Electropolymerization of benzene in a room temperature ionic liquid

In this paper, we report on the electropolymerization of benzene in the room temperature ionic liquid 1-hexyl-3-methylimi-dazolium tris(pentafluoroethyl)trifluorophosphate. This liquid exhibits on platinum an electrochemical window of 4.5 V, furthermore it can easily be dried to water contents below 3 ppm. By potentiodynamic or potentiostatic polymerization of benzene a black deposit is obtained which has a spherulitic morphology with smallest grains of around 500 nm. IR spectrometry reveals that poly(para)phenylene was deposited to a certain extent. The polymer film is electroactive with a quasi-reversible electrochemical behavior and an electrode potential of around 1 V vs. ferrocene/ferrocinium. The importance of ionic liquids as mild solvents for the electropolymerization of benzene is pointed out. (C) 2004 Elsevier B.V. All rights reserved.