Spontaneous rupture of surfactant-covered thin liquid sheets

The rupture of thin free films of Newtonian fluids are analyzed theoretically and computationally when the two free surfaces are covered with insoluble surfactant and surface rheological (viscous) effects are important. For highly viscous fluids in the Stokes limit, we show that the dynamics near the rupture singularity exhibits self-similarity of the second kind and the dominant balance involves van der Waals pressure and bulk and surface viscous stresses. For moderately viscous fluids inertia is also important and self-similarity is of the first kind. Closed-form expressions for the sheet's thinning rate are found and can be used to determine values of surface viscosity from experiments.