Instability and spontaneous oscillations by surfactant transfer through a liquid membrane

The phenomenon of spontaneous non-linear oscillations, produced by surfactant transfer through a liquid membrane at the membrane/acceptor phase interface, is theoretically studied by direct numerical simulation of the model system evolution. The mathematical model, based on the first principles, includes non-linear, non-steady state Navier–Stokes, continuity and convective diffusion equations with the boundary conditions accounting for the momentum and mass balances. The oscillation mechanism and the effect of system geometry and surfactant properties on the oscillation characteristics are considered. The correlation with available experimental results is discussed as well.