title: Synthesis of complex shape gold nanoparticles in water-methanol mixtures.
abstract: Gold nanoparticles with shapes which varied from spheres to multipods and polygons were prepared with a seedless approach in water/methanol mixtures in the presence of polyvinyl alcohol using sodium ascorbate as the reducing agent. The shape of Au nanoparticles is critically affected by the water/methanol ratio, as well as by the ratio of hydrogen tetrachloroaurate (HAuCl4) to sodium ascorbate and the concentration of HAuCl4 in the reaction mixture. A decreased ratio of water to methanol below 30/70 leads to the formation of multi-branched nanoparticles with the size in the range of 30-70 nm at relatively low HAuCl4 concentration, whereas polygons are formed when HAuCl4 concentration increases. The polyvinyl alcohol stabilized multi-branched Au nanoparticle colloids were stable at room temperature for a period of at least six-month.
authors.affiliation: Department of Physics, University of Alabama at Birmingham, AL 35294, USA.
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Stanishevsky
authors.forename: Heather
authors.initials: H
authors.lastname: Williamson
authors.forename: Helene
authors.initials: H
authors.lastname: Yockell-Lelievre
authors.forename: Lauren
authors.initials: L
authors.lastname: Rast
authors.forename: Anna M
authors.initials: AM
authors.lastname: Ritcey
mesh_terms: D003102:Colloids / Q000737:chemistry*; D045424:Complex Mixtures / Q000737:chemistry; D003460:Crystallization / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D008422:Materials Testing; D000432:Methanol / Q000737:chemistry*; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology; D010316:Particle Size; D012996:Solutions; D012997:Solvents / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D003102:Colloids; D045424:Complex Mixtures; D012996:Solutions; D012997:Solvents; D014867:Water; D006046:Gold; D000432:Methanol