Glassy dynamics and aging in a dense ferrofluidA. Robert1, E. Wandersman2, E. Dubois2, V. Dupuis2 and R. Perzynski2
1 European Synchrotron Radiation Facility - 6 rue Jules Horowitz BP 220, F-38043 Grenoble Cedex 9, France
2 Laboratoire Liquides Ioniques et Interfaces Chargées, UMR 7612, Université Paris VI CNRS, ESPCI - 4 place Jussieu, 75252 Paris Cedex 05, France
received 15 February 2006; accepted in final form 17 July 2006
published online 2 August 2006
X-ray Photon Correlation Spectroscopy is used here to probe for the first time a glass-forming dispersion of repulsive particles spherical and sized. The highly concentrated colloidal system is based on the magnetic and charge-stabilized nanoparticles of a ferrofluid. Their out-of-equilibrium translational dynamics capture on nanoscale generic features usually observed on microscale: namely i) stretched exponential relaxation with an exponent around 1.5 and ii) age-dependent characteristic time evolving from exponential at young ages to a slower behavior at large ages. is here scaling as Q-1 in the whole experimental Q-range, below, on and above the scale of the interparticle distance, the driving force for aging in this glass-forming nanosystem being associated to larger scale rearrangements.
61.10.-i - X-ray diffraction and scattering.
82.70.Dd - Colloids.
64.70.Pf - Glass transitions.
© EDP Sciences 2006