Polyvinyl alcohol polynitrogen isoacrylamide cellulose hydrogel with anisotropic structure as well as preparation method and application of polyvinyl alcohol polynitrogen isoacrylamide cellulose hydrogel
By directionally freezing ice crystals to form anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogels, the problems of low transport rate and low absorption efficiency of hydrogel materials are solved, achieving high-efficiency water collection and transport performance, and possessing temperature-responsive hydrophilicity and hydrophobicity regulation.
Patent Information
- Application Number
- CN202511970856.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-25
- Publication Date
- 2026-02-24
AI Technical Summary
Existing hydrogel materials suffer from low transport rates and low absorption efficiency during water transport. In particular, the irregular three-dimensional network structure affects the water transport and absorption efficiency, and traditional materials cannot autonomously regulate the water collection process during the day and night.
By inducing the longitudinal arrangement of polymer macromolecules through directional cryogenic growth of ice crystals, forming vertical channels and lateral networks, anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogels are constructed. Combined with the temperature responsiveness of polyisoacrylamide molecules, the hydrophilicity and hydrophobicity of the material can be autonomously regulated.
It achieves high-efficiency water collection and transmission performance, and can autonomously adjust its hydrophilicity and hydrophobicity according to temperature changes, thereby improving water capture efficiency and water absorption-dehydration performance.
Smart Images
Figure CN121554815A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of water-capturing materials technology, and in particular to an anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel, its preparation method and application. Background Technology
[0002] Water capture technology is indispensable for social development. However, freshwater resources account for only 2.5% of global water resources, and their uneven distribution has led to water crises in many places. Solar-generated steam is a fundamental component of the natural water cycle. Therefore, solar interfacial evaporation technology has received widespread attention due to its advantages such as being environmentally friendly, low-cost, off-grid, and energy-efficient.
[0003] Hydrogel water-capturing devices, with their three-dimensional water channels and hierarchical porous structure, have been proven to exhibit rapid water transport capabilities under strong capillary forces. However, the large pores and randomly arranged micropores within the gel limit water transport rates, hindering efficient water capture. Since heat management and water transport are involved in water capture, improving water absorption capacity and adjusting water transport channels are the most common and effective strategies. Water transport involves the direction and flux of water flow, which depend on the pore structure and size of the material. However, for water-capturing materials, irregular three-dimensional network structures can affect water transport and thus water absorption efficiency. Highly ordered channels with anisotropic structures can effectively circumvent this limitation, and adjusting the pore arrangement can easily regulate water transport. Adjusting the ordered channels and framework structure is a crucial way to improve the balance between heat diffusion and water transport. Furthermore, due to the significant temperature difference between day and night, traditional hydration materials cannot autonomously regulate this process. However, the introduced polyisoacrylamide molecules are temperature-responsive and can autonomously adjust their hydrophilicity. During the day, when temperatures are high, they become hydrophobic, causing the gel to shrink and release and collect moisture. At night, when temperatures are low and humidity is high, the gel becomes hydrophilic, allowing it to collect moisture. Therefore, constructing temperature-sensitive anisotropic hydrogels is key to achieving excellent water-capturing performance. Summary of the Invention
[0004] In view of this, this application provides an anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel, its preparation method and application. By inducing the longitudinal arrangement of polymer macromolecules to form vertical channels through the directionally frozen growth of ice crystals, the material has a highly anisotropic structure, thereby achieving a porous and ordered structure and excellent water collection performance, which can effectively overcome the defects of the above-mentioned prior art.
[0005] The first aspect of this application provides a method for preparing anisotropic polyvinyl alcohol-polyisoacrylamide-cellulose hydrogel, comprising the following steps:
[0006] S1. Polyvinyl alcohol, lithium chloride and glutaraldehyde are added to deionized water and stirred to obtain mixture A;
[0007] S2. Add cellulose nanocrystal powder to deionized water and stir until homogeneous to obtain cellulose nanocrystal dispersion;
[0008] S3. Add nitroisoacrylamide and nitromethylenebisacrylamide to deionized water and stir until homogeneous to obtain mixture B;
[0009] S4. Add mixture A and cellulose nanocrystal dispersion to mixture B, stir evenly, and react under argon protection to obtain polyvinyl alcohol / azinoacrylamide / cellulose nanocrystal mixture C.
