High-strength dual-network nano-composite reinforced self-repairing anti-fouling hydrogel as well as preparation method and application thereof

Abstract

The invention provides high-strength dual-network nano-composite reinforced self-repairing antifouling hydrogel as well as a preparation method and application thereof, and relates to the technical field of marine antifouling. The high-strength dual-network nano-composite reinforced self-repairing antifouling hydrogel provided by the invention is prepared from the following raw materials in parts by mass: 1 to 10 parts of carboxylated cellulose nanocrystals, 7 to 20 parts of polyvinyl alcohol, 1 to 5 parts of MXene and 0.1 to 1 part of polyhexamethylene biguanide. The hydrogel provided by the invention has high strength, high toughness, excellent photo-thermal self-repairing capability, protein adhesion resistance, diatom adhesion resistance and antifouling property, and also has excellent mechanical property, antifouling capability and self-repairing property, so that the problems of poor mechanical strength, single antifouling mechanism and no self-repairing capability of the traditional hydrogel are effectively solved; and a feasible strategy is provided for the antifouling field.

Description

Technical Field

[0001] The present invention relates to the technical field of marine antifouling, and in particular to a high-strength double-network nanocomposite reinforced self-repairing antifouling gel, a preparation method thereof, and applications thereof. Background Art

[0002] Biofouling poses a significant threat to food safety, healthcare systems, and the marine industry. Particularly in complex marine environments, over 4,000 species of marine fouling organisms have been identified. Microorganisms primarily include bacteria, diatoms, and spores, while macrofouling organisms primarily include barnacles, bryozoans, mussels, and algae. These fouling organisms can grow on surfaces such as ship hulls, underwater equipment, marine livestock farming facilities, and cross-sea bridges, severely impacting these structures.

[0003] Hydrogels are increasingly being used in antifouling applications due to their three-dimensional cross-linked network structure and hydrophilicity. However, conventional antifouling gels have poor mechanical properties and are easily damaged, making them difficult to apply in various antifouling scenarios.

[0004] Related art discloses a polylysine-polyvinyl alcohol hydrogel biomimetic antifouling material and its preparation method: after pouring polydimethylsiloxane on the surface of a biomaterial, solidifying it, and then removing the biomaterial to obtain a negative mold; the negative mold is immersed in an anhydrous ethanol solution and then blown dry by ultrasound, and after plasma cleaning, polydimethylsiloxane is poured on the surface, solidified, and separated to obtain a positive mold; then polylysine is added to the polyvinyl alcohol hydrogel and stirred to obtain a polylysine-polyvinyl alcohol hydrogel; then the positive mold is plasma cleaned, and a boric acid solution is sprayed on the surface. After removing the excess boric acid solution, an excess amount of polylysine-polyvinyl alcohol hydrogel is added dropwise; then the uncross-linked polylysine-polyvinyl alcohol hydrogel is removed by spin coating to obtain a polylysine-polyvinyl alcohol hydrogel biomimetic antifouling material. However, the antifouling mechanism of the above-mentioned polylysine-polyvinyl alcohol hydrogel biomimetic antifouling material is relatively simple, the mechanical strength of the hydrogel is poor and it does not have self-repairing properties, and it is easily damaged during use.

[0005] Related technology discloses a hydrogel for marine antifouling and its preparation method: acrylamide monomer is polymerized via free radicals with N,N'-methylenebisacrylamide to produce polyacrylamide, which is then entangled with polyvinyl alcohol to form a hydrogel matrix. Picoxystrobin is then incorporated into the macromolecular network constructed by acrylamide and polyvinyl alcohol in the form of a block sequence. The resulting hydrogel has improved mechanical properties and swelling resistance. However, this hydrogel itself lacks good bactericidal and self-healing properties.

[0006] Related technology discloses a method for preparing an ion-responsive, bio-antifouling hydrogel: using polyethylene glycol diacrylate (PEGDA), 1-vinylimidazole VI, and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfonic acid propyl)ammonium hydroxide (DMAPS) as monomers, a hyperbranched terpolymer (HBPVD) is obtained through RAFT polymerization in the presence of a chain transfer agent and an initiator; gelatin is dissolved, a base is added to adjust the pH, a dispersant is added, and after clarification, methacrylic anhydride is added to react to obtain a polymer (GelMA); a solution of the hyperbranched terpolymer (HBPVD) and the polymer (GelMA) is prepared using deionized water, and a photoinitiator is added and UV-cured to obtain a hydrogel. However, the above hydrogel itself has poor mechanical properties and lacks self-healing properties.

