Environment-Friendly Anti-Biofouling Superhydrophobic Coatings

By Seyed Mohammad, Reza Razavi, Junho Oh, Richard T. Haasch, Kyungsub Kim, Mahmood Masoomi, Rouhollah Bagheri, James McClurg Slauch, Nenad Miljkovic
ACS Publications
August 14, 2019
DOI: 10.1021/acssuschemeng.9b02025

Hydrophobic surfaces have potential to enhance the efficiency of a plethora of applications, from heat exchangers, to underwater structures, to food industry and oil-water filtration. A large fraction of currently available hydrophobic coatings consists of perfluorinated compounds or organosilane-based chemistries, both of which can be toxic and bioaccumulate in nature. Here, we develop environment-friendly and economical superhydrophobic coatings using naturally abundant sepiolite nanoparticles functionalized with naturally extracted fatty acids from cinnamon and myristica. We demonstrate our coating on a variety of metallic and non-metallic surfaces with dip coating of aluminum, adsorbent fabrics, glass and even paper. Contact angle measurements revealed the ability to scalably produce high apparent advancing contact angles (> 160°) with low contact angle hysteresis (< 5°). We characterized our coated surfaces for their anti-biofouling characteristics using Gram negative and Gram positive bacteria. The results showed that the bacterial attachment considerably decreased (< 5%) compared to the untreated surfaces (≈30%), resulting in lower biofouling. The chemical, mechanical, and thermal durability of the coating were studied, with results showing that immersing the samples in different pH aqueous solutions (4 ≤ pH ≤ 10) and different temperatures (T < 300°C) for various times does not have significant effect on the superhydrophobicity of the samples. Our work not only presents the development of a naturally-derived and environment-friendly superhydrophobic anti-biofouling coating, it demonstrates a pathway for future research on the development of sustainable and ecological functional coatings.