Nanoparticle (NP) assemblies exhibit collective optical, electronic, and magnetic properties that enable applications in sensing, catalysis, energy conversion, and optoelectronics. However, achieving independent control over structural integrity and surface functionality within such assemblies remains a significant challenge in NP self-assembly. Here, we report a modular post-functionalization strategy that decouples structural locking from surface reprogramming in colloidal molecules (CMs). ABn symmetry CMs assembled from complementary polymer-grafted Au NPs were selected as representative models and reinforced using multivalent N-heterocyclic carbene (NHC)-containing block copolymers. The NHC anchoring segments form robust C–Au bonds, converting initially noncovalent interparticle junctions into covalently bridged connections without perturbing predefined geometries. This multivalent locking reduces interparticle spacing, enhances plasmonic coupling, and significantly improves chemical, ionic, thermal, and mechanical stability, preserving three-dimensional architectures in the dry state. Importantly, separation of anchoring and functional polymer blocks enables independent introduction of amphiphilic and light-responsive surface properties, allowing solvent-dependent plasmonic modulation and reversible light-triggered hierarchical assembly while maintaining discrete CM geometry.
Runshi Qiao, Huaining Zha, Jing Tao et al.· Nano Reseach· 0 citations
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.
