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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 20: Polymer and Molecular Dynamics, Friction and Rheology

CPP 20.4: Vortrag

Dienstag, 28. März 2023, 10:30–10:45, ZEU 255

Polymers of Intrinsic Microporosity - Molecular Mobility and Physical Aging Revisited by Dielectric Spectroscopy and X-Ray Scattering — •Farnaz Emamverdi, Glen Jacob Smales, Martin Böhning, and Andreas Schönhals — Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany

The applications of polymers of intrinsic microporosity (PIMs) membranes are restrained by their strong tendency to physical aging. Aging phenomenon involves a significant loss of their good performance in gas separation technology. The initial microporous structure approach a denser state via local rearrangements, leading to a reduction of the permeability. In this work, the dielectric behavior of PIM-1 films and their behavior upon hating (aging) were revisited by isothermal frequency scans during different heating/cooling cycles over a broad temperature range between 133 K and 523 K. In addition, the obtained results were compared with data of samples that were annealed at ambient temperatures over different time scales. Multiple dielectric processes were observed: several relaxation processes due to local fluctuations and a Maxwell-Wagner-Sillars polarization effect related to microporosity. The temperature dependence of the rates of all processes follows the Arrhenius law where the estimated activation energy depends on the nature of the process. SAXS/WAXS patterns were measured as a function of temperature during heating/cooling in a temperature range corresponding to that covered by dielectric spectroscopy. The influence of the aging on the processes is discussed in detail.