Surface fluctuations of an aging colloidal suspension: Evidence for intermittent quakesA. 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
received 7 April 2009; accepted in final form 16 November 2009; published December 2009
published online 14 December 2009
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.
82.70.Dd - Colloids.
64.70.P- - Glass transitions of specific systems.
62.30.+d - Mechanical and elastic waves; vibrations.
© EPLA 2009