Apparent molar relative enthalpies were measured for the nonionic ethoxylated surfactant CH3-(CH2)5-(OCH2-CH2)5OH (C6E5) in aq. soln. at const. molality of the ionic surfactant CH3-(CH2)5-SO-3Na+ (C6SNa) at 25°C. The exptl. data obtained by a stepwise diln. process allowed evaluation of the C6E5 first interaction parameter at several const. molalities of C6SNa. The C6E5 crit. micelle compn. as a function of the C6SNa molality was also estd. The exptl. calorimetric data, together with the mixed micelles compn. computed in the past by some of us [Ciccarelli et al., Langmuir 14, 7130 (1998)], allowed computation of the ΔhMic of micellization. The exptl. data are compared to those predicted by the ideal soln. model and regular soln. model of mixed micellization. From a calorimetric study performed on the water-hexanol-C6SNa and water-penthaethylene glycol-C6SNa model systems, it can be argued that the interactions among the hydrophilic heads in the C6E5-C6SNa mixed micelles prevail on the contribution of the hydrophobic tails in ruling the enthalpic properties of the system.

Mixed micellar aggregates of nonionic and anionic surfactants with short hydrophobic tails: a microcalorimetric study

D'ERRICO, GERARDINO;
2002

Abstract

Apparent molar relative enthalpies were measured for the nonionic ethoxylated surfactant CH3-(CH2)5-(OCH2-CH2)5OH (C6E5) in aq. soln. at const. molality of the ionic surfactant CH3-(CH2)5-SO-3Na+ (C6SNa) at 25°C. The exptl. data obtained by a stepwise diln. process allowed evaluation of the C6E5 first interaction parameter at several const. molalities of C6SNa. The C6E5 crit. micelle compn. as a function of the C6SNa molality was also estd. The exptl. calorimetric data, together with the mixed micelles compn. computed in the past by some of us [Ciccarelli et al., Langmuir 14, 7130 (1998)], allowed computation of the ΔhMic of micellization. The exptl. data are compared to those predicted by the ideal soln. model and regular soln. model of mixed micellization. From a calorimetric study performed on the water-hexanol-C6SNa and water-penthaethylene glycol-C6SNa model systems, it can be argued that the interactions among the hydrophilic heads in the C6E5-C6SNa mixed micelles prevail on the contribution of the hydrophobic tails in ruling the enthalpic properties of the system.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11588/2747
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