[0010] S5. Add hydrochloric acid, ammonium persulfate, and tetramethylethylenediamine to the polyvinyl alcohol / isoacrylamide / cellulose nanocrystal mixture C, stir, pour the stirred solution into a mold, place it on a copper column immersed in liquid nitrogen, and perform directional freezing to form an anisotropic structure; perform low-temperature crosslinking on the frozen anisotropic structure, thaw the low-temperature crosslinked sample, and then perform freeze-thaw cycle crosslinking; finally, remove and thaw, dialyze in deionized water to remove unreacted monomers, and finally obtain anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel.
[0011] Preferably, in step S1, the specific conditions for the stirring treatment are as follows: the stirring treatment is carried out in a 90°C water bath for 60 minutes and the stirring speed is 800 rpm; the ratio of polyvinyl alcohol, lithium chloride, glutaraldehyde and deionized water is 2.0 g:0.35 g:2.0 mL:8.0 mL.
[0012] Preferably, in step S2, the stirring speed is 400 rpm, the stirring temperature is 26℃, and the stirring time is 30 min; the ratio of cellulose nanocrystal powder to deionized water is 0.10 g: 5.0 mL.
[0013] Preferably, in step S3, the stirring speed is 400 rpm, the stirring temperature is 26℃, and the stirring time is 30 min; the ratio of the amount of nitrogen isoacrylamide, nitrogen methylenebisacrylamide, and deionized water is 1.50 g: 0.0150 g: 20.0 mL.
[0014] Preferably, in step S4, the reaction time is 1 h and the reaction temperature is 26°C; the stirring speed is 600 rpm, the stirring temperature is 26°C, and the stirring time is 60 min; the volume ratio of the mixture A, the mixture B, and the cellulose nanocrystal dispersion is 10:20:5.
[0015] Preferably, in step S5, the stirring speed is 600 rpm and the stirring time is 5 min; the ratio of the mixture C, hydrochloric acid, ammonium persulfate and tetramethylethylenediamine is 35 mL: 30 µL: 0.02 g: 30 µL.
[0016] Preferably, in step S5, the bottom material of the mold is copper, the remaining material is polytetrafluoroethylene, and its internal length and width are 4 cm × 4 cm.
[0017] Preferably, in step S5, the low-temperature crosslinking time is 24 h, the thawing time is 15 min, the freeze-thaw cycle is twice, and the dialysis time is 1 day.
[0018] The second aspect of this application also provides an anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel, which is prepared by the above method.
[0019] A third aspect of this application also provides the application of the above-described anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel in the field of all-weather water intake.
[0020] Compared with the prior art, this application has the following advantages:
[0021] 1. This application utilizes ice crystals grown under directional freeze-thaw conditions to induce the longitudinal arrangement of polymer macromolecules, forming vertical channels. Cyclic freeze-thaw cycles then create a transverse network, resulting in a material with a dual-network directional freeze-thaw structure of polyvinyl alcohol and polyisoacrylamide, exhibiting high anisotropy in both directions. This enhances the water-capturing efficiency of the gel during the water-capturing process, achieving optimal water-capturing performance. This application provides a sound strategy for acquiring freshwater resources.
[0022] 2. The hydrogel of this application has a highly anisotropic structure with regular vertical channels, which is superior to conventional isotropic three-dimensional network hydrogels. In addition, the introduction of polyisoacrylamide molecules makes the gel temperature responsive, and it can absorb or lose water according to different temperatures, thus having better water absorption and dehydration performance. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0024] Figure 1The image shows an electron microscope image of the anisotropic poly(isoacrylamide) cellulose hydrogel of Comparative Example 2.
