Self-regulated structures in nanocomposites by directed nanoparticle assembly

Adding surface-modified silica nanoparticles (NPs) to polymer blend films, we demonstrate that directed interfacial segregation of NPs stabilize either three-dimensional (3D) interpenetrating or 2D discrete structures at high and low volume fractions of NPs, respectively. A simple interfacial energy argument provides a general guideline for predicting whether the NPs are directed to the interface between phases or into one phase. The final morphology and domain size can be predicted from the volume fraction of NPs, film thickness, and NP size.