Molecular association of cryptand 221D in NaCl-water solutions.
A small-angle neutron scattering study

Caponetti, E.; Martino, Delia Chillura; Floriano, Michele; Triolo, R.

doi:10.1051/jp4:1993834

Cited by 5 publications

(12 citation statements)

References 2 publications

(3 reference statements)

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“…The size growths with the concentration for compounds 4b – d are similar to those observed for aqueous solutions of a large variety of monomeric surfactants [16,17,18,19,20]. …”

Section: Resultssupporting

confidence: 69%

“…However, the results indicate that the micelle sizes depend on the number of carbon atoms in the alkyl chains, and that the growth rate with the concentration is higher for longer compounds. The size growths with the concentration for compounds 4b – d are similar to those observed for aqueous solutions of a large variety of monomeric surfactants [ 16 , 17 , 18 , 19 , 20 ].…”

Section: Resultssupporting

confidence: 69%

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Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group

et al. 2013

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A series of new gemini surfactants without a spacer group, disodium 2,3-dialkyl-1,2,3,4-butanetetracarboxylates, were synthesized in a green chemistry context minimizing the use of organic solvents and applying microwaves (MW) when activation energy was required. Once the desired architecture was confirmed by means of the nuclear magnetic resonance technique (1H-NMR, 1H-1H COSY) for all the studied surfactants, the critical micellization concentration was determined by conductance measurements. The diffusion coefficient of micelles formed by the four compounds was characterized using pulsed field gradient (PFG)-NMR. Diffusion coefficients were found to be dependent on the concentration and on the number of carbon atoms in the alkyl chain. The absence of the spacer group, peculiar to this new series of gemini surfactants, may confer relatively low flexibility to the molecules, with potential implications on the interfacial properties, namely on micellization. These gemini surfactants might have interesting applications in the preparation of composite materials, in nanotechnology, in gene transfection and mainly, due to the low CMCs, as new interesting ingredients of cosmetics and toiletries.

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“…The size growths with the concentration for compounds 4b – d are similar to those observed for aqueous solutions of a large variety of monomeric surfactants [16,17,18,19,20]. …”

Section: Resultssupporting

confidence: 69%

Section: Resultssupporting

confidence: 69%

Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group

et al. 2013

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“…A HG . The aggregation number trend is similar to that observed, as a consequence of an electrolyte addition, in 5-decyl-4,7,13,16,21pentaoxa-1,10-diazabicyclo-[8.8.5]tricosane (Caponetti et al, 1993 and2003) and decyl-18-crown-6 (Turro et al, 1986) but lower than that observed in (dodecyloxy)methyl-18-crown-6 (Ozeki et al, 1990). All cited surfactants consist of a single macrocycle linked to the hydrocarbon moiety.…”

Section: Figuresupporting

confidence: 81%

Formation of α-ω(4,7,10,13-pentaoxa-16-azacyclooctadecane) hexadecane micelles in aqueous solution – effect of HCl addition

2003

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The structure of aggregates of a new bolaform surfactant [α‐ω (4,7,10,13‐pentaoxa‐16‐azacyclooctadecane) hexadecane] in neat aqueous solution has been investigated by small‐angle neutron scattering. Preliminary data analysis unequivocally indicates that globular micelles are formed. This finding has been confirmed by the analysis of data obtained upon addition of hydrochloric acid. The observed significant reduction of micelle aggregation number has been attributed to the peculiar complexing ability of the two aza‐crown ether units in the surfactant molecule; this is in line with information inferred from the complexation of ions into the non alkylated azacrown ethers. As a consequence of hydrogen ion uptake into the aza‐crown ether unit, the partial ionization of surfactant causes a decrease in the micelle dimension that follows the increased repulsion among head groups.

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“…In most cases, deviations from a monodisperse spherical shape or nonhomogeneities in the scattering density have to be taken into account. − …”

Section: Theory and Data Analysismentioning

confidence: 99%

“…The SANS technique is useful for determining structural parameters of the systems under analysis; − in this paper we have used the SANS technique with the purpose of deriving the mixed micelles composition. Previously, the SANS technique had been applied to suggest that, in an aqueous solution containing ammonium decanoate and ammonium perfluorooctanoate, mixed micelles are formed.…”

Section: Theory and Data Analysismentioning

confidence: 99%

Determination of the Composition of Mixed Hydrogenated and Fluorinated Micelles by Small Angle Neutron Scattering

et al. 1997

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The compositions of mixed micelles formed in aqueous solutions of sodium dodecanoate and sodium perfluorooctanoate at different total surfactant concentrations and at three (0.33, 0.53, and 0.73) sodium perfluorooctanoate mole fractions were determined by the small angle neutron scattering technique coupled with the external contrast method. At each concentration, measurements were performed as functions of the solvent H2O/D2O composition in order to determine the micellar neutron scattering densities. The method described has allowed, at least for the cases under study, a direct determination of the micellar compositions, which, in the past, had been particularly difficult and the object of considerable debate. At all concentrations considered and within the experimental error, one kind of mixed micelle was always observed; these micelles were always richer in the component present in solution in greater proportion. An overall qualitative agreement between the present results and literature predictions based on regular solution theory was found, although a significant difference was noticeable at large sodium perfluorooctanoate concentrations, suggesting that further tests of the theory are required in order to include subtle interaction effects due to differences in the chemical nature of the surfactants.

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Molecular association of cryptand 221D in NaCl-water solutions. A small-angle neutron scattering study

Cited by 5 publications

References 2 publications

Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group

Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group

Formation of α-ω(4,7,10,13-pentaoxa-16-azacyclooctadecane) hexadecane micelles in aqueous solution – effect of HCl addition

Determination of the Composition of Mixed Hydrogenated and Fluorinated Micelles by Small Angle Neutron Scattering

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