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Molecular dynamics of Janus Polynorbornenes: Glass Transitions and Nanophase separation

  • We report the dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbone and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl). Dielectric dispersion reveals two active processes at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter relates to the glassy dynamics of the flexible -Si(OR)3 side groups, that creates a nanophase separation in both the alkyl chain rich and backbone rich domains. Temperature modulated DSC measurements and X-ray scattering experiment confirm the nanophase separation. Fast Scanning Calorimetry employing both fast heating and cooling rates detects the glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC. The cooperative length scale of glass transition and the size of the alkyl chainWe report the dielectric and calorimetric investigations of an homologous series of Janus polynorbornenes with rigid main backbone and flexible -Si(OR)3 side groups, of differing length alkyl chains (R = Propyl, Butyl, Hexyl, Octyl, Decyl). Dielectric dispersion reveals two active processes at low temperatures, denoted as β- and α- relaxation. The former can be assigned to localized fluctuations, whilst the latter relates to the glassy dynamics of the flexible -Si(OR)3 side groups, that creates a nanophase separation in both the alkyl chain rich and backbone rich domains. Temperature modulated DSC measurements and X-ray scattering experiment confirm the nanophase separation. Fast Scanning Calorimetry employing both fast heating and cooling rates detects the glass transition temperatures of the backbone rich domains, which are beyond or near to their degradation temperatures in terms of conventional DSC. The cooperative length scale of glass transition and the size of the alkyl chain rich domains increases with 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.zeige mehrzeige weniger

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Metadaten
Autor*innen:Mohamed Aejaz KolmangadiORCiD
Koautor*innen:Andreas Schönhals, Paulina Szymoniak, Glen Jacob Smales, Martin Böhning
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2021
Organisationseinheit der BAM:6 Materialchemie
6 Materialchemie / 6.6 Physik und chemische Analytik der Polymere
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Freie Schlagwörter:Conductivity; Dynamics; Fast Scanning Calorimetry; Glass transition
Themenfelder/Aktivitätsfelder der BAM:Material
Material / Nano
Veranstaltung:IDS Online conference 2021
Veranstaltungsort:Online meeting
Beginndatum der Veranstaltung:06.09.2021
Enddatum der Veranstaltung:09.09.2021
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:17.09.2021
Referierte Publikation:Nein
Eingeladener Vortrag:Nein
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