Publication: Confinement induced densification in supported unentangled polymer films
Date
19-05-2017
Authors
Satapathy, Dillip K.
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
We report the densification phenomena inunentangled and low-molecular weight polystyrene (PS) thin films supported on solid substrates having thickness from 25 nm to 230 nm. The mass density of the thin polymer films were extracted from X-ray reflectivity profiles and also from the refractive index by using Clausius and Mossotti equation. The mass densityof polymeris found to increasesignificantly with decrease in film thickness below ten times the radius of gyration of the polymer. The net increase in mass density of the polymer film upon reduction in thickness is discussed in terms of three-layer model and the presence of unentangled polymer chains. We conjecture that, the densification of ultra-thin polymer films can strongly alter the polymer conformations at film/substrate interface.
Description
Keywords
Densification, glass transition, Polymer thin films, x-ray reflectivity