Fast tailoring of gold nanoflowers by an interface-modified reverse microdroplet strategy

Gold nanoflowers (Au NFs) have received great attention for surface-enhanced Raman scattering (SERS) applications, due to the high surface area, availability of conjugation sites on surface and the localized surface plasmon resonance. However, their further application is much hampered by the complicated and time-consuming synthesis process, which remains better responded. Herein, we propose a novel & straightforward interface-modified reverse microdroplet strategy to configure homogeneously dispersed Au NFs within two hours, where Au³⁺ was reduced by excess aniline as two-in-one medium of reductant and solvent. It is demonstrated that the reaction system is robustly directed by the dynamic built-in reaction interface, thanks to the capping effect of the in-situ formed polyaniline (PANI) and polyvinyl pyrrolidone (PVP). It is further identified that the final morphology of Au NFs is strongly determined by the nucleation & growth rates. Consequently, such a well-tailored microstructure endows the Au NFs with sound performance for SERS applications. When using methylene blue (MB) as a molecular probe, a high SERS enhancement factor above 10⁵ is delivered. This work provides a feasible interface-assisted methodology to investigate multi-level structures, and sheds light toward simply advancing versatile nanomaterials for broad applications.