Direct observation of hydrodynamic rotation-translation coupling between two colloidal spheres.
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.
Martin
S
S
Universität Konstanz, Fachbereich Physik, 78457 Konstanz, Germany.
Reichert
M
M
Stark
H
H
Gisler
T
T
D001718:Birefringence; D003102:Colloids / Q000737:chemistry*; D008853:Microscopy / Q000379:methods; D008962:Models, Theoretical; D009068:Movement; D052898:Optical Tweezers; D012399:Rotation
D003102:Colloids