Contraction of Surfactant-Laden Pores

The contraction of surfactant-laden pores at the microscale has implications for natural and technological processes ranging from the collapse of channels in lipid membranes to the stability of foams in the food processing industry. Despite their prevalence, our understanding of the mechanisms of pore contraction in the presence of surfactants remains unclear. These mechanisms have been challenging to study experimentally given the small length scale near the singularity and simulations capable of accurately characterizing the pore dynamics may help enhance our understanding of the process. Here, we use high-fidelity numerical simulations to gain insight into the fluid dynamics and interfacial phenomena underlying the contraction of viscous pores in the presence of an insoluble surfactant. Results show that surfactants accumulate on the advancing front of a collapsing pore due to the uneven deformation of the pore interface. Because of this accumulation, even a small amount of surfactant plays a major role in the way in which a collapsing pore approaches the singularity.