[0007] Therefore, it is of great significance to design an anti-fouling gel material with good mechanical properties and synergistic anti-fouling ability, as well as self-repairing ability, so as to truly realize the application of hydrogel anti-fouling materials in extreme environments. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel and its preparation method and application. The high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel provided by the present invention has excellent mechanical properties, anti-fouling ability, self-repairing properties, and antibacterial properties.

[0009] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0010] The present invention provides a high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel. The preparation raw materials include, by weight, 1 to 10 parts of carboxylated cellulose nanocrystals, 7 to 20 parts of polyvinyl alcohol, 1 to 5 parts of MXene, and 0.1 to 1 part of polyhexamethylene biguanide.

[0011] The present invention also provides a method for preparing the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel described in the above technical solution, comprising the following steps:

[0012] The aqueous dispersion of polyvinyl alcohol and MXene is hot mixed to obtain a prepolymer solution A;

[0013] Mixing the prepolymer solution A and carboxylated cellulose nanocrystals to obtain a hydrogel prepolymer solution;

[0014] drying the hydrogel prepolymer solution to obtain a double network hydrogel;

[0015] The double network hydrogel is immersed in an aqueous solution of polyhexamethylene biguanide to obtain the high-strength double network nanocomposite reinforced self-repairing anti-sewage gel.

[0016] Preferably, the concentration of the MXene aqueous dispersion is 2.5 to 15 mg / mL.

[0017] Preferably, the temperature of the hot mixing is 80-95° C., and the time is 8-12 hours.

[0018] Preferably, the carboxylated cellulose nanocrystals are used in the form of carboxylated cellulose nanocrystal solids or carboxylated cellulose nanocrystal aqueous dispersions, and the concentration of the carboxylated cellulose nanocrystal aqueous dispersions is 1 to 10 wt %.

[0019] Preferably, the mixing time is 10 to 20 minutes.

[0020] Preferably, the drying temperature is 40-60° C. and the drying time is 8-24 hours.

[0021] Preferably, the concentration of the aqueous solution of polyhexamethylene biguanide is 0.5-2 wt%.

[0022] Preferably, the soaking time is 12 to 24 hours.

[0023] The present invention also provides the application of the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel described in the above technical solution or the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel prepared by the preparation method described in the above technical solution in marine antifouling.

[0024] The high-strength double-network nanocomposite reinforced self-healing anti-sewage gel (abbreviated as anti-sewage gel) provided by the present invention uses MXene, carboxylated cellulose nanocrystals (CNF), polyvinyl alcohol (PVA), polyhexamethylene biguanide (PHMB) and water as preparation raw materials, and controls the PVA / CNF and PVA / MXene mass ratios. PVA and CNF form a double-network structure of the anti-sewage gel. PVA and CNF contain a large number of hydroxyl groups and carboxyl groups, which can form a large number of hydrogen bonds, which can provide energy dissipation for the anti-sewage gel when subjected to external forces. The MXene surface also has a large number of active groups, which can provide more physical cross-linking sites for the anti-sewage gel, and can also form hydrogen bonds with the gel network to achieve a toughening effect. Therefore, the anti-sewage gel provided by the present invention has ultra-high toughness and mechanical strength, and excellent mechanical properties.

[0025] The present invention uses the carboxylate ions (-COO -) and the (-NH2) in PHMB, PHMB can firmly bind to the hydrogel, giving the anti-sewage gel a strong bactericidal effect and anti-fouling ability. At the same time, MXene enhances the mechanical properties and anti-fouling ability of the anti-sewage gel through nano-effects and a large number of active groups on the surface. In addition, in an aqueous environment, because the anti-sewage gel contains a large number of hydroxyl and carboxyl groups, it can form hydrogen bonds with water molecules and thus bind water molecules, forming a layer of water film on the surface of the anti-sewage gel. This layer synergistically acts with the antibacterial agent PHMB to improve the anti-fouling ability of the anti-sewage gel and achieve a synergistic anti-fouling effect.

[0026] Due to the addition of MXene, the color of the anti-sewage gel turns black, and MXene itself has good photothermal effect and thermal conductivity, which makes the anti-sewage gel have excellent photothermal effect. It can heat up to 90°C within 40 seconds under the irradiation of 808nm near-infrared light. After the anti-sewage gel is cut, the connection is irradiated with 808nm near-infrared light for 10 to 60 seconds, and the broken anti-sewage gel self-heals, and the healed anti-sewage gel also has good stretchability. This is because MXene gives the anti-sewage gel a good photothermal effect, which can quickly heat up under the irradiation of near-infrared light. As the temperature rises and approaches its glass transition temperature, the molecular chain of the anti-sewage gel softens and the two broken parts begin to contact. As the number of hydrogen bonds in contact increases, the anti-sewage gel completes self-healing, and has excellent photothermal self-repairing ability. The anti-sewage gel provided by the present invention can better cope with some extreme environmental conditions and truly achieve long-term and stable service in different working environments.

