The Effects of Primary Structures on Photo-Induced Insolubilization of All-Cis Poly(p-phenylenevinylene)s in Thin Films

All-cis poly(p-phenylenevinylene)s (PPVs) prepared by Suzuki-Miyaura-type polycondensation of (Z,Z)-1,4-bis(2-bromoethenyl)benzene with 2,5-dioctyloxybenzene-1,4-diboronic acid undergo photo-induced insolubilization in thin films, along with cis-to-trans isomerization of vinylene linkages to give all-trans PPVs. This phenomenon has been investigated using all-cis and all-trans PPVs with a range of molecular weights and terminal structures. The amounts of PPVs remaining on quartz substrates, after UV-irradiation on spin-coated films, followed by rinsing twice with CHCl 3 , are dependent on the geometries of vinylene linkages, molecular weights, and terminal structures of the starting PPVs. It has been found that the all-cis configuration is of particular importance for insolubilization. The insolubilized films exhibit charge-carrier mobility (μ FET ) up to 1.6 x 10 -4 cm 2 V -1 s -1 .