• Journal of the Korean Chemical Society
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• v.17 no.2
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• pp.73-79
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• 1973

The ultrasonic absorption of Dodecyl pyridinium bromide (D.P.B.) in aqueous solution has been measured at $20^{\circ}C$ over a range of frequencies between 0.1 mc and 90 mc and a range of concentrations from 5 to 100 mM. The excess absorption was observed only in the solutions the concentration of which was higher than the critical micellar concentration (c.m.c.) both in the presence and absence of salt. The excess absorption of sound and the relaxation frequencies obtained from the absorption curves show a discontinuity with the variation of the concentration of D.P.B. in the neighborhood of 60 mM. Other properties such as viscosity, conductivity and velocity of sound also exhibit such a change near the same concentration. It is concluded that a change in the properties of the micelles of D.P.B. occurs in the neighborhood of this concentration. The mechanism of the observed ultrasonic excess absorption in attributed to the reaction $M_2{\rightleftarrow}M_1+2Br^-$where$M_2$ and$M_1$are two types of micelles. The rate constants of forward and backward reactions are found to be $6.9 {\times} 10^5 sec^{-1)$and $6.7{\times}10^{10}sec^{-1}mole{-2}$ respectively. Some kinetic characteristics including free energy, enthalpy, entropy and activation energy were calculated.

• Journal of the Korean Chemical Society
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• v.40 no.6
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• pp.420-426
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• 1996

The critical micelle concentration(CMC) and the counterion binding $constant(\beta)$ at the CMC of the mixtures of Sodium dodecylsulfate(SDS) with Sodium dodecylbenzenesulfonate(DBS) in aqueous solutions have been determined from the concentration dependence of electrical conductance at several temperatures from $15^{\circ}C$ to $35^{\circ}C.$ Thermodynamic parameters(${\Delta}C_p,\;{\Delta}G_m^{\circ},\;{\Delta}H_m^{\circ}$ 및 ${\Delta}S_m^{\circ}$ and ${\Delta}C_p$), associated with the micelle formation of SDS/DBS mixtures, have been estimated from the temperature dependence of CMC and $\beta$ values. The measured values of ${\Delta}G_m^{\circ}\;and\;{\Delta}C_p$ are negative but the values of ${\Delta}S_m/^{\circ}$ are positive in the whole measured temperature region. The significance of these thermodynamic parameters and their relation to the theory of the micelle formation of SDS/DBS mixtures have been also considered.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.136-141
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• 2001

In this study, we analysed tree surface flow by using the experimental and numerical method with a different surfactant concentration. We compared numerical solution with experimental results for one-dimensional model. The result shows that in general the tree surface velocity can well be reproduced by the one-dimensional model for various surfactant concentration.

• Journal of the Korean Chemical Society
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• v.7 no.4
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• pp.277-279
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• 1963

The surface tension of solutions of synthesized ammonium caprylate and ammonium caprate was measured by the ring method. The changes with of surface tension of solution of ammonium caprylate showed evidently that the salt had the critical micelle concentration(c.m.c.) at $30^{\circ}C$. The c.m.c. values of above two salts were determined from the change of surface tension of solution with concentration at various temperatures. The temperature dependence of the c.m.c. and the influence of addition of excess ammonia on the c.m.c. were also investigated.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.224-229
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• 1992

Sodium acyl isethionate, one of the anionic surfactants, was synthesized and purified from the fatty acid and the sodium isethionate. To investigate the tendency of the surface active properties of acyl group, surface tension, foaming power, foam stability, lime soap dispersing power, detergency, and critical micelle concentration were determinded. The results exhibited that sodium acyl isethionates had exellent surface active properties and critical micelle concentrations were measured between $1.1{\times}10^{-4}mol/l$ and $4.8{\times}10^{-3}mol/l$. In this case, surface tensions were indicated between 26.8dyn/cm and 36.7dyn/cm.

• Journal of the Korean Chemical Society
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• v.43 no.6
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• pp.614-620
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• 1999

The critical micelle concentration (CMC) and the counterion binding constant (${\beta}$) at the CMC of the mixtures of Dodecylpyridinium chloride (DPC) and Tetradecyltrimethylammonium bromide (TTAB) have been determined from the concentration dependence of electrical conductance at various temperatures from $4^{\circ}C$ to $36^{\circ}C$. Thermodynamic parameters (${\Delta}C_p$, ${\Delta}G^o_m$, ${\Delta}H^o_m$ and ${\Delta}S^o_m$), associated with the micelle formation of DPC/TTAB mixtures, have been estimated from the temperature dependence of CMC and ${\beta}$values. The measured values of ${\Delta}C_p$ and ${\Delta}G^o_m$ are negative but the values of ${\Delta}S^o_m$ are positive in the whole measured temperature region. The values of ${\Delta}H^o_m$ are positive at low temperature region and negative at high temperature region. The results show that all of the thermodynamic parameters are dependent on temperature and mole fraction of DPC(${\alpha}_DPC$).

