• Categoría: Artículo
  • Título: Simultaneous characterization of rotational and translational diffusion of optically anisotropic particles by optical microscopy
  • Autor (es): Fabio Giavazzi, Catalina Haro-Pérez and Roberto Cerbino
  • Revista: J. Phys.: Condens. Matter
  • Volumen: 28
  • Páginas: 195201
  • Formato: Enlace
  • Subido por: Catalina Ester

Simultaneous characterization of rotational and translational diffusion of optically anisotropic particles by optical microscopy

Fabio Giavazzi, Catalina Haro-Pérez and Roberto Cerbino

We probe the roto-translational Brownian motion of optically anisotropic particles suspended
in water with a simple and straightforward optical microscopy experiment that does not
require positional or rotational particle tracking. We acquire a movie of the suspension
placed between two polarizing elements and we extract the translational diffusion coefficient
DT and the rotational diffusion coefficient DR from the analysis of the temporal correlation
properties of the spatial Fourier modes of the intensity fluctuations in the movie. Our method
is successfully tested with a dilute suspension of birefringent spherical colloidal particles
obtained by polymerizing an emulsion of droplets of liquid crystal in a nematic phase, whose
roto-translational dynamics is found to be well described by theory. The simplicity of our
approach makes our method a viable alternative to particle tracking and depolarized dynamic
light scattering.