An ultrahigh-strength hydrogel sponge with hierarchical porous structure and its preparation method and application

Abstract

The application provides a super-high-strength hydrogel sponge with a hierarchical porous structure and a preparation method and application thereof, and relates to the technical field of porous hydrogel materials.The application provides a preparation method of a super-high-strength hydrogel sponge with a hierarchical porous structure, which comprises the following steps: mixing polyvinyl alcohol raw materials, a hydrogen bond acceptor and paraffin at high temperature, performing sol-gel transformation to obtain a gel; the temperature of the high-temperature mixing is greater than or equal to 90 DEG C; the temperature of the sol-gel transformation is less than or equal to 10 DEG C; and the gel is sequentially subjected to ethanol exchange treatment, n-hexane exchange treatment and water exchange treatment to obtain a super-high-strength hydrogel sponge with a hierarchical porous structure.The application induces the mixed solution to perform sol-gel transformation through temperature reduction, and a gel with high mechanical strength is prepared; and a multi-step solvent (ethanol, n-hexane and water) exchange strategy is used to obtain a hydrogel sponge material with super-high strength, high porosity and elastic recovery performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of porous hydrogel materials, in particular to a super-high-strength hydrogel sponge with hierarchical porous structure and a preparation method and application thereof. BACKGROUND

[0002] Hydrogel sponge is a kind of porous material that can absorb a large amount of water, and has the hydrophilic softness of hydrogel and the light weight of sponge. In recent years, hydrogel sponge has been widely used in seawater evaporation, tissue engineering, biomedical materials and other fields, and significant progress has been made in the preparation process, structure regulation and performance optimization of hydrogel sponge. For example, Chinese patent CN113817214A discloses a method for preparing porous hydrogel sponge, which comprises the following steps: placing a porogen in a hydrogel solution containing double-bonded sodium hyaluronate or double-bonded gelatin and a photoinitiator, maintaining negative pressure vacuum until the hydrogel solution is crosslinked, removing the porogen to obtain a porous hydrogel, and freeze-drying to obtain a porous hydrogel sponge. The porous hydrogel sponge prepared by this method has controllable, uniform and interconnected pore structure, effectively increasing the porosity and specific surface area of the hydrogel sponge. Chinese patent CN106916333A discloses a method for preparing polyvinyl alcohol medical sponge, which comprises the following steps: adding polyvinyl alcohol and starch into distilled water and stirring to dissolve, adding crosslinking agent, emulsifying agent and foam stabilizer and stirring, adding acid catalyst for acetal crosslinking reaction, and heating and curing to obtain polyvinyl alcohol medical sponge. The polyvinyl alcohol medical sponge prepared by this method has a through-opening structure with uniform pore size, and has good biocompatibility, good affinity, high porosity and fast liquid absorption rate. Chinese patent CN113599565A discloses a method for preparing a gradient-degradable medical sponge, which comprises the following steps: constructing a rigid part by providing a first water-soluble cellulose derivative and crosslinking it to form a hydrogel slurry with a first viscosity; constructing a flexible part by providing a second water-soluble cellulose derivative and crosslinking it to form a hydrogel slurry with a second viscosity, wherein the second viscosity is less than the first viscosity; constructing a composite structure by mixing the hydrogel slurry with the first viscosity and the hydrogel slurry with the second viscosity to form a mixed slurry; and vacuum freeze-drying the mixed slurry to form a sponge. The medical sponge prepared by this method has both rigid and flexible structures, and can realize gradient degradation regulation and drug release.

