Preparation method and application of super-tough anti-swelling hydrogel

Abstract

The present application relates to the technical field of hydrogel and its application, in particular to a preparation method and application of super strong and tough swelling-resistant hydrogel. The components of the hydrogel include water, ionic liquid 1-n-butyl-3-methyl imidazole trifluoromethane sulfonate, betaine, acrylic acid, aluminum chloride and zinc methacrylate. The preparation method is as follows: the ionic liquid is mixed with water, the acrylic acid monomer and the betaine are dissolved, the aluminum chloride and the zinc methacrylate crosslinking agent are sequentially added, the mixture is uniformly mixed to form a pre-polymerization liquid, and finally the hydrogel is obtained through ultraviolet polymerization. The method is simple in process, the obtained hydrogel not only has excellent mechanical properties and swelling resistance, but also has further improved mechanical strength, toughness and fatigue resistance after underwater immersion. The application of the hydrogel in the underwater sensing field is also disclosed.

Description

Technical Field

[0001] This invention relates to the field of hydrogels and their applications, and in particular to a method for preparing and applying an ultra-tough, anti-swelling hydrogel. Background Technology

[0002] Underwater sensors are core sensing components in fields such as marine resource development, aquatic environment monitoring, and underwater equipment maintenance. These sensors place stringent requirements on the performance of gel materials: in addition to sufficient mechanical strength to withstand complex underwater stress impacts, they must possess excellent anti-swelling properties to ensure long-term stable operation and maintain signal output reliability and structural integrity under repeated deformation. Hydrogels, as soft materials composed of a hydrophilic polymer network and a large amount of water, have shown broad application potential in flexible electronics, biomedical engineering, and environmental monitoring due to their good biocompatibility, flexibility, and stimulus-responsive characteristics. However, most existing hydrogels generally suffer from problems such as easy swelling and breakage underwater, and a significant decrease in mechanical strength. Even some reinforced hydrogels (such as nanocomposite hydrogels and dual-network hydrogels) can achieve high strength in the dry state, but they still face challenges such as strength decay, excessive swelling rate, and fatigue fracture under cyclic tensile stress after immersion in water. While existing high-performance anti-swelling hydrogels can achieve low swelling and high mechanical strength, their preparation often relies on complex multi-step composite strategies such as annealing, electrostatic crosslinking, and salting out, and they have failed to achieve the reverse strength enhancement after immersion in water. Furthermore, biomimetic impact-resistant hydrogels primarily focus on impact toughness, but still fall short in cyclic tensile stability and adaptability to extreme environments. These issues severely restrict the practical application of hydrogels in complex underwater environments such as seawater and acidic / alkaline conditions.

[0003] Ionic liquids, as green solvents composed entirely of ions, possess advantages such as low vapor pressure, high chemical stability, and tunable polarity and solubility. Introducing them into hydrogel systems has become an effective way to improve material properties. Current research mainly focuses on the regulation of the conductivity, antibacterial properties, and low-temperature resistance of hydrogels by ionic liquids. However, explorations into utilizing ionic liquids in conjunction with monomers and functional additives to simultaneously optimize the mechanical strength, swelling resistance, and cycle stability of hydrogels in underwater environments remain relatively lacking. Betaine-like zwitterionic compounds, due to the formation of internal salt bonds between positive and negative charge centers within the molecule, can enhance the compactness and stability of polymer networks through intermolecular interactions; metal ions can act as crosslinking agents, constructing multi-layered network structures through coordination interactions, thereby improving the mechanical properties of hydrogels. Although strategies such as dual physical crosslinking and stepwise hydrogen bond regulation have been used to enhance the mechanical properties of hydrogels, how to overcome the limitations of existing single or composite modification methods and prepare hydrogels with comprehensive properties such as enhanced strength after immersion, anti-swelling, resistance to cyclic tensile stress and resistance to extreme impacts using simple processes, and realize their effective application in the field of underwater sensing, remains a key problem that urgently needs to be solved. Summary of the Invention

[0004] Based on the above, the purpose of this invention is to provide a method for preparing an ultra-tough, anti-swelling hydrogel and its application in the field of underwater sensing.

