Molecular Order and Dynamics of Tris(2-ethylhexyl)phosphate Confined in Uni-Directional Nanopores
- University of Leipzig, Germany
- University of Leipzig
- ORNL
Infrared Transition Moment Orientational Analysis (IR-TMOA) and Broadband Dielectric Spectroscopy (BDS) are combined to study molecular order and dynamics of the glass-forming liquid Tris(2-ethylhexy)phosphate (TEHP) confined in uni-directional nanopores with diameters of 4, 8, and 10.4 nm. The former method enables one to determine the molecular order parameter of specific IR transition moments. It is observed that the central P=O moiety of TEHP has a weak orientational effect (molecular order parameter Sz = 0.1 0.04) due the nanoporous confinement, in contrast to the terminal C H groups. BDS traces the dynamic glass transition of the guest molecules in a broad spectral range and at widely varying temperature. An enhancement of the mobility takes place when approaching the glass transition temperature and becomes more pronounced with decreasing pore diameter. This is attributed to a slight reduction of the density of the confined liquid caused by the 2-dimensional geometrical constraint.
- Research Organization:
- Oak Ridge National Laboratory (ORNL)
- Sponsoring Organization:
- SC USDOE - Office of Science (SC)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1096358
- Journal Information:
- Zeitschrift fur Physikalische Chemie, Journal Name: Zeitschrift fur Physikalische Chemie Journal Issue: 7-8 Vol. 226; ISSN 0942-9352
- Country of Publication:
- United States
- Language:
- English
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