Details
| Original language | English |
|---|---|
| Pages (from-to) | 115-123 |
| Number of pages | 9 |
| Journal | Materials Research Society Symposium - Proceedings |
| Volume | 543 |
| Publication status | Published - 1999 |
| Externally published | Yes |
| Event | 1998 MRS Fall Meeting - The Symposium 'Advanced Catalytic Materials-1998' - Boston, MA, USA Duration: 30 Nov 1998 → 3 Dec 1998 |
Abstract
Broadband dielectric spectroscopy (10-2Hz - 109Hz) is employed to study the molecular dynamics of low-molecular-weight glassforming liquids being confined to nanopores. For the H-bond forming liquid propylene glycol being confined to (uncoated and silanized) nanopores (pore size: 2.5 nm, 5.0 nm and 7.5 nm) a molecular dynamics is observed which is comparable to that of the bulk liquid. Due to surface effects in uncoated nanopores the relaxation time distribution is broadened on the long term side and the mean relaxation rate is decreased by about half a decade. This effect can be counterbalanced by lubricating the inner surfaces of the pores resulting in a relaxation rate which is slightly faster compared to the bulk liquid. For the H-bonded liquid ethylene glycol (EG) embedded in zeolites of different pore size and topology one observes a sharp transition from a single-molecule dynamics to that of a liquid depending on the coordination number of the confined molecules. While EG in silicalite (showing a single molecule relaxation) has four neighboring molecules, EG in zeolite beta or AlPO4-5 has a coordination number of five and behaves like a bulk liquid.
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
- Engineering(all)
- Mechanics of Materials
- Engineering(all)
- Mechanical Engineering
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In: Materials Research Society Symposium - Proceedings, Vol. 543, 1999, p. 115-123.
Research output: Contribution to journal › Conference article › Research › peer review
}
TY - JOUR
T1 - Glass transition in sub-nanometer confinement
AU - Huwe, A.
AU - Kremer, F.
AU - Arndt, M.
AU - Behrens, Peter
AU - Schwieger, W.
AU - Ihlein, G.
PY - 1999
Y1 - 1999
N2 - Broadband dielectric spectroscopy (10-2Hz - 109Hz) is employed to study the molecular dynamics of low-molecular-weight glassforming liquids being confined to nanopores. For the H-bond forming liquid propylene glycol being confined to (uncoated and silanized) nanopores (pore size: 2.5 nm, 5.0 nm and 7.5 nm) a molecular dynamics is observed which is comparable to that of the bulk liquid. Due to surface effects in uncoated nanopores the relaxation time distribution is broadened on the long term side and the mean relaxation rate is decreased by about half a decade. This effect can be counterbalanced by lubricating the inner surfaces of the pores resulting in a relaxation rate which is slightly faster compared to the bulk liquid. For the H-bonded liquid ethylene glycol (EG) embedded in zeolites of different pore size and topology one observes a sharp transition from a single-molecule dynamics to that of a liquid depending on the coordination number of the confined molecules. While EG in silicalite (showing a single molecule relaxation) has four neighboring molecules, EG in zeolite beta or AlPO4-5 has a coordination number of five and behaves like a bulk liquid.
AB - Broadband dielectric spectroscopy (10-2Hz - 109Hz) is employed to study the molecular dynamics of low-molecular-weight glassforming liquids being confined to nanopores. For the H-bond forming liquid propylene glycol being confined to (uncoated and silanized) nanopores (pore size: 2.5 nm, 5.0 nm and 7.5 nm) a molecular dynamics is observed which is comparable to that of the bulk liquid. Due to surface effects in uncoated nanopores the relaxation time distribution is broadened on the long term side and the mean relaxation rate is decreased by about half a decade. This effect can be counterbalanced by lubricating the inner surfaces of the pores resulting in a relaxation rate which is slightly faster compared to the bulk liquid. For the H-bonded liquid ethylene glycol (EG) embedded in zeolites of different pore size and topology one observes a sharp transition from a single-molecule dynamics to that of a liquid depending on the coordination number of the confined molecules. While EG in silicalite (showing a single molecule relaxation) has four neighboring molecules, EG in zeolite beta or AlPO4-5 has a coordination number of five and behaves like a bulk liquid.
UR - http://www.scopus.com/inward/record.url?scp=0032592591&partnerID=8YFLogxK
M3 - Conference article
AN - SCOPUS:0032592591
VL - 543
SP - 115
EP - 123
JO - Materials Research Society Symposium - Proceedings
JF - Materials Research Society Symposium - Proceedings
SN - 0272-9172
T2 - 1998 MRS Fall Meeting - The Symposium 'Advanced Catalytic Materials-1998'
Y2 - 30 November 1998 through 3 December 1998
ER -