Effect of Fluorine Substitution on Tetraphenylethene-Benzothiadiazole Based AIE-active Copolymers

Abstract

The influence of fluorine substitution on the aggregation-induced emission enhancement of alternating tetraphenylethene-benzothiadiazole copolymers pBTPE and pBFTPE is investigated. The presence of difluorobenzothiadiazole in pBFTPE significantly enhances the intensity of emission upon aggregation, whereas pBTPE without fluorinated substituents exhibits relatively weak aggregation-enhanced emission. Furthermore, both TEM image and 2-D GIWAXS reveal denser packing for pBFTPE. The fluorine atoms on the polymer backbone may promote more pronounced inter-polymer interactions, improving molecular packing and resulting in conformational difference. It may dictate the nature of aggregation between polymers and resulting photophysical behavior.