Diamagnetic orientation of a fluid of hard thin disks and anisotropy of the water diffusivity in the nematic phase of a suspension of clay platelets.
Monte Carlo simulations of the diamagnetic orientation of a fluid of hard thin disks in a magnetic field are presented. The particle density and magnetic field dependences of the eigenvalues of the order parameter tensor are calculated in the presence of a wall which promotes nematic order in a definite direction. The existence of a paranematic region is confirmed, and the approach to the Langevin regime at low densities in the paranematic regime is examined. A relationship between the eigenvalues of the tensor and the anisotropy of water diffusivity in the nematic phase of a colloidal suspension is proposed. This permits a comparison between the Monte Carlo simulations and diffusion-weighted magnetic resonance imaging, which shows consistency with the experimental data.
Engelsberg
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Departamento de Física, Universidade Federal de Pernambuco, and Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, Recife, Pernambuco, Brazil.
de Azevedo
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EN