Cononsolvency-induced Micellization of Diblock Copolymers in Multi-solvent Solutions

Selective solvents are commonly used for inducing micellization of diblock copolymers (DBCs), where the solvophobic and solvophilic blocks form the micellar core and corona, respectively. Here, based on the theoretical concept of cononsolvency developed from our previous studies of multi-solvent polymer solutions, we demonstrate a different path to DBC micellization that is induced by cononsolvent behavior by one of the DBC blocks in a binary solvent mixture. Theoretical calculations and computer simulations will be combined in this study to explore the parameter space in which cononsolvency-induced micellization is stabilized versus macro phase separation, and to characterize the dependence on solvent composition of the critical micelle concentration, the aggregation number, as well as the micellar core-shell structure. Comparing to micelles formed in selective solvent, cononsolvency-induced micelles exhibit sensitive response to solvent composition and allow a greater level of control over morphologies owing to an expanded set of interaction parameters. Findings from this study provide the guiding principles for realizing this new type of micelles in experiments and showcase the versatility in designing polymer self-assembly strategies using multi-component solvent systems.