Changes in the phase morphology of miktoarm PS-b-PMMA copolymer induced by a monolayer surface

It is known that polystyrene (PS) and poly(methyl methacrylate) (PMMA) blocks are immiscible at 383, 413, and 443 K and that their Flory-Huggins interaction parameters have the same blending ratio dependence at those temperatures. In this study, the phase morphologies of six groups of 12 miktoarm PS-b-PMMA copolymers were investigated at 383, 413, and 443 K via MesoDyn simulations. There is nearly no change for the same copolymer under different temperatures. We designed four series of patterned surfaces (18 total) and found that the inducing effect of these surfaces has some influence on the microscopic phase morphology of the polymers, including a reinforcing immiscible effect and a weakening immiscible effect. The degree of phase separation depended on the molecular architecture of the block copolymers, temperature, and the characteristics of the inducing surfaces. Higher temperature and higher PS-rich component copolymers exhibited higher order parameters. The co-4432 and co-8832 surfaces exhibited the most intensive inducing effect because of their 16 and 32 independent micro-environments, respectively. A set of comparative simulations was carried out with a high interaction energy between the polymeric species. The results confirmed the possibility of forming a hexagonal columnar phase with a core shell composed of the designed molecular structures as well as demonstrated the potential application of micro-environments in producing special mesoscopic structures.