Comparison of the electronic properties of poly[2-(2 '- ethylhexyloxy)-1,4-phenylenevinylene] prepared by different precursor polymer routes

The synthesis of poly[2-(2'-ethylhexyloxy)-1,4-phenylenevinylene] 10 via chloro 7, S-methyl xanthate 8, and O-ethyl xanthate 9 precursor polymers has been investigated. We found that the chloro and O-ethyl xanthate precursor polymers could be easily formed whilst the S-methyl xanthate gave only low molecular weight material. The observed molecular weights of the chloro and O-ethyl xanthate precursor polymers were found to decrease with decreased polymer concentration when measured by gel permeation chromatography (GPC) with the decrease probably being due to the dissociation of polymer aggregates or physical networks. In contrast, no decrease of molecular weight was observed by GPC for the S-methyl xanthate precursor polymer on dilution. The chloro, S-methyl xanthate, and O-ethyl xanthate precursor polymers were thermally converted to the conjugated polymer 10. The UV-visible absorption and photoluminescence quantum yield of 10 was determined to be strongly dependent on the precursor route used. For 10 formed from the chloro precursor 7 the PL quantum yield was found to be 55 +/- 5%.