Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 18: Physics of polymers II
CPP 18.4: Vortrag
Dienstag, 8. März 2005, 12:00–12:15, TU C130
NEUTRON SPECTROSCOPY ON POLYMERS CONFINED TO NANOPROUS GLASSES — •Andreas Schoenhals1, Bernhard Frick2, and Reiner Zorn3 — 1Bundesanstalt fuer Materialforschung und -pruefung, Unter den Eichen 87, D-12205 Berlin — 2Institut Max von Laue - Paul Langevin (ILL) 6, rue Jules Horowitz, B.P. 156, F-38042 Grenoble Cedex 9 — 3Forschungszentrum Juelich, Institut für Festkoerperforschung, D-52425 Juelich
The behavior polymers confined to geometries of a nanometer scale has become an interesting field. Neutron scattering (NS) is valuable tool to investigate such systems because of the high penetration depth of neutrons. Incoherent NS was carried out on poly(dimethyl siloxane) and poly(methyl phenyl siloxane) confined to Sol/Gel-glasses (7.5, 5.0, 2.5 nm). To cover a broad dynamical range of the scattering function S(Q,E) time-of-flight and backscattering are combined. For the frequency range of the Boson peak the vibrations at lowest frequencies are depressed by the confinement. Elastic scans were carried out and the mean square displacement msd was calculated. Above Tg the characteristic increase of the msd found for the bulk is strongly influenced by the confinement but for both materials in a different manner. The main influence of the confinement on S(Q,t)=FT(S(Q,E)) is an broadening of S(Q,t) with increasing confinement. These results are discussed together with dielectric measurements.