Self-assembly of polymer-tethered metal nanoparticle (NP) building blocks is studied via an emulsion interface self-assembly strategy. The results show that the hollow colloidosomes with a highly ordered hexagonal arrangement of metal NP building blocks are obtained. The interparticle distance between the adjacent metal NPs within the hollow colloidosomes can be effectively tuned by adjusting the molecular weight of the polymeric ligands. Interestingly, with an increase in the volume fraction of the internal hexadecane phase, the particular sheet-like superlattices can be formed. Moreover, the prepared colloidosomes can serve as an excellent substrate for the surface-enhanced Raman scattering and have potential application in photothermal therapy. We believe that this study can provide a promising way to fabricate hierarchical ordered metal superstructures, which have potential applications in photothermal therapy, chemical sensors, and biological optical-imaging.

Self-assembly of gold nanorods (AuNRs) into hierarchically ordered superstructures is a prerequisite for the fabrication of functional materials and devices. Although 1D linear and 2D sheetlike ordered arrays of AuNRs have been successfully constructed, organizing AuNRs into ordered arrays on 3D spherical surfaces is still quite challenging because of the difficulty in controlling the orientation of anisotropic AuNRs on curved surfaces. Here, a facile yet robust emulsion interface self-assembly strategy is reported to obtain well-defined colloidosomes with highly ordered and oriented AuNRs through the self-assembly of polymer-tethered AuNRs at the emulsion interface, which is constructed with an external aqueous solution and an internal nonsolvent (hexadecane) as a liquid-core template. Moreover, the alignment and orientation of AuNRs can be controlled by varying the curvature of the colloidosome, the length of the AuNRs, and the molecular weight of the polymer ligands. This strategy provides a promising route to the design of hierarchical superstructures with a controlled AuNR arrangement and orientation.