Wetting on regularly structured surfaces from "core-shell" particles: theoretical predictions and experimental findings

In this paper, we report on a systematic and thorough study of wetting phenomenon on regularly patterned surfaces fabricated from inorganic-organic hybrid "core-shell" particles of different radii (100 nm to 10 microm). Inorganic silica particles were modified through chemical anchoring of polymers and silanes with different hydrophobicities. Modified "core-shell" particles were assembled into regular hexagonally packed structures. The use of regular structured surfaces with specifically designed surface roughness allowed mathematic prediction of the wetting behavior according to existing models and its comparison with experimental observations. It was shown that the character of the wetting behavior varies with the particles size and the chemical nature of the surface immobilized substance. For the regular particle assemblies, an increase in the vertical roughness was achieved with increasing particle radius, but without changing the Wenzel roughness factor.