[0027] As shown in the test results of the examples, the tensile strength of the anti-sewage gel provided by the present invention is above 5.3 MPa, and the elongation at break is above 1500%. The results of the live / dead staining method to study the antibacterial ability of the hydrogel showed that a large number of dead bacteria were attached to the surface of the anti-sewage gel provided by the present invention, and basically no live bacteria were attached. There was basically no algae attached to the surface of the anti-sewage gel provided by the present invention. The anti-sewage gel provided by the present invention maintained an excellent anti-fouling effect in an actual marine environment for 6 months. The anti-sewage gel provided by the present invention has an excellent hydrophilic effect and can form a dense water film on the surface, thereby improving its anti-fouling ability. The anti-sewage gel provided by the present invention can be heated to 90°C within 40 seconds under the irradiation of 808nm near-infrared light. After the anti-sewage gel was cut, the connection was irradiated with 808nm near-infrared light for 10 to 60 seconds, and the broken anti-sewage gel self-healed, and the healed anti-sewage gel also had good stretchability. It is explained that the high-strength double-network nano-composite reinforced self-repairing anti-sewage gel provided by the present invention has high strength, high toughness, excellent antibacterial, anti-protein adhesion, anti-diatom adhesion and photothermal self-repairing properties, and has excellent mechanical properties, anti-fouling ability, self-repairing performance and antibacterial properties, which effectively solves the problems of poor mechanical strength, single anti-fouling mechanism and lack of self-repairing ability of traditional hydrogels.

[0028] This method uses an efficient one-pot process to add MXene and carboxylated cellulose nanocrystals (CNF) to polyvinyl alcohol (PVA) to create a double-network hydrogel. This hydrogel is then immersed in an aqueous solution of polyhexamethylene biguanide (PHMB) to produce a high-strength, double-network nanocomposite reinforced, self-healing, anti-sewage gel. The preparation method provided by this invention offers simple process and operation, low production costs, and is suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Graph showing the hydrogel mechanical properties test results of the double-network hydrogels prepared in Examples 1 to 5;

[0030] Figure 2 Graph showing the hydrogel mechanical properties test results of the double-network hydrogels prepared in Example 2 and Examples 6 to 9;

[0031] Figure 3 Bacterial adhesion test images of the hydrogels prepared in Example 2, Example 10 and Comparative Example 1 under a fluorescence microscope;

[0032] Figure 4 Microscope images of the anti-algae adhesion test of the hydrogels prepared in Example 2, Example 10 and Comparative Example 1;

[0033] Figure 5 Images of the hydrogels prepared in Example 10 and Comparative Example 1 after 6 months of marine field antifouling testing;

[0034] Figure 6 Graph showing changes in water contact angles on the surfaces of the hydrogels prepared in Example 2, Example 10, and Comparative Example 2;

[0035] Figure 7 This is a graph showing the test results of the photothermal self-repairing performance of the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel prepared in Example 10. DETAILED DESCRIPTION

[0036] The present invention provides a high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel. Calculated by mass (dry weight), the preparation raw materials include 1 to 10 parts of carboxylated cellulose nanocrystals, 7 to 20 parts of polyvinyl alcohol, 1 to 5 parts of MXene, and 0.1 to 1 part of polyhexamethylene biguanide.

[0037] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0038] In parts by mass, the raw materials for preparing the high-strength double-network nano-composite reinforced self-repairing anti-sewage gel provided by the present invention include 1 to 10 parts of carboxylated cellulose nanocrystals, and in specific embodiments, it can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0039] Calculated by weight of the carboxylated cellulose nanocrystals, the raw materials for preparing the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel provided by the present invention include 7 to 20 parts of polyvinyl alcohol, and in specific embodiments, it can be 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts or 20 parts.

