One-step ultrasound fabrication of corrosion resistant, self-cleaning and anti-icing coatings on aluminium

Abstract

This study aimed to fabricate a highly hydrophobic aluminium surface in a one-step ultrasound process in a sodium hydroxide solution containing various alkoxysilanes. The latter were based on the trimethoxysilane of various type and length of the introducing group at the silyl bond (SiC): Ra-Si(OMe)3 and Rf-(CH2)2-Si(OMe)3, where Ra and Rf are alkyl and perfluoroalkyl introducing groups, respectively, and OMe is the methoxy group. The effect of methoxy and ethoxy groups at the siloxy bond was additionally investigated for perfluorodecyl silanes.The corrosion performance was studied using potentiodynamic electrochemical techniques. The wettability, morphology, surface topography and surface composition of treated aluminium surfaces were characterised using an optical tensiometer, a scanning electron microscope coupled with an energy dispersive X-ray spectrometry system, a contact profilometer and a Fourier transform infrared spectroscopy system.Micro-/nanostructures formed on the treated aluminium surfaces lead to an increase in the water contact angle from 71° for ground surface, up to 115° for the surface treated with alkyl silanes and up to 155° for that treated with fluoroalkyl silanes with a long chain. The superhydrophobic coatings show corrosion-resistant behaviour in chloride solution, while the durability in slightly acidic/alkaline solutions indicates the excellent water-repellent nature of the coatings, the self-cleaning ability for different types of pollutants and improved anti-icing properties with freezing and melting delay.