Issue
EPL
Volume 88, Number 5, December 2009
Article Number 58002
Number of page(s) 5
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/88/58002
Published online 14 December 2009
EPL, 88 (2009) 58002
DOI: 10.1209/0295-5075/88/58002

Surface fluctuations of an aging colloidal suspension: Evidence for intermittent quakes

A. Mamane, C. Frétigny, F. Lequeux and L. Talini

Université Pierre et Marie Curie-Paris 6, UMR CNRS 7615, ESPCI, Laboratoire PPMD - 10 rue Vauquelin, 75005 Paris, France, EU

laurence.talini@espci.fr

received 7 April 2009; accepted in final form 16 November 2009; published December 2009
published online 14 December 2009

Abstract
We present measurements of the thermal fluctuations of the free surface of an aging colloidal suspension, Laponite. The technique consists in measuring the fluctuations of the position of a laser beam that reflects from the free surface. Analysing the data statistics, we show that, as the fluid ages, the dynamics becomes heterogeneous. The intermittent events correspond to large changes in the local slope of the free surface over a few milliseconds. We show that those quakes are uncorrelated, although they are kept in memory by the surface over short time scales.

PACS
82.70.Dd - Colloids.
64.70.P- - Glass transitions of specific systems.
62.30.+d - Mechanical and elastic waves; vibrations.

© EPLA 2009