Electrically switchable colloidal ordering in confined geometries

A novel field-induced approach has been developed that allows the controlled ordering of colloidal particles in confined systems. In this approach, an electric field is used to create a strong lateral dipole-dipole interaction that induces colloidal crystallization in two-dimensional geometries. Because the particle density is relatively low and the interaction of long range, colloidal mobility is high enough to allow rapid crystallization upon the application of the electric field. The observed phase transitions are fully reversible and can be readily controlled by adjusting either the applied field strength or particle confinement.