Dresden 2014 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 4: Crystallization, Nucleation and Self Assembly I

CPP 4.1: Vortrag

Montag, 31. März 2014, 09:30–09:45, ZEU 114

Self-assembly of quasicrystals in colloid-polymer mixtures — •Erdal C. Oğuz, Matthias Sandbrink, and Michael Schmiedeberg — Heinrich-Heine-Universität Düsseldorf

By combining lattice sum calculations and Monte Carlo computer simulations, we investigate the stability of quasicrystals in colloid-polymer mixtures. In our model, the colloidal interactions are dictated by a repulsive Yukawa potential, whereas the presence of polymers yield an attractive depletion force between them. Hence, we obtain an isotropic pair interaction potential with multiple length scales that we use to support the two incommensurate length scales of the desired quasicrystalline structures. By minimizing the corresponding lattice sums, we determine the ground-state phase diagram (T=0) and we search for parameter sets where the system prefers quasicrystalline ordering rather than any other crystalline structure, i.e., we explain what polymer concentration, what depletion length, and what density are needed to grow quasicrystals with a given symmetry. For comparison and in order to extend the ground-state calculations to finite temperatures, we perform Monte Carlo computer simulations of our system. Therefore, our calculations and simulations explain how colloidal building blocks in experiments have to be designed in order to achieve the self-assembly of intrinsic colloidal quasicrystals.