Probing roto-translational diffusion of small anisotropic colloidal particles with a bright-field microscope

Abstract

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. Graphic abstract

Fluorescence Recovery after Photobleaching in Colloidal Science: Introduction and Application

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Diffusion and convection in nature

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Dynamics of prolate spheroids in the vicinity of an air–water interface

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