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Poly(methyl phenyl siloxane) in Random Nanoporous Glasses: Molecular Dynamics and Structure

Published online by Cambridge University Press:  01 February 2011

Andreas. Schönhals ,
Harald. Goering ,
Christoph Schick ,
Bernhard. Frick  and
Reiner Zorn
Andreas. Schönhals
Affiliation:
Federal Institute of Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin, Germany
Harald. Goering
Affiliation:
Federal Institute of Materials Research and Testing, Unter den Eichen 87, D-12205 Berlin, Germany
Christoph Schick
Affiliation:
University of Rostock, Department of Physics, Universitätsplatz 3, D-18051 Rostock, Germany
Bernhard. Frick
Affiliation:
Institute Max von Laue - Paul Langevin 6, rue Jules Horowitz B.P. 156, F-38042 Grenoble Cedex 9, France
Reiner Zorn
Affiliation:
Institute for Solid State Research, D-52425 Jülich, Germany
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Abstract

The effect of a nanometer confinement on the molecular dynamics of poly(methyl phenyl siloxane) (PMPS) was studied by dielectric spectroscopy (DS), temperature modulated DSC (TMDSC) and neutron scattering (NS). DS and TMDSC experiments show that for PMPS in 7.5 nm pores the molecular dynamics is faster than in the bulk which originates from an inherent length scale of the underlying molecular motions. At a pore size of 5 nm the temperature dependence of the relaxation times changes from a Vogel / Fulcher / Tammann like behavior to an Arrhenius one. At the same pore size Δcp vanishes. These results give strong evidence that the glass transition has to be characterized by an inherent length scale of the relevant molecular motions. Quasielastic neutron scattering experiments reveal a strong change even in the microscopic dynamic.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 790: Symposium P – Dynamics in Small Confining Systems–2003 , 2003 , P9.3
Copyright
Copyright © Materials Research Society 2004

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References

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