Positive effect of polymeric silane-based water repellent agents on the durability of superhydrophobic fabrics

Abstract

A series of superhydrophobic polyester fabrics are fabricated via in situ deposition of a sol–gel derived silica primer layer on alkali-treated polyester fabric surfaces and subsequent hydrophobization with silane-based water repellent agents. The contribution of the polymeric silanes on the durability of corresponding superhydrophobic fabrics under mechanical damages (i.e. ultrasonication in THF and Martindale abrasion) has been confirmed, using a small-molecule fluorinated silane (5-(perfluorohexyl)isohexyltrimethoxysilane, FAS) as control. Their water contact angles could still reach at least 137° even after 120 min of ultrasonication in THF and 340 cycles of Martindale abrasion, exhibiting durable water repellency and anti-stain performance. It is acribed to their formation of dense and highly crosslinked hydrophobic layers on the silica modified fabric (SiO2@fabric) surface. Moreover, higher amount of fluorinated monomer unit in the polymeric silanes leads to more efficient hydrophobization of SiO2@fabric and much more durable water repellency for the corresponding superhydrophobic fabrics. The possible mechanism is also proposed.