Thermodynamics of transfer of polar additives from the aqueous to the dodecylsurfactant micellar phases

Causi, S.; Lisi, R. De; Milioto, Stefana

doi:10.1007/bf00650504

Cited by 10 publications

(3 citation statements)

References 52 publications

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“…The experimental enthalpy was corrected for the enthalpy of dilution of PhOH with water (Δ H d,Ph ), and the enthalpy of transfer of PhOH from water to the aqueous copolymer solution (Δ H Ph P ) was calculated. The determined Δ H d,Ph agrees with the literature value …”

Section: Methodssupporting

confidence: 88%

“…In the case of 10R5, the lateral PO segments interact to each other, allowing a positive B PPP value. The pair interaction parameter for phenol is small and negative (−2.1 kJ kg mol -2 ), likely revealing either the interaction between the −OH group and the π electrons of the aromatic ring or the interaction between the two phenolic hydroxylic groups. The B PhP values may be a combination of the effects occurring in the PhOH + water and copolymer + water binary mixtures.…”

Section: Resultsmentioning

confidence: 99%

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Aqueous Nonionic Copolymer-Functionalized Laponite Clay. A Thermodynamic and Spectrophotometric Study To Characterize Its Behavior toward an Organic Material

et al. 2006

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The affinity of functionalized Laponite clay toward an organic material in the aqueous phase was explored. Functionalization was performed by using triblock copolymers based on ethylene oxide (EO) and propylene oxide (PO) units that are EO(11)PO(16)EO(11) (L35) and PO(8)EO(23)PO(8) (10R5). Phenol (PhOH) was chosen as organic compound, which represents a contaminant prototype. To this purpose, densities and enthalpies of mixing as well as PhOH UV-absorption spectra were determined. The enthalpy and the spectrophotometry revealed PhOH-Laponite interactions whereas the volume did not. It emerged that the area occupied by PhOH on the Laponite surface is equal to that computed from the partial molar volume of PhOH in water, corroborating the insensitivity of the experimental volumes to the adsorption process. The situation where both PhOH and copolymer are simultaneously present in the aqueous Laponite suspension was also investigated. It turned out that the copolymer replaces PhOH from the water/Laponite clay interface, resulting in L35 being the more efficient. Moreover, the lateral copolymer-phenol interactions enhance the anchoring of PhOH to the solid surface. The reverse copolymer exercises the most important relevant effect. The UV-absorption spectra of PhOH in the water + copolymer + Laponite mixtures provided information that is consistent with those given by the calorimetric experiments. In conclusion, the aqueous copolymer-functionalized Laponite presents surface properties very different from the bare Laponite, favoring the removal of the organic compound from the solid surface.

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Section: Methodssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Aqueous Nonionic Copolymer-Functionalized Laponite Clay. A Thermodynamic and Spectrophotometric Study To Characterize Its Behavior toward an Organic Material

et al. 2006

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“…In fact, the enthalpy of transfer is positive for the cationic surfactant and negative for the anionic surfactant. This result is reminiscent of that observed for the enthalpy of transfer of phenol from the aqueous to the micellar phases of the same surfactants 9 Osmotic Coefficients of Sodium Dodecyl Sulfate (NaDS), Dodecyltrimethylammonium Bromide (DTAB), Sodium Perfluorooctanoate (NaPFO), and Sodium Chloride (NaCl) in Water−18-Crown-6 Ether (CR) and NaDS and DTAB in Water−β-Cyclodextrin at 310 K a m NaDS φ NaDS m DTAB φ DTAB m NaPFO φ NaPFO m NaCl φ NaCl m CR = 0.2000 m CR = 0.3989 m CR = 0.4000 m CR = 0.40000.010350.2480.009960.9520.009920.6140.049970.910 0.03000−0.0320.020840.5770.016390.0270.10020.886 0.05258−0.1100.024220.4290.019910.1460.14970.887 0.1009−0.1530.047350.2560.02999−0.1640.19960.951 0.1486−0.1420.069520.1750.05861−0.2640.24970.931 0.1980−0.1290.090230.1480.1023−0.2870.29850.947 0.2472−0.0910.13960.0840.1744−0.3120.34970.945 0.3004−0.0770.19990.1340.2370−0.3150.39770.991 0.3494−0.0570.25050.0670.3179−0.2150.44740.970 0.4003−0.0280.30050.1370.49970.939 0.4989−0.0020.34760.1010.39990.114 m CR = 0.39690.009870.3200.04843…”

Section: Resultsmentioning

confidence: 61%

Energetics of Water−Dodecyl Surfactant−Macrocyclic Compound Ternary Systems

et al. 1996

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Enthalpies of dilution and osmotic coefficients of sodium dodecyl sulfate (NaDS) and dodecyltrimethylammonium bromide (DTAB) in water + 18-crown-6 ether (CR) and water + β-cyclodextrin (CD) at a fixed cosolvent concentration were measured at 298 and 310 K, respectively, as functions of the surfactant concentration (m S). Enthalpies of transfer ΔH (W → W + S) of CR (0.03 m) from water to NaDS and DTAB aqueous solutions as functions of m S were also determined at 298 K. From the enthalpies of dilution the apparent (LΦ,S) and partial (L2,S) molar relative enthalpies of both surfactants were calculated. Despite CR forms inclusion complexes with the anionic surfactant only, the L2,S vs m S profiles are similar and the enthalpies of micellization are lower than those in water by about −5 kJ mol-1. In the case of CD as a cosolvent, the L2,S vs m S profile for DTAB is similar to that for NaDS in the postmicellar region but very different in the premicellar one. The trends in the premicellar region are discussed in terms of different solute−solute hydrophilic interactions other than encapsulation while those in the postmicellar region are discussed in terms of the micellization process. The enthalpies of micellization are very large because of the complexed monomers contribution. ΔH (W → W + S) data for CR in DTAB micellar solutions were fitted through an equation previously reported which permits simultaneously obtaining the distribution constant of the uncomplexed CR and its enthalpy of transfer from the aqueous to the micellar phases. The equations were reviewed for CR in NaDS micellar solutions to account for the CR complexation and for the distribution of both the complexed and uncomplexed CR between the aqueous and the micellar phases. The derived properties are briefly discussed. The osmotic coefficient (ΦS) vs m S curve of both surfactants in W + CD shows a minimum at m S equal to the CD concentration (m CD) and a maximum at m S = m CD + cmc. These peculiarities are ascribed to the inclusion complex formation between the macrocyclic compound and the apolar chain of the surfactant. The addition of CR to water leads to the shift of the osmotic coefficient toward lower values. This shift is not very important for DTAB while it is for NaDS for which negative ΦS values were obtained. Sodium perfluorooctanoate behaves like NaDS. Since the osmotic coefficients for NaCl in W + CR are close to those in pure water, the results are interpreted in terms of complexed CR solubilization in the micellar phase.

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Energetics of sodium dodecylsulfate-dodecyldimethylamine oxide mixed micelle formation

1994

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Thermodynamics of transfer of polar additives from the aqueous to the dodecylsurfactant micellar phases

Cited by 10 publications

References 52 publications

Aqueous Nonionic Copolymer-Functionalized Laponite Clay. A Thermodynamic and Spectrophotometric Study To Characterize Its Behavior toward an Organic Material

Aqueous Nonionic Copolymer-Functionalized Laponite Clay. A Thermodynamic and Spectrophotometric Study To Characterize Its Behavior toward an Organic Material

Energetics of Water−Dodecyl Surfactant−Macrocyclic Compound Ternary Systems

Energetics of sodium dodecylsulfate-dodecyldimethylamine oxide mixed micelle formation

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