Superhydrophobic cotton fabric coating based on a complex layer of silica nanoparticles and perfluorooctylated quaternary ammonium silane coupling agent

A superhydrophobic complex coating for cotton fabrics based on silica nanoparticles and perfluorooctylated quaternary ammonium silane coupling agent (PFSC) was reported in this article. The complex thin film was prepared through a sol-gel process using cotton fabrics as a substrate. Silica nanoparticles in the coating made the textile surface much rougher, and perfluorooctylated quaternary ammonium silane coupling agent on the top layer of the surface lowered the surface free energy. Textiles coated with this coating showed excellent water repellent property, and water contact angle (CA) increased from 133 deg on cotton fabrics treated with pure PFSC without silica sol pretreatment up to 145 deg . The oil repellency was also improved and the contact angle of CH2beta droplet on the fabric surface reached to 131 deg . In contrast, the contact angle of CH2beta on the fabric surface treated with pure PFSC was only 125 deg .