[0025] Figure 2 The graph shows the water loss performance of the hydrogels of Comparative Example 2 and Comparative Example 3 at 25%RH and 45℃.
[0026] Figure 3 The graph shows the water loss performance of the hydrogels of Comparative Example 2 and Comparative Example 3 at 25%RH and 55℃.
[0027] Figure 4 The graph shows the water loss performance of the hydrogels of Example 1 and Comparative Example 1 at 25%RH and 45°C.
[0028] Figure 5 The graph shows the water loss performance of the hydrogels of Example 1 and Comparative Example 1 at 25%RH and 55°C.
[0029] Figure 6 The graph shows the mass change of the hydrogels of Examples 1 and Comparative Examples 1-3 after heating at 45°C for 1.5 h, and then regenerating them at 25°C (90%RH) room temperature.
[0030] Figure 7 The graph shows the mass change of water evaporation in the hydrogels of Example 1 and Comparative Examples 1-3.
[0031] Figure 8 The graph shows the water evaporation performance of the hydrogels in Example 1 and Comparative Examples 1-3. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0033] Unless otherwise specified, the experimental methods used in the embodiments of this application are all conventional methods.
[0034] In the following examples and comparative examples, unless otherwise specified, all raw materials can be prepared by commercial purchase or conventional methods.
[0035] Example 1
[0036] The preparation method of the anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel in this embodiment includes the following steps:
[0037] S1. Add 2.00 g polyvinyl alcohol, 0.350 g lithium chloride and 2.0 mL glutaraldehyde to 8.0 mL deionized water, stir at 800 rpm for 60 min in a water bath at 90 degrees Celsius to obtain mixture A;
[0038] S2. Add 0.10 g of cellulose nanocrystal powder to 5.0 mL of deionized water and stir at 400 rpm to obtain a cellulose nanocrystal dispersion.
[0039] S3. Add 1.50 g of N-isoacrylamide and 0.0150 g of N-methylenebisacrylamide to 20.0 mL of deionized water, stir well, and stir at 400 rpm to obtain mixture B.
[0040] S4. Add 10.0 mL of the mixture A obtained in S1 and 5.0 mL of the cellulose nanocrystal dispersion obtained in S2 to 20.0 mL of the mixture B obtained in S3. Stir at 600 rpm until homogeneous, and react for 1 h under argon protection at a reaction temperature of 26℃ to obtain mixture C.
[0041] S5. Add 30 µL hydrochloric acid, 0.020 g ammonium persulfate and 30 µL tetramethylethylenediamine to the 35.0 mL mixture C obtained in S4, and stir at 600 rpm for 5 min.
[0042] S6. Pour the solution obtained in S5 into a mold with a copper bottom (the bottom material of the mold is copper, the rest of the material is polytetrafluoroethylene, and its internal length and width are 4 cm × 4 cm), place it on a copper column immersed in liquid nitrogen, and perform directional freezing for 1 h to form an anisotropic structure. After freezing, place it in a refrigerator for low-temperature cross-linking for 24 h.
[0043] S7. Thaw the sample obtained in S6 for 15 min, then perform two freeze-thaw cycles for crosslinking, and finally thaw it for 15 min. Dialyze it in deionized water for 1 day to remove unreacted monomers. Change the water every other day to finally obtain anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel with two directions, denoted as DF-2.
[0044] Comparative Example 1
[0045] The preparation method of the hydrogel in this comparative example includes the following steps:
[0046] S1. Add 2.00 g polyvinyl alcohol, 0.350 g lithium chloride and 2.0 mL glutaraldehyde to 8.0 mL deionized water, stir at 800 rpm for 60 min in a water bath at 90℃ to obtain mixture A;
[0047] S2. Add 0.10 g of cellulose nanocrystal powder to 5.0 mL of deionized water and stir at 400 rpm to obtain a cellulose nanocrystal dispersion.
[0048] S3. Add 1.50 g of N-isoacrylamide and 0.0150 g of N-methylenebisacrylamide to 20.0 mL of deionized water, stir well, and stir at 400 rpm to obtain mixture B.
