Superhydrophobic surfaces generated from water-borne dispersions of hierarchically assembled nanoparticles coated with a reversibly switchable shell

The method used to fabricate a superhydropbobic coating from aqueous dispersions of hybrid responsive nanoparticles with no application of surfactants, organic solvents or fluorinated organic materials is reported. The hybrid nanoparticles consisted of a silica core with a grafted mixed block copolymer brush of poly[styrene-block-(4-vinylpyridine)] constituting the responsive particle shell. The responsive shell was used to tune and stabilize the secondary aggregates of the particles of the appropriate size and morphology in an aqueous environment. The suspension of the particles formed a textured superhydrophobic coating on various substrates upon casting, evaporation of water and heating above the glass transition temperature.