[0003] The material transport efficiency of the hydrogel depending on the porous structure is a key factor to determine its functional diversity. The increase of porosity can significantly improve the material transport efficiency, but the extreme increase of porosity of the hydrogel synthesized by the above method usually weakens the inherent mechanical modulus, thereby causing obvious deformation and poor bearing capacity, the tensile fracture strength of the hydrogel sponge is limited, and the mechanical properties may have adverse effects such as creep during long-term use or cyclic deformation, thereby shortening the service life, which seriously limits the potential of the porous hydrogel as a load support scaffold in further application. In view of the potential application demand of the hydrogel sponge material in the market, how to improve the strength and durability of the sponge under the premise of ensuring high porosity has become a challenge. SUMMARY

[0004] Therefore, the purpose of the present application is to provide an ultrahigh-strength hydrogel sponge with a hierarchical porous structure and a preparation method and application thereof. The hydrogel sponge provided by the present application has high porosity and high strength.

[0005] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:

[0006] The present application provides a preparation method of an ultrahigh-strength hydrogel sponge with a hierarchical porous structure, comprising the following steps:

[0007] The polyvinyl alcohol raw material, the hydrogen bond acceptor and the paraffin are mixed at high temperature to perform sol-gel transition to obtain a gel; the temperature of the high-temperature mixing is ≥ 90℃; the temperature of the sol-gel transition is ≤ 10℃;

[0008] The gel is sequentially subjected to ethanol exchange treatment, n-hexane exchange treatment and water exchange treatment to obtain an ultrahigh-strength hydrogel sponge with a hierarchical porous structure.

[0009] Preferably, the polyvinyl alcohol raw material comprises polyvinyl alcohol and / or polyvinyl alcohol grafted polymer;

[0010] The weight average molecular weight of the polyvinyl alcohol raw material is 10-2000 kDa;

[0011] The alcoholysis degree of the polyvinyl alcohol is 75-99.9%.

[0012] Preferably, the hydrogen bond acceptor comprises dimethyl sulfoxide and / or N,N-dimethylformamide;

[0013] The mass ratio of the polyvinyl alcohol raw material and the hydrogen bond acceptor is 5-20:80-95.

[0014] Preferably, the mass ratio of the polyvinyl alcohol and the paraffin is 5-20:10-30.

[0015] Preferably, the high-temperature mixing comprises: dissolving the polyvinyl alcohol raw material in dimethyl sulfoxide, and then adding paraffin to stir and mix.

[0016] Preferably, the temperature of the high-temperature mixing is 90-110 DEG C.

[0017] The dissolving time is 1-6 h.

[0018] Preferably, the temperature of the sol-gel transition is -5-10 DEG C, and the time is 2-48 h.

[0019] Preferably, the ethanol exchange treatment time is 24-72 h.

[0020] The n-hexane exchange treatment time is 48-120 h.

[0021] The water exchange treatment time is 24-72 h.

[0022] The time interval for replacing the solvent during the ethanol exchange treatment, n-hexane exchange treatment and water exchange treatment is independently 4-8 h.

[0023] The application further provides the super-high-strength hydrogel sponge with a hierarchical porous structure prepared by the preparation method.

[0024] The application further provides the application of the super-high-strength hydrogel sponge with a hierarchical porous structure in biomedical materials, flexible wearable devices or tissue engineering materials.

[0025] The application provides a preparation method of an ultrahigh-strength hydrogel sponge with a hierarchical porous structure, comprising the following steps: mixing polyvinyl alcohol raw materials, a hydrogen bond acceptor and paraffin at a high temperature to perform sol-gel transition to obtain a gel; the temperature of the high-temperature mixing is greater than or equal to 90 DEG C; the temperature of the sol-gel transition is less than or equal to 10 DEG C; and the gel is sequentially subjected to ethanol exchange treatment, n-hexane exchange treatment and water exchange treatment to obtain the ultrahigh-strength hydrogel sponge with the hierarchical porous structure. By adding the hydrogen bond acceptor, the non-covalent interaction in and between polyvinyl alcohol (PVA) molecular chains can be inhibited, and the hydrogen bond between the hydrogen bond acceptor and PVA is preferentially formed; in the high-temperature mixing process, the PVA molecular chains have an extended conformation and are uniformly distributed; and paraffin is used as a pore-forming agent to construct a macroporous structure in the gel network. The ultrahigh-strength gel is prepared by one-pot integrated molding based on the strategy of a crystal constraint template (i.e., the sol-gel transition of the mixed solution obtained by high-temperature mixing induced by cooling); and the paraffin pore-forming agent is removed by a multi-step solvent (ethanol, n-hexane and water) exchange strategy, the PVA molecular chains which are fully extended and uniformly arranged are shrunk to form a large number of crystalline domains and microporous structures, the pore structure and specific surface area of the hydrogel sponge are improved, the ultrahigh strength and elastic recovery performance of the hydrogel sponge are ensured, and the hydrogel sponge material with ultrahigh strength, high porosity and elastic recovery performance is obtained. Moreover, the preparation method provided by the application has simple preparation process steps, easy conditions and suitability for industrial production.