[0005] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention is a method for preparing an ultra-tough, anti-swelling hydrogel, comprising the following steps: 1-n-Butyl-3-methylimidazolium trifluoromethane sulfonate, betaine, and acrylic acid were dissolved in water and mixed well. Then, aluminum salt, crosslinking agent, and photoinitiator were added and mixed well to obtain a mixed solution. The mixed solution was irradiated with ultraviolet light to obtain the ultra-tough and anti-swelling hydrogel (hereinafter referred to as: hydrogel).

[0006] The second technical solution of the present invention is an ultra-tough and anti-swelling hydrogel prepared by the above-mentioned preparation method.

[0007] The third technical solution of this invention is the application of the above-mentioned ultra-tough and anti-swelling hydrogel in the preparation of underwater sensors.

[0008] The fourth technical solution of the present invention is an underwater sensor, comprising the above-mentioned ultra-tough and anti-swelling hydrogel.

[0009] Compared with the prior art, the present invention has the following beneficial effects: (1) The preparation process of the super-tough and anti-swelling hydrogel provided by the present invention is simple, the gelation time is short, the production cost is low, and the reaction conditions are easy to control.

[0010] (2) The super-tough and anti-swelling hydrogel prepared by this invention has a physical cross-linking network formed by various intermolecular hydrogen bonds, electrostatic interactions between anions and cations, and coordination interactions between metal ions, which has both high strength and toughness. The mechanical properties of the gel not only do not decrease when immersed in water, but are significantly improved, showing excellent fatigue resistance and anti-swelling properties, and are suitable for various environments such as pure water, seawater, and acid and alkali.

[0011] (3) The strain sensor assembled from the hydrogel of the present invention has excellent strain sensitivity and fast response characteristics, and can effectively monitor and sense mechanical deformation in different underwater environments. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1This is a schematic diagram of the preparation process of the ultra-tough and anti-swelling hydrogel of the present invention.

[0014] Figure 2 This is a schematic diagram of the underwater sensor structure of the present invention.

[0015] Figure 3 The tensile stress-strain curve of the hydrogel prepared in Example 1 of the present invention.

[0016] Figure 4 The tensile stress-strain curves are for the hydrogels prepared in Examples 2-5 of this invention.

[0017] Figure 5 The swelling resistance curves of the hydrogel prepared in Example 1 of this invention in different solvents are shown.

[0018] Figure 6 The compressive stress-strain curve of the hydrogel prepared in Example 3 of the present invention.

[0019] Figure 7 An optical photograph of the hydrogel prepared in Example 3 of this invention.

[0020] Figure 8 An optical photograph of the hydrogel compressed in Example 3 of this invention.

[0021] Figure 9 The fatigue stress curve of the hydrogel prepared in Example 3 after 500 cycles is shown.

[0022] Figure 10 Cyclic tensile stress-strain curves of the hydrogel prepared in Example 3 of the present invention under different strains.

[0023] Figure 11 The sensitivity factor curve is the one fitted to the underwater sensor prepared using the hydrogel prepared in Example 1 of this invention.

[0024] Figure 12 The response time curve of the underwater sensor prepared using the hydrogel prepared in Example 1 of this invention is shown.

[0025] Figure 13 The resistance change curve of the underwater sensor prepared using the hydrogel in Example 1 of this invention is shown in seawater.

[0026] Figure 14 The resistance change curve of the underwater sensor prepared using the hydrogel prepared in Example 1 of this invention is shown in an acidic environment.

[0027] Figure 15 The resistance change curve of the underwater sensor prepared using the hydrogel prepared in Example 1 of this invention is shown in an alkaline environment.

[0028] Figure 16 The mass retention rate of the hydrogels prepared in Comparative Example 1 and Example 1 of this invention is measured within 7 days of storage.

[0029] Figure 17 The stress-strain curves are for the hydrogels prepared in Comparative Example 2 and Example 1 of this invention.

