Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 60: Polymer and Molecular Dynamics I

CPP 60.1: Vortrag

Mittwoch, 14. März 2018, 17:00–17:15, C 264

Molecular Mobility and Physical Aging of Polymers with Intrinsic Microporosity (PIMs) as Revealed by Dielectric Spectroscopy — •Huajie Yin, Nora Konnertz, Martin Böhning, and Andreas Schönhals — Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, 12205 Berlin, Germany

Polymeric membranes represent a cost- and energy- efficient solution for gas separation. Recently polymers of intrinsic microporosity (PIMs) outperform many conventional dense polymers by high permeability and appealing selectivity. However, this novel class of glassy polymers are prone to pronounced physical aging. The initial microporous structures approach a denser state via local chain rearrangements, leading to a dramatic reduction in the gas permeability. For the first time, dielectric spectroscopy with state-of-the-art high-resolution analyzers was employed to investigate the molecular mobility and physical aging of various representative PIMs with a systematic change in chain rigidity. The dielectric behavior of the polymeric films was measured by isothermal frequency scans during the different heating cycles in a broad temperature range. Structural relaxation of the films was found during the measurements. Multiple dielectric processes following Arrhenius behavior were observed for the investigated polymers. Moreover, they all showed conductivity in the glassy state. The significant increase in the conductivity with increasing temperature is explained in terms of the formation of local intermolecular agglomerated structures due to interaction of π-electrons in aromatic moieties of the polymer backbone.