title: Gold nanorods as nanoadmicelles: 1-naphthol partitioning into a nanorod-bound surfactant bilayer.
abstract: As-prepared gold nanorods, stable in aqueous solution, bear a bilayer of the cationic surfactant cetyltrimethylammonium bromide (CTAB). This bilayer provides a approximately 3 nm thick hydrophobic layer that could be used to sequester hydrophobic organic molecules from aqueous solution. We have investigated the uptake of 1-naphthol as a model hydrophobic compound by CTAB-coated gold nanorods using both ultraviolet-visible spectroscopy and gas chromatography with flame ionization detection. We find the adsorption isotherm of 1-naphthol partitioning into the CTAB bilayer on gold nanorods fits the Langmuir model. The maximum number of bound 1-naphthol molecules is 14.6 +/- 2.2 x 10(3) molecules per gold nanorod, with an equilibrium binding constant of 1.97 +/- 0.79 x 10(4) M(-1) at room temperature.
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, 631 Sumter Street, Columbia, SC 29208, USA.
authors.forename: Alaaldin M
authors.initials: AM
authors.lastname: Alkilany
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Frey
authors.forename: John L
authors.initials: JL
authors.lastname: Ferry
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Murphy
mesh_terms: D002412:Cations; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D002849:Chromatography, Gas / Q000379:methods; D006046:Gold / Q000737:chemistry*; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008823:Micelles; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D009284:Naphthols / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet / Q000379:methods; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry*; D013696:Temperature
chemical_list: D002412:Cations; D002593:Cetrimonium Compounds; D008051:Lipid Bilayers; D008823:Micelles; D009284:Naphthols; D013501:Surface-Active Agents; C029350:1-naphthol; D006046:Gold; D000077286:Cetrimonium