[0030] Figure 18 The results show the water swelling performance test results of the hydrogel prepared in Comparative Example 3 of this invention. Detailed Implementation

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0034] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] This invention utilizes a composite solvent system of 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate ionic liquid and water, with acrylic acid as the polymer monomer. Betaine is introduced as a functional copolymer component, and aluminum and zinc ions are combined to construct a multi-layer cross-linked network, thereby producing a high-performance hydrogel with high strength, high toughness, and excellent anti-swelling properties. After underwater immersion, the mechanical properties of this gel not only do not decrease but are significantly enhanced, while also exhibiting good fatigue resistance. Strain sensors assembled based on this hydrogel possess high sensitivity and rapid response capabilities underwater, and maintain stable sensing performance even in complex environments such as seawater and acidic / alkaline conditions.

[0037] The first aspect of this invention provides a method for preparing an ultra-tough, anti-swelling hydrogel, comprising the following steps: 1-n-Butyl-3-methylimidazolium trifluoromethane sulfonate, betaine, and acrylic acid were dissolved in water and mixed well. Then, aluminum salt, crosslinking agent, and photoinitiator were added and mixed well to obtain a mixed solution. The mixed solution was irradiated with ultraviolet light to obtain the ultra-tough and anti-swelling hydrogel (hereinafter referred to as: hydrogel).

[0038] In a preferred embodiment of the present invention, the ratio of the amounts of 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, betaine, acrylic acid, water, aluminum salt, crosslinking agent and photoinitiator is (1~4) g : (0.017~0.035) mol : (0.041~0.069) mol : (1~4) g : (0.6~0.9) g : (0.07~0.1) g : (20~30) µL.

[0039] In a preferred embodiment of the present invention, the aluminum salt is aluminum trichloride.

[0040] In a preferred embodiment of the present invention, the crosslinking agent is zinc methacrylate.

[0041] In a preferred embodiment of the present invention, the photoinitiator is one of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone, 2-hydroxy-2-methylpropylphenylacetone, 1-hydroxycyclohexylphenyl ketone, and lithium phenyl-2,4,6-trimethylbenzoylphosphonate.

[0042] In a preferred embodiment of the present invention, the wavelength of the ultraviolet light irradiation is 365 nm or 405 nm, and the irradiation time is 0.5 to 2 min.

[0043] In a preferred embodiment of the present invention, the step of immersing the obtained hydrogel in water after the ultraviolet irradiation is completed is further included.

[0044] The soaking time is 0~48 h.

[0045] This invention yields a hydrogel through simple free radical polymerization, and utilizes the synergistic effect of ionic liquid, betaine, and metal ions to regulate the network structure and properties of the hydrogel. The hydrogel forms a three-dimensional network through physical cross-linking, including hydrogen bonding, metal ion coordination, and electrostatic interactions.

[0046] Electrostatic interactions between anhydrous betaine molecules and hydrogen bonding between acrylic acid molecules form an interpenetrating network, while coordination crosslinking networks are formed between polyacrylic acid chains and zinc and aluminum ions. This synergistic effect increases the crosslinking density, giving the gel excellent toughness and fatigue resistance.

[0047] The incorporated ionic liquid 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate interacts with the polymer chain, limiting the coordination rate between metal ions and carboxyl groups, resulting in a relatively loose cross-linking network. During immersion in water, water molecules gradually replace the weak interaction between the ionic liquid and the polymer chain, promoting the formation of denser dynamic coordination cross-linking sites between metal ions and carboxyl groups. The synergistic coordination of the two metal ions provides strong cross-linking sites to ensure strength and dynamic sites to ensure toughness.

[0048] The zwitterionic groups of betaine form a more stable electrostatic interaction network in water, further enhancing interchain bonding, increasing crosslinking density, and resulting in a denser network structure and significantly improved underwater mechanical properties. This invention can achieve a substantial improvement in gel mechanical properties through a simple water immersion strategy.

[0049] A second aspect of the present invention provides an ultra-tough, anti-swelling hydrogel prepared by the above-described preparation method.

