Polythiophene-graft-styrene and polythiopene-graft-(styrene-graft-C60) copolymers

Poly(3-hexylthiophene) was quantitatively brominated and subsequently used in the Suzuki cross-coupling with a boronic ester of a nitroxide to form a macroinitiator bearing a TEMPO group on each thienyl ring. This macroinitiator initiated the nitroxide-mediated radical polymerization of styrene and 4-chloromethylstyrene (CMS), and subsequently reacted with C-60 to yield soluble graft, rod-coil polymers. Films of the polymers display a bi-continuous phase structure as revealed by AFM. Similar polymers, in which only a fraction of the thienyl units boasted C-60-bearing side chains, displayed optical properties representative of extensive pi-delocalization. The potential application of this methodology for the synthesis of graft polymers for photovoltaic devices is discussed.