Antifouling silicones based on surface-modifying additive amphiphiles

Abstract

Surface-modifying additives (SMAs), which may be readily blended into silicones to improve antifouling behaviour, must have an excellent surface migration potential and must not leach into an aqueous environment. This work evaluated the efficacy of a series of poly(ethylene oxide) (PEO)-based SMA amphiphiles which varied in terms of cross-linkability, siloxane tether length (m) and diblock against triblock architectures. Specifically, cross-linkable, diblock PEO–silane amphiphiles with two oligodimethylsiloxane (ODMS) tether lengths ((EtO)3Si–(CH2)3–ODMS m –PEO8, EtO = ethylene oxide, m = 13 and 30) were compared to analogous non-cross-linkable, diblock (H–Si–ODMS m –PEO8) and triblock (PEO8–ODMS m –PEO8) SMAs. Prior to water conditioning, while all modified silicone coatings exhibited a high degree of water-driven surface restructuring, that prepared with the non-cross-linkable diblock SMA (m = 13) was the most hydrophilic. After conditioning, all modified silicone coatings were similarly hydrophilic and remained highly protein resistant, with the exception of PEO8–ODMS30–PEO8. Notably, despite twice the PEO content, triblock SMAs were not superior to diblock SMAs. For diblock SMAs, it was shown that water uptake and leaching were also similar whether or not the SMA was cross-linkable.