Direct observation of hydrodynamic rotation-translation coupling between two colloidal spheres

Phys Rev Lett. 2006 Dec 15;97(24):248301. doi: 10.1103/PhysRevLett.97.248301. Epub 2006 Dec 15.

Abstract

By combining optical tweezers with polarization microscopy, the hydrodynamic coupling between position and orientation fluctuations in a pair of colloidal spheres has been measured. Imaging of birefringent particles under crossed polarizers allows for the simultaneous determination of the positions and orientations of both particles. The temporal cross-correlation function between random displacements of one particle and orientation fluctuations of its neighbor allows for the quantification of the hydrodynamic rotation-translation coupling between the spheres. Our results are in good agreement with predictions for the hydrodynamic mobility tensors calculated in the creeping-flow limit of the Navier-Stokes equation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Birefringence
  • Colloids / chemistry*
  • Microscopy / methods
  • Models, Theoretical
  • Movement
  • Optical Tweezers*
  • Rotation

Substances

  • Colloids