[0049] S4. Add 10.0 mL of the mixture A obtained in S1 and 5.0 mL of the cellulose nanocrystal dispersion obtained in S2 to 20.0 mL of the mixture B obtained in S3. Stir at 600 rpm until homogeneous, and react for 1 h under argon protection at a reaction temperature of 26℃ to obtain mixture C.
[0050] S5. Add 30 µL hydrochloric acid, 0.020 g ammonium persulfate and 30 µL tetramethylethylenediamine to the 35.0 mL mixture C obtained in S4, and stir at 600 rpm for 5 min.
[0051] S6. Pour the solution obtained in S5 into a mold with a copper bottom (the bottom material of the mold is copper, the rest of the material is polytetrafluoroethylene, and its internal length and width are 4 cm × 4 cm), and crosslink at room temperature for 24 h.
[0052] S7. Dialyze the sample obtained in S6 in deionized water for 1 day to remove unreacted monomers. Change the water every other day to finally obtain anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel in two directions, denoted as YW-2.
[0053] Comparative Example 2
[0054] The preparation method of the hydrogel in this comparative example includes the following steps:
[0055] S1. Add 0.10 g of cellulose nanocrystal powder to 5.0 mL of deionized water and stir evenly at 400 rpm to obtain a cellulose nanocrystal dispersion.
[0056] S2. Add 3.00 g of N-isoacrylamide and 0.030 g of N-methylenebisacrylamide to 30.0 mL of deionized water and stir until homogeneous to obtain mixture B;
[0057] S3. Add 5.0 mL of the cellulose nanocrystal dispersion obtained in S1 to 30.0 mL of the mixture B obtained in S3, stir evenly at 600 rpm, and react for 1 h under argon protection at a reaction temperature of 26℃ to obtain mixture C.
[0058] S4. Add 30 µL hydrochloric acid, 0.20 g ammonium persulfate and 30 µL tetramethylethylenediamine to 35 mL of mixture C obtained in S3, and stir at 600 rpm for 5 min.
[0059] S5. Pour the solution obtained in S4 into a mold with a copper bottom, place it on a copper column immersed in liquid nitrogen, and perform directional freezing to form an anisotropic structure. After freezing, place it in a refrigerator for low-temperature cross-linking for 24 hours.
[0060] S6. Thaw the sample obtained in S5 for 10 min, then perform two freeze-thaw cycles for crosslinking. Finally, thaw the sample and dialyze it in deionized water for one day to remove unreacted monomers. Change the water every other day to obtain anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel in two directions, denoted as DF-1.
[0061] Comparative Example 3
[0062] The preparation method of the hydrogel in this comparative example includes the following steps:
[0063] S1. Add 0.10 g of cellulose nanocrystal powder to 5.0 mL of deionized water and stir evenly at 400 rpm to obtain a cellulose nanocrystal dispersion.
[0064] S2. Add 3.00 g of N-isoacrylamide and 0.030 g of N-methylenebisacrylamide to 30.0 mL of deionized water and stir until homogeneous to obtain mixture B;
[0065] S3. Add 5.0 mL of the cellulose nanocrystal dispersion obtained in S1 to 30.0 mL of the mixture B obtained in S3, stir evenly at 600 rpm, and react for 1 h under argon protection at a reaction temperature of 26℃ to obtain mixture C.
[0066] S4. Add 30 µL hydrochloric acid, 0.20 g ammonium persulfate and 30 µL tetramethylethylenediamine to 35 mL of mixture C obtained in S3, and stir at 600 rpm for 5 min.
[0067] S5. Pour the solution obtained in S5 into a mold with a copper bottom (the bottom material of the mold is copper, the rest of the material is polytetrafluoroethylene, and its internal length and width are 4 cm × 4 cm), and crosslink at room temperature for 24 h.
