The inhibition efficiency of 1-ethyl-3-methylimidazolium dicyanamide (EMID) was studied against mild steel corrosion, in acidic environment. Surface analysis showed that the assembled inhibitor film could protect the metal successfully, during 120 h exposure to 0.1 M H2SO4. The studies considering zero charge potential value (E-pzc) showed that the anion plays the major role for film formation. The surface coverage ratio (theta) values were determined handling the double layer capacitance values (C-dl) calculated from Bode diagrams, for different concentration and temperature conditions. The inhibitor was fixed successfully within polypyrrole film and applied to steel surface as highly protective coating. (C) 2012 Elsevier Ltd. All rights reserved.