Influence of shape and surface properties of microstructured reaction areas on the deposition of silica

Differently shaped reaction areas for silica deposition were created by photochemical grafting of hydrophobic poly(acrylic acid 2-ethyl-hexylester) as barrier and a hydrophilic polymer employing a mask having hexagons, pentagons, squares and stripes. Poly(ethylene glycol), poly(acrylic acid), branched and linear poly(ethylene imine) and linear poly(methylpropylene imine) have been applied as hydrophilic polymer in the reaction area. These patterned films have been used in silica mineralization experiments by dipping them into a silica precursor solution. Investigations of the polymer films and silica depositions have been done by contact angle measurements, ellipsometry and scanning electron microscopy (SEM). Silica deposition occurs only in the hydrophilically coated areas, resulting in regular arrays of lens-like silica particles. There are only minor differences due to the shape of the reaction area. The influence of the different hydrophilic polymers can be explained by their wetting behaviour.