[0050] The super-tough and anti-swelling hydrogel of the present invention is a three-dimensional porous hydrogel formed by 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, betaine, acrylic acid, aluminum trichloride and zinc methacrylate.

[0051] This invention allows for control over the underwater mechanical properties (ultra-toughness) of the gel by altering the content of 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate and water in the gel.

[0052] This invention can regulate the anti-swelling behavior of hydrogels by changing the content of betaine.

[0053] The third aspect of this invention provides the application of the above-mentioned ultra-tough and anti-swelling hydrogel in the preparation of underwater sensors.

[0054] Based on the properties of the ultra-tough and anti-swelling hydrogel of this invention, its application in underwater sensors can promote the engineering application of underwater flexible electronic devices.

[0055] A fourth aspect of the present invention provides an underwater sensor comprising the aforementioned ultra-tough, anti-swelling hydrogel.

[0056] The underwater sensor includes two copper wires, two sections of conductive adhesive, and hydrogel disposed between the two copper wires; the conductive adhesive is used to bond the copper wires and the hydrogel together.

[0057] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0058] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0059] This invention provides a method for preparing an ultra-tough, anti-swelling hydrogel (e.g.) Figure 1 (As shown), the steps are as follows: Step 1: Dissolve 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate, betaine, and acrylic acid in water and stir until homogeneous to obtain the first mixed solution; Step 2: Add aluminum trichloride, crosslinking agent (zinc methacrylate), and photoinitiator sequentially to the first mixed solution to obtain the second mixed solution; Step 3: Inject the second mixed solution into the polytetrafluoroethylene mold and irradiate it under ultraviolet light for a period of time to form a hydrogel.

[0060] Regarding the applications of the ultra-tough, anti-swelling hydrogel prepared by the above method, such as... Figure 2 As shown, an ultra-tough and anti-swelling hydrogel is applied to an underwater sensor. The device includes a water tank 1, two sections of conductive adhesive 2, a piece of hydrogel 3, and two copper wires 4. The two copper wires 4 are connected to both ends of the hydrogel 3, and then the two sections of conductive adhesive 2 are used to bond them together and the device is placed in the water tank 4 for strain sensing tests.

[0061] Examples 1-5 4 g of 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate, 4 g of betaine, and 3.0 g of acrylic acid were dissolved in 1.5 g of water and stirred for 2 hours to obtain a mixed solution. Then, 0.8 g of aluminum trichloride (aluminum ions accounting for 3% of the mass of acrylic acid monomer), 0.09 g of zinc methacrylate, and 25 µL of 2-hydroxy-2-methylpropyl phenyl ketone were added to the resulting mixture, and the mixture was magnetically stirred until a homogeneous solution was formed. Next, the mixed solution was poured into a polytetrafluoroethylene mold and irradiated under a 365 nm UV lamp for 1 minute to obtain a hydrogel. The hydrogel was then immersed in pure water for 0–48 hours.

[0062] Table 1. Proportions of raw materials and soaking time in pure water in Examples 1-5

[0063] A strip-shaped specimen with a length of 40 mm, a width of 10 mm, and a thickness of 2.0 mm was taken from the ultra-tough and anti-swelling hydrogel prepared according to the above method and subjected to a tensile test on an electronic universal testing machine at a speed of 50 mm / min to obtain its stress-strain curve. The results are as follows. Figure 3 As shown, the maximum elongation at break in Example 1 is 675%, and the maximum breaking stress is 3.0 MPa.

[0064] A strip-shaped specimen with a length of 40 mm, a width of 10 mm, and a thickness of 2.0 mm was taken from the ultra-tough and anti-swelling hydrogel prepared in Examples 2-5 and subjected to tensile testing on an electronic universal testing machine at a speed of 50 mm / min to obtain its stress-strain curve. The results are as follows. Figure 4 As shown, compared with Example 1, it can be seen that after soaking in pure water for different periods, the maximum elongation at break and the maximum tensile stress of the hydrogel are significantly increased. Specifically, Example 2, soaked for 12 hours, showed a maximum elongation at break of 780% and a maximum tensile stress that doubled to 6.0 MPa. This is because microphase separation occurs after soaking in water. Water molecules, acting as a co-solvent, optimize the conformation of the polymer chains, causing the hydrophobic imidazole groups to form a specific arrangement with the water molecules. The ionic liquid acts as a physical crosslinking point or reinforcing filler, limiting chain slippage.

