A self-templated etching route to surface-rough silica nanoparticles for superhydrophobic coatings.

A simple, mild, and effective self-templated etching strategy has been developed to directly convert SiO(2) nanospheres into surface-rough SiO(2) (SR-SiO(2)) nanoparticles (NPs) by reaction with NaBH(4). Small SiO(2) NPs on the surface of SR-SiO(2) NPs can be tailored by carefully regulating the reaction time. SiO(2) nanospheres with varied sizes were etched under varied reaction conditions. Subsequently, particulate coatings were constructed on slide glass using SR-SiO(2) NPs as building blocks through the Layer-by-Layer assembly. Slide glasses just coated with two cycles of SR-SiO(2) NPs followed by calcination and hydrophobic modification exhibited superhydrophobicity because of their dual-size surface roughness.