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Project C7

Concentrated Colloidal Suspensions in Modulated Light Fields

Project leaders

  1. Prof. Dr. Stefan U. Egelhaaf


During the previous funding period (our first funding period) we designed, constructed and tested two complementary instruments for the application of light fields and the simultaneous observation of colloidal suspensions. Furthermore, we have developed an analysis programme to extract quantitative structural and dynamic information. Using these instruments and procedures we have started to investigate the effect of a light field on individual particles and the arrangement of concentrated colloids. We have observed light-induced structures which are similar to theoretical predictions developed in project D3. We now want to exploit the equipment and methodology further and investigate the behaviour of concentrated equilibrium (liquid) and non-equilibrium (glassy) samples in modulated potentials. We propose to study the induced structures and dynamics in initially liquid samples, which might be hard spheres or hard spheres with depletioninduced attraction, and compare the results to predictions developed in projects C3, C4 and D3. Furthermore, we plan to investigate whether and under which conditions glasses crystallize under the influence of an external potential and how an external potential affects not only the static, but also the dynamic properties of arrested states. In addition, we wish to investigate partially-quenched systems and compare their behaviour to the dynamics of arrested states. A close interaction with projects A5 and A7 will allow us to compare our experimental results to simulation and theory predictions.