Ultrasonic-assisted fabrication of superhydrophobic ZnO nanowall films

Abstract

Zinc oxide-based superhydrophobic surfaces were fabricated on aluminium oxide-seeded glass substrates via sonochemical approach by varying the parameter, the sonication time duration. The fabricated structures have nanowall-like morphology with an average long axis length and thickness of ∼300 and ∼40 nm, respectively. The surface roughness created by surface-modified ZnO nanowalls and the air pockets trapped within the dense nanowalls, transformed the hydrophobic glass substrates into superhydrophobic surfaces with water contact angle of 156 • during 20 min of sonication. An independent analysis was carried out to study the growth of ZnO nanowalls over glass substrates in the absence of the aluminium oxide seed layer and sonication process. The results suggested that the synergistic effect of the aluminium oxide seed layer and sonochemical process can enable the formation of ZnO nanowall structures favourable for superhydrophobic property. A possible growth mechanism of ZnO nanowalls formation during sonication process has been discussed in detail.

A Facile Method for Preparing a Superhydrophobic Block with Rapid Reparability

“…Qing et al used stearic acid to modify ZnO and prepared a superhydrophobic coating on the surface of stainless steel by dip coating [33]. Sutha et al prepared ZnO nanowalls on glass substrates by sonochemical technology, and then modified them with 1H, 1H, 2H, and 2H-perfluorooctyltrichlorosilane to obtain a superhydrophobic surface [34] Wei et al prepared a flower-like ZnO structure on a foamed nickel substrate through a hydrothermal and decomposition process, and then obtained a superhydrophobic surface by hydrophobic treatment of 1H, 1H, 2H, and 2H-perfluorooctyltrichlorosilane [35]. Although these methods all use ZnO to prepare various microstructures, they are easily damaged when used in harsh outdoor environments and are difficult to repair.…”