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Neutron Reflectivity Measurements of Molecular Weight Effects on Polymer Mobility near the Polymer/Solid Interface

Published online by Cambridge University Press:  01 February 2011

Eric K. Lin ,
Darrin J. Pochan ,
Wen-li Wu  and
Sushil K. Satija
Eric K. Lin
Affiliation:
Polymers Division, Materials Science and Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8541, Gaithersburg, MD 20899–8541 USA
Darrin J. Pochan*
Affiliation:
Polymers Division, Materials Science and Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8541, Gaithersburg, MD 20899–8541 USA
Wen-li Wu
Affiliation:
Polymers Division, Materials Science and Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8541, Gaithersburg, MD 20899–8541 USA
Sushil K. Satija
Affiliation:
Center for Neutron Research, Materials Science and Engineering Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, Stop 8541, Gaithersburg, MD 20899–8541 USA
*
* Department of Materials Science and Engineering, University of Delaware Newark, DE 19716
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Abstract

Neutron reflectometry is used to measure the rate of interdiffusion between bilayer samples of deuterated and hydrogenated poly(methyl methacrylate) (PMMA) films with the polymerpolymer interface near the native oxide surface of a silicon wafer. In this work, the effects of a favorable substrate interaction and the molecular weight of each polymer layer are determined. Both the film thickness and the molecular weight of the lower d-PMMA layer are kept constant with a thickness of approximately one radii of gyration (Rg) of the polymer and the molecular weight of the upper hydrogenated layer is varied. Earlier experiments show that the mobility of the polymer chains within Rg of the substrate is much lower than that of the bulk, suggesting that the mobility of surface-pinned polymers controls the interdiffusion rate. In this study, we find that the rate of interdiffusion is strongly dependent upon the molecular weight of the top layer.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 629: Symposium FF – Interfaces, Adhesion and Processing in Polymer Systems , 2000 , FF2.1
Copyright
Copyright © Materials Research Society 2000

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References

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