Preparation of cylindrical multi-compartment micelles by the hierarchical self-assembly of ABC triblock polymer in solution

Abstract

Amphiphilic linear ABC triblock copolymer PnBA₂₈-b-PS₃₇-b-P2VP₇₃ was prepared by the RAFT method and its two-step hierarchical self-assembly in selected solvents was explored. The triblock copolymer was refluxed in methanol and the micelle product was further dialyzed against acidic water. The effects of the concentration of copolymer on the morphology of the aggregates formed in methanol in the first step were investigated. The structures and morphologies of the micelles formed by the self-assembly were characterized with SEC, ¹H NMR, TEM and DLS. Spherical patchy micelles were obtained in the poor solvent, methanol, for PS and PnBA blocks during the first step assembly. The patchy micelles were dialyzed against water with a pH value of ∼3.0 and aggregated to form multi-compartment micelles (MCMs). The MCMs further aggregated when the concentration of patchy micelles was increased. Cylindrical MCMs were formed with 2 mg mL⁻¹ patchy micelles.