ELECTROACTIVE POLYMERIC FILMS AS COATINGS FOR CORROSION PROTECTION: POLYPYRROLE DEPOSITED FROM SOLUTIONS CONTAINING SURFACTANT AND INHIBITORS

摘要

Electroactive polymers find applications as electrochromic display devices, sensors, electrochemical actuators and, more recently, as coatings for corrosion protection. Many of the studies carried out on their use as coating materials have focused on polyaniline. In this work, the results of an investigation into the use of polypyrrole/surfactant/inhibitor films to prevent the corrosion of mild steel are reported. Initial studies have considered the influence of additives, such as the anionic fluorocarbon surfactant FC-120, on film morphology and porosity. Polymers electrodeposited from FC-120 containing electrolytes produced films with flat and ordered structures. Film porosity was found to be dependent on the concentration of surfactant used but the corrosion resistance offered by surfactant containing polypyrrole films grown on mild steel was largely unaltered from those without such additions. Polypyrrole films doped with molybdate ion (a classical anodic corrosion inhibitor) did not show improved corrosion resistance. However, the corrosion rate of steel samples coated in polypyrrole films deposited from electrolytes containing FC-120 (1 X 10-2 M) and molybdate ions (2000 ppm) was seen to decrease by two orders of magnitude under the experimental conditions employed.