Near-Infrared-Induced High-Performance Antimicrobial Active Coating for Medical Textiles Based on Easy-to-Synthesize Natural Catechin with Full End of Life Circularity

The near-infrared (NIR)-induced antimicrobial textile (CTex) exhibits significant antimicrobial and antibiofilm activity over 4log reductions (more than 99.99% killing efficiency) against methicillin-resistant S. aureus (MRSA), S. aureus, E. coli, and C. albicans within seconds under 808 nm NIR-laser irradiation by rapidly reaching almost 180 °C. A simple yet effective preparation method for an intensely active photothermal polymer backbone from the natural compound catechin is presented. The NIR-responsive polymer backbone was synthesized using a step-growth polymerization reaction between catechin and trimesoyl chloride. Features of this polymer, reported here for the first time, were systematically optimized: reaction conditions, chemical structure, thermal properties, and photothermal capabilities. The enhanced photothermal polymer formulation was integrated into a commercially available laboratory coat textile using a simple dip-coating method. The neat and coated textile products were evaluated by chemical and morphological analyses, as well as resistance to washing, reusability, and conversion of NIR light into thermal energy. On the aspect of sustainability, CTex is amenable to straightforward, cost-effective, and industry-friendly green chemical recycling, which was also indicated. This circular end-of-life recycling was demonstrated using a dry extrusion system, without the need for catalysts or solvents, to depolymerize the textile containing polyethylene terephthalate into constituent monomer, terephthalic acid with high-yield (97.9%) outputs.