Dynamics of Water Absorbed in Polyamides

Beitrag in einer Fachzeitschrift

Details zur Publikation

Autor(en): Laurati M, Sotta P, Long DR, Fillot LA, Arbe A, Alegria A, Embs JP, Unruh T, Schneider GJ, Colmenero J
Zeitschrift: Macromolecules
Jahr der Veröffentlichung: 2012
Band: 45
Heftnummer: 3
Seitenbereich: 1676-1687
ISSN: 0024-9297


We investigate the dynamics of water absorbed in amorphous and semicrystalline aromatic polyamide copolymers. The combination of dielectric spectroscopy and quasi-elastic neutron scattering experiments allows us to characterize the water dynamics over a wide range of temperatures (dielectric spectroscopy) and at microscopic length scales (neutron scattering). The dielectric investigation evidences two relaxations associated with water motions: a fast process corresponding to motions of loosely bonded water molecules and a slower process corresponding to motions of amide-water complexes. While the slower process presents the characteristic Arrhenius temperature dependence of a secondary local relaxation over the whole temperature range, the fast process shows a crossover from Arrhenius to Vogel-Fulcher-Tamman (VFT) behavior at T approximate to 225 K, characteristic of confined water dynamics. The microscopic investigation by neutron scattering shows than in the VFT regime of the fast process the dynamics present a diffusive nature similar to bulk water. A large distribution of diffusion coefficients indicates possible differences in the connectivity of the hydrogen bond network. Diffusive heterogeneous dynamics can arise from a nonuniform distribution of water. The confinement effect of the polymer matrix is detected as a considerable reduction of the diffusion coefficient of water with respect to bulk. The presence of a crystalline phase results in a slowing down of both the fast and slow processes involving water motions. This could give a hint to the presence of a rigid amorphous phase in the semicrystalline material.

FAU-Autoren / FAU-Herausgeber

Unruh, Tobias Prof. Dr.
Professur für Nanomaterialcharakterisierung (Streumethoden)

Autor(en) der externen Einrichtung(en)
Forschungszentrum Jülich GmbH (FZJ)
Paul Scherrer Institute (PSI)
Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC)
University of Basque Country / Universidad del Pais Vasco (UPV) / Euskal Herriko Unibersitatea (EHU)


Laurati, M., Sotta, P., Long, D.R., Fillot, L.A., Arbe, A., Alegria, A.,... Colmenero, J. (2012). Dynamics of Water Absorbed in Polyamides. Macromolecules, 45(3), 1676-1687. https://dx.doi.org/10.1021/ma202368x

Laurati, M., et al. "Dynamics of Water Absorbed in Polyamides." Macromolecules 45.3 (2012): 1676-1687.


Zuletzt aktualisiert 2018-06-08 um 17:23