Eur. Phys. J. E 8, 347-351 (2002)
DOI: 10.1140/epje/i2002-10018-0

Acoustic instabilities in thin polymer films

E. Schäffer^{1, 2} and U. Steiner<sup>1

1</sup>  Department of Polymer Chemistry, Materials Science Center, University of Groningen, Nijenborgh 4, NL-9747 AG Groningen, The Netherlands
²  Fakultät für Physik, Universität Konstanz, D-78456 Konstanz, Germany

u.steiner@chem.rug.nl

(Received 5 March 2002 and Received in final form 21 May 2002)

Abstract
The spatial confinement of a fluctuation spectrum leads to forces at the confining boundaries. While electromagnetic (EM) fluctuations lead to the well-known dispersion forces, the acoustic analogy has widely been neglected. We show that the strength of the forces resulting from confined acoustic modes may be of the same order of magnitude as van der Waals forces. Additionally, the predicted scaling behavior is identical to the non-retarded case of the EM fluctuations. Our results suggest that dewetting experiments using polymer films are strongly influenced by the acoustic dispersion forces.

PACS
47.20.Ma - Interfacial instability.
68.15.+e - Liquid thin films.
05.40.-a - Fluctuation phenomena, random processes, noise, and Brownian motion.


© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002