[0026] The hydrogel sponge provided by the application has the hierarchical porous structure characteristics, has excellent mechanical properties on the basis of ensuring high porosity, has a wide application prospect in the fields of biomedical materials, flexible wearable devices and tissue engineering materials, and can be used for preparing soft substance elastic supports and other devices. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a surface scanning electron microscope image of the ultrahigh-strength hydrogel sponge with the hierarchical porous structure in Example 1.

[0028] Figure 2 It is a cross-sectional scanning electron microscope image of the ultrahigh-strength hydrogel sponge with the hierarchical porous structure in Example 1.

[0029] Figure 3 It is a micro-reconstruction image of the ultrahigh-strength hydrogel sponge with the hierarchical porous structure in Example 1 by high-resolution three-dimensional X-ray microscopy.

[0030] Figure 4 It is a porosity statistical diagram and a pore distribution statistical diagram of the ultrahigh-strength hydrogel sponge with the hierarchical porous structure in Example 1.

[0031] Figure 5A tensile stress-strain curve of a fractured sample of the superhigh-strength hydrogel sponge with hierarchical porous structure in Examples 1-3;

[0032] Figure 6 A compression stress-strain curve of the original sample of the superhigh-strength hydrogel sponge with hierarchical porous structure in Example 1 under different tensile times;

[0033] Figure 7 A compression stress-strain curve of the recovered sample of the superhigh-strength hydrogel sponge with hierarchical porous structure in Example 1 after being soaked in water for 2h under different tensile times;

[0034] Figure 8 A comparison result diagram of energy dissipation of the original sample and the recovered sample of the superhigh-strength hydrogel sponge with hierarchical porous structure in Example 1 under different tensile times. DETAILED DESCRIPTION

[0035] The present application provides a preparation method of a superhigh-strength hydrogel sponge with hierarchical porous structure, comprising the following steps:

[0036] The polyvinyl alcohol raw material, the hydrogen bond acceptor and the paraffin wax are mixed at high temperature to perform sol-gel transition to obtain a gel; the temperature of the high temperature mixing is ≥90℃; the temperature of the sol-gel transition is ≤10℃;

[0037] The gel is sequentially subjected to ethanol exchange treatment, n-hexane exchange treatment and water exchange treatment to obtain the superhigh-strength hydrogel sponge with hierarchical porous structure.

[0038] Unless otherwise specified, the materials and devices used in the present application are commercially available in the art.

[0039] The polyvinyl alcohol raw material, the hydrogen bond acceptor and the paraffin wax are mixed at high temperature to perform sol-gel transition to obtain a gel; the temperature of the high temperature mixing is ≥90℃; the temperature of the sol-gel transition is ≤10℃.

[0040] In the present application, the polyvinyl alcohol raw material preferably comprises polyvinyl alcohol and / or polyvinyl alcohol graft polymer; the polyvinyl alcohol graft polymer preferably comprises citric acid graft modified polyvinyl alcohol (CA-PVA) and / or polyethylene glycol graft modified polyvinyl alcohol (PEG-PVA). In the present application, the weight average molecular weight of the polyvinyl alcohol raw material is preferably 10-2000 kDa, which in specific embodiments can be 10 kDa, 50 kDa, 100 kDa, 146 kDa, 186 kDa, 200 kDa, 300 kDa, 400 kDa, 500 kDa, 1000 kDa, 1500 kDa or 2000 kDa; the alcoholysis degree of the polyvinyl alcohol is preferably 75-99.9%, which in specific embodiments can be 75%, 80%, 85%, 90%, 95%, 99% or 99.9%.

