Some insights into the structure and morphology of surfactant‐doped poly(o‐toluidine)

Abstract

AbstractPoly(o‐toluidine) (POT) doped with dodecylbenzene sulfonic acid (DBSA) was synthesized by inverse emulsion polymerization and characterized systematically for morphological, structural, electrochemical, and thermal properties with scanning electron microscopy (SEM), cyclic voltammetry (CV), X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). SEM demonstrated irregular granular morphology of the polymer with high porosity similar to polyaniline (PANI). The size distribution of POT salts was analyzed using Nano Measurer 1.2.5 software from scanning electron micrographs. The semicrystalline nature, with crystallite size and d‐spacing in the range of 21.4–30.2 nm and 4.93–4.99 Å, respectively, was confirmed from XRD. The activation energy (Ea) of degradation was calculated from TGA curves using Coats and Redfern (39.92–47.50 kJ/mol) & Horwitz and Metzger (50.09 ̶ 57.45 kJ/mol) methods, respectively. The small crystallite size, high thermal stability, and high values of the activation energy of degradation reveal that DBSA is an efficient dopant for POT and imparts interesting characteristics to this otherwise less thermally stable polymer. The fast rate of electron transfer of POT, as confirmed by electrochemical impedance spectroscopy, reveals its high electrochemical activity toward electrolyte. Potentiodynamic polarization measurement of POT‐coated stainless steel showed large anodic potential shift as compared to uncoated stainless steel, illustrated good anticorrosion performance. The enhanced anticorrosion performance is due to synergic effect of dopant which increases the contortion of diffusion pathway of corrosive substance.