• Bulletin of the Korean Chemical Society
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• 제8권2호
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• pp.118-122
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• 1987

The micelle formation of NaDC was studied by fluorometric and viscometric measurements. The thermodynamic parameters of the primary and secondary micellization of the bile salt were evaluated. The primary micelle formation was appeared to be an entropy driven process due to hydrophobic effect, while the major driving force for secondary micelle formation of the bile salt is the large negative enthalpy. The secondary micelle provides less hydrophobic environment to pyrene than the primary micelle does. The cooperative aggregation of primary micelles via hvdrogen bond formation was proposed for the secondary micelle formation.

• 대한화학회지
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• 제33권5호
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• pp.459-467
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• 1989

계면활성제가 수용액 중에 용해되면 용액내에서 micelle이라는 응집체를 형성하며, micelle은 그 내부에 oil를 용해시켜 swollen micelle을 형성하게 된다. 실제로 물-oil-계면활성계의 상평형도상에서 micelle과 swollen micelle은 동일영역에 존재하게 되나 일반적으로 micelle과 swollen micelle의 형성에 관해서는 서로 다른 관점으로 취급되어 왔다. 본 연구에서는 이러한 계면활성제 응집체의 형성에 관한 일관된 열역학적 모델을 제시하고자 한다. 모든 경우에 저농도 영역에서 이상용액 이론을 적용하였으며, micelle 형성에너지는 소수성 작용에너지와 계면에서의 표면에너지의 합으로 표시하였다. 이론식으로부터 임계마이셀농도, 평균응집분자수, 용해비 등을 예측하였으며 실험관측치와 비교하였다.

• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.897-902
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• 2001

The protein back-extraction processes were discussed from the viewpoint of the micelle-micelle interaction. Bovine serum albumin (BSA) suppressing the cluster formation of reverse micelle (positive value of ${\beta}pr)$ has the high back-extra cted fraction (Eb), but cytochrome c enhancing the formation of reverse micelle (negative value of ${\beta}pr)$ has the low back-extracted fraction, relatively. We have also examined quantitatively the effects of alcohol addition and protein solubilization on the percolation process of reverse micelle. The alcohols suppressing the formation of micellar cluster (high values of ${\beta}t)$, remarkably improved the back-extraction rates of BSA and cytochrome c. The values of ${\beta}t$, defined by the variation of percolation process, and the back-extraction behavior of proteins have a good linear correlation. These results indicate that the micelle-micelle interaction or micellar clustering plays an important role in the back-extraction process of proteins.

• 대한화학회지
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• 제10권4호
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• pp.161-165
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• 1966

The critical concentrations of ${\alpha}$-amino capric acid for micelle formation have been determined by the surface tension measurements in both acidic and alkaline solutions, and also by the dye titration using Rhodamine B in alkaline solutions. The critical micelle concentrations obtained by the two methods show the good agreements within experimental errors. Since ${\alpha}$-amino acid is an ampholyte, it may aggregate to form the micelles in both more acidic and basic media than its isoelectric point. It is found that the basic media are rather preferable for the micelle formation than the acidic media. The effect of gegen ions upon the critical concentration for micelle formation in alkaline media is similar to that expected from the salt effect on the CMC (Critical Micelle Concentration).

• Bulletin of the Korean Chemical Society
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• 제7권5호
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• pp.399-402
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• 1986

The critical micelle concentration (CMC) of sodium deoxycholate (NaDC) and the effects of amides on the micellization processes have been studied by fluorometric technique using pyrene as a probe. The addition of amides as cosolvent destabilized the NaDC micelle and increased the CMC. The order of effectiveness for the perturbation of NaDC micelle was N-methylacetamide ${\ge}$ DMF > acetamide > formamide, which is the order of hydrophobicity of the amines. This indicated that the effect of amides on the micellization processes of NaDC arises from diminution of the hydrophobic effect. The electrostatic repulsion between ionic head groups in the NaDC micelle appeared to be much less than that in aliphatic ionic micelle. This was also revealed in the weaker dependence of the CMC on ionic strength. The premicellar association of NaDC was not significantly involved in the micellization processes of the bile salt.

