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arXiv · 1101.1487

Colloids in Cholesterics: Size-Dependent Defects and Non-Stokesian Microrheology

J. S. Lintuvuori·K. Stratford·M. E. Cates·D. Marenduzzo
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Abstract

We simulate a colloidal particle (radius R) in a cholesteric liquid crystal (pitch p) with tangential order parameter alignment at the particle surface. The local defect structure evolves from a dipolar pair of surface defects (boojums) at small R/p to a pair of twisted disclination lines wrapping around the particle at larger values. On dragging the colloid with small velocity v through the medium along the cholesteric helix axis (an active microrheology measurement), we find a hydrodynamic drag force that scales linearly with v but superlinearly with R-in striking violation of Stokes' law, as generally used to interpret such measurements.

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J. S. Lintuvuori, K. Stratford, M. E. Cates, D. Marenduzzo. 2011-01-07. Colloids in Cholesterics: Size-Dependent Defects and Non-Stokesian Microrheology. https://doi.org/10.1103/physrevlett.105.178302

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