Berlin 2005 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 29: POSTER: Polymer physics
CPP 29.44: Poster
Dienstag, 8. März 2005, 16:30–18:30, Poster TU D
Physical Aging in Complex Systems — •Trichy R. Gopalakrishnan, Adnan Javed, and Mario Beiner — FB Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany
We have investigated the influence of quenching and physical aging on the dynamics of nanophase-separated polymers with long alkyl groups in the side chain. These materials show two different relaxation processes with typical features of a dynamic glass transition: (i) The conventional α relaxation at high temperatures and (ii) a polyethylene-like glass transition αPE related to cooperative motions in alkyl nanodomains with a typical dimension of 1-2nm formed by aggregated alkyl groups. Quenched samples and samples annealed between both glass transition temperatures are studied by shear measurements and dielectric spectroscopy. It is shown that the αPE process is amplified in rapidly quenched samples and that annealing slightly below the conventional glass transition temperature reduces the intensity of the αPE process in shear data significantly. Indications for an additional localized dynamics within the alkyl nanodomains are reported. A speculative picture describing the findings based on differences in the contraction of immobile main chains and liquid-like alkyl groups below the conventional glass temperature where the main chains freeze-in is discussed.