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CN-119708539-B - Nanocellulose-reinforced hydrogel wet adhesion hydrogel

CN119708539BCN 119708539 BCN119708539 BCN 119708539BCN-119708539-B

Abstract

The invention discloses a preparation method of a nanocellulose-reinforced wet-state adhesive hydrogel, and belongs to the technical field of hydrogels. The method comprises the steps of controlling the solution environment to enable polydopamine to grow on nanocellulose in a guiding way, adding an acrylic acid matrix, a conductive substance and medicines thereof into the nanocellulose solution with adhesive property, stirring for a period of time, adding an initiator and a cross-linking agent, standing, and polymerizing in a thermal environment to obtain the composite conductive hydrogel material with wet adhesion. The preparation method disclosed by the invention is simple in preparation process and mild in reaction condition, and solves the problem of poor adhesion performance of the flexible sensing underwater conductive hydrogel.

Inventors

  • LIU YINGYING
  • YANG YUJIE
  • LIU HONGBIN
  • CHENG ZHENGBAI

Assignees

  • 天津科技大学

Dates

Publication Date
20260512
Application Date
20241111

Claims (5)

  1. 1. The preparation method of the nanocellulose-reinforced wet-state adhesive hydrogel is characterized by comprising the following steps of: s1, placing 100 g nano cellulose into a beaker, regulating and controlling the pH of a nano cellulose solution to 8.5 by a hydrochloric acid-Tris system, uniformly mixing, adding an equal amount of dopamine hydrochloride according to the ratio of the nano cellulose to the dopamine hydrochloride of 1:1, stirring in a dark place for 6 h, performing centrifugal washing, and centrifuging for 20 min according to the sequence of stock solution, water, alcohol and water at the rotating speed of 10000 r/min to obtain polydopamine modified nano cellulose; S2, adding 2.25-g of polydopamine modified nanocellulose with solid content of 1.14% into 15-g water, uniformly mixing on a magnetic stirrer, controlling the mass ratio of the sulfobetaine methacrylate to the acrylic acid to be 1:5, taking the mixed solution by using a pipette, stirring at room temperature for 20-min, adding 0.4wt% of N, N-methylenebisacrylamide and 0.2wt% of initiator ammonium persulfate, stirring at room temperature for 3-h, transferring to moulds with different shapes, standing at 60 ℃ for 6-h, and obtaining the wet viscous hydrogel material.
  2. 2. The preparation method of the nanocellulose-reinforced wet-state adhesive hydrogel is characterized by comprising the following steps of: s1, placing 100 g nano cellulose into a beaker, regulating and controlling the pH of a nano cellulose solution to 8.5 by a hydrochloric acid-Tris system, uniformly mixing, adding an equal amount of dopamine hydrochloride according to the ratio of the nano cellulose to the dopamine hydrochloride of 1:1, stirring in a dark place for 6 h, performing centrifugal washing, and centrifuging for 20 min according to the sequence of stock solution, water, alcohol and water at the rotating speed of 10000 r/min to obtain polydopamine modified nano cellulose; S2, adding 1.76 g percent of polydopamine modified nanocellulose with the solid content of 2.18 percent into 15g of water, uniformly mixing on a magnetic stirrer, controlling the mass ratio of the sulfobetaine methacrylate to the acrylic acid to be 1:5, taking a solution by a liquid-transferring gun, adding 0.6 g aluminum trichloride and 1.05 g tannic acid, stirring at room temperature for 20 min, adding 0.4 weight percent of N, N-methylenebisacrylamide and 0.2 weight percent of initiator ammonium persulfate, stirring at room temperature for 3 h, transferring to moulds with different shapes, and standing at 60 ℃ for 4h to obtain the wet sticky hydrogel material.
  3. 3. The preparation method of the nanocellulose-reinforced wet-state adhesive hydrogel is characterized by comprising the following steps of: s1, placing 100 g nano cellulose into a beaker, regulating and controlling the pH of a nano cellulose solution to 8.5 by a hydrochloric acid-Tris system, uniformly mixing, adding an equal amount of dopamine hydrochloride according to the ratio of the nano cellulose to the dopamine hydrochloride of 1:1, stirring in a dark place for 6 h, performing centrifugal washing, and centrifuging for 20 min according to the sequence of stock solution, water, alcohol and water at the rotating speed of 10000 r/min to obtain polydopamine modified nano cellulose; S2, adding 5.29. g of polydopamine modified nanocellulose with solid content of 0.97% into 15g of water, uniformly mixing on a magnetic stirrer, controlling the mass ratio of the sulfobetaine methacrylate to the acrylic acid to be 1:5, taking a solution by using a pipette, stirring at room temperature for 15 min, adding 0.4wt% of N, N-methylenebisacrylamide and 0.2wt% of initiator ammonium persulfate, stirring at room temperature for 3 h, transferring to moulds with different shapes, standing at 60 ℃ for 5h, and obtaining the wet sticky hydrogel material.
  4. 4. A method according to any one of claims 1,2, 3, wherein the nanocellulose in step S1 is selected from one or more of nanocellulose crystals, nanocellulose filaments, bacterial cellulose.
  5. 5. The nanocellulose-reinforced wet-state adhesive hydrogel prepared by the preparation method of any one of claims 1-4.

