Abstract
In this work, a series of the novel poly(arlyenevinylene)s has been prepared by ring-opening metathesis polymerization (ROMP) of strained cyclic vinylene monomers composed of conjugated units such as cyclopentadithiophene (CPDT), bis(thienyl)-benzothiadiazole (DTBT), and bis(hexyl)-bithiophene (BTh), which were initiated by ruthenium-based catalysts. The monomers were synthesized by McMurry coupling using TiCl4/Zn and the products were characterized by 1H and 13C NMR spectroscopy and fast atom bombardment (FAB) mass spectrometry. In ROMP, molecular weight of the polymers can be varied by changing the monomer to catalyst ratio. Furthermore, the resulting polymers have less structural defects. Diblock copolymers of poly(arylenevinylene)s were also synthesized by similar procedure, in which first-block was synthesized by ROMP of DTBT monomer, followed by subsequent addition of the second and third monomers of CPDT and BTh. The block copolymers exhibit multiple functions derived from each block, e.g. wider-range UV-vis absorption and higher and lower HOMO-LUMO levels than those of homopolymers. In addition, morphology of homopolymers and block copolymers were studied by atomic force microscopy (AFM) to observe microphase separation in their film state. These type of polymers are potentially useful as efficient light-harvesting materials in OPV devices.