Masurel R J, Gelineau P, Cantournet S, Dequidt A, Long D R, Lequeux F, Montes H
Laboratoire Sciences et Ingénierie de la Matière Molle (SIMM), CNRS-UMR 7615, Ecole Supérieure de Physique et Chimie Industrielles de Paris (ESPCI Paris), PSL Research University, Université Pierre et Marie Curie (UPMC), Sorbonne-Universités, 10 rue Vauquelin, F-75005 Paris, France.
MINES ParisTech, PSL-Research University, MAT-Centre des Matériaux, CNRS UMR 7633, BP 87 91003 Evry, France.
Phys Rev Lett. 2017 Jan 27;118(4):047801. doi: 10.1103/PhysRevLett.118.047801.
Confinement induces various modifications in the dynamics of polymers as compared to bulk. We focus here on the role of dynamical heterogeneities on the mechanics of confined polymers. Using a simple model that allows computation of the mechanical response over 10 decades in frequency, we show that the local mechanical coupling controlling the macroscopic response in the bulk disappears in a confined geometry. The slowest domains significantly contribute to the mechanical response for increasing confinement. As a consequence, the apparent glass transition is broadened and shifted towards lower frequencies as confinement increases. We compare our numerical predictions with experiments performed on poly(ethylacrylate) chains in model filled elastomers. We suggest that the change of elastic coupling between domains induced by confinement should contribute significantly to the polymer mobility shift observed on filled systems.
