• Applied Chemistry for Engineering
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• v.10 no.4
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• pp.628-634
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• 1999

The orientational binding of ${\omega}$-phenylakylammonium ions to the sodium dodecyl (SDS) micellar interface has been studied from $^{1}H\;NMR$ chemical shift data. The NMR resonaces of the methylene protons of SDS and aromatic protons embedded into the micellar interior have shown the upfield shift. The aromatic induced chemical shifts of the alkyl chain methylene protons of SDS demonstrate the deep penetration into the palisade layer by these organic salts. Alkylammonium groups have been considered to be oriented toward outside of the micellar interface. Aromatic rings have been thought to be oriented toward the micellar core. The depth of penetration by organic salts has been observed to increase with the length of alkyl chain.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.679-687
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• 2013

The critical micelle concentration (CMC) and counter-ion binding constant (B) of the pure cationic surfactants (DTAB, TTAB, CTAB), nonionic surfactants (Tween-20, Tween-40, Tween-80), and their mixed surfactants (TTAB/Tween-20, TTAB/Tween-40, TTAB/Tween-80) in aqueous solutions of 4-chlorobenzoic acid were determined by using the UV/Vis absorbance method and the conductivity method from 284 K to 312 K. Thermodynamic parameters (${\Delta}G^o{_m}$, ${\Delta}H^o{_m}$, and ${\Delta}S^o{_m}$), associated with the micelle formation of those surfactant systems, have been estimated from the dependence of CMC and B values on the temperature and carbon length of surfactant molecules. The calculated values of ${\Delta}G^o{_m}$ are all negative within the measured range but the values of ${\Delta}H^o{_m}$ and ${\Delta}S^o{_m}$ are positive or negative, depending on the length of the carbon chain and surfactant.

• Journal of the Korean Chemical Society
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• v.49 no.5
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• pp.435-440
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• 2005

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.129-135
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• 2007

The critical micelle concentrations (CMC) and the counter ion binding constants (B) in a micellar state of the mixed surfactant systems of Tetradecyltrimethylammonium bromide (TTAB) with Polyoxyethylene(23) lauryl ether (Brij 35) in water were determined as a function of α1 (the overall mole fraction of TTAB) by the use of electric conductivity method and surface tensiometer method from 15 oC to 35 oC. Values of thermodynamic parameters (ΔGom, ΔHom, and ΔSom) for the micellization of TTAB/Brij 35 mixtures were calculated and analyzed from the temperature dependence of CMC values. The results say that the measured values of ΔGom are all negative at the whole measured condition but the values of ΔSom and ΔHom are positive or negative, depending on the measured temperature and α1.

• Journal of the Korean Chemical Society
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• v.41 no.6
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• pp.284-291
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• 1997

The critical micelle concentrations($CMC^*$) of a cationic surfactant cetylpyridinium chloride (CPC) and a nonionic surfactant triton X-100(TX-100) in aqueous solutions of n-alcohols(methanol, ethanol, 1-propanol, 1-butanol and 1-pentanol) were determined by UV spectroscopic method at 25$^{\circ}C$. The various thermodynamic values in 0.1 M n-alcohols were calculated by means of the equation derived from the pseudo-phase separation model and compared with the values in the absence of n-alcohols. The results were a good agreement with the nonideal mixed micelle model, and they showed negative deviation from the ideal behavior.

• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.190-195
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• 2006

The critical micelle concentrations (CMC) and the counter ion binding constants (B) in a micellar state of the mixed surfactant systems of sodium dodecylbenzenesulfonate (DBS) with polyoxyethylene(4) lauryl ether (Brij 30) in water were determined as a function of 1 (the overall mole fraction of DBS) by the use of electric conductivity method and surface tensiometer method from 288 K to 308 K. Various thermodynamic parameters (Smo, Hmo, and Gmo) for the micellization of DBS/Brij 30 mixtures were calculated and analyzed from the temperature dependence of CMC values. The measured values of Gomare all negative but the values of Smo are positive in the whole measured temperature region. On the other hand, the values of Hmo are positive or negative, depending on the measured temperature and 1.

• Journal of the Korean Chemical Society
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• v.39 no.12
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• pp.896-901
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• 1995

The critical micelle concentrations(CMC$^*$) of the mixed surfactant systems of Sodium dodecyl sulfate(SDS) with Tetraethylene glycol monododecyl ether(TGME) in the aqueous solutions of NaCl at $25^{\circ}C$ were determined as a function of the overall mole fraction of $SDS(\alpha1)$ by the use of surface tension method. Various thermodynamic parameters for the micellization of SDS/TGME mixed surfactant systems were calculated and analyzed by means of the equations derived from the nonideal mixed micelle model, based on the pseudo-phase separation model.

• Journal of the Korean Chemical Society
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• v.37 no.6
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• pp.562-569
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• 1993

The pseudophase separation model is used to describe the effects of pH and n-propanol on the mixed micellar formation of protonated and unprotonated dimethyldodecylamine oxides. Dimethyl-dodecylamine oxide surfactant molecules may exist in aqueous solution in either nonionic (unprotonated) or cationic (protonated) form, and they can be modeled thermodynamically as a binary mixture of cationic and nonionic surfactants. The composition of the binary mixture is varied by adjusting the solution pH. And activities, micellar compositions, and monomeric compositions of two surfactant species can be calculated directly from the experimental titration data by applying pseudophase separation model to the micellar system of DDAO in water/n-propanol. The critical micellar concentrations and the p$K_a$ values of the binary mixture systems are dependent on the micellar composition of the protonated cationic surfactant (X); especially they show the minimum phenomena when they are plotted against the micellar composition of the protonated cationic surfactant (X). The critical micellar concentration of the binary mixed DDAO system is generally decreased when n-propanol is added to the binary mixture system, and the degree of decrease is dependent on the concentration of n-propanol.

• Journal of the Korean Chemical Society
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• v.59 no.4
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• pp.271-279
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• 2015

The critical micelle concentration (CMC), the counter ion binding constant (B) and the aggregation number (N^* ) for the mixed micellization of sodium dodecanoate and sodium n-octanoate as two anionic surfactants have been investigated by means of electric conductivity and light scattering. As its experimental results are found to be deviated from ideal mixed model, thus two different kinds of regular solution models such as Rubingh and Motomura are used for interpreting our experimental data. The stability of the mixed micelles has been confirmed from the negative values of the standard Gibbs energy of mixed micellization ΔG^micel,0 over all compositions and the measured values of ΔG^micel,0 agreed with the theoretical ones within the experimental error.

• Journal of the Korean Chemical Society
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• v.38 no.3
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• pp.194-199
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• 1994

The solubilization sites of some phenyl alkanols such as phenol, benzyl alcohol, phenethyl alcohol, 3-phenyl-1-propanol solubilized in 0.2 M aqueous sodium dodecylsulfate micelle solution was studied by two dimensional heteronuclear correlation spectroscopy (2D C-H COSY). The results show more quantitative and clear solubilization sites in the SDS micelle than previous results using $^1H$-NMR spectrum integration. We found that most of the phenyl alkanols penetrate into the core of SDS micelle, and the insertion depth was 6.5∼7.0 methylene units from ${\alpha}$-methylene.