Interface Structure and Dynamics in Polymer‐Nanoparticle Hybrids: A Review on Molecular Mechanisms Underlying the Improved Interfaces

Abstract

AbstractIn a nano‐assembly of soft polymer chains and hard filler nanoparticles (NPs), the intermolecular interactions at the polymer‐filler interface lead to variations in viscoelastic properties in the vicinity of the NP surface. However, unravelling the molecular parameters controlling the entropic and enthalpic interactions, including polymer chain conformation, dynamics, dispersion mechanisms and confinement effects across the interfacial region, has been remote and challenging. Even though the polymer‘s molecular structure and the NPs surface chemistry contribute to these interfacial interactions, the underlying mechanism behind the enhanced dynamic‐mechanical performance is still a hot topic of debate. By controlling the chemistry of NPs and polymer matrix in model nanocomposites, many efforts have been made in elucidating the physical origin of the structure and dynamics of the interfacial polymer layer with estimates varying from 1 to 10 nm around the spherical NPs. Therefore, understanding the interface structure and dynamics influenced by polymer‐NP interaction is of great technological importance. In this article, the latest polymer‐particle interface literature developments are reviewed where computational simulations, calorimetry, and dielectric spectroscopy studies have been used to examine the constraints levied by the interface structure on segmental relaxation dynamics of polymer chains in the vicinity of NP surface.