Kinetics of sedimentation in colloidal suspensions

Research output: Contribution to journalArticlepeer-review

Authors

  • Stefano Buzzaccaro
  • Antonio Tripodi
  • Roberto Rusconi
  • Daniele Vigolo
  • Roberto Piazza

Colleges, School and Institutes

External organisations

  • Politecnico di Milano
  • Harvard University

Abstract

Measuring the concentration profiles induced by gravity settling is known to be an efficient route to obtain the equation of state of a colloidal suspension, to inspect the fine details of the phase diagram and to provide clues on the nature of metastable phases. Here we show that a careful analysis of the transient settling profiles may add valuable information for what concerns colloidal hydrodynamics. In particular, we show that a numerical inversion of a kinetic profile yields the full hydrodynamic factor K(Φ) up to the concentration of the original unsettled suspension, and that the dilute part of the profile yields a 'dynamic' gravitation length also related to K(Φ). These predictions are tested on a suspension of monodisperse hard and sticky spheres. Finally we describe and test a novel optical method, allowing us to measure sedimentation profiles on a wide class of colloidal systems, even in the presence of a noticeable turbidity.

Details

Original languageEnglish
Article number494219
JournalJournal of Physics: Condensed Matter
Volume20
Issue number49
Publication statusPublished - 10 Dec 2008