Long-time translational self-diffusion in isotropic and nematic dispersions of colloidal rods

M. P. B. van Bruggen; H. N. W. Lekkerkerker; G. Maret; J. K. G. Dhont

doi:10.1103/PhysRevE.58.7668

Long-time translational self-diffusion in isotropic and nematic dispersions of colloidal rods

M. P. B. van Bruggen, H. N. W. Lekkerkerker, G. Maret, and J. K. G. Dhont

Phys. Rev. E 58, 7668 – Published 1 December 1998

Abstract

Long-time self-diffusion in dispersions of rigid colloidal rods with an aspect ratio of 19 is studied with fluorescence recovery after photobleaching (FRAP) in isotropic and nematic phases. The long-time self-diffusion coefficient $D_{s}^{L}$ is found to decrease linearly with concentration up to $(L / D) φ = 0.12$ (with L the length and D the diameter of the rods, and φ the volume fraction). In the isotropic phase in coexistence with the nematic phase, $D_{s}^{L}$ remains virtually constant at about 1% of its value at infinite dilution. In the nematic phase long-time self-diffusion is found to be ten times slower than in the coexisting isotropic phase. In addition, by modifying the FRAP geometry we were able to distinguish between sidewise and lengthwise diffusion in aligned nematic phases.

Received 27 April 1998

DOI:https://doi.org/10.1103/PhysRevE.58.7668

Authors & Affiliations

M. P. B. van Bruggen¹, H. N. W. Lekkerkerker¹, G. Maret², and J. K. G. Dhont^1,*

¹Van ‘t Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
²Universität Konstanz, Fakultät für Physik, P.O. Box 5560, D-78434 Konstanz, Germany

^*Author to whom correspondence should be addressed.

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Vol. 58, Iss. 6 — December 1998

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