  In binary mixtures, the lifetimes of surface bubbles can be five orders of
magnitude longer than those in pure liquids because of slightly different
compositions of the bulk and the surfaces, leading to a thickness-dependent
surface tension of thin films. Taking profit of the resulting simple surface
rheology, we derive the equations describing the thickness, flow velocity and
surface tension of a single liquid film. Numerical resolution shows that, after
a first step of tension equilibration, a parabolic flow with mobile interfaces
is associated with film pinching in a further drainage step. Our model paves
the way for a better understanding of the rupture dynamics of liquid films.
