Constructing Hierarchical Superstructures of Patchy Micelles and Modulation of Their Supracolloidal Assembly Pathway

Abstract

Patchy particles serve as effective building blocks for engineering colloidal superstructures ranging from clusters and chains to networks. Generally, the geometry of patchy particles governs the resulting structures of colloidal assemblies, but once it is determined by the initial fabrication conditions, it is hard to be further modified. Thus, to enhance the versatility of patchy particles and the structural diversity of superstructures, a system that can achieve multiple pathways of colloidal assemblies should be developed. Here, we demonstrated patchy micelles of diblock copolymers as a versatile building block that can access various superstructures including hierarchical structures and the pathway of colloidal assemblies can be simply tuned by solvent polarity. Patchy micelles having only one patch per micelle (single-patch micelles), were produced from core-crosslinked spherical micelles of diblock copolymers and then assembled into colloidal dimers upon a shift in solvent polarity. Further aging induced the side-by-side connection of the colloidal dimers, resulting in hierarchically assembled ladder-like linear structures. Additionally, we found a critical condition that two-patch micelles can be transformed into single-patch micelles.These reconfigured single-patch micelles exhibited hierarchical assembly behavior yielding colloidal dimers and ladder-like linear structures, while linear chains from the colloidal assemblies of two-patch micelles can still be produced by precisely adjusting solvent polarity. Finally, using the superstructures of patchy micelles as templates, we achieved paired and parallel arrays of gold nanoparticles, showing that this system can serve as a tunable platform for aligning nanomaterials.