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arXiv · 0912.0398

Complete description of re-entrant phase behaviour in a charge variable colloidal model system

Patrick Wette·Ina Klassen·Dirk Holland-Moritz·Dieter M. Herlach·Hans Joachim Schoepe·Nina Lorenz·Holger Reiber·Thomas Palberg·Stephan V. Roth
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Abstract

In titration experiments with NaOH we have determined the full phase diagram of charged colloidal spheres in dependence on the particle density n, the particle effective charge Zeff and the concentration of screening electrolyte c using microscopy, light and Ultra Small Angle X-Ray Scattering (USAXS). For sufficiently large n the system crystallizes upon increasing Zeff at constant c and melts upon increasing c at only slightly altered Zeff. In contrast to earlier work equilibrium phase boundaries are consistent with a universal melting line prediction from computer simulation, if the elasticity effective charge is used. This charge accounts for both counter-ion condensation and many body effects.

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Patrick Wette, Ina Klassen, Dirk Holland-Moritz, Dieter M. Herlach, Hans Joachim Schoepe, Nina Lorenz, Holger Reiber, Thomas Palberg, Stephan V. Roth. 2009-12-02. Complete description of re-entrant phase behaviour in a charge variable colloidal model system. https://doi.org/10.1063/1.3380823

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