title: Janus nanoparticles: preparation, characterization, and applications.
abstract: In chemical functionalization of colloidal particles, the functional moieties are generally distributed rather homogeneously on the particle surface. Recently, a variety of synthetic protocols have been developed in which particle functionalization may be carried out in a spatially controlled fashion, leading to the production of structurally asymmetrical particles. Janus particles represent the first example in which the two hemispheres exhibit distinctly different chemical and physical properties, which is analogous to the dual-faced Roman god, Janus. Whereas a variety of methods have been reported for the preparation of (sub)micron-sized polymeric Janus particles, it has remained challenging for the synthesis and (unambiguous) structural characterization of much smaller nanometer-sized Janus particles. Herein, several leading methods for the preparation of nanometer-sized Janus particles are discussed and the important properties and applications of these Janus nanoparticles in electrochemistry, sensing, and catalysis are highlighted. Some perspectives on research into functional patchy nanoparticles are also given.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, 1156 High Street, Santa Cruz, California 95064 (USA), Fax: (+1) 831-459-2935.
authors.forename: Yang
authors.initials: Y
authors.lastname: Song
authors.forename: Shaowei
authors.initials: S
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques; D002384:Catalysis; D004298:Dopamine / Q000032:analysis; D055664:Electrochemical Techniques; D004579:Electron Transport; D006046:Gold / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D053758:Nanoparticles / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry
chemical_list: C009495:titanium dioxide; D006046:Gold; D014025:Titanium; D004298:Dopamine
keywords: NMR spectroscopy; colloids; gold; ligand exchange; nanoparticles