• 대한화학회지
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• 제10권2호
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• pp.103-108
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• 1966

The effect of temperature on the critical micelle concentration of dodecylpyridinium chloride has been determined by electrical conductance method over the range from $5^{\circ}C\;to\;50^{\circ}C$. The values of the change in heat content, ${\Delta}H_m$, and the other thermodynamic parameters have been estimated using the equation of temperature dependence on the critical micelle concentration for the same temperature range. The significance of these thermodynamic quantities and their relations to the various current theories of micelle forming processes were discussed.

• Archives of Pharmacal Research
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• 제26권8호
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• pp.653-658
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• 2003

It has been reported that at low temperature region, poloxamers existed as a monomer. Upon warming, an equilibrium between unimers and micelles was established, and finally micelle aggregates were formed at higher temperature. In this study, the fluorescence spectroscopy was used to study the micelle formation of the poloxamer 407 in aqueous solution. The excitation and emission spectra of pyrene, a fluorescence probe, were measured as a function of the concentration of poloxamer 407 and temperature. A blue shift in the emission spectrum and a red shift in the excitation spectrum were observed as pyrene transferred from an aqueous to a hydrophobic micellar environment. From the $I_1/I_3 and I_{339}/I_{333}$ results, critical micelle concentration (cmc) and critical micelle temperature (cmt) were determined. Also, from the fluorescence spectra of the probe molecules such as 8-anilino-1-naphthalene sulfonic acid and 1-pyrenecarboxaldehyde, the blue shift of the $\lambda_{max}$ was observed. These results suggest a decrease in the polarity of the microenvironment around probe because of micelle formation. The poloxamer 407 above cmc strongly complexed with hydrophobic fluorescent probes and the binding constant of complex increased with increasing the hydrophobicity of the probe.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.383-388
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• 2000

Multiblock copolymers consisting of poly( g-benzyl L-glutamate) (PBLG) as the hydrophobic part and poly(ethylene oxide) (PEO) as the hydrophilic part (GEG) were synthesized and characterized. GEG polymeric micelles were prepared by the dialysis technique. Particle size distributions based on intensity,volume, and number-average were 22.6 $\pm$ 11.9 nm, 23.5 $\pm$ 4.6 nm, and 23.7 $\pm$ 37 nm, respectively. It was observed that par-ticle size and size distribution of GEG polymeric micelles changed significantly with the choice of initial sol-vent. Transmission electron micrographs (TEM) showed the polymeric micelles to be spherically shaped, with sizes ranging from 20 nm to 40 nm in diameter. Fluorescence spectroscopy measurements suggested that GEG block copolymers wereassociated in water to form polymeric micelles, and the critical micelle concentrations (CMC) value of the block copolymers was 0.0094 g/L. Further evidenceof micelle formation of GEG block copolymers and limited mobility of the PBLG chain in the core ohe micelle was obtained with 1 H NMR in D2O.

• 대한화학회지
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• 제13권1호
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• pp.1-4
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• 1969

Temperature effect on the critical micelle concentration of hexadecyl trimetyl ammonium bromide over the range of $2^{\circ}-50^{\circ}C$ has been investigated by the method of electrical conductivity. The values obtained have been formulated as a power series in T. Several thermodynamic parameters have been calculated for the temparature range examined and their values have been discussed in the light of current theories on the participation of solvent in micelle formation.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.198-201
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• 2000

The capacity of micelle formation between astaxanthin and various surfactants was compared. Tween 20 was identified the most suitable surfactant in terms of astaxanthin extraction capacity. The ethylene oxide group of Tween 20 was identified as the most significant factor to increase the HLB value that determined the extraction capacity. The effect of micelle formation condition, such as molar ratio of astaxanthin and Tween 20, pH and ionic strength was also investigated. pH and ionic strength showed no significant effects. Antioxidant activity of astaxanthin was twice of ${\alpha}-tocopherol$ and 4 times of ${\beta} -carotene$. Crude astaxanthin extract from the yeast cell seemed to be less degraded than pure astaxanthin by air and light exposure, probably because of the presence of other carotenoids and lipids. Under the optimal conditions, the molar ratio of micelle formed was found to be 1 : 12 for astaxanthin : Tween 20.