PANI copolymer micro/nanostructures with different surface wettability were obtained from the chemical oxidation copolymerization of aniline (Ani) with 2-ethyl aniline (EA) at diverse [EA]/[Ani+EA] molar ratios, by employing ammonium persulfate as an oxidant. The results revealed that the poly (aniline-co-2-ethyl aniline) (PANI-EA) copolymer micro/nanostructures exhibited satisfactory anticorrosion performance for carbon steel, and the corrosion protection efficiency increased with the increase of water repellent property. Poly (2-ethyl aniline) (PEA) showed the largest contact angle (CA=145˚) and show the best corrosion protection for the carbon steel ( η = 87.29%). It is found that the superior anticorrosion property of PEA is attributed to its high hydrophobicity, low conductivity and low porosity.