Fluorine-Free Substrate-Independent Superhydrophobic Coatings by Nanoarchitectonics of Polydispersed 2D Materials
Ryota Hikichi, Y. Tokura, Yasuhiko Igarashi, Hiroaki Imai, Yuya Oaki
Abstract
Abstract Fluorine-free superhydrophobic surfaces have been required to meet environmental regulations in recent years. A new nanoarchitectonics is required to achieve superhydrophobicity without using perfluoroalkyl compounds. In the present work, surface-modified exfoliated nanosheets with polydispersed sizes were utilized to prepare coatings with high surface roughness and low surface energy. Fluorine-free superhydrophobic surfaces were obtained by spray coating of surface-modified exfoliated nanosheets based on transition-metal oxides. The water contact angle (θw) 166.0 ± 0.5° is the highest compared with that of the fluorine-free substrate-independent coatings in previous reports. The significant factors related to θw were studied using machine learning combined with our chemical insight in the small data obtained in the present work. The resultant superhydrophobic coatings exhibited unique properties, such as sliding of water droplets, superoleophilic behavior, recyclability, and durability. The present design strategy can be applied to development of various functional coatings using exfoliated 2D materials with polydispersity.