[0068] S6. Thaw the sample obtained in S5 for 10 min, then perform two freeze-thaw cycles for crosslinking. Finally, thaw the sample and dialyze it in deionized water for one day to remove unreacted monomers. Change the water every other day to obtain anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel in two directions, denoted as YW-1.
[0069] It should be noted that the maximum amount of polyvinyl alcohol added in 8.0 mL of deionized water in this application is 2.00 g. Too much polyvinyl alcohol will make it difficult to prepare a gel. This application does not investigate the case where more than 2.00 g of polyvinyl alcohol is added in 8.0 mL of deionized water.
[0070] Test case
[0071] 1. The morphology and structure of the hydrogel from Comparative Example 2 were observed using scanning electron microscopy. Figure 1 As can be seen, Comparative Example 2 has regular channels in the vertical direction, which is conducive to water storage. The thermosensitive polymers in the gel can shrink and expand with temperature, causing the pores to shrink and expand, thereby facilitating water loss and replenishment.
[0072] 2. The water loss performance of the hydrogels of Comparative Example 2 and Comparative Example 3 at 25% RH and 45℃ was tested. Figure 2 As can be seen, at 25%RH and 45℃, due to the anisotropic structure of Comparative Example 2, Example 2 has better temperature response and can lose water more quickly, which is beneficial for water collection.
[0073] 3. Water loss performance graphs of the hydrogels of Comparative Example 2 and Comparative Example 3 at 25% RH and 55℃. Figure 3 As can be seen, at 25%RH and 55℃, due to the anisotropic structure of Comparative Example 2, Comparative Example 2 has better temperature response and can lose water more quickly, which is beneficial for water collection.
[0074] 4. The water loss performance of the hydrogels of Example 1 and Comparative Example 1 was tested at 25% RH and 45°C. Figure 2 and Figure 4 As can be seen, at 25%RH and 45℃, both Example 1 and Comparative Example 1 added hygroscopic lithium ions, which increased water storage performance and resulted in lower water loss performance compared to Comparative Example 2 and Comparative Example 3. Although this reduced water loss performance, it increased water absorption performance. Figure 4 As shown, since Example 1 is an anisotropic structure, it has better temperature response and can lose water more quickly, which is beneficial for water collection.
[0075] 5. The water loss performance of the hydrogels of Example 1 and Comparative Example 1 at 25% RH and 45°C was tested. Figure 3 and Figure 5 It can be seen that at 25%RH and 55℃, both Example 1 and Comparative Example 1 added hygroscopic lithium ions, which increased the water storage performance and resulted in lower water loss performance compared to Comparative Example 2 and Comparative Example 3. Although this reduced water loss performance, it increased water absorption performance. Figure 5As shown, since Example 1 is an anisotropic structure, it has better temperature response and can lose water more quickly, which is beneficial for water collection.
[0076] 6. The mass change of Examples 1 and Comparative Examples 1-3 after heating at 45°C for 1.5 hours, followed by performance testing at 25°C (90% RH) room temperature, was compared. Figure 6 It can be seen that Example 1 has the ability to absorb and reabsorb water, while Comparative Examples 1-3 lose water and hardly absorb water or have low water absorption efficiency. Meanwhile, Example 1, which has an anisotropic structure and hygroscopic ions, can replenish water to saturation in the shortest time.
[0077] 7. The water evaporation performance of the hydrogels from Example 1 and Comparative Examples 1-3 was tested, such as... Figure 7 As shown, all samples exhibited stable evaporation mass loss, representing the stability of outdoor solar evaporation and dehydration.
[0078] 8. The water evaporation performance of the hydrogels from Example 1 and Comparative Examples 1-3 was tested, such as... Figure 8 As shown, the water evaporation performance of the samples is not high, which means that the samples lose less water during the day outdoors and can be replenished at night when the humidity is high and the temperature is low.
