Abstract The growth of electropolymerized polyaniline nanograins has been carried out from aqueous solution of 0.45 M aniline (C 6H 5NH 2) + 0.5 M H 2SO 4. These polyaniline nanograins were characterized using Raman spectroscopy, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), contact angle measurement and optical studies. The presence of characteristic bonds of polyaniline was observed from Raman shift experiment. Based on field emission scanning electron microscopy and transmission electron microscopy analysis, the formation of the polyaniline nanograins with average diameter of about 50 nm was inferred. Surface of the polyaniline film was hydrophilic with contact angle 17 ± 1°. A blue shift of 0.30 eV with characteristic absorption peak at 427 nm has been attributed due to quantized size of polyaniline nanograins.