Chemical and Biomolecular Engineering Faculty Research


Assessments of Capsaicin Incorporated Silicone Rubber as Antifouling Coatings

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Capsaicin, a natural pepper extract that is substantially less toxic than most currently used antifoulants such as organotin compounds, could be a potential environmentally friendly antifoulant. The antibacterial effectiveness of capsaicin has been reported. However, no detailed study on incorporating the compound into silicone coatings has been conducted. In this study, capsaicin was incorporated into silicone coatings to achieve a synergistic effect by combining the antifouling properties of capsaicin with the foul release performance of silicone rubbers. The silicones used were polydimethylsiloxane rubbers with two different curing mechanisms. Due to the poisonous effect of capsaicin to Pt-based catalysts used for hydrosilylation curing of some silicone coatings, a swelling technique of precured coatings in the capsaicin/benzene solution was utilised. For silicone cured with tin-based catalysts, whose catalysis capability was unaffected by capsaicin, capsaicin was blended into the coating in the presence of a common solvent. Surface and bulk properties of the capsaicin-incorporated coatings were controlled closely to those of the silicone coatings alone, thus minimising their contribution to antifouling. The bacterial attachment studies indicated that all capsaicin-incorporated coatings exhibited initial enhancement in antibacterial performance as compared to coatings containing no capsaicin. However, due to the fast leaching of capsaicin and the adverse effect of the increase surface roughness upon water immersion, the antibacterial effectiveness for capsaicin incorporated coatings only exhibited for a short period of time.

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Journal of Rubber Research





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