Facet-selective asymmetric functionalization of anisotropic gold nanoprisms for Janus particle synthesis

Janus particles, which possess asymmetric structures and/or multiple surface chemistries, have attracted intense interest due to their capability of multiple distinct interactions with their environment. Most Janus particles synthesis techniques rely on applying coating molecules on isotropic particles. Herein, we demonstrate a method to controllably functionalize both major facets of geometrically anisotropic triangular gold nanoprisms in the size range of 100–200 nm with two distinct molecular coatings (hexadecane thiol or thiolated poly (ethylene) glycol and thiol-modified oligonucleotide), giving rise to the formation of Janus gold nanoprisms. Janus particles orient themselves on the interface of water-chloroform mixture and exhibit variable interaction with both hydrophilic and hydrophobic surfaces due to their amphiphilicity and undergo asymmetric self-assembly behavior with other nanoparticles.