Marine Antifouling Behavior of Lubricant-Infused Nanowrinkled Polymeric Surfaces25 March 2022
A new family of polymeric, lubricant-infused, nanostructured wrinkled surfaces was designed that effectively retains inert non-toxic silicone oil, upon draining by spin-coating and vigorous shear for two weeks. The wrinkled surfaces were fabricated using three different polymers (Teflon AF, polystyrene, and poly(4-vinylpyridine)) and two shrinkable substrates (polyshrink and shrinkwrap), and Teflon on polyshrink was found to be the most effective system. The volume of trapped lubricant was quantified by adding Nile red to the silicone oil before infusion, then extracting the oil and Nile red from the surfaces in heptane and measuring by fluorimetry. Higher volumes of lubricant induced lower roll-off angles for water droplets, and in turn induced better antifouling performance. The infused surfaces displayed stability in seawater and inhibited growth of Pseudoalteromonas spp. bacteria up to 99%, with as little as 0.9 μL cm-2 of silicone oil infused. Field tests in the waters of Sydney Harbour over seven weeks showed that silicone oil infusion inhibited the attachment of algae, but as the silicone oil was slowly depleted over time algal attachment increased. The infused wrinkled surfaces have high transparency and are moldable, making them suited to protecting the windows of underwater sensors and cameras.