Nanoparticle-induced morphology evolution and property expression in immiscible polymer blend composites-A review of fundamental understanding on nanoparticle migration and interface crossing

This article provides a critical overview of the fundamentals related to the migration and localization of nanoparticles in immiscible polymer blends, with a discussion on recent advances, including knowledge gaps related to the effect of nanofiller localization on the properties of polymer blend composites. Thermodynamic equilibrium primarily guides the migration and localization of nanoparticles in immiscible polymer blends. However, the effect of kinetics cannot be ignored when nanoparticles are initially distributed in a thermodynamically less favored phase. By controlling various process parameters during melt processing, one can exploit the effect of kinetics for tailoring the localization of nanoparticles. Furthermore, filler particles can be localized at the interface by surface modification of the filler particles and inducing interfacial reactions or by tailoring their wettability using surface functionalization. Such control of the migration of nanoparticles is crucial for getting desired properties, such as high electrical conductivity and low percolation threshold of conductive polymer blend nanocomposites. By providing a holistic understanding of all critical aspects (thermodynamic and kinetic) related to the control of migration of all commonly used nanoparticles and its subsequent effect on properties, this review offers a direction for future advances in the development of high-performance multiphase nanocomposite materials used for various high-end applications.