Development of Coatings for The Prevention of Contamination, Water Wetting, and Ice Formation

Abstract

The modification of glass for prevention of contamination has been a subject of active research in materials science. The key property to attain this feature is the self-cleaning in glass. Self-cleaning can occur via different mechanisms, such as hydrophobic, hydrophilic, and hydrophilic mechanism coupled with photocatalysis. Self-cleaning has been gaining a lot of attention in the academic as well as commercial sectors mainly due to the immense variety of its potential applications, which include daily-life as well as industrial and hightech uses, such as self-cleaning windows, windshields, exterior paints for building, roof tiles, textiles, and drag reduction in fluid flow etc. A lot of research has been ongoing for the development of self-cleaning glass by application of superhydrophobic material on the surface of glass. In this work, formation of hydrophobic coating on glass substrates was carried out via sol-gel thin-film synthesis route, with the use of Triethyl orthosilicate as the starting precursor. Attempts to increase the hydrophobicity of silica films by surface modification using Trimethyl silane. Effects of surface modification through introduction of varying amounts of CTAB was also studied. In order to enhance the strength and durability of the coatings while retaining super hydrophobicity, the silica films were reinforced with small amounts of multi-walled carbon nanotubes (MWCNTs), and its effects on wetting characteristic and morphology of the films were studied. To overcome the problem of adhesion and durability of the films, another method was explored, which utilized colorless epoxy resin to adhere silica particles onto the substrate surface. The morphology of the films prepared was analyzed using Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM). To characterize the wettability of the films, contact angle measurements were carried out using Drop Shape Analyzer. The contact angles of silica modified surfaces were observed to approach 95o.