1. State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, China
2. Polymer Physics Research Laboratory, Institute of Chemical Materials, China Academy of Engineering Physics (CAEP), Mianyang 621900, China
Abstract：Hierarchical self-assembly of triblock terpolymers (TTPs) in dilute solution to form multicompartment micelles (MCMs) typically involves two main steps: self-assembly of TTPs chains into intermediate star-like micelles and further self-assembly of star-like micelles into MCMs. The former step, in theory, has two possible pathways: single-stage self-assembly or hierarchical self-assembly, which has not yet been fully revealed. Here, an amorphous linear A-b-C type TTP polystyrene-block-polybutadiene-block-poly(methyl methacrylate) (abbrev. PS-b-PB-b-PMMA or SBM) was used as a model molecule; solvent exchange strategy was employed to induce self-assembly of SBM in dilute solution. Dynamic light scattering (DLS), static light scattering (SLS), and auxiliary transmission electron microscope (TEM) were used for real-time and dynamic monitoring of the self-assembly process of SBM into star-like micelles and further self-assembly of star-like micelles into MCMs. The results revealed that the self-assembly pathway of SBM in dilute solution into star-like micelles was a direct single-stage self-assembly pathway from SBM chain clusters/networks to form star-like micelles, rather than a hierarchical self-assembly pathway involving intermediate states such as single-chain or multi-chain micelles. Additionally, the concentration of SBM dilute solution had no significant effect on this self-assembly pathway, and the self-assembly process reached dynamic equilibrium within 12 hours. The results provide valuable information for the thermodynamic and kinetic studies of the self-assembly process of multi-component block copolymers in dilute solution, and for applying light scattering technology to characterize polymer solutions.
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