Regensburg 2013 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 9: Glasses and Glass Transition I (joint session with CPP, DY)

DF 9.5: Vortrag

Montag, 11. März 2013, 16:15–16:30, H34

Liquid to glass transition in a Wigner glass — •Fabian Westermeier, Michael Sprung, and Gerhard Grübel — HASYLAB, Deutsches Elektronen-Synchrotron, 22607 Hamburg, Germany

One of the interesting problems of disordered systems is the nature of the liquid to glass transition. While the glass transition in molecular glass formers can be typically achieved by cooling down the system, in colloidal systems the glassy state is experimentally accessible by changing the strength of the direct particle interactions.

Colloidal systems can be distinguished by their type of interaction. While so called hard sphere systems interact via a repulsive, short range interaction potential, electrostatically stabilized systems are interacting via a long-range, screened Coulomb potential which depends inter alia on the charge of the particles and the concentration of additional ions in the solvent screening the direct particle interactions. As it is thus possible to tune the direct particle interaction strength of these systems, the glass transition can already occur at much lower volume fractions when compared to the hard sphere case.

We have used X-ray scattering techniques to investigate the glass transition of a charge stabilized system at a constant volume fraction, varying only the strength of the direct particle interactions. While the average structure of the colloidal suspensions shows only minor changes, the dynamics of the system vary strongly as a function of the direct particle interaction strength.