The microwave (MW) synthesis of polyaniline (PANI) is performed using potassium iodate (KIO3) as oxidizing agent in different concentrations of aqueous hydrochloric acid (HCl) at 8 and 93 W applied microwave power for duration of 10 min. The morphological and structural changes in synthesized MW PANI samples are investigated using Scanning Electron Microscopy (SEM) and Fourier transform Infrared Spectroscopy (FTIR). With decreasing pH of the reaction medium the morphology of MW PANI samples changed from slab-like with a small amount of fibrils to porous products which consist of short, rod-like structures. The FTIR spectra confirm that the microwave generated materials structurally consist of PANI, but aniline oligomer peaks are observed in the FTIR at 725 and 686 cm(-1) for MW PANI synthesized using 0.5 M aqueous HCl. The influence of acid dopant on the spin concentration of MW PANI synthesized at 8 and 93 W are examined. (C) 2014 Elsevier B.V. All rights reserved.