Dynamics, Rheology and Critical Properties of Colloidal Fluid Mixtures

Liquids under the influence of external fields§exhibit a wide range of intriguing phenomena that can§be markedly different from the behaviour of a§quiescent system. This work considers two different§systems - a glassforming Yukawa system and a§colloid-polymer mixture - by Molecular Dynamics§computer simulations. §The former consists of a 50-50 binary mixture of§differently-sized, like-charged colloids interacting§via a screened Coulomb (Yukawa) potential. Near the§glass transition the influence of an external shear§field is studied. In particular, the transition from§elastic response to plastic flow is of interest. The§obtained results are important for advancing new§theoretical approaches in the framework of the§mode-coupling theory of the glass transition.§Furthermore, they suggest new experimental§investigations on colloidal systems.§As second system a colloid-polymer mixture is studied§in the context of its behaviour near the critical§point of phase separation. Based on the§Asakura-Oosawa model a new effective model with soft§interaction potentials is introduced and§characterised in equilibrium. Finally its suitability§for shear simulations is shown.