# Regensburg 2019 – wissenschaftliches Programm

## Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

# CPP: Fachverband Chemische Physik und Polymerphysik

## CPP 25: Poster Session II

### CPP 25.1: Poster

### Dienstag, 2. April 2019, 14:00–16:00, Poster B1

**Thermodiffusion of Binary Halobenzene-n-Alkane Mixtures** — •Bastian Pur, Florian Schock, and Werner Köhler — Universität Bayreuth, 95440 Bayreuth, Germany

The Soret effect (thermophoresis) describes a diffusion flux that is driven by a temperature gradient in a multicomponent mixture. For dilute solutions of polymers with large Kuhn segments there is a remarkable universality for the thermophoretic velocity: it depends only on the viscosity η of the solvent. The thermal diffusion coefficient *D*_{T}, also known as the thermophoretic mobility, multiplied by the solvent viscosity leads to a constant value (η *D*_{T} ≈ const.). This universality is asymptotically also found for binary mixtures of methylnaphtalene and toluene in n-alkanes.
To pursue these observations we have conducted measurements with halobenzene-n-alkane mixtures. The measured mixtures correspond to the series of halobenzenes fluoro-, chloro- and bromobenze mixed with n-alkanes nC_{i} (i=6,7,8,10,12,14 and 16).
By means of a holographic grating technique we have obtained the Fickian diffusion coefficient *D*, the Soret coefficient *S*_{T} and the thermal diffusion coefficient *D*_{T}.
These results will be compared to the universal asymptotic limit of η *D*_{T} reported for polymer solutions.