Stabilizing Complex Spherical Phases via Local Segregation in Polymer Blends

Complex spherical phases have been observed in a variety of soft matter systems, which attracts tremendous attention in the last decade. Interestingly, a number of Frank-Kasper phases including A15, σ, C14 and C15 phases emerged and stabilized in various blending systems, such as AB-diblock-copolymer/A-homopolymer blends, binary mixtures of AB/AB diblock copolymers and lyotropic surfactants mixed with water and oil, etc. These informative experimental observations indicate that blending different components together dramatically enhances the stability of those complex spherical phases. Theoretical works revealed that local segregation of distinct components promotes the formation of spherical domains with different sizes, which is essential to the complex packing of spheres. In this presentation, we summarize in details the mechanisms to stabilize complex spherical packing phases through local segregation in various blending systems containing diblock copolymers based on our recent self-consistent field theory (SCFT) study. We believe that these universal principles could guide the design of other soft matter systems to get access to the novel complex spherical phases.