title: Observation of a low-viscosity interface between immiscible polymer layers.
abstract: X-ray photon correlation spectroscopy was employed in a surface standing wave geometry in order to resolve the thermally driven in-plane dynamics at both the surface/vacuum (top) and polymer/polymer (bottom) interfaces of a thin polystyrene (PS) film on top of Poly(4-bromo styrene) (PBrS) and supported on a Si substrate. The top vacuum interface shows two relaxation modes: one fast and one slow, while the buried polymer-polymer interface shows a single slow mode. The slow mode of the top interface is similar in magnitude and wave vector dependence to the single mode of the buried interface. The dynamics are consistent with a low-viscosity mixed layer between the PS and PBrS and coupling of the capillary wave fluctuations between this layer and the PS.
authors.affiliation: Intense Pulsed Neutron Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Xuesong
authors.initials: X
authors.lastname: Hu
authors.forename: Zhang
authors.initials: Z
authors.lastname: Jiang
authors.forename: Suresh
authors.initials: S
authors.lastname: Narayanan
authors.forename: Xuesong
authors.initials: X
authors.lastname: Jiao
authors.forename: Alec R
authors.initials: AR
authors.lastname: Sandy
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Sinha
authors.forename: Laurence B
authors.initials: LB
authors.lastname: Lurio
authors.forename: Jyotsana
authors.initials: J
authors.lastname: Lal