Syntheses and properties of copolymers containing indolocarbazole moiety in the side chain

Abstract

Novel copolymers containing the indolo3,2-bcarbazole (INC) moiety were synthesized, and the effects of the INC content on their physical properties were investigated. The homopolymer of the INC-containing monomer, 1-octyl-7-(4-vinylbenzyl)indolo3,2-bcarbazole and copolymers with styrene were prepared by radical polymerization. Four kinds of copolymers with different compositions were obtained. The glass transition temperatures (Tgs) were observed in the range of 101-112 °C, and the decomposition temperatures were nearly 400 °C. The photonic properties of the copolymers were also evaluated in solution in tetrahydrofuran and for spin-coated films on a fused silica substrate. In the ultraviolet-visible absorption spectra, maximum absorption peaks were observed at 340-345 nm in both the solutions and the films. In the case of the solutions, the photoluminescence intensities of the copolymers increased with increasing INC monomer units in the copolymer. On the contrary, the photoluminescence intensities of the copolymer films decreased with increasing INC content in the copolymer, which is likely due to the concentration quenching caused by the condensation of intermolecular interactions derived from INC components. The copolymer with a low content of the INC moiety exhibited high emission and good film-forming ability. © The Society of Polymer Science, Japan (SPSJ) All rights reserved.