title: Anomalous surface relaxations of branched-polymer melts.
abstract: The dynamics of thermally stimulated surface fluctuations of 100 nm thick films of long-branched polymers are measured for the first time. In contrast to comparable films of linear or cyclic chains that show no change in viscosity upon confinement, films of 6-pom, 6-star, and 6-end end-branched stars show viscosities, inferred from x-ray photon correlation spectroscopy, as much as 100 times higher than in the bulk. This difference varies in magnitude with chain architecture. Branching has a profound effect on confinement, even for these unentangled chains.
authors: Department of Polymer Science, The University of Akron, Akron, Ohio 44325-3909, USA.
authors: Shih-fan
authors: SF
authors: Wang
authors: Sewoo
authors: S
authors: Yang
authors: Jaesik
authors: J
authors: Lee
authors: Bulent
authors: B
authors: Akgun
authors: David T
authors: DT
authors: Wu
authors: Mark D
authors: MD
authors: Foster