A study on how to control the supramolecular amphiphilic assembly of anionic bola surfactant with calixpyridinium

The fabrication of supramolecular amphiphiles by the host–guest interactions between macrocycles and surfactants is an effective method to improve the physical and chemical properties of amphiphiles. However, as far as we know, lowering the critical micelle concentration of anionic surfactant by the complexation of macrocyclic host is scarcely studied. In this work, we systematically studied the host–guest interactions between calixpyridinium and four select anionic bola surfactants. Only congo red that has a conjugated linker could assemble into supramolecular amphiphile with calixpyridinium accompanied by a decreased critical micelle concentration. As a result, the p K a value of congo red shifted significantly. Moreover, the calixpyridinium–congo red supramolecular amphiphilic assembly exhibited a valuable visible-light response for the complete photodegradation of congo red.