Processing routes have been developed for the production of thin ceramic films through precipitation from aqueous solutions. The techniques are based on crystal nucleation and growth onto functionalized interfaces. Surface functionalization routes have been developed by the mimicking of schemes used by organisms to produce complex ceramic composites such as teeth, bones, and shells. High-quality, dense polycrystalline films of oxides, hydroxides, and sulfides have now been prepared from "biomimetic" synthesis techniques. Ceramic films can be synthesized on plastics and other materials at temperatures below 100 degrees C. As a low-temperature process in which water rather than organic solvents is used, this synthesis is environmentally benign. Nanocrystalline ceramics can be produced, sometimes with preferred crystallite orientation. The direct deposition of high-resolution patterned films has also been demonstrated. The process is well suited to the production of organic-inorganic composites.

Many organisms construct structural ceramic (biomineral) composites from seemingly mundane materials; cell-mediated processes control both the nucleation and growth of mineral and the development of composite microarchitecture. Living systems fabricate biocomposites by: (i) confining biomineralization within specific subunit compartments; (ii) producing a specific mineral with defined crystal size and orientation; and (iii) packaging many incremental units together in a moving front process to form fully densified, macroscopic structures. By adapting biological principles, materials scientists are attempting to produce novel materials. To date, neither the elegance of the biomineral assembly mechanisms nor the intricate composite microarchitectures have been duplicated by nonbiological processing. However, substantial progress has been made in the understanding of how biomineralization occurs, and the first steps are now being taken to exploit the basic principles involved.

Synthetic elaboration of self-assembled monolayers (SAMs) provides a powerful method for the preparation of smooth, ordered surfaces with carefully controlled functionality. Chemically rugged siloxane-based SAMs have been employed as a foundation for the preparation of a variety of functionalized surfaces. Nucleophilic displacements are described between halide-terminated SAMs and anionic nucleophiles (e.g. azide, thiocyanate, thiolate). Problems were encountered due to the steric congestion surrounding the terminal bromomethylene carbon. The concept of trajectory control is applied to these displacement reactions. In addition, reactions between ester-terminated SAMs and neutral nucleophiles (e.g. amines, hydrazine, hydroxylamine) are described. Evidence is presented suggesting that a modest amount of cross-linking (i.e. imide formation) takes place in the amidation reactions, while reaction stoichiometry indicates that cross-linking is virtually complete for the bifunctional nucleophiles. These synthetic elaborations were also carried out on mixed monolayers to create functionalized SAMs with systematically varied loading densities. Linear correlation (or lack thereof) of elemental composition to predicted functional composition is used to provide an estimation of reaction efficiency.

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