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Elastic properties of 2D colloidal crystals from video microscopy

K. Zahn·A. Wille·G. Maret·S. Sengupta·P. Nielaba
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Abstract

Elastic constants of two-dimensional (2D) colloidal crystals are determined by measuring strain fluctuations induced by Brownian motion of particles. Paramagnetic colloids confined to an air-water interface of a pending drop are crystallized under the action of a magnetic field, which is applied perpendicular to the 2D layer. Using video-microscopy and digital image-processing we measure fluctuations of the microscopic strain obtained from random displacements of the colloidal particles from their mean (reference) positions. From these we calculate system-size dependent elastic constants, which are extrapolated using finite-size scaling to obtain their values in the thermodynamic limit. The data are found to agree rather well with zero-temperature calculations.

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K. Zahn, A. Wille, G. Maret, S. Sengupta, P. Nielaba. 2002-10-05. Elastic properties of 2D colloidal crystals from video microscopy. https://doi.org/10.1103/physrevlett.90.155506

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