[0041] In the present application, the hydrogen bond acceptor preferably comprises dimethyl sulfoxide and / or N,N-dimethylformamide. Hydrogen bond acceptors can inhibit non-covalent interactions within / between PVA molecular chains and preferentially form hydrogen bonds with PVA.

[0042] In the present application, the mass ratio of the polyvinyl alcohol raw material and hydrogen bond acceptor is preferably 5-20:80-95, which in specific embodiments can be 5:80, 5:85, 5:90, 5:95, 10:80, 10:85, 10:90, 10:95, 15:80, 15:85, 15:90, 15:95, 20:80, 20:85, 20:90 or 20:95.

[0043] In the present application, the mass ratio of the polyvinyl alcohol and paraffin is preferably 5-20:10-30, which in specific embodiments can be 5:10, 5:15, 5:20, 5:25, 5:30, 10:10, 10:15, 10:25, 15:10, 15:20, 15:25, 20:10, 20:15 or 20:25. The present application uses paraffin as a pore-forming agent to construct a macroporous structure within the gel network.

[0044] In the present application, the high-temperature mixing preferably comprises: dissolving the polyvinyl alcohol raw material in dimethyl sulfoxide, and then adding paraffin and stirring and mixing. In the present application, the temperature of the high-temperature mixing is ≥ 90℃, preferably 90-110℃, and in specific embodiments can be 90℃, 95℃, 100℃, 105℃ or 110℃. In the present application, the dissolving time is preferably 1-6h, and in specific embodiments can be 1h, 2h, 3h, 4h, 5h or 6h; during the dissolving process, the PVA molecular chain has an extended conformation and is uniformly distributed. In the present application, the stirring and mixing preferably comprises sequentially performing first stirring and mixing and second stirring and mixing, the rotation speed of the first stirring and mixing is preferably 500-1000r / min, and in specific embodiments can be 500r / min, 600r / min, 700r / min, 800r / min, 900r / min or 1000r / min; the time of the first stirring and mixing is preferably 1-4h, and in specific embodiments can be 1h, 2h, 3h or 4h; the rotation speed of the second stirring and mixing is preferably 6000-10000r / min, and in specific embodiments can be 6000r / min, 7000r / min, 8000r / min, 9000r / min or 10000r / min; the time of the second stirring and mixing is preferably 10-30min, and in specific embodiments can be 10min, 15min, 20min, 25min or 30min.

[0045] In the present application, the temperature of the sol-gel transition is ≤ 10℃, preferably -5-10℃, and in specific embodiments can be -5℃, -4℃, -3℃, -2℃, -1℃, 0℃, 1℃, 2℃, 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, 9℃ or 10℃; the time of the sol-gel transition is preferably 2-48h, and in specific embodiments can be 2h, 5h, 10h, 15h, 20h, 24h, 25h, 30h, 35h, 36h, 40h, 45h or 48h. The present application is based on the strategy of crystal constraint template (i.e. the mixed solution obtained by the cooling-induced high-temperature mixing undergoes sol-gel transition) one-pot method integrated molding, and a gel with high mechanical strength is prepared.

[0046] After obtaining the gel, the present application sequentially performs ethanol exchange treatment, n-hexane exchange treatment and water exchange treatment on the gel, to obtain an ultrahigh-strength hydrogel sponge with a hierarchical porous structure.

