One-Step Anchoring of Tannic Acid-Scaffolded Bifunctional Coatings of Antifouling and Antimicrobial Polymer Brushes

An effective and environmentally benign strategy for tethering functional polymers on various substrates is highly desirable, especially for the introduction of multiple surface functionalities. Herein, a natural-occurring polyphenol, tannic acid (TA), functionalized with chain transfer agents and azide moieties, was employed as a scaffold from which zwitterionic poly­(2-methacryloyloxyethyl phosphorylcholine) brushes were first grafted via reversible addition–fragmentation chain transfer (RAFT) polymerization. Cationic polylysine brushes, synthesized via ring-opening polymerization (ROP), were subsequently conjugated via copper-free azide–alkyne cycloaddition. The TA scaffold conjugated with binary polymer brushes self-assembled via coordination chelation with stainless steel (SS) surfaces, in a simple “one-step” coating process, to form the antifouling and antimicrobial surfaces. In comparison to the pristine SS surface, the functionalized SS surfaces exhibited significantly improved resistance to protein adsorption, bacterial adhesion and microalgal attachment. The antimicrobial efficacy of the resulting surfaces was indicated by the observed eradication of adhered bacteria. In addition, the stability, durability and low cytotoxicity of the TA-scaffolded bifunctional coating suggested feasibility of its extended applications in aquatic and healthcare environments