Preparation of functionalized polystyrene-block-polyisoprene copolymers and their luminescence properties

Abstract

A series of block copolymers functionalized with aromatic 1,3,4-oxadiazole and stilbene derivatives have been synthesized by the palladium catalyzed reaction between polystyrene-block-polyisoprene and different functional units. These polymers exhibited different emission properties in solution and in the solid state. In chloroform solution, they showed relatively narrow and featured emission bands while, in the solid state, the emission band was broadened and showed a significant red shift. These observations were attributed to the formation of aggregates between the luminophores. After some oxadiazole functionalized copolymers were annealed at elevated temperature, such aggregation was enhanced and there were further changes in the emission spectra. For the bifunctional copolymers, such a shift in the emission band was not significant because the presence of two different chemical species in the same block may prevent the same type of luminophores from aggregating together.