• Journal of the Korean Chemical Society
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• v.50 no.5
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• pp.355-361
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• 2006

The critical micelle concentration (CMC) and the counterion binding constant (B) in a mixed micellar state of the sodium dodecylbenzenesulfonate (DBS) with the polyoxyethylene(23) lauryl ether (Brij 35) at 25oC in water and aqueous solutions of n-butanol (0.1M, 0.2M, and 0.3M) were determined as a function of a1 (the overall mole fraction of DBS) by the use of electric conductivity method and surface tensiometer method. Various thermodynamic parameters (Xi, i, Ci, aiM, , and Hmix) were calculated by means of the equations derived from the nonideal mixed micellar model. The effect of n-butanol on the micellization of the DBS/Brij 35 mixtures has been also studied by analyzing the measured and calculated thermodynamic parameters.

• Journal of the Korean Chemical Society
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• v.41 no.1
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• pp.12-17
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• 1997

The critical micelle concentrations(CMC*) and the counterion binding constants(B) in a micellar state of the mixed surfactant systems of sodium dodecylsulfate(SDS) with sodium dodecylbenzenesulfonate(DBS) at 25℃ in pure water and in aqueous solutions of n-butanol were determined as a function of α1 (the overall mole fraction of SDS) by the use of electric conductivity method. Various thermodynamic parameters(Xi, γi, Ci, aiM, β, ΔHmix and ΔGm0 for the micellization of SDS/DBS mixtures were calculated and analyzed by means of the equations derived from the nonideal mixed micelle model. The effect of n-butanol on the mixed micellization of SDS/DBS mixtures have been measured and analyzed by comparing the values of the thermodynamic parameters in pure water with those in aqueous solutions of n-butanol(0.1 M, 0.2 M, and 0.3 M).

• Applied Chemistry for Engineering
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• v.8 no.6
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• pp.1041-1047
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• 1997

The influence of $\omega$-phenylalkylammonium salt on the critical micelle concentration (CMC) of SDS has been examined using the electric conductivity method. CMC of SDS exhibited the tendency to decrease with the length of alkyl group of additives. The effect of temperature on CMC of SDS in additive solutions has been observed in the range of $18^{\circ}C-50^{\circ}C$. The free energy(${\Delta}G_m^{\circ}$) for the micellization of SDS is negative and the entropy(${\Delta}S_m^{\circ}$) is a large positive value. The enthalpy(ΔHm0is positive in low temperature($18^{\circ}C$) and negative in high temperature($>25^{\circ}C$). In the prensence of organic additives, the micellization of SDS was considered as a spontaneous process and to involve a phase transition. The values of ΔGm0has shown the tendency to increase but the values of ${\Delta}S_m^{\circ}$ and ${\Delta}H_m^{\circ}$ to decrease with the length of alklyl group of additive salts. The changes in ${\Delta}\kappa$(difference of specific conductivity) with increasing mole ratio of additives in the mixed solutions indicated the formation of mixed micelles between SDS and additives. The effect of the length of alkyl chain on the micellization of SDS demonstrated the penetration of organic additives into the palisade layer of the SDS micelle.

• 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.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.55 no.3
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• pp.379-384
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• 2011

The critical micelle concentration (CMC) and the counter ion binding constant (B) for the mixed micellizations of DBS (sodium dodecylbenzenesulfonate), SDS (sodium dodecylsulfate), and Brij 30 (polyoxyethylene(4) lauryl ether) at $25^{\circ}C$ in pure water were determined by the use of electric conductivity and surface tension measuring methods. Various thermodynamic parameters ($X_i,\;{\gamma}i,\;C_i,\;a_i^M,\;{\beta}$, and ${\Delta}H_{mix}$) were calculated and compared with each other mixed surfactant system by means of the equations derived from the nonideal mixed micellar model. The results show that the SDS molecule interacts more strongly with Brij 30 molecule than DBS molecule and that the SDS/Brij 30 mixed surfactant system has the greatest negative deviation from the ideal mixed micellar model and the SDS/DBS mixed system has followed almost the ideal mixed micellar model.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.2
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• pp.282-295
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• 2005

