Dielectric spectroscopy studies of conformational relaxation dynamics in molecular glass-forming liquids
We review experimental results obtained with broadband dielectric spectroscopy concerning the relaxation times and activation energies of intramolecular conformational relaxation processes in small-molecule glass-formers. Such processes are due to the interconversion between different conformers of...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2023 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:upcommons.upc.edu:2117/403413 |
| Acceso en línea: | https://hdl.handle.net/2117/403413 https://dx.doi.org/10.3390/ijms242417189 |
| Access Level: | acceso abierto |
| Palabra clave: | Broadband dielectric spectroscopy Molecular rotation Glass manufacture -- Chemistry Molecular conformers Secondary relaxations Activation barrier Characteristic relaxation time Internal rotation Ring buckling Ring inversion Rotational isomerism Rotació molecular Vidre -- Fabricació -- Química Àrees temàtiques de la UPC::Física::Física molecular |
| Sumario: | We review experimental results obtained with broadband dielectric spectroscopy concerning the relaxation times and activation energies of intramolecular conformational relaxation processes in small-molecule glass-formers. Such processes are due to the interconversion between different conformers of relatively flexible molecules, and generally involve conformational changes of flexible chain or ring moieties, or else the rigid rotation of planar groups, such as conjugated phenyl rings. Comparative analysis of molecules possessing the same (type of) functional group is carried out in order to test the possibility of assigning the dynamic conformational isomerism of given families of organic compounds to the motion of specific molecular subunits. These range from terminal halomethyl and acetyl/acetoxy groups to both rigid and flexible ring structures, such as the planar halobenzene cycles or the buckled saccharide and diazepine rings. A short section on polyesters provides a generalisation of these findings to synthetic macromolecules. |
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