  In this paper, we derive a lubrication model to describe the non-stationary
free liquid film that is created when a vertical frame is pulled out of a
liquid reservoir at a given velocity. We here focus on the case of a pure
liquid, corresponding to a stress-free boundary condition at the liquid/air
interfaces of the film, and thus employ an essentially extensional description
of the flow. Taking into account van der Waals interactions between the
interfaces, we observe that film rupture is well-defined in time as well as in
space, which allows us to compute the critical thickness and the film height at
the moment of rupture. The theoretical predictions of the model turn out to be
in quantitative agreement with experimental measurements of the break-up height
of silicone oil films in a wide range of pulling velocities and supporting
fiber diameters.
