The scaling of the molecular dynamics of liquid crystals as revealed by broadband dielectric, specific heat, and neutron spectroscopy
- A combination of different complementary methods is employed to investigate scaling of the molecular dynamics of two different liquid crystals. Each method is sensitive to different kind of fluctuations and provides therefore a different window to look at the molecular dynamics. In detail, broadband dielectric spectroscopy is combined with specific heat spectroscopy and neutron scattering. As systems the nematic liquid crystal E7 and a discotic liquid crystalline pyrene are considered. First of all it was proven that both systems show all peculiarities which are characteristic for glassy dynamics and the glassy state. Especially for the nematic liquid crystal E7 it could be unambiguously shown by a combination of dielectric and specific heat spectroscopy that the tumbling mode is the underlying motional process responsible for glassy dynamics. Dielectric investigations on the discotic liquid crystalline pyrene reveal that at the phase transition from the plastic crystalline to theA combination of different complementary methods is employed to investigate scaling of the molecular dynamics of two different liquid crystals. Each method is sensitive to different kind of fluctuations and provides therefore a different window to look at the molecular dynamics. In detail, broadband dielectric spectroscopy is combined with specific heat spectroscopy and neutron scattering. As systems the nematic liquid crystal E7 and a discotic liquid crystalline pyrene are considered. First of all it was proven that both systems show all peculiarities which are characteristic for glassy dynamics and the glassy state. Especially for the nematic liquid crystal E7 it could be unambiguously shown by a combination of dielectric and specific heat spectroscopy that the tumbling mode is the underlying motional process responsible for glassy dynamics. Dielectric investigations on the discotic liquid crystalline pyrene reveal that at the phase transition from the plastic crystalline to the hexagonal columnar liquid crystalline phase the molecular dynamics changes from a more strong to fragile temperature dependence of the relaxation rates. Moreover a combination of results obtained by specific heat spectroscopy with structural methods allows an estimation of the length scale relevant for the glass transition.…
Autor*innen: | Andreas SchönhalsORCiD, B. Frick, R. Zorn |
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Persönliche Herausgeber*innen: | Friedrich Kremer, Alois Loidl |
Dokumenttyp: | Buchkapitel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | The scaling of relaxation processes, Advances in dielectrics |
Auflage: | 1. |
Jahr der Erstveröffentlichung: | 2018 |
Organisationseinheit der BAM: | 6 Materialchemie |
6 Materialchemie / 6.6 Physik und chemische Analytik der Polymere | |
Verlag: | Springer International publishing AG |
Verlagsort: | Cham, Switzerland |
Erste Seite: | 279 |
Letzte Seite: | 306 |
DDC-Klassifikation: | Naturwissenschaften und Mathematik / Chemie / Analytische Chemie |
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten | |
Freie Schlagwörter: | Broadband dielectric spectroscopy; Discotic liquid crystals; Rod-like liquid crystals; Specific heat spectroscopy |
Themenfelder/Aktivitätsfelder der BAM: | Chemie und Prozesstechnik |
Material | |
DOI: | 10.1007/978-3-319-72706-6_9 |
URL: | https://link.springer.com/content/pdf/10.1007%2F978-3-319-72706-6.pdf |
ISSN: | 2190-930X |
ISSN: | 2190-9318 |
ISBN: | 978-3-319-72705-9 |
ISBN: | 978-3-319-72706-6 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 01.08.2018 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 04.01.2019 |