Berlin 2015 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Colloids and Complex Liquids II (joint session CPP, BP, DY)
CPP 8.10: Vortrag
Montag, 16. März 2015, 17:30–17:45, C 130
Supramolecular structure of pure and mixed monohydroxy alcohols — •Thomas Büning1, Christian Sternemann1, Sebastian Peter Bierwirth1, Catalin Gainaru1, Jennifer Bolle1, Michael Paulus1, Christoph J. Sahle2, Roland Böhmer1, and Metin Tolan1 — 1Fakultät Physik / DELTA, Technische Universität Dortmund, D-44221 Dortmund, Germany — 2European Synchrotron Radiation Facility (ESRF), F-38000 Grenoble, France
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) are often studied as model systems for hydrogen-bonded fluids in general [1]. MAs are supposed to form supramolecular structures such as chains and rings via hydrogen bonding in the liquid phase. Based on their small dielectric absorption, ringlike arrangements were suggested for neat MAs with a sterically hindered polar hydroxyl group [1], e.g., for 4-methyl-3-heptanol and 2-hexyl-1-decanol. Mixtures of these MAs show a significantly enhanced dielectric absorption which hints at a change of supramolecular topology [2]. We present combined X-ray diffraction and X-ray Raman measurements of MA mixtures. Here, the first X-ray diffraction peak and the shape of the oxygen K-edge, respectively, are sensitive to the local arrangement of MAs. The results are interpreted with respect to a transformation from ringlike to chainlike structures upon mixing. [1] R. Böhmer et al. Phys. Reports 545 125-195 (2014) and references therein; [2] S. P. Bierwirth, et al. Phys. Rev. E 90, 052807 (2014).