[0047] In the present application, the temperature of the ethanol exchange treatment is preferably room temperature, and the time of the ethanol exchange treatment is preferably 24-72 h, and in specific embodiments can be 24 h, 25 h, 26 h, 28 h, 30 h, 32 h, 34 h, 35 h, 36 h, 38 h, 40 h, 42 h, 44 h, 45 h, 48 h, 49 h, 50 h, 52 h, 54 h, 55 h, 56 h, 60 h, 63 h, 64 h, 65 h, 66 h, 68 h, 70 h, or 72 h. The amount of ethanol used in the present application is not particularly limited, and the gel can be immersed. In the present application, the time interval for replacing the solvent (ethanol) during the ethanol exchange treatment is preferably 4-8 h, and in specific embodiments can be 4 h, 5 h, 6 h, 7 h, or 8 h.

[0048] In the present application, the temperature of the n-hexane exchange treatment is preferably room temperature, and the time of the n-hexane exchange treatment is preferably 48-120 h, and in specific embodiments can be 24 h, 25 h, 26 h, 28 h, 30 h, 32 h, 34 h, 35 h, 36 h, 38 h, 40 h, 42 h, 44 h, 45 h, 48 h, 49 h, 50 h, 52 h, 54 h, 55 h, 56 h, 60 h, 63 h, 64 h, 65 h, 66 h, 68 h, 70 h, 72 h, 75 h, 76 h, 77 h, 78 h, 80 h, 84 h, 85 h, 88 h, 90 h, 91 h, 92 h, 95 h, 96 h, 98 h, 100 h, 102 h, 104 h, 105 h, 108 h, 110 h, 112 h, 114 h, 115 h, 116 h, 119 h, or 120 h. The amount of n-hexane used in the present application is not particularly limited, and the gel can be immersed. In the present application, the time interval for replacing the solvent (n-hexane) during the n-hexane exchange treatment is preferably 4-8 h, and in specific embodiments can be 4 h, 5 h, 6 h, 7 h, or 8 h.

[0049] In the present application, the temperature of the water exchange treatment is preferably room temperature, and the total time of the water exchange treatment is 24-72 h, and in specific embodiments can be 24 h, 25 h, 26 h, 28 h, 30 h, 32 h, 34 h, 35 h, 36 h, 38 h, 40 h, 42 h, 44 h, 45 h, 48 h, 49 h, 50 h, 52 h, 54 h, 55 h, 56 h, 60 h, 63 h, 64 h, 65 h, 66 h, 68 h, 70 h, or 72 h; the number of times of water exchange is preferably 2-4 times, and in specific embodiments can be 3 times; and the water preferably comprises deionized water. The amount of water used in the present application is not particularly limited, and the gel can be immersed. In the present application, the time interval for replacing the solvent (water) during the water exchange treatment is preferably 4-8 h, and in specific embodiments can be 4 h, 5 h, 6 h, 7 h, or 8 h.

[0050] The present application sequentially carries out solvent exchange treatment in ethanol, n-hexane and water, in the process, not only the paraffin pore former is removed, but also the PVA molecular chain which is fully stretched and uniformly arranged is contracted and a large number of crystalline domains and microporous structures are formed. On the basis of improving the pore structure and specific surface area of the hydrogel, the super-high strength and elastic recovery performance of the hydrogel are ensured.

[0051] The present application is based on the strategy of crystal constraint template (i.e. sol-gel transition of the mixed solution obtained by cooling induced high temperature mixing), one-pot method integrated molding, and a gel with high mechanical strength is prepared, and the uniform and dense gel network is constructed by synergistic multi-step solvent exchange and pore structure, the whole structure of the hydrogel sponge is toughened, and the prepared hydrogel sponge has multi-level and interconnected pore structure characteristics, and excellent elastic recovery capacity. Moreover, the preparation method provided by the present application has simple preparation process steps and easy conditions, and is suitable for industrial production.

