Highly scalable, dialysis-controlled synthesis of colloidal molecules via regulated self-assembly of polymer-grafted gold nanoparticles

Colloidal molecules (CMs) are assemblies of nanoparticles (NPs) that accurately replicate the structure and symmetry of actual molecules. Regarded as modular building blocks, CMs enable the creation of hierarchical structures that are challenging to achieve through the direct self-assembly of individual NPs. However, the limited availability of efficient and scalable methods for nanoscale CM synthesis has constrained their broader use in constructing hierarchical structures. Here we show that long-range electrostatic attraction, combined with short-range hydrogen-bonding interactions, enables the assembly of binary NPs into CMs in an aqueous medium, attaining high yields of up to 95% and concentrations three orders of magnitude higher than previously reported values. These CMs can serve as building blocks for constructing CM arrays and non-close-packed hierarchical structures with open pores. Our approach marks an efficient self-assembly strategy for fabricating nanoscale CMs and demonstrates their potential in constructing innovative hierarchical structures. Colloidal molecules mimic real molecules and can serve as nanoscale building blocks. Here, the authors use dialysis-guided aqueous self-assembly to produce them with high yield and concentration, highlighting their potential for hierarchical structure formation.