This title appears in the Scientific Report :
2005
Please use the identifier:
http://dx.doi.org/10.1016/j.jnoncrysol.2005.03.061 in citations.
Inelastic neutron scattering for investigating the dynamics of confined glass forming liquids
Inelastic neutron scattering for investigating the dynamics of confined glass forming liquids
Inelastic neutron scattering was employed over recent years to investigate the influence of spatial confinement on the dynamics of glass-forming systems. We review the common phenomena observed by neutron scattering in such different confining hosts like porous glasses, molecular sieves, clays or fr...
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Personal Name(s): | Frick, K. H. |
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Alba-Simionesco, C. / Dosseh, G. / Le Quellec, C. / Moreno, A. / Colmenero, J. / Schönhals, A. / Zorn, R. / Chrissopoulou, K. / Anastasiadis, S. / Dalnoki-Verres, K. / Higgins, A. | |
Contributing Institute: |
Neutronenstreuung; IFF-INS |
Published in: | Journal of non-crystalline solids, 351 (2005) S. 2657 - 2667 |
Imprint: |
Amsterdam [u.a.]
Elsevier Science
2005
|
Physical Description: |
2657 - 2667 |
DOI: |
10.1016/j.jnoncrysol.2005.03.061 |
Document Type: |
Journal Article |
Research Program: |
Kondensierte Materie |
Series Title: |
Journal of Non-Crystalline Solids
351 |
Subject (ZB): | |
Publikationsportal JuSER |
Inelastic neutron scattering was employed over recent years to investigate the influence of spatial confinement on the dynamics of glass-forming systems. We review the common phenomena observed by neutron scattering in such different confining hosts like porous glasses, molecular sieves, clays or free standing polymer films, which impose a spatial limitation to the motion of small organic molecules, oligomers or polymers. Near the glass transition temperature the mean squared displacements of the confined molecules show clear deviations from the bulk behavior. The observed increase or decrease of the mean squared displacements confirms the high relevance of the interface interaction near walls of confining media without excluding additional real confinement effects. We show a new comparison of the mean squared displacement for PDMS and PMPS in bulk and in different type of restricting geometries, which evidence a weak influence of the restricting geometry on the local methyl group motion, but a strong influence on the glass transition dynamics, if wall interactions are taken into account. Strong wall interaction is also supported by the intermediate scattering function, measured either by combining neutron backscattering and time-of-flight experiments to cover 3 decades in time from ns to ps or by neutron spin echo, which reveal above T-g an increasing elastic fraction with decreasing pore size and a slowing down of the dynamics. Furthermore we show that a reduction of modes below the Boson peak frequency is a more general feature of confined glass-forming systems. (c) 2005 Elsevier B.V. All rights reserved. |