Luminescent hydrogels based on di(4-propoxyphenyl)-dibenzofulvene exhibiting four emission colours and organic solvents/thermal dual-responsive properties

Abstract

The present study reports the fabrication of intelligent luminescent hydrogels by physically incorporating a propeller-shaped di(4-propoxyphenyl)-dibenzofulvene molecule, which shows unusual aggregation-induced emission (AIE) and crystallization-induced emission enhancement (CIEE) effects, into a hydrogel matrix. Hydrogels with orange, yellow and green emissions are obtained by adjusting the water contents of the dispersions of di(4-propoxyphenyl)-dibenzofulvene for hydrogel syntheses. It is interesting to note that the blue emission of di(4-propoxyphenyl)-dibenzofulvene is observed for the first time when its dispersions are frozen and thawed, and the subsequently prepared hydrogels also emit blue colour. The emissions of these luminescent hydrogels can be switched between different colours by fuming with organic solvent vapours or a heating–cooling process, and some of the switches are reversible.