SKM 2023 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Poster Session II

CPP 35.10: Poster

Mittwoch, 29. März 2023, 11:00–13:00, P1

Temperature dependent measurments of the diffusion- and Soret-coefficient in a binary polystyrene/toluene mixture — •Jannik Kantelhardt and Werner Köhler — Physikalisches Institut Universität Bayreuth, Germany

In this work we investigate the dependence of the diffusion- and Soret-coefficient in respect to different ambient temperatures with a temperature range from 10^∘C to 50^∘C in steps of 5^∘C. The here investigated system, a solution of polystyrene (PS) in toluene with a weight fraction of c_PS=1%, has in a similar concentration also been used in the binary companion cell of the DCMIX4 microgravity campaign on ternary mixtures. Furthermore, binary and ternary polystyrene solutions are candidates for the forthcoming GIANT FLUCTATIONS project of ESA for the investigation of non-equilibrium fluctuations under microgravity conditions.

The measuements were performed with a Thermal-Diffusion-Forced-Rayleigh-Scattering (TDFRS) setup. Through a writing beam a holographic grating is created inside the mixture where a small amount of an inert dye is added. The grating heats the sample periodically which leads to temperature gradients. Through the Soret-effect concentration gradients appear and both lead to changes in the refractive index. The signal is measured with a readout beam under Bragg diffraction.