Dresden 2014 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 54: Poster Session 3
CPP 54.39: Poster
Thursday, April 3, 2014, 15:00–19:00, P2
Molecular Dynamics of a Discotic Liquid Crystals studied by Inelastic Neutron Scattering — •Christina Krause1, Reiner Zorn2, Bernhard Frick3, and Andreas Schönhals1 — 1BAM Federal Institute for Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin — 2Forschungszentrum Jülich, Jülich Centre for Neutron Science (JCNS), D-52425 Jülich — 3Institut Max von Laue -Paul Langevin (ILL), B.P. 156, F-38042 Grenoble Cedex 9
Discotic liquid crystals (DLC) consist of a flat and rigid aromatic core and attached flexible aliphatic chains. DLCs are self-assembled materials. The disc-shaped molecules organize into columns that further assemble into two-dimensional arrays with a hexagonal mesophase. The alkyl chains fill the intercolumnar space giving rise to a nanophase separated state. Dielectric relaxation spectroscopy, quasielastic and inelastic neutron scattering are employed to investigate the molecular dynamics of a homologous series of discotic liquid crystal based on the triphenylene core (Hexakis [nalkyloxy] triphenylene, HATn; n=5, 6, 10, 12) with varying length of the side chain in the bulk state. All materials under study show a boson peak (BP). Therefore, the influence of the length of the alkyl chains on its position and shape is investigated. With increasing lengths n of the side chains the BP shifts to lower frequencies and gains in intensity. This can be discussed employing a self-organized confinement model, where the confinement is generated by the highly ordered columns to the intercolumnar space, where with increasing n the confinement is weakened.