[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A method for preparing an anisotropic polyvinyl alcohol-polyazineoacrylamide-cellulose hydrogel, characterized in that, Includes the following steps: S1. Polyvinyl alcohol, lithium chloride and glutaraldehyde are added to deionized water and stirred to obtain mixture A; S2. Add cellulose nanocrystal powder to deionized water and stir until homogeneous to obtain cellulose nanocrystal dispersion; S3. Add nitroisoacrylamide and nitromethylenebisacrylamide to deionized water and stir until homogeneous to obtain mixture B; S4. Add mixture A and cellulose nanocrystal dispersion to mixture B, stir evenly, and react under argon protection to obtain polyvinyl alcohol / azinoacrylamide / cellulose nanocrystal mixture C. S5. Add hydrochloric acid, ammonium persulfate, and tetramethylethylenediamine to the polyvinyl alcohol / isoacrylamide / cellulose nanocrystal mixture C, stir, pour the stirred solution into a mold, place it on a copper column immersed in liquid nitrogen, and perform directional freezing to form an anisotropic structure; perform low-temperature crosslinking on the frozen anisotropic structure, thaw the low-temperature crosslinked sample, and then perform freeze-thaw cycle crosslinking; finally, remove and thaw, dialyze in deionized water to remove unreacted monomers, and finally obtain anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel.
2. The method for preparing anisotropic polyvinyl alcohol polyazine isoacrylamide cellulose hydrogel according to claim 1, characterized in that, In step S1, the specific conditions for the stirring treatment are as follows: the stirring treatment is carried out in a 90°C water bath for 60 minutes and the stirring speed is 800 rpm; the ratio of polyvinyl alcohol, lithium chloride, glutaraldehyde and deionized water is 2.0 g:0.35 g:2.0 mL:8.0 mL.
3. The method for preparing anisotropic polyvinyl alcohol-polyazine-isoacrylamide-cellulose hydrogel according to claim 1, characterized in that, In step S2, the stirring speed is 400 rpm, the stirring temperature is 26℃, and the stirring time is 30 min; the ratio of cellulose nanocrystal powder to deionized water is 0.10 g: 5.0 mL.
4. The method for preparing anisotropic polyvinyl alcohol polyazine isoacrylamide cellulose hydrogel according to claim 1, characterized in that, In step S3, the stirring speed is 400 rpm, the stirring temperature is 26℃, and the stirring time is 30 min; the ratio of the amount of nitrogen isoacrylamide, nitrogen methylenebisacrylamide, and deionized water is 1.50 g: 0.0150 g: 20.0 mL.
5. The method for preparing anisotropic polyvinyl alcohol polyazine isoacrylamide cellulose hydrogel according to claim 1, characterized in that, In step S4, the reaction time is 1 h and the reaction temperature is 26℃; the stirring speed is 600 rpm, the stirring temperature is 26℃, and the stirring time is 60 min; the volume ratio of the mixture A, the mixture B, and the cellulose nanocrystal dispersion is 10:20:
5.
6. The method for preparing the anisotropic polyvinyl alcohol-polyazine-isoacrylamide-cellulose hydrogel according to claim 1, characterized in that, In step S5, the stirring speed is 600 rpm and the stirring time is 5 min; the ratio of the mixture C, hydrochloric acid, ammonium persulfate and tetramethylethylenediamine is 35 mL: 30 µL: 0.02 g: 30 µL.
7. The method for preparing anisotropic polyvinyl alcohol-polyazine-isoacrylamide-cellulose hydrogel according to claim 1, characterized in that, In step S5, the bottom material of the mold is copper, the rest of the material is polytetrafluoroethylene, and its internal length and width are 4 cm × 4 cm.
8. The method for preparing anisotropic polyvinyl alcohol polyazine isoacrylamide cellulose hydrogel according to claim 1, characterized in that, In step S5, the low-temperature cross-linking time is 24 h, the thawing time is 15 min, the freeze-thaw cycle is twice, and the dialysis time is 1 day.
9. An anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel, characterized in that, Anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel prepared by the method according to any one of claims 1 to 8.
10. The application of the anisotropic polyvinyl alcohol polyisoacrylamide cellulose hydrogel according to claim 9 in the field of all-weather water intake.