SKM 2023 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Modeling and Simulation of Soft Matter II
CPP 12.8: Talk
Monday, March 27, 2023, 17:15–17:30, MER 02
Dynamic susceptibility of magnetic nanoplatelet suspensions — •Margaret Rosenberg1, Sofia S. Kantorovich1, and Philip J. Camp2 — 1Department of Physics, University of Vienna, Vienna, 1090, Austria — 2School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, UK
Particle anisometry and anisotropy provide valuable control parameters to alter the self-assembly, and thermodynamic, rheological, and phase behaviour, of colloidal suspensions. This work is concerned with the dynamic magnetic susceptibility (DMS) of a ferrofluid with platelet-shaped anisotropic particles, which have a fixed out-of-plane dipole moment providing additional, magnetic anisometry. Such a colloidal suspensions is of particular interest as, above a threshold concentration, it exhibits a ferromagnetic nematic phase. Recent experimental work [1] has shown that the DMS spectrum exhibits multiple dynamical modes, suggesting that there might be clusters of particles with distinct rotational timescales. Using Brownian dynamics simulations, we explore the effects of varying nanoparticle concentration - and therefore microstructure - on the DMS, and explain the gap in relaxation times, and changes in the spectrum, that are observed experimentally.
[1] M. Küster et al., "Magnetic dynamics in suspensions of ferrimagnetic platelets", Journal of Molecular Liquids, Vol. 360, (2022), 119484