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Layering of bidisperse charged nanoparticles in sedimentation
Xufeng Xu1, P M Biesheuvel, Helmut Cölfen
1Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, 5612 AE Eindhoven, The Netherlands. x.xu3@tue.nl.
Abstract:
Bidisperse mixtures of charged nanoparticles form separate layers upon centrifugation as a result of minimization of the system's free energy in sedimentation-diffusion equilibrium. Different factors were investigated experimentally for their effects on the layering, and are supported by theoretical calculations of the full sedimentation profiles. Surprisingly, lighter/smaller nanoparticles can even sink below heavier/larger ones when the particle surface charge is carefully tuned. This study provides deeper insights into the control of layering in polydisperse particle mixtures during sedimentation.
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