mz7b00374_si_001.pdf (607.26 kB)
Role of “Hard” and “Soft” Confinement on Polymer Dynamics at the Nanoscale
journal contribution
posted on 2017-08-11, 19:05 authored by Ravi P. Sharma, Peter F. GreenWe
investigated the segmental dynamics of asymmetrically confined
polymer films and report an unusual phenomenon in which the presence
and thickness of a soft confining layer are responsible for significant
changes in the segmental dynamics of the confined films. Specifically,
the segmental dynamics of poly(vinyl alcohol) (PVA) thin films asymmetrically
confined between hard aluminum (Al), and soft polystyrene (PS) films
are shown to shift by as much as half an order of magnitude upon changes
in the thicknesses of the confining PS layer. These effects are more
significant than those due to symmetric confinement between hard Al
substrates or exposure to a free surface. These observations, partially
rationalized in terms of recent simulations and theory, implicate
the role of the moduli of the confining layers.