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Published on: May 29, 2018
Origin of the complex molecular dynamics in functionalized discotic liquid crystals
M M Elmahdy1, G Floudas, M Mondeshki
1Department of Physics, University of Ioannina, 451 10 Ioannina, Greece and Foundation for Research and Technology-Hellas, Biomedical Research Institute, Ioannina, Greece.
Physical Review Letters
|March 21, 2008
Summary
Molecular dynamics of functionalized hexa-peri-hexabenzocoronenes reveal thermodynamic control over their response. This study clarifies dynamic processes and presents the first phase diagram for these materials.
Area of Science:
- Materials Science
- Physical Chemistry
- Organic Electronics
Background:
- Hexa-peri-hexabenzocoronenes (HHCs) are discotic liquid crystals with potential applications in organic electronics.
- Understanding their molecular dynamics is crucial for optimizing material properties.
- Dipole functionalization can significantly alter the self-assembly and dynamic behavior of HHCs.
Purpose of the Study:
- To investigate the molecular dynamics of three dipole-functionalized HHCs.
- To elucidate the relationship between thermodynamic state and dynamic response.
- To identify the origins of multiple dynamic processes and establish a phase diagram.
Main Methods:
- Site-specific Nuclear Magnetic Resonance (NMR) techniques.
- Dielectric spectroscopy.
- Variable temperature and pressure measurements.
Main Results:
- The thermodynamic state was found to completely govern the molecular dynamic response.
- Two distinct dynamic processes were identified, linked to two observed glass transition temperatures.
- The first comprehensive phase diagram for this class of functionalized HHCs was constructed.
Conclusions:
- Molecular dynamics in these functionalized HHCs are dictated by their thermodynamic conditions.
- The presence of two glass transitions arises from distinct molecular motions.
- This work provides fundamental insights into the phase behavior of HHC derivatives.
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