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Science 20 November 1992:
Vol. 258. no. 5086, pp. 1339 - 1342
DOI: 10.1126/science.258.5086.1339
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Articles

Viscoelastic Dynamics of Confined Polymer Melts

Hsuan-Wei Hu 1 and Steve Granick 1

1 Materials Research Laboratory and Department of Materials Science and Engineering, University of Illinois, Urbana, IL 61801

The frequency-dependent shear response of an ultrathin polymer melt (polyphenylmethylsiloxane) confined between adsorbing surfaces (parallel plates of mica) is described. The sinusoidal deformations were sufficiently small to give linear response, implying that measurement did not perturb the film structure. A remarkable transition was observed with decreasing thickness. When the film thickness was less than five to six times the unperturbed radius of gyration, there emerged a strong rubber-like elasticity that was not characteristic of the bulk samples. This result indicates enhanced entanglement interactions in thin polymer films and offers a mechanism to explain the slow mobility of polymers at surfaces.

Submitted on July 31, 1992
Accepted on October 5, 1992


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Spatial and Temporal Dependence of Diffusion in Polystyrene Thin Films on Silicon and Carbon Surfaces.
Y Strzhemechny, V Zaitsev, K Zhou, S A Schwarz, J Sokolov, and M H Rafailovich (2000)
High Performance Polymers 12, 611-619
   Abstract »    PDF »
From Static to Kinetic Friction in Confined Liquid Films.
G. Reiter, A. L. Demirel, and S. Granick (1994)
Science 263, 1741-1744
   Abstract »    PDF »


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