Fabrication of stable fluorine-free superhydrophobic fabrics for anti-adhesion and self-cleaning properties

This study is aimed at the fabrication of superhydrophobic fluorine-free films on cotton fabrics through incorporating a rough sub-structure followed by chemical modification. Stable titania hydrosols were prepared via sol-gel using 0.44 mol/L titanium tetraisopropoxide in acidic media followed by chemical modification of the sol using vinyltrimethoxysilane (VTMS) for surface energy reduction and spraying over the surface. Upon drying at 60 degrees C, covalent attachment of vinyl modified TiO2 particles to hydrophilic surface was occurred. Water contact angle increased from 0 degrees on pure fabric up to 134.1 degrees with sliding angles > 90 degrees. Further enhancement in water contact angles up to similar to 170 degrees and reduction of sliding angle to < 10 degrees was achieved by introduction of polydimethylsiloxane (PDMS). Hydrodynamic particle size of TiO2 sol was determined using dynamic light scattering (DLS). Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and Attenuated total reflectance-Fourier Transform Infra-Red (ATR-FTIR) analyses were conducted to verify the morphology and rough structure, elemental analysis and surface chemical modification of treated surfaces, respectively. Furthermore, the superhydrophobic coating was applied on a commercial sponge for oil-water separation. According to the results, self-cleaning, anti-adhesion, chemical resistant and durable super-hydrophobic fabric was prepared through spraying of low-cost environmentally friendly materials.