• Treffer 4 von 4
Zurück zur Trefferliste

Molecular dynamics of polymers in random nanometer confinements investigated by relaxational scattering techniques

  • Dielectric spectroscopy and temperature-modulated differential scanning calorimetry are employed to study the molecular dynamics of oligomeric poly(propylene glycol) (PPG) melts of different molecular weights confined to nanoporous glasses (pore sizes 2.5, 5.0, 7.5 and 20 nm). Moreover, the results obtained for the polymers are compared with those for the corresponding monomer. The experimental results are discussed in the framework of the interplay of confinement and adsorption effects. For large pore sizes (> 5 nm) a speeding up of the molecular dynamics is observed (the confinement effect), whereas for small pore sizes (< 5 nm) a slowing down of the segmental fluctuations is found (the adsorption effect). In addition, a minimal length scale for the glass transition of 1.6 nm is estimated for PPG confined in nanoporous glasses. This supports the idea that the molecular motions responsible for the glassy dynamics must be describable by a characteristic length scale. Polarized RamanDielectric spectroscopy and temperature-modulated differential scanning calorimetry are employed to study the molecular dynamics of oligomeric poly(propylene glycol) (PPG) melts of different molecular weights confined to nanoporous glasses (pore sizes 2.5, 5.0, 7.5 and 20 nm). Moreover, the results obtained for the polymers are compared with those for the corresponding monomer. The experimental results are discussed in the framework of the interplay of confinement and adsorption effects. For large pore sizes (> 5 nm) a speeding up of the molecular dynamics is observed (the confinement effect), whereas for small pore sizes (< 5 nm) a slowing down of the segmental fluctuations is found (the adsorption effect). In addition, a minimal length scale for the glass transition of 1.6 nm is estimated for PPG confined in nanoporous glasses. This supports the idea that the molecular motions responsible for the glassy dynamics must be describable by a characteristic length scale. Polarized Raman scattering investigations are carried out to investigate the conformations of the macromolecules inside the pores. These experiments show that the confined polymer chains are locally stretched. This effect increases with decreasing pore size.zeige mehrzeige weniger

Metadaten exportieren

Weitere Dienste

Teilen auf Twitter Suche bei Google Scholar Anzahl der Zugriffe auf dieses Dokument
Metadaten
Autor*innen:Andreas SchönhalsORCiD, Harald Goering, Klaus-Werner Brzezinka, C. Schick
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Journal of physics / Condensed matter
Jahr der Erstveröffentlichung:2003
Verlag:IOP Publ. Ltd.
Verlagsort:Bristol
Jahrgang/Band:15
Ausgabe/Heft:11
Erste Seite:S1139
Letzte Seite:S1148
Veranstaltung:3rd Workshop on Non-Equilibrium Phenomena in Supercooled Fluids, Glasses and Amorphous Materials
Veranstaltungsort:Pisa, Italy
Beginndatum der Veranstaltung:2003-09-22
Enddatum der Veranstaltung:2003-09-27
DOI:10.1088/0953-8984/15/11/334
ISSN:0953-8984
ISSN:1361-648X
Verfügbarkeit des Dokuments:Weder Datei noch physisches Exemplar vorhanden ("No Access")
Datum der Freischaltung:19.02.2016
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:05.03.2003
Einverstanden
Diese Webseite verwendet technisch erforderliche Session-Cookies. Durch die weitere Nutzung der Webseite stimmen Sie diesem zu. Unsere Datenschutzerklärung finden Sie hier.