Mechanics and Microstructures of Concentrated Colloidal Gels

It is often assumed that the viscoelastic properties of dense colloidsare determined by the colloid volume fraction, the interactionpotential, as well as the particle size distribution andshape. The dependence of the viscoelastic behavior of particlesuspensions and gels on these parameters has been widely studied,and is well understood in many cases. In contrast, ourknowledge on the influence of microstructure on mechanical andrheological properties, in particular for high solid loading suspensionsas used in ceramic processing, is much less developed.This aspect has been the focus of recent experiments, whichshow that small changes in microstructure can have dramaticeffects on the mechanics and dynamics of concentrated colloidalgels. In this article, we attempt to give an overview of the influenceof microstructure on the mechanical and rheological propertiesof colloidal systems. Particular attention is given tocolloidal particle gels at high volume fractions.