[0052] The present application also provides the super-high strength hydrogel sponge with hierarchical porous structure prepared by the preparation method of the above technical solution. In the present application, the porosity of the super-high strength hydrogel sponge with hierarchical porous structure is preferably 60-90%, and in specific embodiments, it can be 60%, 65%, 70%, 75%, 80%, 81.69%, 85% or 90%; the pore distribution of the super-high strength hydrogel sponge with hierarchical porous structure is preferably 2-10 μm, and in specific embodiments, it can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm. The present application induces the mixed solution to undergo sol-gel transition by cooling, and a gel with high mechanical strength is prepared; and by synergistic multi-step solvent (ethanol, n-hexane and water) exchange strategy, a hydrogel sponge material with super-high strength, high porosity and elastic recovery performance is obtained.

[0053] The present application also provides the application of the super-high strength hydrogel sponge with hierarchical porous structure in the above technical solution in biomedical materials, flexible wearable devices or tissue engineering materials. In the present application, the biomedical material preferably includes biomedical device material, and more preferably includes soft matter elastic scaffold or artificial joint cartilage material.

[0054] The super-high strength hydrogel sponge with hierarchical porous structure provided by the present application has super-high strength, high porosity and elastic recovery performance, and at the same time has excellent mechanical properties, and has wide application prospect in the field of biomedical materials, flexible wearable devices and tissue engineering materials, and can be used for preparing soft matter elastic scaffold and other devices.

[0055] In order to further illustrate the present application, the super-high-strength hydrogel sponge with hierarchical porous structure and the preparation method and application thereof provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the protection scope of the present application.

[0056] In the following examples, the weight average molecular weight of the polyvinyl alcohol is 146-186 kDa, and the alcoholysis degree is 99%.

[0057] Example 1

[0058] Into 90 g of dimethyl sulfoxide, 10 g of polyvinyl alcohol was added, heated to 90℃ in an oil bath and continuously stirred for 4 h, 20 g of paraffin was added, stirred at 800 r / min for 2 h, and high-speed stirring at 8000 r / min for 20 min to obtain a mixed solution, which was poured into a mold and placed in a refrigerator at 4℃ for 6 h, demolded to obtain a gel. The gel was immersed in anhydrous ethanol at room temperature for 48 h (the ethanol was replaced every 6 h), then immersed in n-hexane for 96 h (the n-hexane was replaced every 6 h), and immersed in deionized water for three times of water exchange, with a total water exchange time of 48 h (the deionized water was replaced every 6 h) to obtain a super-high-strength hydrogel sponge with hierarchical porous structure. The mass ratio of polyvinyl alcohol, dimethyl sulfoxide and paraffin was 10:90:20.

[0059] Example 2

[0060] The super-high-strength hydrogel sponge with hierarchical porous structure was prepared according to the method of Example 1, and the only difference from Example 1 was that the mass ratio of polyvinyl alcohol, dimethyl sulfoxide and paraffin was 15:85:20.

[0061] Example 3

[0062] The super-high-strength hydrogel sponge with hierarchical porous structure was prepared according to the method of Example 1, and the only difference from Example 1 was that the mass ratio of polyvinyl alcohol, dimethyl sulfoxide and paraffin was 20:80:20.

[0063] Test Example

[0064] 1. Structure characterization of hydrogel sponge

[0065] The surface SEM image of the super-high-strength hydrogel sponge with hierarchical porous structure prepared in Example 1 is shown in Figure 1 , and the cross-sectional SEM image is shown in Figure 2 . It can be seen that the pore structures with different pore sizes can be observed on the surface and cross-section of the hydrogel sponge. The internal micro-pore structure was reconstructed by high-resolution three-dimensional X-ray microscopy, as shown in Figure 3 . It can be seen that the internal hydrogel sponge is a mutually connected channel. The porosity statistics and pore distribution statistics chart are shown in Figure 4As shown, according to the pore structure data chart, the porosity of the hydrogel sponge is as high as 81.69%, and the pore distribution is 5.36±1.52 μm.

