Visible light-induced surface grafting polymerization of perfluoropolyether brushes as marine low fouling materials

Abstract

Perfluoropolyether dimethacrylate (PFPE-DMA) was polymerized onto surfaces via visible light-induced surface grafting polymerization. Surfaces were prepared by depositing an octadecyltrichlorosilane-monolayer on the substrates, followed by the covalent coupling of the photoinitiator isopropylthioxanthone. Subsequently, perfluoropolyethers were polymerized from the surface by the controlled use of visible light-induced surface grafting polymerization. This approach was used to obtain surfaces terminated by low surface energy PFPE-DMA brushes with different chain lengths. Coating thickness and wetting were characterized by spectroscopic ellipsometry and contact angle goniometry. Different coating thicknesses were tested for their antifouling properties against three different proteins (lysozyme, fibrinogen, bovine serum albumin). In addition, the coatings were subjected to biological evaluation against the attachment of the diatom Navicula perminuta under dynamic conditions, settlement of Ulva linza zoospores, and in dynamic short-term field immersion experiments. PFPE-DMA with the highest chain length showed the strongest fouling reduction, which indicates that a certain chain mobility supports fouling resistance which could be explained by an improved lubricity of the interface.