On the electrochemical polymerization of poly(p-phenylene vinylene) and poly(o-phenylene vinylene)

This paper describes the electrochemical synthesis of poly(p-phenylene viny lene) and poly(o-phenylene vinylene), via potentiostatic cathodic reduction of alpha,alpha,alpha',alpha'-tetrabromo-p-xylene and alpha,alpha,alpha',al pha'-tetrabromo-o-xylene. The polymerization yield obtained from the electr ochemical quartz crystal microbalance were 88 and 25% for poly(p-phenylene vinylene) and poly(o-phenylene vinylene), respectively. The films were char acterized by infrared spectroscopy. The polymer has been identified by the vibrational features characteristic of the trans-vinylene units (3024 and 9 65 cm(-1) for the p-PPV and 2991 and 1002 cm(-1) for the o-PPV). A quinoid structure has been identified, indicating that the polymer is partially dop ed, probably the Br-2, formed during the polymerization process. The insolu ble phase was identified as p-PPV and o-PPV oligomers by the characteristic bands of the vinylene group. The p-PPV presents oligomers with molar mass corresponding to oligomers of seven monomeric units, while the o-PPV presen ts shorter chains, probably containing three to four units, as determined b y gel permeation chromatography. (C) 2001 Elsevier Science B.V. All rights reserved.