the ultra-high mechanical strength and excellent toughness of the hydrogel material in the application through standard mechanical tests.
[0036] Example 4: Rapid mechanical property recovery test of the hydrogel material in the application.
[0037] In order to verify the strength and toughness of the hydrogel material in the application, the hydrogel material was subjected to continuous tensile and continuous compression mechanical tests. Here, the hydrogel added with polypeptide but without ion coordination (s-Pep) was used as a control. As shown in Figure 6 a-c, the hydrogel material in the application showed substantially completely coinciding mechanical test curves in the continuous 100-cycle tensile cycle test, indicating that the hydrogel material can complete the recovery of mechanical properties within a time scale of seconds, and the maximum stress and dissipated energy are maintained at more than 95% after 100-cycle continuous tensile cycle, which is much higher than the control group. Similarly, as shown in Figure 6 d-f, the hydrogel material in the application showed substantially completely coinciding mechanical test curves in the continuous 100-cycle compression cycle test, and the maximum stress and dissipated energy were maintained at more than 92% after 100-cycle continuous tensile cycle, which is much higher than the control group. These experiments show that the hydrogel material in the application has the ability of rapid mechanical property recovery, and the recovery time scale is seconds.
[0038] Example 5: Anti-fatigue mechanical property test of the hydrogel material in the application.
[0039] In order to show the excellent anti-fatigue mechanical properties of the hydrogel material in the application, the applicant conducted a standard fatigue threshold test on the hydrogel material in the application, i.e. a multi-cycle tensile test of the hydrogel with a notch. Similarly, the hydrogel without adding polypeptide (PAM) and the hydrogel added with polypeptide but without ion coordination (s-Pep) were used as controls. As shown in Figure 7 a-c, the control hydrogels were completely broken after 300 and 3000 cycles of continuous stretching, while the hydrogel material (s-Pep / Cu2+) in the present application showed no significant increase in the notch after 10000 cycles of continuous stretching, demonstrating its excellent fatigue resistance. As shown in Figure 7 d-i, the notch growth of notched hydrogels under different stretching deformations was tested and analyzed in detail, and the corresponding energy release rate was calculated. The hydrogel material in the present application exhibited a fatigue threshold as high as 451 J / m2, which was 40 times the fatigue threshold of rubber, exceeding all single-network hydrogel materials. These experiments demonstrated the ultra-high breaking threshold and excellent fatigue resistance of the hydrogel material in the present application.
Claims
1. A superstrong, super tough, fast-recovery and fatigue-resistant hydrogel material, characterized in that, The hydrogel material is a string fiber through double bond copolymerization of multi-arm hydrophilic polymer; and the metal ion is stably coordinated on the polypeptide of the string fiber; the string fiber is a self-assembled double bond modified polypeptide polymerization unsaturated bond monomer; the multi-arm hydrophilic polymer is a hydrophilic cross-linking molecule with unsaturated bond at the end; the metal ion is copper ion or zinc ion; the multi-arm hydrophilic polymer is a methylene bisacrylamide molecule or a four-arm polyethylene glycol molecule with double bond at the end, and the self-assembled double bond modified polypeptide is ACLT-GK 11 The polypeptide is self-assembled to form a nanoscale fiber through an unsaturated bond, wherein ACLT-GK 11 The polypeptide sequence is acrylate-glycine-histidine-valine-histidine-threonine-histidine-arginine-valine-leucine-histidine-lysine; and the unsaturated bond monomer is acrylamide or acrylic acid.
2. The method for preparing the superstrong, super tough, fast-recovery and fatigue-resistant hydrogel material of claim 1, characterized in that, The unsaturated bond-containing monomer, ACLT-GK 11 The polypeptide, the multi-arm hydrophilic polymer, and the double bond polymerization initiator ammonium persulfate with a concentration of 6 mg / mL were dissolved in deoxygenated ultrapure water at a mass ratio of 45:12:10, and uniformly mixed to obtain a hydrogel precursor solution; the hydrogel precursor solution was left to stand at 25℃ for 2 hours to complete the self-assembly of the polypeptide, i.e., the self-assembly of the unsaturated bond-containing monomer ACLT-GK 11 The polypeptide was first subjected to self-assembly to form a self-assembled double bond modified polypeptide, the self-assembled double bond modified polypeptide and the unsaturated bond-containing monomer were subjected to one-step polymerization to form a string fiber; then, the hydrogel precursor solution was subjected to ultraviolet irradiation, the string fiber crosslinked the multi-arm hydrophilic polymer through a covalent bond to obtain a primary hydrogel material; the obtained primary hydrogel material was immersed in a 50-fold volume of a buffer solution containing metal ions for more than 24 hours to complete the ion coordination of the string fiber and the swelling of the overall hydrogel, thereby obtaining a super-strong, super-tough, fast-recovery, and fatigue-resistant hydrogel material.
3. The production method according to claim 2, characterized by, The buffer solution containing metal ions is Tris-HCl buffer solution with a concentration of 1M, a pH of 7.6, copper ions or zinc ions as metal ions, and a metal ion concentration of 200mM; the multi-arm hydrophilic polymer is a four-arm polyethylene glycol polymer modified with a terminal double bond, with a molecular weight of 20kDa, and an unsaturated bond monomer of acrylamide.
4. The use of the super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material of claim 1 in flexible electronic devices.
5. The use of the super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material of claim 1 in soft robots.
6. The use of the super-strong, super-tough, fast-recovery and fatigue-resistant hydrogel material of claim 1 in biomedical and medical devices for non-diagnostic and therapeutic purposes.
Citation Information
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