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Diblock Copolymers at Surfaces*

Published online by Cambridge University Press:  22 February 2011

Peter F. Green ,
Thomas M. Christensen ,
Thomas P. Russell  and
Spiros H. Anastasiadis
Peter F. Green
Affiliation:
Sanda National Laboratories Albuquerque N.M. 87185-5800
Thomas M. Christensen*
Affiliation:
Sanda National Laboratories Albuquerque N.M. 87185-5800
Thomas P. Russell
Affiliation:
IBM Research Division Almaden Research Center 650 Harry Road San Jose, California 95120-6099
Spiros H. Anastasiadis
Affiliation:
IBM Research Division Almaden Research Center 650 Harry Road San Jose, California 95120-6099
*
Current Address: Dept. of Physics, Univ. of Colorado, Colorado Springs, Colorado 80933
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Abstract

The surface properties of symmetric microphase separated diblock copolymers of polystyrene (PS) and polymethylmethacrylate (PMMA) were investigated using X-ray photoelectron spectroscopy (XPS), the specular reflectivity of neutrons and secondary ion mass spectrometry (SIMS). PS, the lower surface energy component, exhibited a preferential affinity for the free surface. For copolymers that are far from the bulk microphase separation transition (MST), the surface consists of a layer of pure PS. When the system is close to the MST the surface is a mixture of PS and PMMA. The PS surface excess can be described bya N-1/2 dependence, where N is the number of segments that comprise the copolymer chain. It is shown that the surface undergoes an ordering transition at a temperature T2 that is above that of the bulk MST. The ordering of the bulk lamellar morphology is induced by an ordering at the surface. This is analogous to the ferromagnetic order observed in systems such as Gd at temperatures above the bulk Curie temperature. The results here are discussed in light of previous work on copolymer surfaces and in light of mean field theory.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 171: Symposium O – Polymer Based Molecular Composites , 1989 , 317
Copyright
Copyright © Materials Research Society 1990

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Footnotes

*

This work was supported in part by U. S. DOE under Contract DE-AC046-DP00789

References

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