A Novel Water-Soluble, Conducting Polymer Composite for Mild Steel Acid Corrosion Inhibition

A novel water-soluble conducting polymer composite, poly(vinyl alcohol-histidine) was synthesized from aqueous solution by free radical condensation using persulfate. The composite was characterized using UV-Visible, Fourier transform infrared, scanning electron microscopy, thermogravimetric analysis (TG/DTG), and differential scanning calorimetry techniques while its AC conductance was measured by LCZ analyzer. The inhibitive action of the composite on the corrosion behavior of mild steel in 1M HCl was studied by conventional weight loss method, potentiodynamic polarization studies (Tafel), linear polarization studies, and electrochemical impedance spectroscopy. The effects of inhibitor concentrations, exposure time, and temperature have been investigated. The corrosion rate, inhibition efficiency (IE), and other parameters have been evaluated for different inhibitor concentrations. The composite provided more than 95% IE at an optimum concentration of 0.6% by weight. The results showed the composite as an effective mixed type inhibitor. The adsorption of this inhibitor obeyed Temkin adsorption isotherm. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 127: 3084-3092, 2013