Dynamics of concentrated dicolloid particles

Nonspherical colloidal particles exhibit a variety of equilibrium structures, including colloidal crystals. However, with increasing concentration, particle dynamics in these suspensions slow, and the creation of equilibrium close-packed structures may be ultimately inhibited by the presence of a glass transition. For dicolloid particles, dimer particles with asymmetric or symmetric lobes, suspension dynamics have been studied using Stokesian dynamics simulations [1] and mode-coupling theory [2], and the glass transitions have been determined using rheology [3]. In this study, the dynamics of polystyrene dicolloids in water are measured by diffusing wave spectroscopy (DWS) at particle concentrations between 1 and 60 volume percent. Relaxation times of the dicolloid particle suspensions are determined as a function of particle concentration and shape. Strong particle localization occurs at the highest concentrations. The localization lengths measured by DWS are compared to their mode coupling theory predictions.\\[4pt] [1] Kumar A, Higdon JJL\textit{. J. Fluid. Mech}. \textbf{2011}, \textit{675, 297-335.}\\[0pt] [2] Zhang R, Schweizer KS. \textit{J. Chem. Phys. }\textbf{\textit{2010}}\textit{, 133 104902.}\\[0pt] [3] Kramb R.C. et al., \textit{J. Phys.: Condens. Matter. }\textbf{\textit{2011, }}\textit{23, 035102}