Copolymer compatibilizer sequence effects on polymer interfaces across a range of chi

Copolymer compatibilizers provide a promising pathway towards bio-based and upcycled composites comprised of otherwise immiscible polymers. Evidence in block copolymers and statistical copolymers has long indicated that copolymer sequence plays an important role in mediating the effectiveness of these compatibilizers. One mechanism of compatibilization is simple interfacial tension reduction, with strengthens adhesion across interfaces and favors formation of smaller, more tightly intercalated phases. Here, we employ molecular dynamics simulations to study how compatibilizer sequence effects on interfacial tension vary with the chi parameter of the underlying polymer blend. We find that the optimum sequence, and the overall effectiveness of compatibilization, vary nontrivially with chi. Perhaps counterintuitively, the most highly immiscible systems are found to be more readily compatibilized than more miscible systems, such that for at least some compatibilizer concentrations it is possible to obtain lower interfacial tensions with an intrinsically more immiscible polymer pair. These results provide new insights into the design of sequence-controlled polymers for use in high performance compatibilized polymer blend composites.