[0040] Measured by the mass fraction of the carboxylated cellulose nanocrystals, the raw materials for preparing the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel provided by the present invention include 1 to 5 parts of MXene, and in specific embodiments, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts or 5 parts. Due to the addition of MXene, the color of the anti-sewage gel turns black, and MXene itself has a good photothermal effect and thermal conductivity, so that the anti-sewage gel has an excellent photothermal effect and can be heated to 90°C within 40 seconds under the irradiation of 808nm near-infrared light. After the anti-sewage gel is cut, the connection is irradiated with 808nm near-infrared light for 10 to 60 seconds, and the broken anti-sewage gel undergoes self-healing, and the healed anti-sewage gel also has good stretchability. This is because MXene imparts a favorable photothermal effect to the anti-sewage gel, allowing it to rapidly heat up under near-infrared light. As the temperature approaches its glass transition temperature, the molecular chains of the anti-sewage gel soften, and the two broken parts begin to contact. As the number of hydrogen bonds formed increases, the anti-sewage gel self-heals, demonstrating excellent photothermal self-repair capabilities. The anti-sewage gel provided by the present invention can better cope with some extreme environmental conditions, truly achieving long-term and stable service in various working environments.

[0041] The present invention controls the PVA / CNF and PVA / MXene mass ratios so that PVA and CNF form a dual-network structure of the sewage-proof gel. PVA and CNF contain a large number of hydroxyl and carboxyl groups, which can form a large number of hydrogen bonds between the two, thereby providing energy dissipation for the sewage-proof gel when subjected to external forces. MXene also has a large number of active groups on its surface, which can provide more physical cross-linking sites for the sewage-proof gel and form hydrogen bonds with the gel network to achieve a toughening effect. Therefore, the sewage-proof gel provided by the present invention has ultra-high toughness and mechanical strength, and excellent mechanical properties.

[0042] The raw materials for preparing the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel provided by the present invention include 0.1 to 1 parts of polyhexamethylene biguanide, based on the mass fraction of the carboxylated cellulose nanocrystals. In specific embodiments, the raw materials may be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts or 1 parts. The present invention uses the carboxylate ions (-COO -) and the (-NH2) in PHMB, PHMB can firmly bind to the hydrogel, giving the anti-sewage gel a strong bactericidal effect and anti-fouling ability. At the same time, MXene enhances the mechanical properties and anti-fouling ability of the anti-sewage gel through nano-effects and a large number of active groups on the surface. In addition, in an aqueous environment, because the anti-sewage gel contains a large number of hydroxyl and carboxyl groups, it can form hydrogen bonds with water molecules and thus bind water molecules, forming a layer of water film on the surface of the anti-sewage gel. This layer synergistically acts with the antibacterial agent PHMB to improve the anti-fouling ability of the anti-sewage gel and achieve a synergistic anti-fouling effect.

[0043] In the present invention, the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel is preferably stored in water, and the water is preferably deionized water.

[0044] The present invention also provides a method for preparing the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel described in the above technical solution, comprising the following steps:

[0045] The aqueous dispersion of polyvinyl alcohol and MXene is hot mixed to obtain a prepolymer solution A;

[0046] Mixing the prepolymer solution A and carboxylated cellulose nanocrystals to obtain a hydrogel prepolymer solution;

[0047] drying the hydrogel prepolymer solution to obtain a double network hydrogel;

[0048] The double network hydrogel is immersed in an aqueous solution of polyhexamethylene biguanide to obtain the high-strength double network nanocomposite reinforced self-repairing anti-sewage gel.

[0049] In the present invention, polyvinyl alcohol and an aqueous dispersion of MXene are thermally mixed to obtain a prepolymer solution A.

[0050] In the present invention, the concentration of the aqueous dispersion of MXene is preferably 2.5 to 15 mg / mL, and in specific embodiments may be 2.5 mg / mL, 5 mg / mL, 8 mg / mL, 10 mg / mL, 12 mg / mL or 15 mg / mL.

[0051] In the present invention, the temperature of the heat mixing is preferably 80-95°C, and in specific embodiments, it can be 80°C, 85°C, 90°C, or 95°C; the heat mixing time is preferably 8-12 hours, and in specific embodiments, it can be 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours. In the present invention, during the heat mixing process, the polar groups (such as hydroxyl groups) form hydrogen bonds with the hydroxyl groups in the polyvinyl alcohol.

[0052] In the present invention, the method for preparing the aqueous dispersion of MXene preferably includes the following steps: mixing titanium aluminum carbide (Ti3AlC2), lithium fluoride and hydrochloric acid, and sequentially performing etching, ultrasonic treatment and solid-liquid separation, wherein the liquid component is an aqueous dispersion of MXene.

[0053] In the present invention, the ratio of the mass of lithium fluoride to the molar amount of HCl in the hydrochloric acid is preferably 1g:30-200mmol, and in specific embodiments, it can be 1g:30mmol, 1g:80mmol, 1g:100mmol, 1g:112.5mmol, 1g:120mmol, 1g:150mmol, 1g:180mmol, or 1g:200mmol. In the present invention, the concentration of the hydrochloric acid is preferably 6-10mol / L, and in specific embodiments, it can be 6mol / L, 7mol / L, 8mol / L, 9mol / L, or 10mol / L.

