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Polymorphism of the glass former ethanol confined in mesoporous silicon
Publikationstyp
Journal Article
Publikationsdatum
2010-05-12
Sprache
English
Enthalten in
Volume
90
Issue
7
Start Page
481
End Page
491
Citation
Philosophical Magazine Letters 90 (7): 481-491 (2010-05-12)
Publisher DOI
Scopus ID
ArXiv ID
Publisher
Taylor & Francis
X-ray diffraction patterns of ethanol confined in parallel-aligned channels of approx. 10 nm diameter and 50 micrometer length in mesoporous silicon have been recorded as a function of filling fraction, temperature and for varying cooling and heating rates. A sorption isotherm, recorded in the liquid state, indicates a three monolayer thick, strongly adsorbed wall layer and a capillary condensed fraction of molecules in the pore center. Though the strongly adsorbed film remains in an amorphous state for the entire temperature range investigated, the capillary condensed molecules reproduce the polymorphism of bulk solid ethanol, that is the formation of either crystalline or glass-like states as a function of cooling rate. The critical rate necessary to achieve a vitrification in the mesopores is, however, at least two orders of magnitude smaller than in the bulk state. This finding can be traced both to pure geometrical constraints and quenched disorder effects, characteristic of confinement in mesoporous silicon.
Schlagworte
Glass transition
Nanoscale
X-ray diffraction
Physics - Soft Condensed Matter
Physics - Soft Condensed Matter
Physics - Disordered Systems and Neural Networks
Physics - Mesoscopic Systems and Quantum Hall Effect
Physics - Materials Science
Physics - Chemical Physics
DDC Class
530: Physik
More Funding Information
This work has been supported by the Deutsche Forschungsgemeinschaft via the Sonderforschungsbereich 277, Saarbrücken.