INIFTA   05425
INSTITUTO DE INVESTIGACIONES FISICO-QUIMICAS TEORICAS Y APLICADAS
Unidad Ejecutora - UE
artículos
Título:
Real-Time Monitoring Distance Changes in Surfactant-Coated Au Nanoparticle Films upon Volatile Organic Compounds (VOCs)
Autor/es:
MARÍA CELESTE DALFOVO; LISANDRO J. GIOVANETTI; JOSE MARTIN RAMALLO LOPEZ; ROBERTO C. SALVAREZZA; FÉLIX GREGORIO REQUEJO; FRANCISCO J. IBAÑEZ
Revista:
JOURNAL OF PHYSICAL CHEMISTRY C
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2015 vol. 119 p. 5098 - 5106
ISSN:
1932-7447
Resumen:
We explore into the role of the organic ligands composition surrounding Au nanoparticles (NPs) toward internanoparticles distance changes and film structure during vapor sensing by the use of in situ grazing-incidence small-angle X-ray scattering (GISAXS) and other relevant techniques. We observed distinct changes in core-to-core distance and film structure upon measured concentrations of polar ethanol (EtOH) and nonpolar toluene (Tol) vapors. As-formed tetraoctylammonium bromide (TOABr)-coated Au NPs (SNPs) film exhibited ∼0.4 nm core-to-core increase in distance and improved SNPs correlation upon 80% Tol. In the presence of EtOH, SNPs distance seems not to change and correlation critically diminishes, leading to an amorphous film. As-formed films were exchanged with nonanedithiol (NDT) and exposed to 100% Tol vapor. Interestingly, the incorporation of NDT increased distance between NPs and rendered film flexibility. It is determine that just a small number of S, from NDT ligands, binds to Au NPs, and those exchanged alkanedithiol chains adopted a loop conformation around the Au NPs as evidenced by X-ray absorption near-edge structure (XANES) and kink defects by Fourier transformed infrared (FT-IR) experiments, respectively. These findings may solve some fundamental questions about internanoparticle distance-dependent phenomena such as electron transport in chemiresistors and coupling effects in localized surface plasmon resonance (LSPR) solid-state sensors.