IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Long-time dynamics and dynamic scaling in suspensions of charged and neutral colloidal particles
Autor/es:
M. HEINEN; ADOLFO J. BANCHIO; P. HOLMQVIST; G. NÄGELE
Lugar:
Ljubljana
Reunión:
Conferencia; Physics of Complex Colloids - COMPLOIDS 2013; 2013
Resumen:
We investigate the time-dependent intermediate and self-intermediate dynamic scattering functions (DSF?s), describing the spatio-temporal pair correlations of charged (CS) and neutral hard spheres (HS) both theoretically and experimentally. Extensive Brownian dynamics and accelerated Stokesian dynamics simulations and mode-coupling theory calculations of the DSF?s have been performed for a large range of correlation times, for HS and for pair potential parameters representing strongly charged silica spheres in a refractive index matching organic solvent. Our theoretical results for CS silica systems are amended by dynamic light scattering (DLS) data. While the temporal decay of the intermediate DSF is clearly diffusive at short times, the physical nature of its long-time decay is still under debate [1-4]. A DLS study of Segre and Pusey [1] for HS systems suggests that the long-time decay is diffusive for wavenumbers around and above the principal peak position of the static structure factor, with factorized time- and wavenumber dependence of the relaxation rate. This factorization feature, referred to as dynamic scaling, has been questioned for HS in [2] and [3], for different reasons. As an approximate feature, it has been observed also for CS suspensions in [4]. To identify the true long-time decay of the DSF?s from experimental and theoretical data is a challenging task [3]. Our comprehensive theoretical-experimental study adds to the understanding of the DSF?s and dynamic scaling at intermediate to long times.