Engineering a hard sol-gel adaptive coating with nonleaching antifoulant against marine biofouling in static conditions

Covalently tethered, nonleaching antifoulant groups to surface or coating matrix are being explored as an ecofriendly option to develop a robust antifouling coating with enhanced static antifouling ability. And most of marine antifouling coatings usually have a relatively low coating hardness owing to intrinsically polymeric property. In this work, we exploited the self-assembly of random zwitterionic amphiphilic copolymers with an isothiazolinone-based antifoulant to develop a scalable hard (> 6H pencil hardness) coating against marine biofouling under static conditions. Upon exposure to aqueous media, strong fluorinate-zwitterion interactions drive microphase separation into bicontinuous networks of hydrophobic and zwitterionic nanodomains, leading to the enrichment of antifoulant moieties on the coating surface. The obtained hybrid coating could significantly restrain the growth of bacteria biofilms, the settlement of marine diatoms and mussel larvae owing to the presence of covalently tethered antifoulants. Oxidative stress levels in the body of bacteria and marine diatoms were significantly enhanced nearby the coating containing nonteaching antifoulants. On the other hand, the fouling release capability was not compromising on the developed hybrid coating with such high Young's modulus and large coating hardness, implying an obviously different antifouling mechanism. We attempt to report an ecofriendly and hard coating system to simultaneously prohibit fouling settlement and promote fouling removal in static conditions.