The role of surface rheology in liquid film formation

¹  School of Engineering and Applied Sciences, Harvard University - Cambridge, MA 02138, USA
²  TIPs - Fluid Physics unit, Université Libre de Bruxelles - C.P. 165/67, 1050 Brussels, Belgium, EU
³  Laboratoire de Physique des Solides UMR8502, Université Paris-Sud - 91405 Orsay, France, EU
⁴  Institut de Physique de Rennes UMR6251, Université de Rennes - 35042 Rennes, France, EU
⁵  Department of Mechanical and Aerospace Engineering, Princeton University - Princeton, NJ 08544, USA

Corresponding author: bscheid@ulb.ac.be

Received: 26 March 2010
Accepted: 19 April 2010

Abstract

The role of surface rheology in fundamental fluid dynamical systems, such as liquid coating flows and soap film formation, is poorly understood. We investigate the role of surface viscosity in the classical film-coating problem. We propose a theoretical model that predicts film thickening based on a purely surface-viscous theory. The theory is supported by a set of new experimental data that demonstrates slight thickening even at very high surfactant concentrations for which Marangoni effects are irrelevant. The model and experiments represent a new regime that has not been identified before.