OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 1987 · 13 citations · 0 references
Natural SciencesMaterials EngineeringMaterials ScienceMaterials ChemistrySurface ScienceThin FilmsGelsNucleationPolymer Thin FilmsSurface MorphologyThin-film DepositionCondensation RateFilm FormationFilm MorphologyMicrostructure Of GelsSol-gel MaterialsSol-gel ProcessingSol-gel SystemsSol-gel Thin Films
It is shown that the structure of sol-gel-derived thin films depends on the precursor structure and deposition conditions. Weakly branched precursors (reduced D) applied under reaction-limited conditions result in the densest films, whereas branching or aggregation (increased D) combined with transport-limited deposition conditions result in the most porous films. A complete spectrum of microstructures is achievable by independent control of both precursor size and structure and the condensation rate or sticking probability. Application of shear during deposition is shown to restructure tenous, fractal structures and align weakly branched precursors.