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, and Nenad Miljkovic
August 14, 2019
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.