title: Molecular dynamics of hyperbranched polyesters in the confinement of thin films.
abstract: Broadband Dielectric Spectroscopy is employed to investigate the molecular dynamics in thin films of hyperbranched polyesters (type AB(1)B(2), with -OH and -OCOCH(3) as terminal groups). Three relaxation processes are detected: alpha, beta and gamma. While the latter two are not influenced by the confinement, a pronounced effect is observed on the alpha relaxation: with decreasing film thickness the slower relaxation modes of the dynamic glass transition are gradually suppressed, resulting in an increase of the average relaxation rate and in a linear decrease of the dielectric strength. This is attributed to an immobilization in confinement of the polymeric segments located at the periphery of the hyperbranched macromolecular structures.
authors.affiliation: Leipzig University, Institute for Experimental Physics I, Leipzig, Germany. serghei@rz.uni-leipzig.de
authors.forename: A
authors.initials: A
authors.lastname: Serghei
authors.forename: Y
authors.initials: Y
authors.lastname: Mikhailova
authors.forename: H
authors.initials: H
authors.lastname: Huth
authors.forename: C
authors.initials: C
authors.lastname: Schick
authors.forename: K-J
authors.initials: KJ
authors.lastname: Eichhorn
authors.forename: B
authors.initials: B
authors.lastname: Voit
authors.forename: F
authors.initials: F
authors.lastname: Kremer