Regenerable Biocidal Surfaces Enabled by Self-Assembled Block Copolymer Polyelectrolytes

A promising antibacterial strategy relies on surfaces that combine contact-killing activity with controlled release, enabling rapid response and long-term reusability. Herein, we report such kill-and-release antibacterial surfaces based on lamellar-organized amphiphilic diblock copolymer thin films. Amphiphilic diblock copolymers comprising a hydrophobic, hydrolyzable poly(tetrahydropyranyl methacrylate) (PTHPMA) block and a hydrophilic poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) block are synthesized via group transfer polymerization and subsequently quaternized with propyl iodide to convert the DMAEMA units into cationic, biocidal quaternary ammonium groups (PQDMAEMA). Upon solvent annealing, the PQDMAEMA-b-PTHPMA thin films self-assemble into lamellae oriented parallel to the substrate, with the biocidal PQDMAEMA block forming the outermost surface layer. Mild hydrolysis converts the hydrophobic THPMA units into hydrophilic methacrylic acid moieties, rendering the copolymer water-soluble and enabling its layer-by-layer removal, renewing the active antibacterial surface. Structural ordering of the diblock copolymers is confirmed by optical and atomic force microscopy, X-ray reflectivity, and grazing incidence small-angle X-ray scattering. The film's self-polishing behavior in water is monitored by ellipsometry for 300 days. The annealed films exhibit effective and durable antibacterial activity, achieving ∼2-log reduction against both Gram-positive and Gram-negative bacteria, both annealed and after 30 days of immersion in pH 7.4 water, demonstrating sustained long-term antimicrobial performance.