[0065] The properties of the hydrogels prepared in the examples were further tested: (1) Anti-swelling properties of hydrogels A strip of hydrogel with a length of 20 mm, a width of 10 mm, and a thickness of 2.0 mm was soaked in different solvents for 8 days from the hydrogel prepared in Example 1. The results are as follows. Figure 5 As shown, after soaking in different solvents, the hydrogel reached swelling equilibrium on the 4th day, indicating that the hydrogel is acid and alkali resistant and has good anti-swelling properties.

[0066] (2) Mechanical properties of hydrogels A cylindrical hydrogel with a diameter of 10 mm and a height of 12 mm was taken from the hydrogel prepared in Example 3, and its stress-strain curve was obtained by performing a compression test on an electronic universal testing machine at a speed of 10 mm / min. The results are as follows. Figure 6 As shown, the hydrogel has a maximum pressure of 5.9 MPa under 80% strain and can quickly recover its original shape, indicating that the hydrogel has good toughness.

[0067] A strip of hydrogel with a length of 50 mm, a width of 10 mm, and a thickness of 2.0 mm was taken from the hydrogel prepared in Example 3 and subjected to a load test. The results are as follows. Figure 7 As shown, the hydrogel can lift a 20 kg bucket without breaking.

[0068] A cylindrical hydrogel with a diameter of 10 mm and a height of 12 mm was taken from the hydrogel prepared in Example 3 and subjected to pressure testing. The results are as follows. Figure 8 As shown, the hydrogel was repeatedly run over by a car weighing one ton without being damaged and quickly returned to its original state.

[0069] (3) Hysteresis performance and fatigue resistance test The hysteresis and fatigue resistance properties of the hydrogel were determined using an electronic universal testing machine. A strip of hydrogel with a length of 40 mm, a width of 10 mm, and a thickness of 2.0 mm was taken from the hydrogel prepared in Example 3 and subjected to a tensile test at a speed of 50 mm / min on the electronic universal testing machine. The results are as follows... Figure 9 As shown, continuous nonstatic load-unload tensile tests (500 cycles in total) were conducted with a constant strain of 100%. The stress intensity remained almost constant in subsequent cycles, indicating that the hydrogel has good fatigue resistance and is suitable for constructing highly elastic and stable sensors. Figure 10 The hysteresis curves of the hydrogel prepared in Example 3 under different strains during tensile cycling are shown. The degree of fracture in the hydrogel network gradually increases, and the hysteresis loops also gradually increase in size.

[0070] (4) Application in underwater sensors The hydrogel prepared in Example 1 (30 mm × 10 mm × 2 mm) was connected to two copper conductors and assembled into a strain sensor by binding with conductive adhesive. Its structure is as follows: Figure 2 As shown.

[0071] To further investigate the sensitivity of the underwater sensor assembled from the prepared ultra-tough and anti-swelling hydrogel, the sensitivity factor (GF) was fitted by monitoring the relative resistance change under different underwater strains. Figure 11 As shown, the results indicate that the water sensor has a sensitivity factor of 0.4 in the strain range of 0 to 50 and a sensitivity factor of 1.39 in the strain range of 50 to 250, indicating that the strain sensor assembled from the ultra-tough and anti-swelling hydrogel has excellent sensitivity underwater.

[0072] Figure 12 The response time curve of the underwater sensor made of hydrogel as described in Example 1 of this invention shows that the sensor has fast response (205 ms) and recovery (300 ms) underwater.

