Real-space imaging of translational and rotational dynamics of hard spheres from the fluid to the crystal
Stefan Schuetter, Jörg Roller, Andrea Kick, Janne-Mieke Meijer and Andreas Zumbusch; Soft Matter, 2017,13, 8240-8249 DOI: 10.1039/C7SM01400G
Abstract: Using real-space imaging of single particles, we investigate the interplay between translational and rotational motion of tracer particles in suspensions of colloidal particles over a wide range of volume fractions from dilute fluid to densely packed crystal. To this end, we introduce a new type of spherical colloidal tracer particles containing two differently labelled fluorescent cores. The tracer particles can be combined with host particles enclosing a single fluorescent core and chemical and physical properties identical to the tracers. This leads to a system of spherical colloidal particles, in which spatio-temporal trajectories of rotation and translation of individual particles can be recorded simultaneously with full 360° resolution of rotational dynamics. Our analysis shows that translation and rotation of colloidal particles are uncorrelated and decoupled for all volume fractions irrespective of the phase of the particle system.