Deposition of ceramic materials from aqueous solution induced by organic templates

Besides conventional high-temperature sintering processes for the preparation of ceramics, synthesis routes like chemical and physical vapor phase deposition or molecular beam epitaxy as well as sol-gel and polymer thermolysis carried out at decreased temperatures gain in significance. Such a trend is especially pronounced in the case of the deposition of oxide-based solids from aqueous solutions induced by organic templates. This approach is inspired by biomineralization that in general involves the formation of well-structured and complex-shaped organic/inorganic composites by the deposition of an inorganic solid on an organic matrix that consists of biomolecules like proteins. It occurs at ambient conditions with respect to temperature, pressure and atmosphere. The imitation of these processes by technical means is the deposition of thin oxide films from aqueous solutions in the presence of organic self-assembled monolayers. Besides general features of this technique like low synthesis temperatures, processing costs and equipment expenditure as well as the line-of-sight deposition suitable for coating complex shaped and/or temperature-sensitive substrates the characteristics of the films and their mechanisms of formation are discussed by way of the oxide systems TiO2, ZrO2 and ZnO.