Controlled ionic complexation of positively charged phenylene-based conjugated polymers by modulated backbone structures

Abstract

Understanding the role of the polymer backbone structure on the aggregation of conjugated polymers in an aqueous environment is of prime interest as the physical, photophysical and biophysical properties required for many applications are closely related to the nature of aggregation structures. We report unique and ordered aggregation behaviours of four positively charged conjugated polymers, which differ in backbone chemical structure and connectivity, upon complexation with a linear polyanion hyaluronic acid. Opposite signals of induced circular dichroism were observed from achiral poly(phenyleneethynylene) (PPE) and flexible linker containing poly(phenylenebutadiynylene) (PPB) with the same side chain structure, implying the formation of highly ordered ionic complexes. The intrinsic difference in the interpolymer interaction between PPE and PPB is probably the contributing factor for different aggregation structures upon complexation with hyaluronic acid. The structure-property relationship can be useful to design and fabricate highly ordered macromolecular materials exhibiting unique electrical, photophysical or biophysical properties. (c) 2018 Society of Chemical Industry