[0054] In the present invention, the mass ratio of the aluminum titanium carbide to lithium fluoride is preferably 1:0.8-2, and in specific embodiments can be 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.6, 1:1.8 or 1:2.

[0055] In the present invention, the mixing of aluminum titanium carbide, lithium fluoride, and hydrochloric acid preferably includes: mixing lithium fluoride with hydrochloric acid to obtain a lithium fluoride-hydrochloric acid mixed solution, and dissolving the aluminum titanium carbide in the lithium fluoride-hydrochloric acid mixed solution. In the present invention, the dissolution temperature is preferably room temperature, and the dissolution time is preferably 10 to 60 minutes, and in specific embodiments, can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, or 60 minutes.

[0056] In the present invention, the etching temperature is preferably 30-40°C, and in specific embodiments it can be 30°C, 32°C, 35°C, 38°C or 40°C; the etching time is preferably 24-60h, and in specific embodiments it can be 24h, 30h, 40h, 50h or 60h; the etching is preferably carried out under stirring conditions, and the stirring speed is preferably 300-500r / min, and in specific embodiments it can be 300r / min, 350r / min, 400r / min, 450r / min or 500r / min.

[0057] After completing the etching, the present invention preferably further comprises: subjecting the mixed solution obtained by the etching to a first centrifugal separation, washing the obtained solid component with 0.5-2 mol / L (more preferably 1-1.5 mol / L) hydrochloric acid, washing the supernatant with water for automatic stratification, and then washing 2-5 times (more preferably 3-4 times), and adding water for dilution. In the present invention, the ratio of the mass of the aluminum titanium carbide to the volume of the dilution water is preferably 1g:10-45mL, and in specific embodiments it can be 1g:10mL, 1g:20mL, 1g:30mL, 1g:40mL or 1g:45mL.

[0058] In the present invention, the ultrasonic stripping time is preferably 60 to 120 minutes, and in specific embodiments it can be 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes or 120 minutes; the ultrasonic stripping is preferably carried out in an ice-water bath and under a protective atmosphere; the protective atmosphere preferably includes nitrogen, argon or helium.

[0059] The present invention has no special limitation on the solid-liquid separation, and a solid-liquid separation method well known to those skilled in the art may be adopted, such as filtration, suction filtration or centrifugal separation; the rotation speed of the centrifugal separation is preferably 3000-4000 r / min, and in specific embodiments, it can be 3000 r / min, 3200 r / min, 3500 r / min, 3800 r / min or 4000 r / min; the time of the centrifugal separation is preferably 30-90 min, and in specific embodiments, it can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min or 90 min.

[0060] After obtaining prepolymer solution A, the present invention mixes the prepolymer solution A with carboxylated cellulose nanocrystals to obtain a hydrogel prepolymer solution. In the present invention, the carboxylated cellulose nanocrystals are preferably used in the form of carboxylated cellulose nanocrystal solids or a carboxylated cellulose nanocrystal aqueous dispersion. The concentration of the carboxylated cellulose nanocrystal aqueous dispersion is preferably 1 to 10 wt%, and in specific embodiments, can be 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%. In the present invention, the mixing temperature is preferably room temperature, and the mixing time is preferably 10 to 20 minutes, and in specific embodiments, can be 10 minutes, 12 minutes, 15 minutes, 18 minutes, or 20 minutes.

[0061] After obtaining the hydrogel prepolymer solution, the present invention dries the hydrogel prepolymer solution to obtain a double-network hydrogel. In the present invention, the drying temperature is preferably 40-60°C, and in specific embodiments, it can be 40°C, 45°C, 50°C, 55°C, or 60°C. The drying time is preferably 8-24 hours, and in specific embodiments, it can be 8 hours, 10 hours, 15 hours, 20 hours, or 24 hours. In the present invention, the drying step is preferably pouring the hydrogel prepolymer solution into a mold before drying. In the present invention, the mold size is preferably 3-10 cm x 3-10 cm, and in specific embodiments, it can be 3 cm x 3 cm, 5 cm x 5 cm, 8 cm x 8 cm, or 10 cm x 10 cm.

[0062] After obtaining the double network hydrogel, the present invention soaks the double network hydrogel in an aqueous solution of polyhexamethylene biguanide to obtain the high-strength double network nanocomposite enhanced self-repairing anti-sewage gel. In the present invention, the concentration of the aqueous solution of polyhexamethylene biguanide is preferably 0.5 to 2 wt%, and in specific embodiments it can be 0.5 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt% or 2 wt%. In the present invention, the soaking temperature is preferably room temperature, and the soaking time is preferably 12 to 24 h, and in specific embodiments it can be 12 h, 15 h, 18 h, 20 h, 22 h or 24 h. In the present invention, the high-strength double network nanocomposite enhanced self-repairing anti-sewage gel is preferably stored in water, and the water is preferably deionized water.

