Anti-mold properties of hydrophobic and superhydrophobic coatings based on cyanoacrylate adhesive, zinc and silicon oxides nanoparticles, and silicon organic compounds

Fungal spores are dispersed through the air but settle and germinate on moist surfaces to form fungal hyphae and conidia, which can develop, digest organic matter, produce mycotoxins, and pose human health concerns. In this study, the hydrophobic and superhydrophobic coatings based on cyanoacrylate adhesive, 1H,1H,2H,2H-perfluorodecyltriethoxysilane (HDFS), 1H,1H,2H,2H-perfluorooctyltriethoxysilane (ODFS), SiO 2 and ZnO nanoparticles (NPs) were fabricated and evaluated for their wettability as well as the resistance against molds. All coating samples #1 - #4 were resistant to mold growth when tested by pipetting the spore suspensions on the coating surfaces. In particular, sample #1 composed of cyanoacrylate adhesive, ZnO NPs, and ODFS exhibited the best anti-mold effect against Aspergillus and Penicillium species in fungal spore exposure test. Wettability tests demonstrated that coating sample #1 displays the highest value of water contact angle 159.6° and its contact angle hysteresis does not exceed 8 o . Our findings pointed out, for the first time, that there were no mold hyphae colonized on the tested coating surfaces; only the mold spores adhered to the top of the textured structure, but no spore germination was observed. Notably, neither Penicillium sp. nor A. niger spores were able to penetrate inside the porous textured structure of all coatings.