Marine biofouling is a longstanding problem because of the constant challenges placed by various fouling species and increasingly restricted environmental regulations for antifouling coatings. Novel nonbiocidal strategies to control biofouling will necessitate a multifunctional approach to coating design. Here we show that slippery liquid-infused porous surfaces (SLIPSs) provide another possible strategy to obtaining promising antifouling coatings. Microporous butyl methacrylate-ethylene dimethacrylate (BMA-EDMA) surfaces are prepared via UV-initiated free-radical polymerization. Subsequent infusion of fluorocarbon lubricants (Krytox103, Krytox100, and Fluorinert FC-70) into the porous microtexture results in liquid-repellent slippery surfaces. To study the interaction with marine fouling organisms, settlement of zoospores of the alga Ulva linza and cypris larvae of the barnacle Balanus amphitrite is tested in laboratory assays. BMA-EDMA surfaces infused with Krytox103 and Krytox100 exhibit remarkable inhibition of settlement (attachment) of both spores and cyprids to a level comparable to that of a poly(ethylene glycol) (PEG)-terminated self-assembled monolayer. In addition, the adhesion strength of sporelings (young plants) of U. linza is reduced for BMA-EDMA surfaces infused with Krytox103 and Krytox100 compared to pristine (noninfused) BMA-EDMA and BMA-EDMA infused with Fluorinert FC-70. Immersion tests suggest a correlation between the stability of slippery coatings in artificial seawater and fouling resistance efficacy. The results indicate great potential for the application of this concept in fouling-resistant marine coatings.

Gibbs surface energy has long been considered to be an important parameter in the design of fouling-resistant surfaces for marine applications. Rigorous testing of the hypothesis that settlement is related to Gibbs surface energy however has never been accomplished, due mainly to practical limitations imposed by the necessary combination of surface engineering and biological evaluation methods. In this article, the effects of surface charge and Gibbs surface energy on the settlement of cyprids of an important fouling barnacle, Balanus amphitrite, were evaluated. Settlement assays were conducted on a range of self-assembled monolayers (SAMs) (CH(3)-, OH-, COOH-, N(CH(3))(3) (+)-, NH(2)-terminated), presented in gold-coated polystyrene well plates, varying in terms of their surface charge and Gibbs surface energy. Contrary to contemporary theory, settlement was not increased by high-energy surfaces, rather the opposite was found to be the case with cyprids settling in greater numbers on a low-energy CH(3)- SAM compared to a high-energy OH- SAM. Settlement was also greater on negatively-charged SAMs, compared to neutral and positively-charged SAMs. These findings are discussed in the context of data drawn from surfaces that varied in multiple characteristics simultaneously, as have been used previously for such experiments. The finding that surface charge, rather than total surface energy, may be responsible for surface selection by cyprids, will have significant implications for the design of future fouling-resistant materials.

In this study, we investigated the possibility to improve a new behavioural bioassay (Swimming Speed Alteration test-SSA test) using larvae of marine cyst-forming organisms: e.g. the brine shrimp Artemia sp. and the rotifer Brachionus plicatilis. Swimming speed was investigated as a behavioural end-point for application in ecotoxicology studies. A first experiment to analyse the linear swimming speed of the two organisms was performed to verify the applicability of the video-camera tracking system, here referred to as Swimming Behavioural Recorder (SBR). A second experiment was performed, exposing organisms to different toxic compounds (zinc pyrithione, Macrotrol MT-200, and Eserine). Swimming speed alteration was analyzed together with mortality. The results of the first experiment indicate that SBR is a suitable tool to detect linear swimming speed of the two organisms, since the values have been obtained in accordance with other studies using the same organisms (3.05 mm s(-1) for Artemia sp. and 0.62 mm s(-1) for B. plicatilis). Toxicity test results clearly indicate that swimming speed of Artemia sp. and B. plicatilis is a valid behavioural end-point to detect stress at sub-lethal toxic substance concentrations. Indeed, alterations in swimming speed have been detected at toxic compound concentrations as low as less then 0.1-5% of their LC(50) values. In conclusion, the SSA test with B. plicatilis and Artemia sp. can be a good behavioural integrated output for application in marine ecotoxicology and environmental monitoring programs.

were no significant differences in biofouling coverage among the surfaces. While charged polymers are unsuitable as antifouling coatings in natural environment, they provide valuable insights into fouling processes, and are relevant for studies due to charging of nominally neutral surfaces.

In conclusion, it is demonstrated that despite previous suggestions to the contrary, these two species of barnacle show similar preferences in response to surface free energy; they also respond similarly to charge. These findings have positive implications for the development of novel antifouling coatings and support the importance of consistency in substrate choice for assays designed to compare surface preferences of fouling organisms.