Stimuli-responsive brush-shaped conjugated polymers with pendant well-defined poly(vinyl ether)s

Abstract

For the synthesis of brush-shaped conjugated polymers consisting of a poly(phenylene butadiynylene) backbone and well-defined poly(vinyl ether) (polyVE) side chains, we designed polyVE-based macromonomers bearing a diethynyl benzene group at the terminus and applied them to the grafting through synthesis. The macromonomer (DE-PIBVE) was synthesized by living cationic polymerization of isobutyl VE (IBVE) using a functionalized initiator (TMS-DEVE-TFA) having a TMS protected diethynyl benzene moiety, followed by deprotection of the TMS groups. As a result, we succeeded in the synthesis of the target brush-shaped conjugated polymers [poly(DE-PIBVE)] by oxidative coupling reaction of the diethynyl benzene groups. We found that the solution of poly(DE-PIBVE) with a specific side chain length exhibited solvatochromism and thermochromism depending on the polarity of the media employed. This phenomenon was attributed to self-assembly in polar media due to the intermolecular π–π interaction between neighboring conjugated polymer backbones, where the self-assembly behavior would be closely related to the pendant polyVE structure. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3318–3325