Role of dynamical heterogeneities on the mechanical response of confined polymer

R.J. Masurel (1) , P. Gelineau (1) , Sabine Cantournet (2) , A. Dequidt (3) , D.R. Long (4) , F. Lequeux (1) , H. Montes (1)

1 SIMM - Sciences et Ingénierie de la Matière Molle (UMR 7615)
2 CDM - Centre des Matériaux
3 ICCF - Institut de Chimie de Clermont-Ferrand
4 LPMA - Laboratoire Polymères et Matériaux Avancés

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.

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Matière Molle [cond-mat.soft]

R.J. Masurel, P. Gelineau, Sabine Cantournet, A. Dequidt, D.R. Long, et al.. Role of dynamical heterogeneities on the mechanical response of confined polymer. Physical Review Letters, 2017, 118 (4), pp.047801. ⟨10.1103/PhysRevLett.118.047801⟩. ⟨hal-01498220⟩