gamma-Fe2O3 polystyrene (PS) composite films were prepared by a gel-casting technique to obtain monodisperse composite films. To understand the effect of additives on the prepared composite films, additives such as rice husk ash and thiourea were made to disperse unto the PS matrix. The as-prepared gamma-Fe2O3 PS composite films, along with their additives, were subjected to characterization and study by X-ray diffraction, scanning electron microscopy, thermal, IR, and dielectric measurement techniques. These studies showed monodisperse and chemically homogenous composite films with an increase in thermal behavior. An interesting self-assembly of rod-like nanoparticles of gamma-Fe2O3 particles into the polymer matrix, which formed spherical packets, was observed for the gamma-Fe2O3PS composite film. The electrical behavior of these films was interesting, as some showed conduction whereas others showed an increase in dielectric behavior. This nature was explained by the dielectric measurements. (C) 2004 Wiley Periodicals, Inc.