Incorporation of pyrene into an oriented transparent film of layered silica-hexadecyltrimethylammonium bromide nanocomposite

A layered silica-hexadecyltrimethylammonium halide nanocomposite was used as a novel transparent support to immobilize pyrene. For the incorporation of pyrene into the layered composites, pyrene was first solubilized into an aqueous solution of hexadecyltrimethylammonium halide and the solution was allowed to react with partially hydrolyzed tetramethoxysilane. By spin coating the solution on a quartz substrate, thin films were obtained. The films are transparent in a wavelength region from the visible to the near-infrared regions and possessed a layered structure. Fluorescence spectra of the incorporated pyrene suggest that the pyrene molecules were incorporated in the hydrophobic part of the layered composites without aggregation. The present system is a novel state of surfactant aggregates. Applications such as the immobilization of guest species (especially photoactive ones) are promising because of the simplicity of preparation, the micro- and macroscopic anisotropy, and transparency of these layered composites.