Iron Corrosion Protection by Ultra-thin Conductive Films Based on Polypyrrole/Poly(methyl methacrylate) Composite

Abstract

ABSTRACT The metallic surfaces can be protected from the corrosive media by conducting polymer coating which provides passivation mechanism by redox chemistry. Their poor solubility and processibility were improved by the use of soluble polypyrrole (PPy) and composite with poly(methyl methacrylate) (PMMA). Soluble PPy was synthesized by controlling the monomer-to-oxidant ratio in the presence of dodecylbenzenesulfonic acid (DBSA) as a dopant. And then MMA was mixed with PPy/m-cresol solution to spin-coat onto iron. The 4-probe method was used to measure electrical conductivity and FTIR spectra were used to study the conjugation length of PPy. Scanning electron microscopic (SEM) images were obtained to observe the surface morphology. Tafel plots showed that the PMMA/PPy composite film caused a positive shift of around 200 mV in the corrosion potential and the anodic current decreased by two orders of magnitude compared with bare iron.