Synthesis and self-organization of PPV-based block copolymers for photonicapplications

Rod-coil block copolymers have been synthesized with the objective of enhan cing the photovoltaic efficiency by the incorporation of both donor and acc eptor components in a molecular architecture that is self-structuring. Bloc k copolymers were obtained by using an end-functionalized rigid-rod block o f poly(2,5-dioctyloxy-1,4-phenylenevinylene) (PPV) as a macroinitiator for the nitroxide-mediated controlled radical polymerization of a flexible, sty rene-based block. Under suitable conditions the formation of honeycomb stru ctures by PPV-block-polystyrene (PPV-b-PS) is observed. The honeycomb struc ture consists of a 2-dimensional array of spherical air holes with an inner diameter of 3 - 5 mum in a polymeric film, which results in similar to 6.5 million hexagonally packed holes per square centimeter. The application of these structures as templates for highly ordered functional patterns is de monstrated by evaporating aluminum on this regularly structured surface and subsequently washing away the polymer.