Hydrophobic polystyrene/electro-spun polyaniline coatings for corrosion protection

Herein, bi-layer coatings were prepared through a superposition combination method, which contains polystyrene (PS) topcoat and polyaniline (PANI)/polymethyl methacrylate (PMMA) primer. PS topcoats prepared by different preparation methods show diverse microstructures, hydrophobicity, anti-medium permeability and corrosion resistance. In order to study the anti-corrosion mechanism of (PANI/PMMA primer - PS topcoat) coating system, Q235 carbon steel covered with bi-layer coatings were immersed in 3% NaCl solution for 720 h. And the anti-corrosion properties of samples were studied by open circuit potential, visual observations, electrochemical impedance spectroscopy and Tafel polarization test. Electrochemical techniques confirm that collocation of PS topcoat and PANI/PMMA primer could give full play to the shielding performance of topcoat and anodic protection performance of PANI/PMMA primer, Observed results show (PANI/PMMA primer - PS topcoat) coating system prepared by spray method has the best anti-medium permeability and outstanding corrosion protection property, which is attributed to the special microstructure.