2004/06/14 by Roberto Di Leonardo, R. Di Leonardo, F. Ianni +2 · 1 citation
Chemical Engineering · Engineering · Materials Science · Mathematics · Physics and Astronomy · #Autocorrelation #Classical mechanics #Composite material #Material Dynamics and Properties #Materials science #Mathematics #Mechanics #Phase Equilibria and Thermodynamics #Physics #Rheology #Shear (geology) #Shear flow #Shear rate #Simple shear #Statistics #Superposition principle #Thermodynamic properties of mixtures #Thermodynamics #cond-mat.dis-nn #cond-mat.soft
paper · pdf · doi:10.1103/physreve.71.011505
5 pages, 5 figures
arxiv created 2004/06/14 · openalex publication_date 2005/01/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The influence of an applied shear field on the dynamics of an aging colloidal suspension has been investigated by the dynamic light-scattering determination of the density autocorrelation function. Though a stationary state is never observed, the slow dynamics crosses between two different nonequilibrium regimes as soon as the structural relaxation time \ensuremathτs approaches the inverse shear rate \stackrel\ifmmode \else \.\fi\ensuremathγ^\ensuremath-1. In the shear-dominated regime (at high \stackrel\ifmmode \else \.\fi\ensuremathγ values) the structural relaxation time is found to be strongly sensitive to the shear rate (\ensuremathτs\ensuremath∼\stackrel\ifmmode \else \.\fi\ensuremathγ^\ensuremath-\ensuremathα, with \ensuremathα\ensuremath∼1) while aging proceeds at a very slow rate. The effect of the shear on the detailed shape of the density autocorrelation function is quantitatively described, assuming that the structural relaxation process arises from the heterogeneous superposition of many relaxing units, each one independently coupled to shear with a parallel composition rule for time scales: 1∕\ensuremathτ\ensuremath→1∕\ensuremathτ+A\stackrel\ifmmode \else \.\fi\ensuremathγ.