The traditional use of organic solvents in various branches of industry is being rethought as these compounds very often display high volatility, toxicity and lipophilicity (related to the ability to interact with biological membranes). More recently, developments in the field of Green Chemistry are focusing on the design of more sustainable and cost-effective solvent alternatives like Ionic Liquids (ILs), bio-based solvents and natural deep eutectic solvents (NADESs). The present study aimed at performing an ecotoxicological screening of 15 NADESs using an extensive set of marine and freshwater bioassays, based on different endpoints as the following: immobilization of the crustacean Daphnia magna, growth inhibition of Raphidocelis subcapitata and of Phaeodactylum tricornutum, larval development alterations on the serpulid Ficopomatus enigmaticus and bioluminescence inhibition of Aliivibrio fischeri. What emerged was a general absence of toxicity of all samples. However, both algal assays showed a certain degree of biostimulation, up to over 100% growth increase in respect to controls with 8 out of 15 compounds tested with Raphidocelis subcapitata. Despite NADESs-induced negligible toxicity effects to invertebrates, encouraging their labelling as “sustainable” solvents, the liability of their intentional or accidental release into aquatic systems may represent a serious risk in terms of ecosystem functioning impairments.

Amphiphilic methacrylate copolymers (Si-co-EF) containing polysiloxane (Si) and mixed poly(oxyethylene)–perfluorohexyl (EF) side chains were synthesized with different compositions and used together with polysiloxane-functionalized nanoparticles as additives of condensation cured nanocomposite poly(siloxane) films. The mechanical properties of the nanocomposite films were consistent with the elastomeric behavior of the poly(siloxane) matrix without significant detriment from either the copolymer or the nanoparticles. Films were found to be markedly hydrophobic and liphophobic, with both properties being maximized at an intermediate content of EF units. The high enrichment in fluorine at the film surface was proven by angle-resolved X-ray photoelectron spectroscopy (AR-XPS). Long-term marine antifouling performance was evaluated in field immersion trials of test panels for up to 10 months of immersion. Both nanoparticles and amphiphilic copolymer were found to be highly effective in reducing the colonization of foulants, especially hard macrofoulants, when compared with control panels. Lowest percentage of surface coverage was 20% after 10 months of immersion (films with 4 wt% copolymer and 0.5 wt% nanoparticles), which was further decreased to less than 10% after exposure to a water jet for 10 s. The enhanced antifouling properties of coatings containing both nanoparticles and copolymer were confirmed by laboratory assays against the polychaete Ficopomatus enigmaticus and the diatom Navicula salinicola.