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BP: Fachverband Biologische Physik

BP 10: Posters DY - Fluid Physics, Active Matter, Complex Fluids, Soft Matter and Glasses (joint session DY/BP)

BP 10.4: Poster

Montag, 22. März 2021, 14:00–16:30, DYp

Molecular dynamics of janus polynorbornenes: glass transitions and nanophase separation — •Mohamed A Kolmangadi, Paulina Szymoniak, Martin Böhning, and Andreas Schönhals — Bundesantalt für Materialforschung und -prüfung (BAM), Berlin, Germany

For the first time, dielectric and calorimetric investigations of a homologous series of Janus polynorbornenes with rigid main backbones and flexible Si(OR)3 side groups of differing length alkyl chains (R = propyl, butyl, hexyl, octyl, and decyl) is reported.Two dielectrically active processes are observed at low temperatures, denoted as β- and α-relaxation. The former can be assigned to localized fluctuations, while the latter is related to the glassy dynamics of the flexible Si(OR)3 side groups, creating a nanophase separation in both the alkyl chain-rich and backbone-rich domains. This is confirmed through temperature-modulated differential scanning calorimetry (TMDSC) measurements and X-ray scattering experiments. The glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC, are determined for the first time using fast scanning calorimetry employing both fast heating and cooling rates. This is complemented with scattering experiments that show how the size of the alkyl chain-rich domains increases with the side chain length. Alongside these results, a significant conductivity contribution was observed for all poly(tricyclononenes) with Si(OR)3 side groups, which is interpreted in terms of a percolation model