Dresden 2017 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 55: Posters - Soft Matter, Glasses

DY 55.3: Poster

Donnerstag, 23. März 2017, 17:00–19:30, P1A

Supramolecular structure of monohydroxy alcohols at high pressure — Thomas Büning, •Christian Sternemann, Catalin Gainaru, Michael Paulus, Holger Göhring, Susanne Dogan, Julian Schulze, Jennifer Bolle, Roland Böhmer, and Metin Tolan — Fakultät Physik / DELTA, Technische Universität Dortmund, D-44221 Dortmund, Germany

Hydrogen bonds are essential for the structure and dynamics of alcohols, aqueous solutions, and water. Due to their low tendency of crystallization and large variability in molecular configuration, monohydroxy alcohols (MAs) have often been studied as model systems for hydrogen-bonded fluids in general [1]. MAs are supposed to form supramolecular structures via hydrogen bonding in the liquid phase. Tracking the Debye process, dielectric absorption studies suggest ringlike arrangements for 4-methyl-3-heptanol (4M3H) with a sterically hindered hydroxyl group and chainlike structures in 2-ethyl-1-hexanol (2E1H) with the hydroxyl group in a terminal position. Surprisingly, an oppositional behavior of the strength of the Debye process has been observed at increasing pressure for the MAs ponting towards a structural reorganization on the molecular level [2]. We present x-ray diffraction measurements of 2E1H and 4M3H at pressures up to 4500 bar over a temperature range from 273 K to 343 K. The results indicate a breaking of supramolecular structures in both MAs that manifest in significant changes in the first diffraction peak.

[1] R. Böhmer et al., Phys. Reports 545, 125 (2014) and references therein; [2] S. Pawlus et al., J. Chem. Phys. 139, 064501 (2013).