Spontaneously Ordered Sol−Gel Composites with Submicrometer Periodicity

We report a template-free sol−gel route to ordered organic−inorganic structures with submicrometer periodicity. Room-temperature, condensation reactions of acrylate-substituted alkoxysilanes and transition-metal alkoxides followed by photoinitiated polymerization of olefin units formed composites with long-range, microstructural organization. Samples could be prepared as transparent, three-dimensional monoliths with ordered cross sections (A) or as microstructured, bicontinuous thin films (B). Composites formed in this way, for the first time, possess a periodicity that corresponds to optical wavelengths.