[0063] The present invention also provides the application of the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel described in the above technical solution or the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel prepared by the preparation method described in the above technical solution in marine antifouling.

[0064] In order to further illustrate the present invention, the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel provided by the present invention, its preparation method and application are described in detail below in combination with the examples, but they should not be understood as limiting the scope of protection of the present invention.

[0065] Example 1

[0066] 11g of PVA was added to 100mL of deionized water, heated at 90°C for 10 hours, and cooled to room temperature to obtain a PVA aqueous solution. 7.5g of the PVA aqueous solution and 12.5g of a 6% wt% CNF aqueous dispersion were stirred and mixed for 20 minutes to obtain a hydrogel prepolymer solution. This hydrogel prepolymer solution was poured into a mold (5cm x 5cm) and dried in a 50°C oven for 12 hours to obtain a double network hydrogel, which was then stored by immersion in deionized water.

[0067] Example 2

[0068] A double network hydrogel was prepared according to the method of Example 1, with the only difference from Example 1 being that 12 g of PVA aqueous solution and 8 g of CNF aqueous dispersion were stirred and mixed.

[0069] Example 3

[0070] A double network hydrogel was prepared according to the method of Example 1, with the only difference from Example 1 being that 15 g of the PVA aqueous solution and 5 g of the CNF aqueous dispersion were stirred and mixed.

[0071] Example 4

[0072] A double network hydrogel was prepared according to the method of Example 1, with the only difference from Example 1 being that 16.3 g of PVA aqueous solution and 3.7 g of CNF aqueous dispersion were stirred and mixed.

[0073] Example 5

[0074] A double network hydrogel was prepared according to the method of Example 1, with the only difference from Example 1 being that 17.2 g of PVA aqueous solution and 2.8 g of CNF aqueous dispersion were stirred and mixed.

[0075] Test Example 1

[0076] Mechanical properties test of double network hydrogels prepared in Examples 1 to 5

[0077] The tensile properties of the hydrogels at room temperature were tested using a tensile testing machine (GP-6113A, Gaopin Testing Instrument Co., Ltd.). Dumbbell specimens (20 mm × 4 mm × 2 mm) were used for tensile testing at a rate of 10 mm / min. Toughness was calculated by integrating the area under the stress-strain curve. All double-network hydrogel samples were fully immersed in seawater for 7 days, and the seawater was wiped off the surface before testing.

[0078] Figure 1 The figure shows the hydrogel mechanical properties test results for the double-network hydrogels prepared in Examples 1-5. It can be seen that the double-network hydrogel prepared in Example 2 has the strongest toughness. Therefore, the mass ratio of PVA to CNF in the double-network hydrogel in Example 2 is the optimal, and this mass ratio was selected for subsequent experiments. During actual testing, the stress-strain curve did not change significantly after two days.

[0079] Example 6

[0080] 3.2g of lithium fluoride was dissolved in 40mL of 9mol / L hydrochloric acid to obtain a lithium fluoride-hydrochloric acid mixed solution. 2g of carbon titanium aluminum (Ti3AlC2) was slowly added (15min) to the lithium fluoride-hydrochloric acid mixed solution, stirred at 40℃ and 400r / min for 40h, centrifuged, discarded the upper liquid, washed 3 times with 1mol / L hydrochloric acid, washed with deionized water until the supernatant was automatically separated and then washed 3 times, transferred to a wide-mouth bottle, added 60mL of deionized water, passed through nitrogen protection, and ultrasonicated in an ice-water bath for 90min. The ultrasonic product was centrifuged at 3500r / min for 60min, the precipitate was discarded, and the upper liquid was the MXene aqueous dispersion (the mass of the dry unit volume of the MXene aqueous dispersion was weighed to test its concentration).

[0081] 11 g of PVA was added to 100 mL of MXene aqueous dispersion (MXene concentration was 2.5 mg / mL), heated at 90°C for 10 h, and cooled to room temperature to obtain prepolymer solution A. 12 g of prepolymer solution A was stirred and mixed with 8 g of CNF aqueous dispersion for 20 min to obtain a hydrogel prepolymer solution. The hydrogel prepolymer solution was then poured into a mold (5 cm × 5 cm) and dried in an oven at 50°C for 12 h to obtain a double network hydrogel, which was then stored by immersion in deionized water.

