Modes of motion in a confined colloidal suspension under shearR. Biehl and T. Palberg
Universität Mainz, Institut für Physik, KOMET 336 Staudinger Weg 7, D-55128 Mainz, Germany
(Received 12 January 2004; accepted in final form 9 February 2004)
We investigated aqueous suspensions of charged polystyrene latex spheres at low salt concentration under the combined influence of steady shear and confining walls. Their equilibrium structure was adjusted via the particle and salt concentration to be either fluid or body centred cubic. Using high-resolution real-space microscopy, we here present a first direct observation of collective modes of motion under shear. As a function of either shear rate and/or salt concentration, we find a continuous transition from registered to free sliding of layers accompanied by an equally continuous structural rearrangement lowering the dimensionality of long-ranged order.
82.70.Dd - Colloids.
64.70.Md - Transitions in liquid crystals.
83.10.Tv - Structural and phase changes.
© EDP Sciences 2004