title: Sulfate-Mediated End-to-End Assembly of Gold Nanorods.
abstract: There is interest in the controlled aggregation of gold nanorods (GNRs) for the production of extended nanoassemblies. Prior studies have relied upon chemical modification of the GNR surface to achieve a desired final aggregate structure. Herein we illustrate that control of electrolyte composition can facilitate end-to-end assembly of cetyltrimethylammonium-bromide-coated (CTAB) GNRs. By adjusting either the sulfate anion concentration or the exposure time it is possible to connect GNRs in chain-like assemblies. In contrast, end-to-end assembly was not observed in control experiments using monovalent chloride salts. We attribute the end-to-end assembly to the localized association of sulfate with exposed quaternary ammonium head groups of CTAB at the nanorod tip. To quantify the assembly kinetics, visible-near-infrared extinction spectra were collected over a predetermined time period, and the colloidal behavior of the GNR suspensions was interpreted using plasmon band analysis. Transmission electron microscopy and atomic force microscopy results support the conclusions reached via plasmon band analysis, and the colloidal behavior is consistent with Derjaguin-Landau-Verwey-Overbeek theory.
authors.affiliation: Virginia Tech , Department of Civil and Environmental Engineering, Blacksburg, Virginia 24061, United States.|Virginia Tech, Institute for Critical Technology and Applied Science (ICTAS) Center for Sustainable Nanotechnology (VTSuN) , Blacksburg, Virginia 24061, United States.|Center for the Environmental Implications of Nanotechnology (CEINT), Duke University , Durham, North Carolina 27708, United States.
authors.forename: S M H
authors.initials: SM
authors.lastname: Abtahi
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Matthews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Nathan D
authors.identifier: 0000-0002-3973-1017
authors.initials: ND
authors.lastname: Burrows
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Matthews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Fred A
authors.initials: FA
authors.lastname: Idesis
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign , 600 South Matthews Avenue, Urbana, Illinois 61801, United States.
authors.forename: Catherine J
authors.identifier: 0000-0001-7066-5575
authors.initials: CJ
authors.lastname: Murphy
authors.affiliation: The University of Texas at Austin , Department of Civil, Architectural and Environmental Engineering, Austin, Texas 78712, United States.
authors.forename: Navid B
authors.initials: NB
authors.lastname: Saleh
authors.affiliation: Virginia Tech , Department of Civil and Environmental Engineering, Blacksburg, Virginia 24061, United States.|Virginia Tech, Institute for Critical Technology and Applied Science (ICTAS) Center for Sustainable Nanotechnology (VTSuN) , Blacksburg, Virginia 24061, United States.|Center for the Environmental Implications of Nanotechnology (CEINT), Duke University , Durham, North Carolina 27708, United States.
authors.forename: Peter J
authors.identifier: 0000-0003-2654-5132
authors.initials: PJ
authors.lastname: Vikesland