Tackling the Short-Lived Marangoni Motion Using a Supramolecular Strategy

Inspired by the intriguing capability of beetles to quickly slide on water, scientists have long imagined the use of this surface-tension-gradient-dominated Marangoni motion in various applications, for example, self-propulsion. However, this classical spontaneous motion is limited by a short lifetime due to the loss of the surface tension gradient; the propellant of amphiphilic surfactants can rapidly reach an adsorption equilibrium and an excessive aggregation state at the air/liquid interface. Herein, we demonstrate a supramolecular host-guest chemistry strategy that allows the breaking of the physical limit of the adsorption equilibrium and the simultaneous removal of surfactant molecules from the interface. By balancing the competitive kinetics between the two processes, we have prolonged the lifetime of the motion 40-fold. This work presents an important advance in the study of long-lived self-propulsion transport through flexible interference at the molecular level and holds promise in electricity generation applications.