Anisotropic Dynamics of Binary Particles in Confined Geometries. Issue 6 (21st February 2020) - Liu, Kun
Abstract: The diffusion dynamics of colloidal particles in a good solvent confined between two parallel quartz walls have been studied within the framework of dynamical density functional theory. The highly ordered density layers induced by interfacial effects give rise to the oscillating dynamics, resulting in position‐dependent structural relaxations and diffusivities. Further investigation reveals that particle size, particle‐wall interaction, and slitpore width play different roles in affecting the oscillating behaviors along different directions. As a result, the theory yields the local mean square displacements in perpendicular and parallel directions, which agree remarkably well with prior experimental measurements. The results indicate that the mean square displacements can be quantitatively predicted based on the knowledge of inhomogeneous thermodynamics and dynamics. The local and averaged free energy evolution of the binary particles has been described and presented to understand their dynamic mechanism in confined geometry. Abstract : We apply DDFT to study the position‐dependent dynamics for understanding the diffusion mechanism of particles in confined geometries and for clarifying the confinement effect on the diffusion obstruction. The theoretical approach is constructed upon a thermodynamic route that correlates the single‐particle dynamics to the excess free energy functional. By integrating the Smoluchowski equation and the local density fluctuation, the static structure and transport properties are derived out simultaneously to display a thermodynamic‐driven diffusion evolution.