Antifouling Systems Based on a Polyhedral Oligomeric Silsesquioxane-Based Hexyl Imidazolium Salt Adsorbed on Copper Nanoparticles Supported on Titania

Abstract

The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labelled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity of these two compounds revealed the higher antimicrobial performances of HQ-POSS against Gram-positive and Gram-negative microorganisms, proving its broad-spectrum activity. Due to its very viscous nature, HQ-POSS was adsorbed in variable amounts on the surface of biologically active oxides to gain advantages regarding the expendability of such formulations from an applicative perspective. Titania and 5 wt% Cu on titania were used as supports. The materials 10HQ-POSS/Ti and 15HQ-POSS/5CuTi strongly inhibited the ability of Pseudomonas PS27 cells—a bacterial strain described for its ability to handle very toxic organic solvents and perfluorinated compounds—to grow as planktonic cells. Moreover, the best formulations (i.e., 10HQ-POSS/Ti and 15HQ-POSS/5CuTi) could prevent Pseudomonas PS27 biofilm formation at a certain concentration (250 μg mL−1) which greatly impaired bacterial planktonic growth. Specifically, 15HQ-POSS/5CuTi completely impaired cell adhesion, thus successfully prejudicing biofilm formation and proving its suitability as a potential antifouling agent. Considering that most studies deal with quaternary ammonium salts (QASs) with long alkyl chains (>10 carbon atoms), the results reported here on hexylimidazolium-based POSS further deepen the knowledge of QAS formulations which can be used as antifouling compounds.

New Biocide Based on Tributyltin(IV) Ferulate-Loaded Halloysite Nanotubes for Preserving Historical Paper Artworks

“…The best working concentrations (50 µg mL −1 ) of TBT-F and HNT/TBT-F were tested to evaluate whether these formulations could prevent K. rhizophila biofilm formation, as described elsewhere [39]. K. rhizophila cells were pre-cultivated as described earlier and inoculated at an initial microbial titer of approximately 107 CFU mL −1 .…”

Adhesive and Rheological Features of Ecofriendly Coatings with Antifouling Properties

“…Among the permissible materials, nanocomposites based on Cu/TiO 2 and Ag/TiO 2 oxides with a low metal content (≤5 wt%) have been studied for their antifouling properties. These nanocomposites exhibit remarkable properties that resist the adhesion and growth of marine organisms, such as algae, barnacles, and mussels, which can affect the performance of marine structures, ships, and underwater pipelines [23][24][25][26][27][28]. Recently, our research group highlighted the antifouling and antimicrobial activity of Ag, Cu and Fe nanoparticles supported on silica and titania [29].…”