SKM 2021 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 6: Poster Session II

CPP 6.4: Poster

Tuesday, September 28, 2021, 17:30–19:30, P

Mesoscale computer simulations of diffusion and sedimentation of colloidal suspensions — •Yashraj Wani¹, Penelope Grace Kovakas², Arash Nikoubashman¹, and Michael Howard² — ¹Institute of Physics, Johannes Gutenberg University Mainz, Staudingerweg 7, 55128 Mainz, Germany — ²Department of Chemical Engineering, Auburn University, Auburn, AL 36849, USA

The diffusive motion in colloidal suspensions is a central process in soft matter, and it also plays an essential role for a wide range of applications. Through simulations, we investigated the self- and collective diffusion in suspensions of spherical colloids at various solute concentrations. To this end, we tested several methods with and without hydrodynamic interactions (HI). We found reasonable agreement for the long-time self-diffusion coefficients between all methods, which is in agreement with previous theoretical considerations. There were, however, fundamental differences in the collective diffusivity (quantified via the sedimentation coefficients) between the various methods: When HI were neglected, the collective diffusivity was identical to the short-time self-diffusion, whereas in the simulations with HI, the sedimentation coefficients decreased with increasing solute concentration. Finally, we applied our methodology to study the equilibrium dynamics of cubic colloids.