# The break-up of free films pulled out of a pure liquid bath

## TL;DR

This paper develops a lubrication model for free liquid films pulled from a reservoir, incorporating van der Waals forces, and predicts rupture conditions that match experimental data.

## Contribution

It introduces a new theoretical model accounting for van der Waals interactions to predict film rupture in pulling experiments.

## Key findings

- Model accurately predicts rupture height across various velocities and fiber sizes.
- Rupture is well-defined in both space and time, enabling precise critical thickness calculation.
- Theoretical results align quantitatively with experimental measurements.

## Abstract

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.