Self-assembly of inverted phases in AB/CD diblock copolymer blends

Conventional ordered phases of block copolymers are nanoscopic structures with discrete domains (spheres or cylinders) composed of the minority blocks embedded in a continuous matrix composed of the majority blocks. Inverted phases of block copolymers refer to the novel ordered structures with discrete domains composed of the majority blocks. In this work, the formation and relative stability of various inverted phases in AB/CD diblock copolymer blends are studied using self-consistent field theory. The results reveal that the ratio of the block copolymer lengths and the copolymer concentration play a crucial role in stabilizing the inverted structures, and the relative stability of various inverted phases depends sensitively on the interaction strengths. The spatial distribution of the different blocks is used to elucidate mechanisms for the formation of inverted phases. The findings provide insights into the formation of inverted phases and suggest design strategies for functional nanostructures with potential applications in nanolithography and photonic crystals.