Regular Article - Soft Matter
Probing roto-translational diffusion of small anisotropic colloidal particles with a bright-field microscope
Dipartimento di Biotecnologie Mediche e Medicina Traslazionale, Università degli Studi di Milano, via F.lli Cervi 93, 20090, Segrate, Italy
2 Division of Physical Chemistry Department of Chemistry, Lund University, Lund, Sweden
3 Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090, Vienna, Austria
Accepted: 29 March 2021
Published online: 26 April 2021
Soft and biological materials are often composed of elementary constituents exhibiting an incessant roto-translational motion at the microscopic scale. Tracking this motion with a bright-field microscope becomes increasingly challenging when the particle size becomes smaller than the microscope resolution, a case which is frequently encountered. Here we demonstrate squared-gradient differential dynamic microscopy (SG-DDM) as a tool to successfully use bright-field microscopy to extract the roto-translational dynamics of small anisotropic colloidal particles, whose rotational motion cannot be tracked accurately in direct space. We provide analytical justification and experimental demonstration of the method by successful application to an aqueous suspension of peanut-shaped particles.
© The Author(s) 2021
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