• Polymer(Korea)
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• v.24 no.6
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• pp.854-859
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• 2000

The synthesis of poly(N,N-dimethylamino ethyl methacrylate (DMAEMA)-block-poly(ethylene glycol) (PEG)) copolymer has been carried out and the block copolymer was characterized by FT-IR, DSC, and $^1$H-NMR. The formation of polymeric nanoaggregation was observed in the solution mixture of poly(DMAEMA) -block-PEG copolymer and poly (ethyl acrylamide) (EAAm) due to the intermolecular interaction via hydrogen bond between DMAEMA and poly(EAAm). The formation of polymeric nanoaggregation was observed above critical micelle concentration (CMC).

• Journal of the Korean Chemical Society
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• v.19 no.5
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• pp.289-293
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• 1975

According to the viscosity and density studies of an aqueous solution of dodecyl pyridinium chloride (DPC) it was shown that the 2nd critical micelle concentration (2nd cmc) existed in the solution in addition to the 1st cmc. The volume fraction ${\phi}_m$ of the hydrated micelle was calculated by using the following equation: ${\Pi}_{rm}=1+2.5{\phi}_m+14.1{\phi}_m^2$ It has been found that the increment of ${\phi}_m$ in the ${\phi}_m$ vs. $C_m$ curve decreased at near the 2nd cmc. And the partial specific volume ($\={v}$) of DPC obtained from the density measurement also decreased rapidly at near the 2nd cmc and remains constant value above the 2nd cmc. This may be attributed to a change in the micelle structure at the 2nd cmc caused by a variation in the type of aggregation and by a decrease in the counterion binding by the micelle.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.545-551
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• 2010

Hydrophobically monoendcapped poly(sodium acrylate)s formed hydrophobic microdomains in water. This was concluded on poly(sodium acrylate)s with a linear $C_{12}$-alkyl chain attached specifically at the end of the polymer. There was no well defined CMC (critical micelle concentration), but rather a gradual transition from a micelle free solution to a micelle solution. Steady state fluorescence spectroscopy indicates that the micro domains are rather hydrophobic. At pH 5 in the abscence of salt and at pH 9 in the prescence of 1 M sodium citrate the CAC (critical aggregation concentration) was in the range of 0.1 to 2.4 mM. However at pH 5 there was a linear increase in the transition concentration with a head-group size due to an increase in steric and electrostatic repulsions between polymer main chains. At pH 9 in the abscence of salt the transition concentration was in the range of 1 to 80 mM. For the larger polymers there was a effect which consisted of a concentration gradient of sodium counterion toward the hydrophobic domain. The effect was larger for the larger polymers because of the higher total sodium concentration and the less steep counterion concentration gradient.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.4
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• pp.51-54
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• 2007

Surfactants can be used as a cosmetics and chemical dispersants. The variation of critical micelle concentration(CMC) with temperature for hexadecyl pyridinium bromide over the range $40^{\circ}C$ to $60^{\circ}C$ has been measured by drop methods. Thermodynamic quantities for micellization of hexadecyl pyridinium bromide in water have been calculated by polynominal equation.

• Journal of the Korean Applied Science and Technology
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• v.28 no.4
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• pp.449-454
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• 2011

This surfactant can be used as a cosmetics and chemical dispersants. The variation of critical micelle concentration(CMC) with temperature for N-eicosyl pyridinium bromide over the range $40^{\circ}C$ to $60^{\circ}C$ has been measured by drop methods. Thermodynamic quantities for micellization of N-eicosyl pyridinium bromide in water have been calculated by polynominal equation.

