Vibrational density of states and molecular mobility in a polymer with intrinsic microporosity PIM-1 as revealed by inelastic neutron scattering
- Polymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. Here, by means of inelastic neutron scattering, the vibrational density of states (VDOS) and the molecular mobility were investigated for PIM-1, the prototypical polymer with intrinsic microporosity. The results are compared to data measured for a more conventional high-performance polyimide used in gas separation membranes (Matrimid). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. In comparison to the Boson peak of Matrimid, that of PIM-1 is shifted to lower frequencies. This shift is discussed considering the microporous, sponge-like structure of PIM-1 as providing a higher compressibility at the molecular scale than for conventional polymers. Elastic fixed window scans were measured on a neutron backscattering spectrometerPolymers with intrinsic microporosity are promising candidates for the active separation layer in gas separation membranes. Here, by means of inelastic neutron scattering, the vibrational density of states (VDOS) and the molecular mobility were investigated for PIM-1, the prototypical polymer with intrinsic microporosity. The results are compared to data measured for a more conventional high-performance polyimide used in gas separation membranes (Matrimid). The measured data show the characteristic low frequency excess contribution to the VDOS above the Debye sound wave level, generally known as the Boson peak in glass-forming materials. In comparison to the Boson peak of Matrimid, that of PIM-1 is shifted to lower frequencies. This shift is discussed considering the microporous, sponge-like structure of PIM-1 as providing a higher compressibility at the molecular scale than for conventional polymers. Elastic fixed window scans were measured on a neutron backscattering spectrometer to have an overview about the molecular dynamics at a time scale of ca. 1 ns. The temperature dependence of the estimated mean squared displacement shows a step-like increase in the temperature range from 100 K to 250 K indicating the onset of some molecular mobility. The nature of this motional process was analyzed in detail by quasielastic neutron scattering combining Time-of-Flight and backscattering where the data are discussed with regard to both the q- and the temperature dependence.…
Autor*innen: | Andreas SchönhalsORCiD |
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Koautor*innen: | R. Zorn, Martin BöhningORCiD |
Dokumenttyp: | Vortrag |
Veröffentlichungsform: | Präsentation |
Sprache: | Englisch |
Jahr der Erstveröffentlichung: | 2019 |
Organisationseinheit der BAM: | 6 Materialchemie |
6 Materialchemie / 6.6 Physik und chemische Analytik der Polymere | |
7 Bauwerkssicherheit | |
7 Bauwerkssicherheit / 7.5 Technische Eigenschaften von Polymerwerkstoffen | |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik |
Freie Schlagwörter: | Neutron Scattering; Polymers of Intrinsic Microporosity |
Themenfelder/Aktivitätsfelder der BAM: | Energie |
Veranstaltung: | JCNS Workshop for Neutron Scattering |
Veranstaltungsort: | Tutzing at Munich, Germany |
Beginndatum der Veranstaltung: | 07.10.2019 |
Enddatum der Veranstaltung: | 10.10.2019 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 16.10.2019 |
Referierte Publikation: | Nein |
Eingeladener Vortrag: | Nein |