Development of Environmentally-Friendly, Anti-fouling Coatings Based on Tethered Quaternary Ammonium Salts in a Crosslinked Polydimethylsiloxane Matrix

摘要

The concept of tethering quaternary ammonium salts (QASs) to a crosslinked polysiloxane matrix to produce a hybrid antifouling/fouling-release coating was investigated. A statistical experimental design was used to determine the effect of QAS concentration on biocidal activity toward a marine bacterium, Cellulophaga lytica (C. lytica). In addition to measuring biocidal activity, coating cure and film quality as well as stability upon water immersion were evaluated. The results of the study showed that biocidal activity was strongly dependent on QAS concentration. For addition-curable coatings, the presence of 4 wt. % QAS groups resulted in approximately a 50% reduction in C. lytica biofilm etention without any leachate toxicity. Attempts to increase the level of QAS groups to increase biocidal activity resulted in coating delamination from the substrate and unacceptable film quality upon sea water immersion due to excessive swelling. As a result, a moisture-curable system based on tethered QASs was inv stigated since moisture-curing allows for higher crosslink densities to be achieved which would be expected to minimize swelling upon sea water immersion. The moisture- curable coating developed showed enhanced stability upon sea water immersion, greater than 80% reduction in C. lytica biofilm retention, and greater than 90% reduction in biofilm growth for the marine algae, Navicula incerta.