Dresden 2017 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 25: Posters - Soft Particles, Microswimmers, Microfluidics

DY 25.17: Poster

Tuesday, March 21, 2017, 18:15–21:00, P3

Thermoelectric Charging of a Hot Spot in Electrolyte Solution — •Martin Fränzl and Frank Cichos — Molecular Nanophotonics, Institute for Experimental Physics I, Universität Leipzig, Germany

We discuss the thermoelectric charging of a hot spot in an electrolyte solution. The underlying thermal forces depend on the temperature gradient through different mechanisms. In the last decades thermophoresis of colloids is mainly discussed in terms of thermoosmotic pressure. However, in the recent years it has become clear that, for charged systems in an electrolyte solution the thermoelectric or Seebeck effect provides a non-local driving force that presents remarkable effects. At a non-uniform temperature, positive and negative ions have the tendency to migrate in opposite directions, thus giving rise to a thermoelectric field E=S∇ T that is proportional to the temperature gradient. This field drives charged particles to the hot or to the cold, depending on the sign Seebeck coefficient S and so on electrolyte. The present work investigates the thermoelectric properties by locally heating a gold film with a focused laser beam within a colloidal suspension and investigates the resulting colloidal transport.