TY - JOUR
T1 - Polymer dynamics under cylindrical confinement featuring a locally repulsive surface
T2 - A quasielastic neutron scattering study
AU - Krutyeva, M.
AU - Pasini, S.
AU - Monkenbusch, M.
AU - Allgaier, J.
AU - Maiz, J.
AU - Mijangos, C.
AU - Hartmann-Azanza, B.
AU - Steinhart, M.
AU - Jalarvo, N.
AU - Richter, D.
N1 - Publisher Copyright:
© 2017 Author(s).
PY - 2017/5/28
Y1 - 2017/5/28
N2 - We investigated the effect of intermediate cylindrical confinement with locally repulsive walls on the segmental and entanglement dynamics of a polymer melt by quasielastic neutron scattering. As a reference, the corresponding polymer melt was measured under identical conditions. The locally repulsive confinement was realized by hydrophilic anodic alumina nanopores with a diameter of 20 nm. The end-to-end distance of the hydrophobic infiltrated polyethylene-alt-propylene was close to this diameter. In the case of hard wall repulsion with negligible local attraction, several simulations predicted an acceleration of segmental dynamics close to the wall. Other than in attractive or neutral systems, where the segmental dynamics is slowed down, we found that the segmental dynamics in the nanopores is identical to the local mobility in the bulk. Even under very careful scrutiny, we could not find any acceleration of the surface-near segmental motion. On the larger time scale, the neutron spin-echo experiment showed that the Rouse relaxation was not altered by confinement effects. Also the entanglement dynamics was not affected. Thus at moderate confinement conditions, facilitated by locally repulsive walls, the dynamics remains as in the bulk melt, a result that is not so clear from simulations.
AB - We investigated the effect of intermediate cylindrical confinement with locally repulsive walls on the segmental and entanglement dynamics of a polymer melt by quasielastic neutron scattering. As a reference, the corresponding polymer melt was measured under identical conditions. The locally repulsive confinement was realized by hydrophilic anodic alumina nanopores with a diameter of 20 nm. The end-to-end distance of the hydrophobic infiltrated polyethylene-alt-propylene was close to this diameter. In the case of hard wall repulsion with negligible local attraction, several simulations predicted an acceleration of segmental dynamics close to the wall. Other than in attractive or neutral systems, where the segmental dynamics is slowed down, we found that the segmental dynamics in the nanopores is identical to the local mobility in the bulk. Even under very careful scrutiny, we could not find any acceleration of the surface-near segmental motion. On the larger time scale, the neutron spin-echo experiment showed that the Rouse relaxation was not altered by confinement effects. Also the entanglement dynamics was not affected. Thus at moderate confinement conditions, facilitated by locally repulsive walls, the dynamics remains as in the bulk melt, a result that is not so clear from simulations.
UR - http://www.scopus.com/inward/record.url?scp=85011339273&partnerID=8YFLogxK
U2 - 10.1063/1.4974836
DO - 10.1063/1.4974836
M3 - Article
C2 - 28571352
AN - SCOPUS:85011339273
SN - 0021-9606
VL - 146
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 20
M1 - 203306
ER -