Issue 18, 2021

Dynamic stabilisation during the drainage of thin film polymer solutions


The drainage and rupture of polymer solutions was investigated using a dynamic thin film balance. The polymeric nature of the dissolved molecules leads to significant resistance to the deformation of the thin liquid films. The influence of concentration, molecular weight, and molecular weight distribution of the dissolved polymer on the lifetime of the films was systematically examined for varying hydrodynamic conditions. Depending on the value of the capillary number and the degree of confinement, different stabilisation mechanisms were observed. For low capillary numbers, the lifetime of the films was the highest for the highly concentrated, narrowly-distributed, low molecular weight polymers. In contrast, at high capillary numbers, the flow-induced concentration differences in the film resulted in lateral osmotic stresses, which caused a dynamic stabilisation of the films and the dependency on molecular weight distribution in particular becomes important. Phenomena such as cyclic dimple formation, vortices, and dimple recoil were observed, the occurrence of which depended on the relative magnitude of the lateral osmotic and the hydrodynamic stresses. The factors which lead to enhanced lifetime of the films as a consequence of these flow instabilities can be used to either stabilise foams or, conversely, prevent foam formation.

Graphical abstract: Dynamic stabilisation during the drainage of thin film polymer solutions

Supplementary files

Article information

Article type
16 Feb 2021
08 Apr 2021
First published
08 Apr 2021
This article is Open Access
Creative Commons BY license

Soft Matter, 2021,17, 4790-4803

Dynamic stabilisation during the drainage of thin film polymer solutions

E. Chatzigiannakis and J. Vermant, Soft Matter, 2021, 17, 4790 DOI: 10.1039/D1SM00244A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity