title: Self-assembled biomimetic superhydrophobic hierarchical arrays.
abstract: Here, we report a simple and inexpensive bottom-up technology for fabricating superhydrophobic coatings with hierarchical micro-/nano-structures, which are inspired by the binary periodic structure found on the superhydrophobic compound eyes of some insects (e.g., mosquitoes and moths). Binary colloidal arrays consisting of exemplary large (4 and 30 μm) and small (300 nm) silica spheres are first assembled by a scalable Langmuir-Blodgett (LB) technology in a layer-by-layer manner. After surface modification with fluorosilanes, the self-assembled hierarchical particle arrays become superhydrophobic with an apparent water contact angle (CA) larger than 150°. The throughput of the resulting superhydrophobic coatings with hierarchical structures can be significantly improved by templating the binary periodic structures of the LB-assembled colloidal arrays into UV-curable fluoropolymers by a soft lithography approach. Superhydrophobic perfluoroether acrylate hierarchical arrays with large CAs and small CA hysteresis can be faithfully replicated onto various substrates. Both experiments and theoretical calculations based on the Cassie's dewetting model demonstrate the importance of the hierarchical structure in achieving the final superhydrophobic surface states.
authors.affiliation: Department of Chemical Engineering, National Chung Hsing University, 250 Kuo Kuang Road, Taichung, Taiwan. hyang@dragon.nchu.edu.tw
authors.forename: Hongta
authors.initials: H
authors.lastname: Yang
authors.forename: Xuan
authors.initials: X
authors.lastname: Dou
authors.forename: Yin
authors.initials: Y
authors.lastname: Fang
authors.forename: Peng
authors.initials: P
authors.lastname: Jiang
mesh_terms: D000818:Animals; D032701:Biomimetics; D003102:Colloids / Q000737:chemistry*; D054910:Compound Eye, Arthropod; D004129:Dimethylpolysiloxanes / Q000737:chemistry; D005461:Fluorine / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008855:Microscopy, Electron, Scanning; D049329:Nanostructures / Q000737:chemistry; D009757:Nylons / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D017155:Wettability
chemical_list: D003102:Colloids; D004129:Dimethylpolysiloxanes; D009757:Nylons; D011108:Polymers; C085707:poly(dimethylsiloxane)-polyamide copolymer; D005461:Fluorine