2008/11/07 by Jacek Gapiński, J. Gapinski, A. Patkowski +10 · 1 citation
Chemistry · Materials Science · Physics and Astronomy · #Electrostatics and Colloid Interactions #Material Dynamics and Properties #Spectroscopy and Quantum Chemical Studies #cond-mat.dis-nn #cond-mat.soft
paper · pdf · doi:10.1063/1.3078408
arxiv created 2008/11/07 · openalex publication_date 2009/02/27 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present an experimental study of short-time diffusion properties in fluidlike suspensions of monodisperse charge-stabilized silica spheres suspended in dimethylformamide. The static structure factor S(q), the short-time diffusion function D(q), and the hydrodynamic function H(q) have been probed by combining x-ray photon correlation spectroscopy experiments with static small-angle x-ray scattering. Our experiments cover the full liquid-state part of the phase diagram, including de-ionized systems right at the liquid-solid phase boundary. We show that the dynamic data can be consistently described by the renormalized density fluctuation expansion theory of Beenakker and Mazur over a wide range of concentrations and ionic strengths. In accordance with this theory and Stokesian dynamics computer simulations, the measured short-time properties cross over monotonically, with increasing salt content, from the bounding values of salt-free suspensions to those of neutral hard spheres. Moreover, we discuss an upper bound for the hydrodynamic function peak height of fluid systems based on the Hansen-Verlet freezing criterion.