Polyaniline (PANI) nanolayers were shown to form spontaneously during the chemical oxidation in the presence of retinol using pure water and aqueous ethanol as reaction media. The effects of the retinol, the volume fraction of ethanol, and the acidity of the polymerization medium on the D.C. conductivity of PANI were investigated through two-probe method at room temperature. The introduction of 0.2 g retinol improved the D.C. conductivity value of PANI to 3.0 S/cm in pure water and 4.46 S/cm in 50% aqueous ethanol when the H+ concentration was 0.5M. The D.C. conductivity values were 5.1 and 5.49 S/cm when the concentration of H+ was 1.0M in pure water and 2.5M in 50%, aqueous ethanol, respectively. The products were also characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscope, cyclic voltammetry, and X-ray diffraction techniques. Moreover, the resulting PANI nanolayers exhibited an unusual electromagnetic loss at the microwave frequency (f = 8.2-12.4 GHz) and it arose from order arrangement of polaron as charge carrier caused by nanolayers morphologies and the materials can be used for the potential application as microwave absorbing materials. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110:3162-3171, 2008