Morphological Control and Formation Kinetics of Polymer-Induced Self-Assembly in Binary Mixed Solvents

Polymerization-induced self-assembly (PISA) is a versatile synthetic method that integrates polymerization and molecular self-assembly in a single step. It essentially relies on the decreasing solubility of polymers as their chain lengths increases during polymerization, a change that drives the spontaneous formation of nanoscale assembled structures via intermolecular interactions, thereby offering distinct advantages of operational simplicity, high efficiency, and controllable nanostructure morphology. To expand the range of achievable aggregate morphologies and clarify the underlying mechanisms from a kinetic perspective, this study proposes an in silico research to investigate the regulatory mechanisms of binary mixed solvents in PISA systems. The results show that incorporating a second solvent with an affinity for solvophobic blocks induces the formation of large interconnected micelles. This phenomenon arises because the second solvent preferentially accumulates near the core of the aggregate formed by the solvophobic blocks, causing slight dissolution of the core and further promoting the extension and fusion of micelles. Additionally, as the monomer feed ratio and polymer molecular weight increase, these micelles undergo further fusion to form hollow vesicular structures, which is further confirmed by experimental observations. This study not only enriches the diversity of aggregate morphologies obtained via PISA but also provides new insights into the morphological control mechanisms of mixed solvent systems.