Eur. Phys. J. E 8, 217-224 (2002)
DOI: 10.1140/epje/i2001-10088-4
Some relevant parameters affecting the glass transition of supported ultra-thin polymer films
Y. Grohens1, L. Hamon2, G. Reiter2, A. Soldera3 and Y. Holl41 Laboratoire Polymères et Procédés, Université de Bretagne Sud, Rue St. Maudé, BP 92116, 56325 Lorient Cedex, France
2 Institut de Chimie des Surfaces et Interfaces, 15 Rue J. Starcky, BP 2488, 68057 Mulhouse, France
3 Université de Sherbrooke, Faculté des Sciences, Département de Chimie, Sherbrooke, J1K2R1, Canada
4 Institut Charles Sadron, 6 rue Boussingault, 67083 Strasbourg Cedex, France
yves.grohens@univ-ubs.fr
(Received 4 October 2001 and Received in final form 14 February 2002)
Abstract
We have measured, the thickness dependence of the glass
transition temperature
, using ellipsometry at variable
temperature, for poly(methyl-methacrylate) (PMMA) of various tacticity in
confined geometry. We report that several factors significantly affect
: i) polymer microstructure (stereoregularity of PMMA) related
to local dynamics; ii) interfacial interactions; iii) conformation of the
polymer chains.
These results raise many fundamental questions on the origin of the
thickness-dependent glass transition. Why and how do the interactions with
the substrate significantly affect
? Does
depend on
the modifications of conformational parameters of the chains (their
entropy)? What is the correlation between local dynamics and
in thin
films? The aim of this paper is to summarise these open questions, which
should stimulate further investigations in the thin polymer film scientific
community.
64.70.Pf - Glass transitions.
61.41.+e - Polymers, elastomers, and plastics.
68.60.-p - Physical properties of thin films, nonelectronic.
61.20.-p - Structure of liquids.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2002