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The Morphology of Symietric Diblock Copolymers as Revealed by Neutron Reflectivity

Published online by Cambridge University Press:  21 February 2011

S. K. Satija
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD
C. F. Majkrzak
Affiliation:
National Institute of Standards and Technology, Gaithersburg, MD
S. H. Anastasiadis
Affiliation:
IBM Research Division, San Jose, CA
T. P. Russell
Affiliation:
IBM Research Division, San Jose, CA
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Abstract

The specular reflectivity of neutrons has been used to characterize quantitatively the microphase separated morphology of symmetric, diblock copolymers of polystyrene, PS and polymethylmethacrylate, PMMA, as a function of the total molecular weight of the copolymer where either block is perdeuterated. It is shown that the hyperbolic tangent function, as opposed to a linear or cosine squared function, most closely describes the concentration gradient at the interface between the lamellar copolymer microdomains. The effective width of the interface is found to be independent of the molecular weight of the copolymer blocks and has a value of 50 ± 3Å. This interface is also found to be identical to that of PS and PMMA, homopolymers. However, using measured values of the Flory-Huggins interaction parameter for PS and PMMA current theoretical treatments cannot describe the observed widths of the interface.

Type
Research Article
Copyright
Copyright © Materials Research Society 1990

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References

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