Electrochemical Synthesis of Superhydrophobic Polyaniline/Silane Coating Towards Corrosion Protection of Mild Steel

In this study, a two-step electrodeposition strategy was proposed to fabricate an eco-friendly superhydrophobic polyaniline (PANI)/silane composite coating on mild steel for corrosion protection. The first step consists of creating a pure PANI adherent coating using a cyclic voltammetry technique and the second step consists of realizing superhydrophobic features using electrodeposition in mixed silane monomers at constant potential. The structure and composition characterization results revealed successful modification of the underlying pure PANI layer with superhydrophobic surface silane film. Wettability tests indicated a high contact angle of 155° and a low sliding angle of 4.2°. Electrochemical measurements revealed that the corrosion current density of PANI/silane-coated mild steel decreased by approximately three orders of magnitude compared to the uncoated sample and the corrosion protection efficiency was as high as 99.6%. Moreover, the prepared PANI/silane hybrid coating exhibited good chemical stability and strong adhesion after 10 days of corrosion in 3.5 wt.% NaCl solution.