[0066] 2. Mechanical property test of hydrogel sponge

[0067] The mechanical properties of the super-high-strength hydrogel sponge with hierarchical porous structure prepared in Examples 1-3 were tested using an electronic universal material testing machine (EZ-Test, SHIMADZU) (tensile mode, tensile rate of 50 mm / min). The tested hydrogel sponge was a dumbbell-shaped sample with a gauge length of 13.5 mm and a width of 2 mm. The results are shown in Figure 5 The results show that the tensile stress at break of the hydrogel sponge containing different mass fractions of polyvinyl alcohol is greater than 2 MPa.

[0068] The recovery ability of the super-high-strength hydrogel sponge with hierarchical porous structure (original sample) in Example 1 was tested. After the first tensile cycle test (strain: 150%), the hydrogel sponge was soaked in deionized water for 2 h, and then subsequent cyclic tensile tests were performed, with a cycle number of 1-10.

[0069] Figure 6 The compression stress-strain curves of the original sample under different tensile numbers are shown in Figure 7 The compression stress-strain curves of the recovered sample after soaking in water for 2 h under different tensile numbers are shown in Figure 8 The energy dissipation comparison results of the original sample and the recovered sample under different tensile numbers are shown in Figures 6-8 As can be seen from , the initial tensile test causes a certain degree of strain residual in the hydrogel sponge. After it is recovered for 2 h, the elastic modulus and the tensile stress at 150% strain do not show significant decrease, and there is no obvious difference in the subsequent cyclic tensile test, thus indicating that the hydrogel sponge has excellent elastic recovery ability.

[0070] The above only describes the preferred embodiments of the present application. It should be noted that those skilled in the art can make several improvements and refinements without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.

Claims

1. A method for preparing an ultrahigh-strength hydrogel sponge with hierarchical porous structure, comprising the following steps: mixing a polyvinyl alcohol raw material, a hydrogen bond acceptor and paraffin at a high temperature to perform sol-gel transition to obtain a gel; the temperature of the high-temperature mixing is ≥ 90 ℃; the temperature of the sol-gel transition is ≤ 10 ℃; the hydrogen bond acceptor comprises dimethyl sulfoxide and / or N, N-dimethylformamide; the mass ratio of the polyvinyl alcohol raw material and the hydrogen bond acceptor is 5-20:80-95; the mass ratio of the polyvinyl alcohol and the paraffin is 5-20:10-30; sequentially performing ethanol exchange treatment, n-hexane exchange treatment and water exchange treatment on the gel to obtain an ultrahigh-strength hydrogel sponge with hierarchical porous structure. The polyvinyl alcohol raw material comprises polyvinyl alcohol and / or polyvinyl alcohol graft polymer. The weight average molecular weight of the polyvinyl alcohol raw material is 10-2000 kDa.

2. The production method according to claim 1, characterized by, The alcoholysis degree of the polyvinyl alcohol is 75-99.9%. The high-temperature mixing comprises: dissolving the polyvinyl alcohol raw material in dimethyl sulfoxide, and then adding paraffin and stirring to mix. The temperature of the high-temperature mixing is 90-110 ℃.

3. The preparation method according to claim 1, characterized in that, The time of the dissolving is 1-6 h.

4. The production method according to claim 3, characterized by, The temperature of the sol-gel transition is -5-10 ℃, and the time is 2-48 h. The time of the ethanol exchange treatment is 24-72 h.

5. The preparation method according to claim 1, characterized in that, The time of the n-hexane exchange treatment is 48-120 h.

6. The method of claim 1, wherein, The time of the water exchange treatment is 24-72 h. The time interval for replacing the solvent during the ethanol exchange treatment, the n-hexane exchange treatment and the water exchange treatment is independently 4-8 h. 7.An ultrahigh-strength hydrogel sponge with hierarchical porous structure prepared by the method of any one of claims 1-6. 8.The ultrahigh-strength hydrogel sponge with hierarchical porous structure of claim 7 is applied in biomedical materials, flexible wearable devices or tissue engineering materials. ​ ​

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