Molecular dynamics in thin grafted and spin-coated polymer layersF. Kremer1, L. Hartmann1, A. Serghei1, P. Pouret2 and L. Léger2
1 University of Leipzig, Faculty of Physics, Linnéstr. 5, D-04103 Leipzig, Germany
2 Laboratoire de Physique de la Matière Condensée, Collège de France, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
(Received 1 January 2003 / Published online: 8 October 2003)
Broadband Dielectric Spectroscopy is employed to study the molecular dynamics in thin layers of grafted and spin-coated polydimethylsiloxane (PDMS) and of the type-A polymer cis-1,4-polyisoprene (PI). Strong resemblance with low-molecular-weight systems is found but additionally the conformation of the chain and its extension becomes important. For PI a confinement-induced relaxation is found. It is observable if the layer thickness is comparable to the end-to-end vector of the chain and it depends strongly on the separation between interfaces. In contrast, the dynamic (and hence the calorimetric) glass transition is not affected by the geometrical confinement.
64.70.Pf - Glass transitions.
83.10.Mj - Molecular dynamics, Brownian dynamics.
68.60.-p - Physical properties of thin films, nonelectronic.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2003