Description

Nanocellulose-reinforced hydrogel wet adhesion hydrogel Technical Field The invention belongs to the technical field of hydrogels, and particularly relates to a nanocellulose-reinforced wet-state adhesive hydrogel. Background The hydrogel is a polymer material with a three-dimensional crosslinked network structure formed by chemical bond crosslinking or physical entanglement, and is applied to various fields such as tissue engineering, drug sustained release, artificial skin, water resource treatment, medical rehabilitation, flexible wearable equipment and the like. Conductive hydrogels are formed by combining a variety of different substrates and conductive media in a flexible device that has high sensitivity, strong self-healing, adjustable mechanical strength, and customizable electronic properties. At present, most of conductive hydrogels have adhesive performance, and are directly adhered to the surface of a substrate under the condition of no external force, so that the possibility of signal blocking is reduced, and therefore, tiny sensing signals in the process of capturing and transmitting are applied to the fields of human motion monitoring, clinical diagnosis, human-computer interaction and the like. However, conductive hydrogels may be limited in underwater applications. The water absorption of the hydrogel can make the hydrogel absorb water and swell, so that the internal structure of the gel rapidly collapses and loses the adhesive property, the hydrogel falls off from the surface layer of the skin, the physical condition of a user is difficult to detect from the outside, and tragedy can occur. At present, it is widely believed that the primary cause of the impact of hydrogels in wet environment applications is hydration layer formation and water absorption swelling. It is necessary to disrupt the formation of the hydration layer, hydrophobic groups being able to solve, remove the hydration layer from the interface by hydrophobic interactions and cause the hydrogel to adhere away from the contact interface when adhered under water. Mussels are marine organisms living in a humid environment, can realize long-term adhesion in a water environment, are inspired by the marine organisms, combine small molecules containing catechol groups with nanocellulose, endow the nanocellulose with the adhesion property, and further enhance the underwater adhesion property of the hydrogel. The adhesion properties of nanocellulose in a wet environment imparted by catechol groups are rarely reported. Disclosure of Invention Aiming at the problems of collapse of an internal structure and reduced adhesiveness of the existing conductive hydrogel sensing material in a wet environment, the invention provides a preparation method of a nanocellulose-reinforced wet adhesion hydrogel, which is simple to operate, economical and feasible. In order to achieve the technical purpose, the invention adopts the following technical scheme: S1, taking a certain amount of nanocellulose in a beaker, adjusting pH, adding dopamine hydrochloride, sealing and stirring in a dark place; S2, after stirring for a period of time, centrifuging to obtain polydopamine modified nanocellulose; S3, dispersing the modified nanocellulose into solutions with different mass fractions, taking a proper amount of sulfobetaine methacrylate, aluminum trichloride, tannic acid, acrylic acid and the like, adding the solutions, and uniformly stirring at room temperature; s4, weighing a small amount of initiator (ammonium persulfate and N, N-methylene bisacrylamide), adding the solution, stirring for 3 h, transferring to a die, and standing for 6 h at 60 ℃ to obtain the nanocellulose-reinforced wet adhesion hydrogel. Further, in the step S1, one or more of nanocellulose-derived nanocellulose crystals, nanocellulose filaments and bacterial cellulose is/are nanocellulose and dopamine hydrochloride in a mass ratio of 10-1, and the polymerization environment of dopamine hydrochloride requires pH to be controlled at 6-10. Further, in the step S2, the centrifugal operation is performed for a plurality of times, the centrifugal time is 10-100 min each time, and the rotating speed is controlled to be 3000-12000 r/min. In the step S2, the polydopamine modified nanocellulose is dispersed into solutions with different cellulose contents, and the mass fraction is 0.005-0.5%. In step S3, in the medicines added in the solution, the mass ratio of the methyl acrylic acid sulfobetaine to the acrylic acid is 0.1-5, the total molar concentration of the methyl acrylic acid sulfobetaine and the acrylic acid is controlled to be 0.5-5 mol/L, the mass fraction of aluminum trichloride is 0.5-5%, and the amount of tannic acid is controlled to be 100-500 mg. Further, in the step S4, ammonium persulfate in the mixed solution accounts for 0.01-0.05% of the mass fraction of the solution, and N, N-methylenebisacrylamide accounts for 0.01-0.1% of the total mass of the solution. According to the