A simple one-step approach to fabrication of highly hydrophobic silk fabrics

Highly hydrophobic silk fabric surfaces were successfully fabricated using a simple one-step atomic layer deposition (ALD) process. The surface morphology , chemical composition , and structure of bare silk fabric and silk fabrics coated with titanium dioxide (TiO 2 ) subjected to 800 and 1600 ALD cycles were measured using scanning electron microscopy (SEM), field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and scanning probe microscopy (SPM). The surface wettability of the silk fabrics was evaluated by determining their static water contact angles (WCAs) and roll-off angles. The results suggest that the good hydrophilicity of the surfaces of bare silk fabrics can be changed to high hydrophobicity by the application of TiO 2 nanoparticles to their surfaces using ALD. The high hydrophobicity achieved can be attributed to the increase in roughness of the silk fabric surface. The laundering durability of TiO 2 -coated silk fabrics is greatly improved by increasing the thickness of the ALD TiO 2 films.