title: Reversible Kirkwood-Alder transition observed in Pt3Cu2 nanoctahedron assemblies under controlled solvent annealing/drying conditions.
abstract: We report a Kirkwood-Alder transition in a system of nonspherical Pt(3)Cu(2) nanoctahedra coated with oleic acid and oleylamine ligands. Using both transmission electron microscopy tomography with 3D reconstruction analysis and synchrotron-based in-situ grazing-incidence small-angle X-ray scattering (GISAXS) techniques, we specifically determined that these nanoctahedra can assemble into an open structure in which the nanoctahedra are arranged tip-to-tip to form a bcc superlattice with a low packing efficiency. Using in-situ and real-time GISAXS, we further observed a "nanoctahedron crystallization" as a soft Kirkwood-Alder transition, that is, the soft nanoactahedra crystallize at a critical concentration and possess continuous crystalline states during a period of solvent evaporation. Finally, we found a reversible change of the superlattice constant during the solvent annealing and evaporation/drying processes.
authors: Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, USA.
authors: Jun
authors: J
authors: Zhang
authors: Zhiping
authors: Z
authors: Luo
authors: Benjamin
authors: B
authors: Martens
authors: Zewei
authors: Z
authors: Quan
authors: Amar
authors: A
authors: Kumbhar
authors: Nathan
authors: N
authors: Porter
authors: Yuxuan
authors: Y
authors: Wang
authors: Detlef-M
authors: DM
authors: Smilgies
authors: Jiye
authors: J
authors: Fang
mesh_terms: D000588:Amines / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D019301:Oleic Acid / Q000737:chemistry*; D017671:Platinum Compounds / Q000737:chemistry*; D053838:Scattering, Small Angle; D012997:Solvents / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000588:Amines; D017671:Platinum Compounds; D012997:Solvents; D019301:Oleic Acid; D003300:Copper; C008703:oleylamine