Measurement of the short-time self-mobility of particles in concentrated suspension. Evidence for many-particle hydrodynamic interactions

The short-time self-mobilities of spherical colloidal particles in concentrated liquid suspensions were measured by photon correlation spectroscopy. For volume fractions Φ ≳ 0.3, theory incorporating two-particle hydrodynamic interactions was not adequate to describe the data, indicating the importance of many-particle contributions.