title: Organic mediator-induced structural transformation in superlattices of monolayer-protected gold nanoparticles.
abstract: N-acetylglutathione (NAG)-protected gold nanoparticles self-assemble into three-dimensional (3D) face-centered cubic (fcc)-type superlattices at an air/water interface under highly acidic conditions. To prepare the well-defined superlattices, 1month's incubation is at least necessary since the size growth of the as-prepared nanoparticles is essential. Addition of 4-pyridinecarboxyic acid (PyC), a bifunctional hydrogen-bonding mediator, promotes the formation of the superlattices, which are created for about 2weeks' storage. Interestingly, PyC-induced nanoparticle superlattices are in a body-centered tetragonal (bct) structure. The fcc-to-bct phase transformation would be due to stronger interaction between NAG and PyC than that between NAG molecules on the gold nanoparticle surfaces.
authors.affiliation: Graduate School of Material Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan. yao@sci.u-hyogo.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yao
authors.forename: Ai
authors.initials: A
authors.lastname: Kuriyama
authors.forename: Takayuki
authors.initials: T
authors.lastname: Minami
authors.forename: Keisaku
authors.initials: K
authors.lastname: Kimura