Nucleation and Growth of Oriented Ceramic Films onto Organic Interfaces

New materials synthetic methods are being investigated involving heterogeneous nucleation and growth of ceramic films from aqueous solutions onto surfaces modified with organic functional groups. Dense, nanocrystalline, iron hydroxide films were deposited onto sulfonated polystyrene and sulfonated self-assembling monolayers on oxidized silicon. (020) oriented goethite films were formed resulting in chains of edge-shared octahedra in the [001] direction lying parallel to the surface. Deposition amounts varied with pH primarily due to changes in solution supersaturation. The best films were formed when deposition occurred heterogeneously at supersaturations just below the critical supersaturation. Induction times decreased with increasing sulfonate site density due to a reduction in interfacial energy. Nucleation was initiated by binding of cationic species to sulfonate sites and hydrolysis and condensation reactions resulted in the growth and coalescence of crystallites.