Polystyrene/poly(3,4-ethylenedioxythiophene) (PS/PEDOT) nanocomposite particles with uniform size and well-defined morphology have been synthesized using the proposed strategy, which involves swelling of 3,4-ethylenedioxythiophene (EDOT) into PS seed particles, followed by its diffusion and polymerization on the PS surface. This process affords much more effective control over the structure and morphology of the resultant nanocomposites by changing the EDOT/PS weight ratio, reaction temperature, and the rate of addition of the doping acid. The PS/PEDOT nanocomposite particles have been extensively characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), elemental microanalyses and X-ray photoelectron spectroscopy (XPS). Furthermore, the correlation between nanostructure of the resultant nanocomposite particle and its electromagnetic response performance (e.g., mass extinction effect in infrared region) was investigated. (C) 2011 Elsevier Ltd. All rights reserved.