Isothermal Diffusion and Intradiffusion in Surfactant Solutions

Vitagliano, Vincenzo; D’Errico, Gerardino; Ortona, Ornella; Paduano, Luigi

doi:10.1016/b978-012513910-6/50017-7

Cited by 7 publications

(5 citation statements)

References 235 publications

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“…In the literature, diffusion data are available only for a limited number of surfactants . Particularly, some of us studied the aqueous solutions of various nonionic alkyl ethoxylated, – anionic sodium alkyl sulfonate, , and cationic alkyl trimethyl ammonium bromide surfactants .…”

Section: Introductionmentioning

confidence: 99%

“…In the literature, diffusion data are available only for a limited number of surfactants. 1 Particularly, some of us studied the aqueous solutions of various nonionic alkyl ethoxylated, [2][3][4] anionic sodium alkyl sulfonate, 5,6 and cationic alkyl trimethyl ammonium bromide surfactants. 7 In all cases, we considered surfactants with a relatively short hydrophobic tail (i.e., an alkyl chain formed by less than 12 carbon atoms) that, aggregating at quite high surfactant concentration, allow us to investigate in detail the self-aggregation mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Mutual and Intradiffusion Coefficients for the Binary System n-Decyl Dimethyl Phosphine Oxide + Water at 25 °C

2008

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Diffusion coefficients for the binary system n-decyl dimethyl phosphine oxide + water have been studied at 25 °C, with the aim to quantitatively describe the surfactant micellization process in aqueous medium. Accurate mutual diffusion coefficients have been measured by the Taylor dispersion technique. Intradiffusion coefficients of both components have been measured by the pulsed gradient spin echo (PGSE)-FT NMR technique. The data have been compared and interpreted in the framework of the equilibrium model of surfactant self-aggregation. Interpolation of the mutual diffusion coefficients has allowed us to estimate reliable values of the average number of surfactant molecules involved in the formation of a micellar aggregate and the constant of the equilibrium between these aggregates and surfactant unimers. Interpolation of water intradiffusion coefficients has allowed us to estimate the number of water molecules involved in the hydration of surfactants in unimeric and micellized form.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mutual and Intradiffusion Coefficients for the Binary System n-Decyl Dimethyl Phosphine Oxide + Water at 25 °C

2008

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“…The addition of surfactant in sodium aluminate solution caused a decrease in the solution's surface tension. After reaching a certain concentration, the surface tension will be constant even though the surfactant concentration increases [43]. There is a difference in the length of the alkyl chain (tail), so the size of micelles will be different.…”

Section: Characteristics Of Silica-rich Sodalite Zeolite Catalystsmentioning

confidence: 99%

Hydrocracking of Coconut Oil on the NiO/Silica-Rich Zeolite Synthesized Using a Quaternary Ammonium Surfactant

et al. 2020

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NiO/silica-rich zeolite catalysts were used for coconut oil hydrocracking. The catalyst was prepared with a mixture of Na2SiO3, Al(OH)3, NaOH, and quaternary ammonium surfactants. The surfactant was varied of types like as tetrapropylammonium bromide (TPAB) and cetyltrimethylammonium bromide (CTAB). The acidity of the silica-rich sodalite zeolites enhances with the increase in nickel oxide added through a wet impregnation. The hydrocracking process was carried out by a semi-batch method. Liquid products were analyzed using GC-MS. The results showed that the addition of surfactants increased the catalyst surface area and acidity. Meanwhile, the presence of nickel oxide increases the acidity of the catalyst. The hydrocracking results showed an increase in gas products when the surface area was high, i.e., 23.781% in silica-rich sodalite zeolite without template (Z), 32.68% in silica-rich sodalite zeolite with tetrapropylammonium (ZTPA), and 39.673% in silica-rich sodalite zeolite with cetyltrimethylammonium (ZCTA). The presence of NiO increased the liquid product and the selectivity of the bioavtur fraction (C10-C15), where the highest percentage of liquid product was 60.07% at NiO/ZTPA.

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“…Among the various experimental techniques that have been used to characterize surfactant mixtures, the pulsed-gradient spin−echo (PGSE)-NMR technique and its improved versions are some of the most informative. This technique, which was first applied to this kind of system by Carlfors and Stilbs, allows the independent determination of the intradiffusion coefficients of all the components present in the system (i.e., water and surfactants) in various aggregation states (i.e., monomers or micelles). , Consequently, a complete description of the system can be obtained, which constitutes a reliable basis to test theoretical treatments representative of the mixed aggregation process.…”

Section: Introductionmentioning

confidence: 99%

“…This technique, which was first applied to this kind of system by Carlfors and Stilbs, 14 allows the independent determination of the intradiffusion coefficients of all the components present in the system (i.e., water and surfactants) in various aggregation states (i.e., monomers or micelles). 15,16 Consequently, a complete description of the system can be obtained, which constitutes a reliable basis to test Here, the pulsed-gradient stimulated-echo (PGSTE)-NMR technique is used to investigate the heavy water-C 6 E 5 -C 6 DMPO ternary mixtures. The intradiffusion data, analyzed in the framework of the pseudo-phase separation model for mixed micellization, 17 have allowed the determination of the critical micellar concentration (cmc) and the partitioning of both surfactants between the aqueous and the micellar pseudophases.…”

Section: ' Introductionmentioning

confidence: 99%

On the Segregative Tendency of Ethoxylated Surfactants in Nonionic Mixed Micelles

D’Errico

2011

Langmuir

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The aqueous mixtures of two nonionic surfactants, pentaethyleneglycol monohexyl ether (C(6)E(5)) and hexyl dimethyl phosphine oxide (C(6)DMPO), were investigated by the pulsed-gradient stimulated-echo NMR technique. Quite unexpectedly, the results show that the mixture behavior significantly deviates from ideality. Particularly, analysis of the data indicates that, in the mixed aggregates, C(6)E(5) molecules prefer to be surrounded by other C(6)E(5) molecules, forming domains of hydrated ethoxilic chains on the micellar surface. Molecular reasons for the segregative tendency of ethoxylated surfactants and its applicative implications in formulation technology are discussed.

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Isothermal Diffusion and Intradiffusion in Surfactant Solutions

Cited by 7 publications

References 235 publications

Mutual and Intradiffusion Coefficients for the Binary System n-Decyl Dimethyl Phosphine Oxide + Water at 25 °C

Mutual and Intradiffusion Coefficients for the Binary System n-Decyl Dimethyl Phosphine Oxide + Water at 25 °C

Hydrocracking of Coconut Oil on the NiO/Silica-Rich Zeolite Synthesized Using a Quaternary Ammonium Surfactant

On the Segregative Tendency of Ethoxylated Surfactants in Nonionic Mixed Micelles

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