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

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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.

Original languageEnglish
Article number178302
Pages (from-to)-
Number of pages4
JournalPhysical Review Letters
Volume105
Issue number17
DOIs
Publication statusPublished - 22 Oct 2010

Keywords

  • NEMATIC LIQUID-CRYSTAL
  • PARTICLE
  • DRAG
  • EMULSIONS
  • SPHERE
  • SHEAR
  • FLOW

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