Glass transition in ultrathin polymer films: a thermal expansion study

Bhattacharya, M. ; Sanyal, M. K. ; Geue, Th. ; Pietsch, U. (2005) Glass transition in ultrathin polymer films: a thermal expansion study Physical Review E, 71 (4). 041801_1-041801_5. ISSN 1063-651X

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Official URL: http://pre.aps.org/abstract/PRE/v71/i4/e041801

Related URL: http://dx.doi.org/10.1103/PhysRevE.71.041801

Abstract

The glass transition process gets affected in ultrathin films having thickness comparable to the size of the molecules. We observe systematic broadening of the glass transition temperature (Tg) as the thickness of an ultrathin polymer film reduces below the radius of gyration but the change in the average Tg was found to be very small. The existence of reversible negative and positive thermal expansion below and above Tg increased the sensitivity of our thickness measurements performed using energy-dispersive X-ray reflectivity. A simple model of the Tg variation as a function of depth expected from sliding motion could explain the results.

Item Type:Article
Source:Copyright of this article belongs to The American Physical Society.
ID Code:61322
Deposited On:15 Sep 2011 03:46
Last Modified:18 May 2016 11:04

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