Preparation and EIS studies on polyimide/polyaniline blend film for corrosion protection

A corrosion protection coating from polyimide/polyaniline (PI/PAn) blend was prepared by solution blending and the anti‐corrosion property of this coating was studied with electrochemical impedance spectroscopy technique. The results show that PAn can react with PI to form chemical bonds between these two polymers and these bonds keep these two polymers as a miscible system. The corrosion protection property of this coating increases with a growth in the PAn component and an excellent anti‐corrosion effect emerges when the PAn content reaches 10–15%. The reason why PAn can improve the anti‐corrosion property is that PI/PAn blend can form a dense and non‐porous polymer film that would prevent some corrupting components from access to the underlying steel surface. And also, PAn may serve as a corrosion inhibiting agent to scavenge any protons and foster a local basic surface environment. Copyright © 2001 John Wiley & Sons, Ltd.