Responsive reverse giant vesicles and gel from self-organization of a bolaamphiphilic pillar[5]arene

Abstract

A novel bolaamphiphilic pillar[5]arene was prepared. It spontaneously forms responsive reverse multilamellar giant vesicles in chloroform and a gel in water–tetrahydrofuran (5 : 1, v/v). Dynamic light scattering, transmission electron microscopy, scanning electron microscopy, optical microscopy, and fluorescent microscopy were used to characterize its self-assembly in different solvents and aggregation behavior under external stimuli. These vesicles were not only stable for weeks, but also showed reversible thermal and dynamic properties under external physical stimuli. KPF₆ and benzo-18-crown-6 can also be used as switches to turn-off and re-turn-on the assembly of vesicles. Moreover, the aggregation behaviour of this bolaamphiphilic pillar[5]arene can be changed by simply introducing host–guest chemistry. Besides, the gel formed from it showed reversible gel–sol phase transitions by heating and cooling, or adding and removing potassium cations.