Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 50: Poster Session III

CPP 50.10: Poster

Tuesday, March 17, 2020, 14:00–16:00, P1C

Thermal diffusion of a single colloidal particle — •Daniel Benjamin Mayer and Thomas Franosch — Institut für Theoretische Physik, Universität Innsbruck, Technikerstraße 21A, A-6020 Innsbruck, Austria

We tackle the problem of a single charged colloid immersed in an electrolyte solution in the presence of an external applied small temperature gradient. Consequently electrical body forces are no longer counter balanced by pressure gradients, thereby inducing solvent flow and a directed motion of the colloidal particle.

The associated linearized electro-kinetic equations are solved numerically by adapting an adjusted solution scheme, originally invented by O’Brien and White [1] for the electrophoresis problem. Thus the thermal diffusivity is determined from the velocity field of a force-free Stokes flow. In addition a decomposition of the thermophoresis problem in two auxilary ones simplifies the aim of calculating the thermal mobility considerably as it does not appear explicitly as a boundary condition. In the end we examine its dependence on the surface potential and the Soret coefficients of the different ions in the electrolyte for arbitrary Debye-layer thickness.

[1] R. W. O’Brien and L. R. White, J. Chem. Soc.,Faraday Trans. 2, 1978, 74, 1607.