Surface-field-induced microstructures of asymmetric diblock copolymer nanoparticles

The microstructures of asymmetric diblock copolymer nanoparticles were investigated using real-space self-consistent field theory. The nanoparticle boundary provides a spherical confinement in which the highly deformable copolymers are forced into a closed and crowded space. The surface-field-induced effects on the microstructures were examined systematically, and a rich variety of novel structures, such as mixtures of distorted cylinders and spherical lamellae, was observed in the copolymer nanoparticles. Investigations of the free energies indicate that the surface-field-induced structural transitions are of the first order. The formation mechanism of the confinement-induced structures was reasonably elucidated, based on the interactions between the polymer chains and confinement boundaries, and on the spherical symmetry from confinements. Our theoretical results are in good agreement with available simulation and experimental observations.