Dramatic differences in the fluorescence of AIEgen-doped micro- and macrophase separated systems

Abstract

A block copolymer (BCP) and a polymer blend containing small amounts of fluorogenic molecules with aggregation-induced emission (AIE) characteristics exhibited dramatic differences in the fluorescence properties. In particular, AIEgens with different polarities were doped in BCP polystyrene-b-polylactide (PS-b-PLA) and the PS/PLA blend. For the BCP, whether the AIEgens were selectively located in one phase or not, the intramolecular motions of the phenyl rings in AIEgens were affected by both the PS and PLA segment motions, due to the covalent bonds between the constitutive blocks. Therefore, the fluorescence was affected by the segment movements of PS and PLA. In contrast, the AIEgen-doped polymer blend exhibited location dependent fluorescence. The fluorescence was affected by the segment movements where the AIEgens were located, because there were no connections between the PS and PLA chains. This visualization method will provide new insights into monitoring the chain motions of macromolecules with more complex structures.