[0082] Example 7

[0083] A double-network hydrogel was prepared according to the method of Example 6, except that the concentration of the MXene aqueous dispersion was 5 mg / mL.

[0084] Example 8

[0085] A double-network hydrogel was prepared according to the method of Example 6, except that the concentration of the MXene aqueous dispersion was 10 mg / mL.

[0086] Example 9

[0087] A double-network hydrogel was prepared according to the method of Example 6, except that the concentration of the MXene aqueous dispersion was 15 mg / mL.

[0088] Test Example 2

[0089] The mechanical properties of the double network hydrogels prepared in Example 2 and Examples 6 to 9 were tested using the same testing method as in Test Example 1.

[0090] Figure 2 The hydrogel mechanical properties test results of the double network hydrogels prepared in Example 2 and Examples 6 to 9 are shown. It can be seen that the double network hydrogel prepared in Example 9 has the strongest toughness, so the addition amount of MXene in Example 9 is optimal.

[0091] Example 10

[0092] A double network hydrogel was prepared according to the method of Example 9. The double network hydrogel was placed in a 1 wt% PHMB solution and soaked at room temperature for 18 hours to obtain a high-strength double network nanocomposite reinforced self-repairing anti-sewage gel, which was then soaked in deionized water for storage.

[0093] Comparative Example 1

[0094] 10g of PVA was added to 90mL of water, heated to 90°C and stirred for 10 hours to obtain a PVA aqueous solution. 2g of acrylamide (AM) was added to 8g of the PVA aqueous solution and stirred to mix thoroughly. The initiator potassium persulfate (the initiator mass was 0.5% of the mass of acrylamide) and the crosslinker N,N'-methylenebisacrylamide (the initiator mass was 0.05% of the mass of acrylamide) were added in sequence and stirred to obtain a prepolymer solution. The prepolymer solution was poured into a mold and placed in a 55°C water bath to initiate free radical polymerization of the monomers. The reaction was allowed to proceed for 3 hours to obtain a composite hydrogel. To obtain a double network hydrogel, the composite hydrogel was completely dried in a 50°C oven. The dried gel was then soaked in water for 2 hours to re-swell, obtaining a double network hydrogel, which was then soaked in deionized water for storage.

[0095] Comparative Example 2

[0096] 11g of PVA was added to 100mL of deionized water, heated at 90°C for 10 hours, and cooled to room temperature to obtain a PVA solution. The PVA solution was then poured into a mold (5cm×5cm) and dried in a 50°C oven for 12 hours to obtain a double network hydrogel, which was then stored in deionized water.

[0097] Test Example 3

[0098] Performance test of the double network hydrogel prepared in Example 2 and Comparative Examples 1-2, and the high-strength double network nanocomposite reinforced self-repairing anti-sewage gel prepared in Example 10

[0099] (1) Antibacterial properties

[0100] The antibacterial ability of the hydrogel was studied by live / dead staining. The block hydrogel sample was placed in a solution with a concentration of 1×10 4The cells were cultured in a bacterial solution (Pseudoalteromonas) with a CFU / mL concentration for 3 days, then taken out and stained with PI and SYTO 9 for 20 minutes in a dark environment. The bacteria swimming on the hydrogel surface were then washed three times with phosphate buffered saline (PBS, 0.05 mol / L, pH = 7.4). All live bacteria were labeled with SYTO 9 and displayed green fluorescence, while dead bacteria were labeled with PI and displayed red fluorescence. A fluorescence microscope (DM5000B, LEICALtd.) was used to photograph live / dead bacteria attached to the sample surface, obtain fluorescent images, and analyze the fluorescent photos. The area coverage of live / dead bacteria was calculated using ImageJ software.

[0101] Figure 3 From the bacterial adhesion test images of the hydrogels prepared in Example 2, Example 10 and Comparative Example 1 under a fluorescence microscope, it can be seen that a large number of dead bacteria are attached to the surface of the high-strength double-network nano-composite reinforced self-repairing anti-sewage gel prepared in Example 10, and basically no live bacteria are attached. Therefore, the high-strength double-network nano-composite reinforced self-repairing anti-sewage gel prepared in Example 10 has the best bactericidal effect.

[0102] (2) Anti-algae adhesion performance

[0103] Anti-algae adhesion assay: Hydrogel samples were cut into specific sizes and placed in a silica-containing f / 2 medium with Phaeodactylum tricornutum. The samples were incubated at 23°C day and night for one week. The hydrogel samples were then removed and observed under a biological microscope (E200MV, Nikon Ltd.) to observe the adhesion of Phaeodactylum tricornutum to the hydrogel surface. Finally, the coverage of the attached area was calculated using ImageJ software.

