• 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.

• Macromolecular Research
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• v.13 no.6
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• pp.467-476
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• 2005

The main objective of this study was to develop and characterize pH-sensitive biodegradable polymeric materials. For pH-sensitivity, we employed three kinds of moieties: 2-amino-3-(lH-imidazol-4-yl)-propionic acid (H), N-[4-( 4,6-dimethyl-pyrimidin-2ylsulfamoyl)-phenyl]succinamic acid (SM), and 2- {3-[ 4-( 4,6-dimethyl-pyrim­idin- 2-ylsulfamoyl)-phenylcarbamoyl]-propionylamino} -3-(3 H - imidazol-4-yl)-propionic acid (SH). The pH -sensitive diblock copolymers were synthesized by ring opening polymerization and coupling reaction from poly(ethylene glycol) (MPEG), $\varepsilon$-caprolactone (CL), D,L-lactide (LA) and pH-sensitive moieties. The pH-sensitive SH molecule was synthesized in a two-step reaction. The first step involved the synthesis of SHM, a methyl ester derivative of SH, by coupling reaction of SM and L-histidine methyl ester dihydrochloride, whereas the second step involved the hydrolysis of the same. The synthesized SM, SHM and SH molecules were characterized by FTIR, $^{1}H$-NMR and $^{13}C$-NMR spectroscopy, whereas diblock copolymers and pH-sensitive diblock copolymer were characterized by $^{1}H$-NMR and GPC analysis. The critical micelle concentrations were determined at various pH conditions by fluorescence technique using pyrene as a probe. The micellization and demicellization studies of pH-sensitive diblock copolymers were also done at different pH conditions. The pH-sensitivity was further established by acid-based titration and DLS analysis.

• Macromolecular Research
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• v.13 no.5
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• pp.373-384
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• 2005

Novel pH-sensitive moieties containing an s-triazine ring were synthesized with sulfonamide and secondary amino groups. The synthesized pH-sensitive moieties were used for the synthesis of a pH-sensitive amphiphilic ABA triblock copolymer. The pH-sensitive triblock copolymer was composed of diblock copolymers, methoxy poly(ethylene glycol)-poly ($\varepsilon$-caprolactone-co-D,L-lactide) (MPEG-PCLA), and pH-sensitive moiety. These copolymers could be dissolved molecularly in both acidic and basic aqueous media at room temperature due to secondary amino and sulfonamide groups. The synthesized s-triazine rings containing pH-sensitive compounds were characterized by ${^1}H-NMR,\;{^13}C-NMR$, and LC/MSD spectral data. The synthesized diblock and triblock copolymers were also characterized by ${^1}H-NMR$ and GPC analyses. The critical micelle concentrations at various pH conditions were determined by fluorescence technique using pyrene as a probe. Furthermore, the micellization and demicellization study of the triblock copolymer was done with pH-sensitive groups. The sensitivity towards pH change was further established by acid-base titration.

• Applied Chemistry for Engineering
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• v.5 no.5
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• pp.779-785
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• 1994

The interaction between the cationic dye, thionin(Th) and the anionic surfactant, sodium dodecyl sulfate (SDS) has been investigated by absorption spectra. As the temperature of surfactant solution was increased in premicellar range(S/D=10, 80, and 160) which was much lower than the critical micelle concentration(CMC), the increment or decrement of the molar extinction coeffecient ratio appeared. It was found that the most stable temperature range of the oligomer aggregate in Th-SDS system at S/D=160 was below $60^{\circ}C$. With increasing the concentration of inorganic salt and organic solvents in Th-SDS system, ${\alpha}$-band was increased, but ${\gamma}$=band or J-band was decreased. The orders of ${\alpha}$-band increasing power were $Cl^-$>$ClO{_4}{^-}$>$SO{_4}{^{2-}}$>$NO{_3}{^-}$ and 2-propanol>ethanol>methanol>ethylene glycol.

• 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.

• Journal of the Korean Applied Science and Technology
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• v.17 no.2
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• pp.105-112
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• 2000

Surface tension as a function of concentration and temperature was measured for aquous solution of sodium N-acyl sarcosinate, $RCON(CH_{3})CH_{2}$ COONa, From the intersection points in the (${\gamma}-logC$) curves, the critical micelle concentration (cmc) was determined at 20, 30, 40, and $50^{\circ}C$. Structural effects on the cmc maximum and the minimum area per molecule at the aquous solution/air interface were discussed. The free energy, enthalpy, and entropy of micellization and adsorption of surfactant solution also were investigated. Numberous investigators have dealt with sodium N-acyl sarcosinates and their applications as wettings, flooding and reducing agents and as corrosion inhibitors.

• Journal of the Korean Chemical Society
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• v.19 no.6
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• pp.398-402
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• 1975

The light scattering studies of the aqueous solution of dodecyl pyridinium chloride (DPC) and tetradecyl pyridinium chloride (TPC) over the concentration range of 0~70 mM revealed that there exists a so-called 2nd critical micelle concentration (cmc) at about 43 mM and 8 mM respectively in addition to their 1st cmc at 17 mM and 3.5 mM. The 2nd cmc was greatly influenced by additives KCl, which lowered the 2nd cmc. The micelle molecular weight of DPC and TPC solutions at 1st cmc were 20800 and 15600 and the degree of ionization of their micelles at 1st cmc were 0.092 and 0.226 respectively.

• Journal of the Korean Chemical Society
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• v.52 no.5
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• pp.461-467
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• 2008

• 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

• Bulletin of the Korean Chemical Society
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• v.9 no.5
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• pp.308-311
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• 1988

The hydrophobic interaction occurring between rhodamine 6G and tetraphenylborate was investigated spectroscopically by varying the medium with the addition of surfactants or ethanol. The ion aggregates formed between the two ions were destroyed by the additives. The dye existed as monomeric species in the presence of a cationic surfactant whereas it was incorporated with anionic and nonionic surfactants. For the complete dissociation more than the critical micelle concentration (cmc) was required with a nonionic surfactant while less than cmc was necessary with the others.