A Simple Route to Hierarchical Rings of Diblock Copolymer Micelles

A hierarchically assembled necklace composed of amphiphilic diblock copolymer micelles is exquisitely produced by capitalizing on two concurrent self-assembly processes at different scales (i.e., "breath figure" strategy of diblock copolymer micelles solution evaporating in humid air to yield rings at the microscopic scale in conjunction with self-assembly of diblock copolymer micelles within individual ring at the nanometer scale). Intriguingly, hierarchical rings of diblock copolymer micelles comprising gold precursors or fluorescent dyes can also be crafted using this strategy. Upon exposure to hydrophilic block-selective solvent, core-corona inversion of micelles within the microscopic rings occurs. In contrast, such inversion is inhibited when the micelles are impregnated by gold precursors. This simple yet effective strategy for engineering diblock copolymer micelles may be extended to produce hierarchically assembled structures consisting of other functional block copolymers (e.g., stimuli-responsive block copolymer) and nanocrystals (e.g., semiconducting, magnetic, ferroelectric, etc.) with unique catalytic, magnetic, ferroelectric, optical, electronic, and optoelectronic properties.