Argon Plasma Treatment of Fluorine-Free Silane Coatings: A Facile, Environment-Friendly Method to Prepare Durable, Superhydrophobic Fabrics

Abstract

A novel method to prepare durable superhydrophobic fabrics through pre-applying an alkyl silane (alkyl chain longer than C15) onto fabric substrate and by subsequent vacuum plasma treatment in argon is reported. The treated fabrics show a contact angle of 154.2° with low contact angle hysteresis (sliding angle 4.5°). The coatings are durable and can withstand 150 cycles of standard laundries. The argon plasma treatment is found to significantly enhance SiOSi bonding among the silane molecules, leading to a highly crosslinked silica network. The silane coating also shows high optical transparency. Apart from fabrics, other substrates such as filter paper, plastic film, glass slide, silicon wafer, and metal are treated in a similar way, and all the treated surface show durable hydrophobicity, though the contact angle is lower than that of the coated fabrics. Post-crosslinking of silane through argon plasma treatment may offer a facile but environment-friendly way to prepare durable superhydrophobic fabrics.