Reconfigurable Liquids Constructed by Pillar[6]arene-Based Nanoparticle Surfactants.

The interfacial jamming of nanoparticle surfactants offers the possibility of structuring liquids and fabricating all-liquid constructs with advanced functionality. However, less attention has been given to structured liquids with multiple responsiveness. Here, we show a novel, yet highly simplified nanoparticle surfactant model, pillar[6]arene (PA[6]) surfactant, by taking advantage of the host-guest interactions between a water-soluble PA[6] and an oil-soluble ligand, ferrocenium terminated polystyrene. PA[6] surfactants form rapidly at the oil-water interface, assemble into an elastic film with excellent mechanical strength, and when jammed, offer a "solid-like" assembly to lock-in highly nonequilibrium shapes of the liquids. The interfacial assembly/jamming and disassembly/unjamming of PA[6] surfactants can be controlled by chemical redox or competitive guest reagents, endowing the structured liquids with redox or guest-competitive responsiveness.