Sol-gel polysiloxane films containing different surface-active trialkoxysilanes for the release of the marine foulant Ficopomatus enigmaticus

Abstract

Sol-gel polysiloxane films containing varied amounts of different trialkoxyorganosilanes, carrying hydrophobic perfluoroalkyl (F) and/or hydrophilic polyoxyethylene (P) side chains, were prepared. The effect of the surface-active agents F and P on the film surface properties were investigated by contact angle measurements and angle-resolved X-ray photoelectron spectroscopy (AR-XPS) analysis. In particular, AR-XPS proved that the fluorinated side chains migrated to the film surface depending on both the nominal amount of F and the presence of P in the formulation. Moreover, the films underwent surface chemical modification upon contact with water, as a result of an increase in P chains and a concomitant decrease in F chains at the film surface. The biological performance of the films was evaluated against the serpulid Ficopomatus enigmaticus, a widespread and invasive marine biofoulant, and demonstrated the potential of the amphiphilic films containing P chains as fouling-release coatings in the marine environment.