Nonspherical Nanoparticles in Block Copolymer Composites: Nanosquares, Nanorods, and Diamonds

A hybrid two-dimensional block copolymer (BCP) nanocomposite computational model is proposed to study nanoparticles (NPs) with a generalized shape including square, rectangle, and rhombus. Simulations are used to study the role of anisotropy in the assembly of colloids within BCPs, ranging from NPs that are compatible with one phase to neutral NPs. The ordering of squarelike NPs into grid configurations within a minority BCP domain was investigated, as well as the alignment of nanorods in a lamellar-forming BCP, comparing the simulation results with experiments of mixtures of nanoplates and polystyrene-b-poly(methyl methacrylate) BCP. The assembly of rectangular NPs at the interface between domains resulted in alignment along the interface. The aspect ratio is found to play a key role in the aggregation of colloids at the interface, which leads to a distinct co-assembly behavior for low- and high-aspect-ratio NPs.