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Updated: May 20, 2026

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
Nature of molecular rotation in supercooled glycerol under nanoconfinement
Andrey A Levchenko1, Pragati Jain, Olga Trofymluk
1Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California at Davis, Davis, California 95616, USA.
Abstract:
The dynamics of glass-forming liquids under nanoconfinement is key to understanding a variety of phenomena in nature and modern technology. We report a (13)C NMR spectroscopic study that directly demonstrates that alpha-relaxation in bulk glycerol involves an isotropic rotational jump of the constituent molecules. The activation energy of this motion is approximately 78 kJ mol(-1) in the bulk, which abruptly changes to a low value of approximately 27.5 kJ mol(-1), characteristic of beta-processes, upon confinement of glycerol into approximately 2 nm pores in mesoporous silica. This observation implies that the molecular dynamics associated with structural relaxation near glass transition are inherently different in supercooled glycerol in the bulk and under extreme nanoconfinement.
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