Liquid crystalline,highly luminescent poly(2,5-dialkoxy-p-phenyleneethynylene)

A high-molecular-weight poly(2,5-dialkoxy-p-phenyleneethynylene) derivative has been prepared by the Heck reaction of 1,4-bis(2-ethylhexyloxy)-2,5-diiodobenzene and 1,4-diethynyl-2,5-dioctyloxybenzene. The highly luminescent polymer exhibits excellent solubility and can readily be processed into high-optical-quality films. The weight-average molecular weight M?_w was 240000 g · mol^?1, with a polydispersity index of 2.9. Thermal analysis revealed a glass transition around 90°C, and an onset of chemical crosslinking at 130°C. The high M?_w and the remarkable solubility enabled the preparation of liquid crystalline solutions of the new PPE.