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Differential Dynamic Microscopy for Anisotropic Colloidal Dynamics: Langmuir

Research output: Contribution to journalArticle

Original languageUndefined/Unknown
Pages (from-to)4618-4624
Number of pages7
JournalLangmuir
Volume28
Issue number10
DOIs
StatePublished - 10 Feb 2012

Abstract

Differential dynamic microscopy (DDM) is a low-cost, high-throughput technique recently developed for characterizing the isotropic diffusion of spherical colloids using white-light optical microscopy.1 We develop the theory for applying DDM to probe the dynamics of anisotropic colloidal samples such as various ordered phases, or particles interacting with an external field. The q-dependent dynamics can be measured in any direction in the image plane. We demonstrate the method on a dilute aqueous dispersion of anisotropic magnetic particles (hematite) aligned in a magnetic field. The mea- sured diffusion coefficients parallel and perpendicular to the field direction are in good agreement with theoretical values. We show how these measurements allow us to extract the orientational order parameter S2 of the system.

ID: 1745282