Abstract
The viscoelastic behaviour at 40 kHz and the steady flow properties of monodisperse polystyrene latexes, i.e. aqueous suspensions of charged polystyrene spheres, were measured through an order-disorder transition as varying the salt concentration in the solvent and the volume fraction of spheres. A latex in the ordered lattice structure showed the rigidity of about 103 dyn/cm2 and the yield stress of about 1 dyn/cm2, which indicates that the ordered latex is a crystal in view of the mechanical properties. The ratio, 10-3, of the yield stress to the rigidity suggests a dislocation mechanism of the plastic flow of the ordered latex.