The processing of dietary lipids can be distinguished in several sequential steps, including their emulsification, hydrolysis and micellization, before they are absorbed by the enterocytes. Emulsification of lipids starts in the stomach and is mediated by physical forces and favoured by the partial lipolysis of the dietary lipids due to the activity of gastric lipase. The process of lipid digestion continues in the duodenum where pancreatic triacylglycerol lipase (PTL) releases 50 to 70% of dietary fatty acids. Bile salts at low concentrations stimulate PTL activity, but higher concentrations inhibit PTL activity. Pancreatic triacylglycerol lipase activity is regulated by colipase, that interacts with bile salts and PTL and can release bile salt mediated PTL inhibition. Without colipase, PTL is unable to hydrolyse fatty acids from dietary triacylglycerols, resulting in fat malabsorption with severe consequences on bioavailability of dietary lipids and fat-soluble vitamins. Furthermore, carboxyl ester lipase, a pancreatic enzyme that is bile salt-stimulated and displays wide substrate reactivities, is involved in lipid digestion. The products of lipolysis are removed from the water-oil interface by incorporation into mixed micelles that are formed spontaneously by the interaction of bile salts. Monoacylglycerols and phospholipids enhance the ability of bile salts to form mixed micelles. Formation of mixed micelles is necessary to move the non-polar lipids across the unstirred water layer adjacent to the mucosal cells, thereby facilitating absorption.

• 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.53 no.2
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• pp.118-124
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• 2009

The values of critical micelle concentration (CMC) and counter ion binding constants (B) in a micellar state of CPC (1-hexadecylpyridinium chloride) with Brij 35 (polyoxyethylene(23) lauryl ether) in water were determined as a function of ${\alpha}_1$ (the overall mole fraction of CPC) by the use of electric conductivity method. Various thermodynamic parameters ($X_i,\;{\gamma}_i,\;C_i,\;a_{i}^{M},\;\beta,\;and\;{\Delta}H_{mix}$) were calculated and analyzed by means of the equations derived from the non-ideal mixed micellar model. And thermodynamic parameters (${\Delta}{G^o}_m,\;{\Delta}{H^o}_m,\;and\;{\Delta}{S^o}_m$) for the micellization of CPC/Brij 35 mixtures were also calculated from the temperature dependence of the CMC values. The values of ${\Delta}{G^o}_m$ are all negative, but the values of ${\Delta}{S^o}_m$ and ${\Delta}{H^o}_m$ are positive or negative, depending on the measured temperature and ${\alpha}_1$.

• Journal of the Korean Chemical Society
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• v.42 no.5
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• pp.519-525
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• 1998

The critical micelle concentration $(CMC^{\ast})$ and the counterion binding constant (B) in a micellar state of the mixed surfactant systems of dodecylpyridinium chloride (DPC) with dodecyltrimethylammonium bromide (DTAB), tetradecyltrimethylammonium bromide (TTAB), and cetyldimethylethylammonium bromide (CDEAB) were determined at $25^{\circ}C$ as a function of ${\alpha}_1$ (the overall molc fraction of DPC) by the use of electric conductivity method. Various thermodynamic parameters $(X_{i},\;{\gamma}_{I},\;C_{i},\;a^{M}_{i}, \beta,\;{\Delta}H_{mix}, \;and\; {\Delta}G^{o}_{m})$ for the micellization of DPC/DTAB, DPC/TTAB, and DPC/CDEAB mixtures were calculated and analyzed for each system by means of the equations derived from the pseudophase separation model. The results show that the DPC/DTAB mixed system has the greatest deviation and the DPC/CDEAB mixed system has the smallest deviation from the ideal mixed micellar model.