Fabrication of ionic liquid-functionalized dual cross-linked hydrogel coatings for antibacterial and antifouling applications

In this study, a novel ionic liquid-functionalized dual cross-linked hydrogel was developed via ring-opening reaction grafting ionic liquid. The hydrogel matrix containing epoxy groups was first synthesized via a one-pot polymerization reaction of acrylic acid, acrylamide, methylene diarylamide and glycidyl methacrylate, followed by the introduction of Fe 3+ ions to improve its mechanical strength, and then the ionic liquid MIm-Br with amino group was grafted onto the hydrogel matrix by amino-epoxy ring-opening reaction. The resulting ionic liquid-functionalized hydrogel exhibited excellent hydrophilicity and anti-adhesion properties, achieving an antibacterial rate exceeding 98 % against two species of bacteria and a removal rate of over 95 % for two types of algae. The synergistic effect of the hydrogel and the ionic liquid was responsible for these efficient antibacterial and antifouling properties. The hydrogel's high hydrophilicity and low adhesion confer them excellent anti-adhesion effects for bacteria and alga. Meanwhile, the positively charged imidazole ring of MIm-Br interacts with the negatively charged bacterial cell membranes through electrostatic adsorption, altering the cell's membrane permeability and causing leakage of intracellular substances. Moreover, the ionic liquid-functionalized hydrogel exhibited significantly improved swelling properties, water retention and water lubrication performance, enhancing its utility.