Fusion of block copolymer micelles in ionic liquids

Block copolymer micelles in dilute solutions have been the subject of extensive research aimed at investigating equilibrium structures. However, fundamental understanding of the self-assembly process and relaxation dynamics of block copolymer micelles remains incomplete. This research contributes to the ongoing exploration of micelle self-assembly and relaxations, shedding light on the intricate kinetics of micelle fusion. We explored the relaxation and growth kinetics of 1,2-polybutadiene-block-poly(ethylene oxide) micelles in ionic liquids using dynamic light scattering and liquid-phase transmission electron microscopy. Our observations revealed that the growth of micelles follows a biphasic kinetic mechanism, characterized by a two-step process, where the second step exhibits an order of magnitude lower rate compared to the initial step. When micelles are far from equilibrium, the growth shows second-order kinetics, yet understanding the growth mechanism of micelles near equilibrium remains a complex challenge. These findings enhance our understanding of the dynamic behavior of block copolymer micelles and have potential implications for a wide range of applications, including drug delivery, surfactant design, and nanoreactors.