Electrochemical synthesis of polymer based on 4-(2-thienyl)benzenamine in aqueous solutions: Electrochemical properties, characterization and application

•4-(2-Thienyl)-aniline monomer synthesized via a simple two step method.•Poly 4-(2-thienyl)-aniline was synthesized in aqueous solution for the first time.•The electroactivity and electrochromic behavior of the polymer was investigated.•Polymer shows superior anticorrosion activity in electrolyte containing chloride.

4-(2-Thienyl)benzenamine (TBA) was successfully synthesized by a simple method including substitution of thiophene on p-nitroaniline followed by reduction of nitro group. Structure of the synthesized monomer was verified using IR, 1H NMR, GC–MS and elemental analysis techniques. Corresponding poly 4-(2-thienyl)benzenamine) (PTBA) was electrochemically synthesized in acidic aqueous solution by cyclic potential sweep method for the first time. Characterization of the resulting polymer was performed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), UV–vis and IR spectroscopies, and scanning electron microscopy (SEM). Effects of pH and temperature on the electroactivity of the polymer modified electrode were investigated. The corrosion behavior of PTBA in 3.5 wt% NaCl solution was studied by potentiodynamic polarization test and electrochemical impedance spectroscopy. The PTBA was found to exhibit enhanced corrosion protection effect on stainless steel electrode in comparison with polyaniline (PANI) and polythiophene (PTh) homopolymers.

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