[0073] Figure 13 The resistance change curve of the underwater sensor made of hydrogel as described in Embodiment 1 of the present invention in seawater. Figure 14 This is the resistance change curve of the underwater sensor made of hydrogel as described in Example 1 of the present invention in an acidic environment. Figure 15This is the resistance change curve of the underwater sensor fabricated from the hydrogel described in Example 1 of this invention in an alkaline environment. The results show that the underwater sensor assembled from the ultra-tough, anti-swelling hydrogel can transmit electrical signals stably in extreme environments, exhibiting good stability and durability.

[0074] Comparative Example 1 The only difference from Example 1 is that the addition of 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate is omitted; all other steps and parameters are the same as in Example 1.

[0075] The hydrogel prepared in this comparative example was subjected to the same effect verification as in Example 1, such as... Figure 16 As shown, the hydrogel prepared in Example 1 without the addition of 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate retained 87% of its initial mass on day 1, but only 51% of its mass after 7 days of storage. In contrast, the hydrogel prepared in Example 1 retained more than 95% of its mass after 7 days. The results indicate that the ionic liquid 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate is a key component for the excellent water retention properties of the hydrogel.

[0076] Comparative Example 2 The only difference from Example 1 is that the addition of aluminum trichloride and zinc methacrylate is omitted; all other steps and parameters are the same as in Example 1.

[0077] The hydrogel prepared in this comparative example was subjected to the same effect verification as in Example 1, such as... Figure 17 As shown, the hydrogel prepared in Comparative Example 2 without the addition of aluminum trichloride and zinc methacrylate exhibits poor strength and toughness. The results indicate that aluminum and zinc ions, through coordination with carboxylate groups, form a strong and tough dynamic physical cross-linking network, endowing the hydrogel with ultra-high strength and toughness.

[0078] Comparative Example 3 The only difference from Example 1 is that the addition of betaine is omitted; all other steps and parameters are the same as in Example 1.

[0079] The hydrogel prepared in this comparative example was subjected to the same effect verification as in Example 1, and the results are as follows: Figure 18 As shown, gels without betaine swell significantly after soaking in water, resulting in a large loss of metal ions and ionic liquids, which leads to the destruction of the coordination network and a significant decrease in mechanical properties. This indicates that betaine is the key component for achieving gel anti-swelling and improved mechanical properties after soaking in water.

[0080] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing an ultra-tough, anti-swelling hydrogel, characterized in that, Includes the following steps: 1-n-Butyl-3-methylimidazolium trifluoromethane sulfonate, betaine, and acrylic acid were dissolved in water and mixed well. Then, aluminum salt, crosslinking agent, and photoinitiator were added and mixed well to obtain a mixed solution. The mixed solution was irradiated with ultraviolet light to obtain the ultra-tough and anti-swelling hydrogel.

2. The preparation method according to claim 1, characterized in that, The ratio of 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate, betaine, acrylic acid, water, aluminum salt, crosslinking agent and photoinitiator is (1~4) g : (0.017~0.035) mol : (0.041~0.069) mol : (1~4) g : (0.6~0.9) g : (0.07~0.1) g : (20~30) µL.

3. The preparation method according to claim 1, characterized in that, The aluminum salt is aluminum trichloride.

4. The preparation method according to claim 1, characterized in that, The crosslinking agent is zinc methacrylate.

5. The preparation method according to claim 1, characterized in that, The photoinitiator is one of 2-hydroxy-4′-(2-hydroxyethoxy)-2-methylphenylacetone, 2-hydroxy-2-methylpropylphenylacetone, 1-hydroxycyclohexylphenyl ketone, and lithium phenyl-2,4,6-trimethylbenzoylphosphonate.

6. The preparation method according to claim 1, characterized in that, The wavelength of the ultraviolet light irradiation is 365 nm or 405 nm, and the irradiation time is 0.5 to 2 min.

7. The preparation method according to claim 1, characterized in that, The process further includes immersing the resulting hydrogel in water after the ultraviolet light irradiation is completed.

8. A super-tough, anti-swelling hydrogel prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the ultra-tough and anti-swelling hydrogel as described in claim 8 in the preparation of underwater sensors.

10. An underwater sensor, characterized in that, Including the ultra-tough, anti-swelling hydrogel as described in claim 8.

Images