[0104] Figure 4 Microscope images of the anti-algae adhesion test of the hydrogels prepared in Example 2, Example 10 and Comparative Example 1 show that there is basically no algae attached to the surface of the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel prepared in Example 10, proving that it has the best anti-algae effect.

[0105] (3) Actual sea antifouling performance

[0106] The hydrogel marine field antifouling test lasted 6 months.

[0107] Figure 5 These are images of the hydrogels prepared in Example 10 and Comparative Example 1 after 6 months of marine field antifouling testing. It can be seen that the high-strength double-network nanocomposite reinforced self-healing anti-fouling gel prepared in Example 10 has no obvious fouling attached on its surface after 180 days of marine antifouling testing, demonstrating its excellent antifouling effect.

[0108] (4) Water contact angle test

[0109] In order to study the anti-fouling bioadhesion ability of the hydrogel after it is fully swollen, a water contact test was carried out. During the test, the entire process of the droplet contacting the hydrogel surface was recorded, and video and photos were taken. After the test, the water contact angle of the surface was calculated using software.

[0110] Figure 6 The water contact angle change diagram of the hydrogel surface prepared in Example 2, Example 10 and Comparative Example 2 shows that the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel prepared in Example 10 has the best hydrophilic effect and can form a dense water film on the surface, thereby improving its anti-fouling ability.

[0111] (5) Photothermal self-repair performance test

[0112] like Figure 7 As shown, after the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel prepared in Example 10 is cut, the two ends are connected and then the connection is irradiated with 808nm near-infrared light for 10 to 60 seconds. It is found that the broken hydrogel has self-healed, and the healed hydrogel still has a certain stretchability. The high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel prepared in Example 10 can be heated to 90°C within 40 seconds under the irradiation of 808nm near-infrared light. This is because MXene gives the hydrogel a good photothermal effect, which can be rapidly heated under the irradiation of near-infrared light. As the temperature rises and approaches its glass transition temperature, the molecular chain of the hydrogel softens and the two broken parts begin to contact. As the number of hydrogen bonds in contact increases, the hydrogel completes self-healing. The experimental results prove that the hydrogel prepared by the present invention has a certain self-healing effect, can better cope with some extreme environmental conditions, and truly achieve long-term and stable service in different working environments.

[0113] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel, the preparation raw materials of which include 1-10 parts by weight of carboxylated cellulose nanocrystals, 7-20 parts by weight of polyvinyl alcohol, 1-5 parts by weight of MXene, and 0.1-1 part by weight of polyhexamethylene biguanide.

2. The method for preparing the high-strength double-network nanocomposite reinforced self-repairing anti-sewage gel according to claim 1 comprises the following steps: The aqueous dispersion of polyvinyl alcohol and MXene is hot mixed to obtain a prepolymer solution A; Mixing the prepolymer solution A and carboxylated cellulose nanocrystals to obtain a hydrogel prepolymer solution; drying the hydrogel prepolymer solution to obtain a double network hydrogel; The double network hydrogel is immersed in an aqueous solution of polyhexamethylene biguanide to obtain the high-strength double network nanocomposite reinforced self-repairing anti-sewage gel.

3. The preparation method according to claim 2, characterized in that The concentration of the MXene aqueous dispersion is 2.5 to 15 mg / mL.

4. The preparation method according to claim 2 or 3, characterized in that The temperature of the hot mixing is 80-95° C., and the time is 8-12 hours.

5. The preparation method according to claim 2, characterized in that The carboxylated cellulose nanocrystals are used in the form of carboxylated cellulose nanocrystal solids or carboxylated cellulose nanocrystal aqueous dispersions. The concentration of the carboxylated cellulose nanocrystal aqueous dispersions is 1 to 10 wt %.

6. The preparation method according to claim 2 or 5, characterized in that The mixing time is 10 to 20 minutes.

7. The preparation method according to claim 2, characterized in that The drying temperature is 40-60° C. and the drying time is 8-24 hours.

8. The preparation method according to claim 2, characterized in that The concentration of the polyhexamethylene biguanide aqueous solution is 0.5-2 wt %.

9. The preparation method according to claim 2 or 8, characterized in that The soaking time is 12 to 24 hours.

10. Use of the high-strength double-network nanocomposite reinforced self-repairing anti-fouling gel according to claim 1 or the high-strength double-network nanocomposite reinforced self-repairing anti-fouling gel prepared by the preparation method according to any one of claims 2 to 9 in marine antifouling.

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