Self-assembly and dynamic behavior of colloidal rods in the isotropic phase

In this study, we have investigated the dynamic behavior of colloidal rods within their isotropic phase, employing multispeckle ultrasmall-angle x-ray photon correlation spectroscopy (UA-XPCS) focusing on the understanding of the interplay between structure and dynamics at the nearest-neighbor length scale. While prior research has primarily focused on the structural aspects, our work addresses the lesser-explored realm of dynamic behavior. Through ultrasmall-angle x-ray scattering and UA-XPCS, we have measured the key parameters, such as the effective structure factor ( S eff ( q ) ) and the effective diffusion coefficient ( D eff ( q ) ) . A significant finding is the scaling relationship between D eff ( q ) and 1 / S eff ( q ) , implying a connection between particle diffusion and structural arrangement. Additionally, the estimated scaling parameter (effective amplitude function, A eff ( q ) ), which can be directly related to the effective hydrodynamic function ( H eff ( q ) ) shows a similar dependence on wave vector ( q ) as S eff ( q ) . Furthermore, our study precisely determines the volume fraction at which the arrest transition occurs. These findings shed light on the influence of structures on the intricate dynamics of anisotropic colloidal systems.