Search results for "reversed micelles"

showing 5 items of 5 documents

Supramolecular Aggregates in Vacuum: Positively Mono-Charged Sodium Alkanesulfonate Clusters

2010

The formation and structural features of positively mono-charged aggregates of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and sodium methane—(MetS), butane—(ButS) and octane—(OctS) sulfonate molecules in the gas phase have been investigated by electrospray ionization mass spectrometry, energy-resolved mass spectrometry and density functional theory (DFT) calculations. The experimental results show that the center-of-mass collision energy required to dissociate 50% of these mono-charged aggregates scantly depends on the length of the alkyl chain as well as on the aggregation number. This, together with the large predominance of mono-charged species in the mass spectra, was rationalized i…

AlkanesulfonatesSpectrometry Mass Electrospray IonizationAmphiphilic moleculeVacuumChemistryElectrospray ionizationSodiumSodiumSupramolecular chemistrychemistry.chemical_elementGeneral MedicineAtomic and Molecular Physics and Opticschemistry.chemical_compoundSulfonateTandem Mass SpectrometrySupramolecular aggregates amphiphilic molecules surfactants reversed micelles ESI MS ESI MS/MS energy resolved mass spectrometry DFT calculationsQuantum TheoryOrganic chemistrySpectroscopyEuropean Journal of Mass Spectrometry
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Physicochemical investigation of cobalt?iron cyanide nanoparticles synthesized by a novel solid?solid reaction in confined space

2004

Cobalt–iron cyanide (Cox[Fe(CN)6]) nanoparticles have been synthesized by a novel solid–solid reaction in the confined space of dry sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reversed micelles dispersed in n-heptane. The reaction has been carried out by mixing two dry AOT/n-heptane solutions containing CoCl2 and K4Fe(CN)6 or K3Fe(CN)6 nanoparticles in the micellar core, respectively. By UV-Vis spectroscopy it was ascertained that, after the mixing process, the formation of stable nanoparticles is fast and complete. Microcalorimetric measurements of the thermal effect due to the Cox[Fe(CN)6] nanoparticle formation allowed the determination of the stoichiometric ratio (x) and of the molar e…

Polymers and PlasticsSmall-angle X-ray scatteringCyanidechemistry.chemical_elementNanoparticleMicellechemistry.chemical_compoundColloid and Surface ChemistryAdsorptionCobalt–iron cyanide complexes Nanoparticles Solid–solid reaction Confinement effect AOT reversed micelleschemistryX-ray photoelectron spectroscopyMaterials ChemistryPhysical chemistryOrganic chemistryPhysical and Theoretical ChemistryCobaltStoichiometrySettore CHIM/02 - Chimica FisicaColloid and Polymer Science
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Self-assembly in surfactant-based mixtures driven by acid–base reactions: bis(2-ethylhexyl) phosphoric acid–n-octylamine systems

2013

Structural and dynamic features of bis(2-ethylhexyl) phosphoric acid (HDEHP)-n-octylamine (NOA) mixtures as a function of the NOA mole fraction (X-NOA) have been investigated by SAXS, WAXS, IR, dielectric spectroscopy and polarized optical microscopy. In the 0 <= X-NOA < 0.5 range, mixtures are transparent liquids, while the abrupt formation of a waxy solid characterized by an hexagonal bidimensional structure occurs at X-NOA = 0.5. Such a composition-induced phase transition results from the synergetic effect of the progressive increase in number density of ordered HDEHP-NOA nanodomains with X-NOA. Mainly driven by an HDEHP to NOA proton transfer, the increase of structural order with X-NO…

Steric effectsPhase transitionself-assembly surfactant mixtures nanostructures dynamical propertiesReversed micelles liquid crystals phosphate dielectric spectroscopyChemistrySmall-angle X-ray scatteringGeneral Chemical EngineeringReversed micellesGeneral ChemistryMole fractionDielectric spectroscopychemistry.chemical_compoundCrystallographyliquid crystalsChemical engineeringPulmonary surfactantSelf-assemblydielectric spectroscopyPhosphoric acidSettore CHIM/02 - Chimica FisicaphosphateRSC Advances
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Localization and interactions of melatonin in dry cholesterol/lecithin mixed reversed micelles used as cell membrane models

2005

The state of melatonin confined in dry cholesterol/lecithin mixed reversed micelles dispersed in CCl4 was investigated using 1H-NMR and FT-IR spectroscopies as a function of the melatonin to lecithin molar ratio (R(MLT)) and of the cholesterol to lecithin molar ratio (R(CHL)). An analysis of experimental results leads to the hypothesis that, independent of R(MLT) and as a consequence of anisotropic melatonin/lecithin, melatonin/cholesterol and cholesterol/lecithin interactions, melatonin is totally solubilized in reversed micelles. Melatonin is mainly located in and oriented in the nanodomain constituted by the hydrophilic groups of cholesterol and lecithin. A competition of melatonin and c…

endocrine systemMagnetic Resonance Spectroscopyfood.ingredientCCL4Models BiologicalLecithinMicelleMelatoninCell membranechemistry.chemical_compoundEndocrinologyfoodPhosphatidylcholineSpectroscopy Fourier Transform InfraredmedicineMicellesMelatoninChromatographyCholesterolCell Membranetechnology industry and agricultureNuclear magnetic resonance spectroscopyCholesterolmedicine.anatomical_structurechemistryPhosphatidylcholineslipids (amino acids peptides and proteins)cell membrane models cholesterol confinement effects lecithin melatonin reversed micelleshormones hormone substitutes and hormone antagonistsmedicine.drugJournal of Pineal Research
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Physicochemical investigation of surfactant-coated gold nanoparticles synthesized in the confined space of dry reversed micelles

2006

Abstract Gold nanoparticle/surfactant composites have been synthesized by a novel reduction reaction in the confined space of dry sodium bis(2- ethylhexyl)sulfosuccinate (AOT) or lecithin reversed micelles dispersed in n-heptane and cyclohexane, respectively. The reaction was carried out by adding an opportune amount of anhydrous hydrazine/tetrahydrofuran solution to a suspension of HAuCl4-containing dry reversed micelles dispersed in organic solvent. UV–vis investigation ascertained the formation of stable metal gold nanoparticles and the analysis of FT-IR spectra highlighted the formation of an oriented surfactant monolayer at the nanoparticle surface. Simple evaporation under vacuum of t…

reversed micellesNanocompositeMaterials scienceCyclohexaneInorganic chemistryNanoparticleCondensed Matter PhysicsMicelleNanomaterialschemistry.chemical_compoundlecithinChemical engineeringchemistryPulmonary surfactantColloidal goldMonolayerconfinement effectAOTGeneral Materials Sciencegold nanoparticlesurfactant adsorptionMaterials Chemistry and Physics
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