Synthesis of ultrasmall metal nanoparticles and continuous shells at the liquid/liquid interface in Ouzo emulsions

International audienceHerein, we report a novel method to synthesize metal nanoparticle-shells (NP-shells) and continuous shells at the liquid/liquid interface, via an interfacial reaction in an Ouzo emulsion. Ouzo emulsions spontaneously form submicronic droplets with a narrow size distribution, without any energy-intensive process. The Ouzo system in this work comprises water, tetrahydrofuran (THF) and butylated hydroxytoluene (BHT), and forms BHT-rich droplets (similar to 100 nm). The addition of a reducing agent (NaBH4) in the aqueous phase, and of a metal precursor (AuPPh3Cl and/or Pd(PPh3)(2)Cl-2) in the BHT-rich droplets, results in the formation of Au nanoparticles (AuNPs), continuous Pd shells, or bimetallic shells, at the interface of the droplets. Control over the NP-shell size was achieved by the addition of a water-soluble polymer during the synthesis, which in turn leads to smaller NP-shells