• Applied Chemistry for Engineering
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• v.18 no.3
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• pp.267-272
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• 2007

The critical micelle concentration (CMC) and the counterion binding constant (B) in a mixed micellar state of the trimethyltetradecylammonium bromide (TTAB) with the polyoxyethylene (23) lauryl ether (Brij 35) at $25^{\circ}C$ in water and in aqueous solutions of n-butanol (0.1 M, 0.2 M, and 0.3 M) were determined as a function of ${\alpha}_1$ (the overall mole fraction of TTAB) by the use of electric conductivity method and surface tensiometer method. Various thermodynamic parameters ($X_i$, ${\gamma}_i$, $C_i$, ${a_i}^M$, ${\beta}$, and ${\Delta}H_{mix}$) were calculated by means of the equations derived from the nonideal mixed micellar model. The effects of n-butanol on the micellization of TTAB/Brij 35 mixtures have been also studied by analyzing the measured and calculated thermodynamic parameters.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.49-54
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• 1993

The effects of added alcohols on the critical micelle concentration(CMC) of cetylpyridinium bromide(CPB) were investigated by the UV-Vis spectrophotometer at the temperature range of 8∼45$^{\circ}C$. The CMC of CPB was increased with the addition of methanol in the whole temperature region studied, while decreased with the addition of ethanol and propanol. The increase of CMC with the addition of methanol may be attributable to the increasing solvent power of the methanol-water mixture, because methanol was scarcely solubilized into the palisade layer of the micelle of CPB. The decrease of CMC with the inclusion of ethanol and propanol may be derived from the solubilization of alcohols into the micelles. On the other hand, the CMC was decreased with the temperature rise in the low-temperature region below about 25$^{\circ}C$, and the CMC was increased in the high-temperature region above that. The thermodynamic parameters (${\Delta}G_M^{\circ},\;{\Delta}H_M^{\circ},\;and\;{\Delta}S_M^{\circ}$) of the micellization of CPB were obtained in some aqueous alcohol solutions. In the whole temperature region (8∼45$^{\circ}C$), the values of ${\Delta}G_M^{\circ}$ were negative, while those of ${\Delta}S_M^{\circ}$ were positive. And in the temperature region below about 25$^{\circ}C$ the ${\Delta}H_M^{\circ}$ values were positive, while in the temperature region above that the values were negative.

• Journal of the Korean Chemical Society
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• v.20 no.3
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• pp.193-197
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• 1976

The ultrasonic absorption has been measured in aqueous solution of dodecyl pyridinium chloride (DPC) at $20^{\circ}C$ over the frequency range of 0.1${\sim}$90 Mc.The excess absorption was observed only in solutions in which the concentration was higher than the critical micellar concentration(cmc). The mechanism for this feature was attributed to the reaction $M_2\;{\rightleftharpoons}\;M_1\;＋\;1.2Cl^-$ Where $M_2$ and $M_1$ and M1 are two types of micelle. The rate constants of the forward and the reverse reactions were $6.6{\times}10^5 sec^{-1}\;and\;2.7{\times}10^11sec^{-1}mol^{-1.2}$respectively. Some kinetic charateristics including the free energy, enthalpy and entropy were calculated.

• Analytical Science and Technology
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• v.8 no.2
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• pp.107-116
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• 1995

The critical micelle concentration(CMC) of CTAB was determined with changes in absorbance at 202nm band of 4-biphenyl acetate($BPA^-$). With $BPA^-$ as a probe, the effect of temperature on CMC of CTAB has been observed between $30^{\circ}C{\sim}70^{\circ}C$. In this range of temperature the values of CMC are $1.18{\times}10^{-4}{\sim}2.02{\times}10^{-4}M$. The free energy(${\Delta}G^{\circ}m$) and enthalpy(${\Delta}H^{\circ}m$)for the micellization of CTAB was negative and the entropy(${\Delta}S^{\circ}m$) was a large positive value. The micellization of CTAB is considered as a spontaneous process and to involve a phase transition. The orientational binding of 4-biphenyl acetate anion to the CTAB micelle interface has been studied with $300MHz\;H^1-NMR$ data. The change in chemical shift of proton in CTAB as well as those of the protons in $BPA^-$ have been investigated by increasing the mole fraction of the anion in the mixed solutions. The changes in chemical shift with increasing mole fraction of anion($BPA^-$) indicate the formation of mixed micelle between CTAB and $BPA^-$. The changes in chemical shifts of methylene protons in CTAB, demonstrate the penetration of $BPA^-$ into the palisade layer of the CTAB micelle.