Synthesis and anticorrosive properties of a novel electroactive polyurea containing oligoaniline pendants

A novel polyurea containing oligoaniline pendants (PU-p-OA) was synthesized by one-step synthetic route. The molecular structure of PU-p-OA was confirmed by Fourier transform infrared spectra (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC), and its thermal stability was probed via thermal gravimetric analysis (TGA). Due to the introduction of the oligoaniline segments, PU-p-OA showed expected spectroscopic properties and reversible electroactivity. The electrochromic behavior of a PU-p-OA/ITO electrode was investigated by spectrochronoamperometry in detail, exhibiting good electrochromic properties with high contrast value. Moreover, the inhibition effect of the electroactive PU-p-OA coatings on the cold rolled steel (CRS) in 5 wt% sodium chloride solution was investigated by Tafel plot analysis and electrochemical impedance spectroscopy. Furthermore, comparative anticorrosive study among PU-p-OA, normal polyurea (NPU), parent aniline tetramer (PAT), and NPU/PAT blend was accomplished, which indicated that the obtained PU-p-OA was a good corrosion inhibitor for CRS in brine medium.