• Journal of Microbiology
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• v.43 no.3
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• pp.272-276
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• 2005

Bacillus subtilis ATCC 6633 was grown in BHIB medium supplemented with $Mn^{2+}$ for 96 h at $37^{\circ}C$ in a shaker incubator. After removing the microbial biomass, a lipopeptide biosurfactant was extracted from the supernatant. Its structure was established by chemical and spectroscopy methods. The structure was confirmed by physical properties, such as Hydrophile-Lipophile Balance (HLB), surface activity and erythrocyte hemolytic capacity. The critical micelle concentration (cmc) and erythrocyte hemolytic capacity of the biosurfactant were compared to those of surfactants such as SDS, BC (benzalkonium chloride), TTAB (tetradecyltrimethylammonium bromide) and HTAB (hexadecyltrimethylammonium bromide). The maximum hemolytic effect for all surfactants mentioned was observed at concentrations above cmc. The maximum hemolytic effect of synthetic surfactants was more than that of the biosurfactant produced by B. subtilis ATCC 6633. Therefore, biosurfactant would be considered a suitable surface-active agent due to low toxicity to the membrane.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.286-293
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• 2006

Three hundred thirty two bacterial colonies which were able to degrade crude oil were isolated from soil samples that were contaminated with oil in Daejon area. Among them, one bacterial strain was selected for this study based on its low surface tension ability, and this selected bacterial strain was identified as Pseudomonas sp. G314 through physiological-biochemical tests and analysis of its 16S rRNA sequence. Pseudomonas sp. G314 showed a high resistance to antibiotics such as ampicillin, chloramphenicol, spectinomycin, and streptomycin, and heavy metals such as Li, Cr, and Mn. It was found that the optimal pH and temperature for biosurfactant production of Pseudomonas sp. G314 were pH 7.0 and $30^{\circ}C$, respectively. After seven hours of inoculated, the biosurfactant activity reached the maximum, and surface tension of the culture broth was decreased from 72 to 25 dyne/cm. The crude biosurfactant was obtained from the culture broth by acid precipitation, followed by solvent extraction, evaporation and then freeze drying. The CMC (critical micelle concentration) value of the crude biosurfactant was 20 mg/L.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.119-126
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• 2001

This research was carried out to evaluate the effect of recycled wastewater and surfactant above CMC(critical micelle concentration) on the removal rate of PAHs in bench-scale slurry bioreactor. Kinetic parameters based on zero order and first order kinetic models were estimated. The first order model was able to describe the removal of phenanthrene and pyrene with high correlation coefficients. Addition of recycled wastewater could enhance the removal rates of phenanthrene and pyrene. Addition of surfactant above CMC could enhance desorption rate and removal rate of phenanthrene and pyrene.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.188-194
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• 2012

The interaction of 4-alkylbenzoic acid isomers with the micellar system of TTAB (tetradecyltrimethylammonium bromide) was studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of 4-alkylbenzoic acid isomers into the TTAB micellar system and the critical micelle concentration (CMC) of TTAB have been measured with the change of temperature. Various thermodynamic parameters have been calculated and analyzed from those measurements. The results show that the values of ${\Delta}G^o{_s}$ for the solubilization of all the isomers are negative and the values of ${\Delta}H^o{_s}$ and ${\Delta}S^o{_s}$ are all positive within the measured temperature range. The effects of additives (n-butanol and NaCl) on the solubilization of 4-alkylbenzoic acid isomers have been also measured. There was a great change on the values of $K_s$ and CMC simultaneously with these additives. From these changes we can postulate that the solubilization sites of 4-alkylbenzoic acids are the core or deep palisade region of the TTAB micelle.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.473-478
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• 2011

The interaction of para-halogenated benzoic acid isomers with the micellar system of tetradecyltrimethylammonium bromide was studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of benzoic acid isomers into the micellar system of TTAB and the critical micelle concentration (CMC) of TTAB have been measured with the change of temperature. Various thermodynamic parameters have been calculated and analyzed from those measurement. The results show that the values of ${\Delta}G^{\circ}{_s}$ for the solubilization of all isomers are negative and the values of ${\Delta}H^{\circ}{_s}$ and ${\Delta}S^{\circ}{_s}$ are all positive within the measured temperature range. The effects of additives (n-butanol and NaCl) on the solubilization of benzoic acid isomers have been also measured. There was a great decrease on the values of $K_s$ and CMC simultaneously with these additives. From these changes we can postulate that the solubilization sites of each isomers in the TTAB micellar system are the surface or the palisade region of the micelle.