Wetting Kinetics-Controlled Interplay between Nanoparticles and Polymer Domains in Multiphase Polymer Blends

The interplay between nanoparticles and polymer domains dominates the particle distribution and structural evolution of multiphase polymer blends. We herein report the controlled distribution of silica (SiO₂) nanoparticles in poly(l-lactic acid) (PLLA)/ethylene-acrylic ester-glycidyl methacrylate terpolymer (EGMA) blends with a typical droplet-matrix morphology. Due to the thermodynamic equilibrium, SiO₂ nanoparticles migrate from their predispersing PLLA matrix into the droplet EGMA domains during stepwise melt compounding. However, SiO₂ nanoparticles will assemble at the interface to form a hybrid particle-bridged droplet domain network when EGMA is slightly cross-linked. The increased elasticity of EGMA after cross-linking will restrain the formation of the “wetting ridge” induced by the interfacial tension during its wetting process on the SiO₂ surface; the increased viscous force (viscosity) interacting with capillary force at the wetting ridge will slow the dynamics of spreading (wetting) of EGMA on the SiO₂ surface. Thus, SiO₂ nanoparticles are arrested at the PLLA/EGMA interface to suppress the coalescence of the EGMA domains.