The prevention of microfouling and macrofouling on hydrogels impregnated with either Arquad 2C-75 or benzalkonium chloride

Optically clear, surfactant loaded poly (2-hydroxyethyl methacrylate) (pHEMA) hydrogels can be used to prevent fouling on optical windows of marine underwater sensors. To act successfully in this capacity, hydrogels need to prevent both microfouling and macrofouling. Panel trials were conducted using four different materials: unloaded hydrogels, hydrogels containing either benzalkonium chloride (BAC) or dicocodimethylammonium chloride (Arquad 2C-75) and PMMA coupons. Three panels were deployed at staggered intervals (2, 4 and 6 weeks) before the main settlement season of Semibalanus balanoides and Mytilus edulis in the Firth of Clyde, Scotland. Panels were left for a total period of 10, 12 and 14 weeks respectively. Results showed that no sample completely resisted fouling, but Arquad 2C-75 hydrogels were extremely effective at preventing both microfouling and macrofouling. The most heavily fouled materials were unloaded hydrogels and PMMA, despite differences in initial hydrophilicities. Arquad 2C-75 hydrogels were equally effective at preventing larval settlement, for up to 14 weeks.