• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2269-2282
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• 2018

Mixed micelle formation behavior of cationic surfactant-cetyltrimethylammonium bromide (CTAB) and anionic surfactant sodium dodecyl sulfate (SDS) in aqueous as well as in urea medium from 303.15 K to 323.15 K at 5 K interval was carried out by conductometric method. The differences between the experimental values of critical micelle concentrations (cmc) and ideal critical micelle concentrations ($cmc^{id}$) illustrate the interaction between the amphiphiles studied. The values of micellar mole fraction ($X_1^{Rub}$ (Rubingh), $X_1^M$ (Motomura), $X_1^{Rod}$ (Rodenas) and $X_1^{id}$(ideal) of surfactant CTAB determined by different proposed models and outcome indicate high involvement of CTAB in SDS-CTAB mixed micellization, which enhance by means of the augment of mole fraction of CTAB. The negative value of interaction parameter (${\beta}$) showed an attractive interaction involving CTAB and SDS. Activity coefficients were less than unity in all case, which also reveals the presence of interaction between CTAB & SDS. The negative ${\Delta}G^0_m$ values imply the spontaneous mixed micellization phenomenon. The attained values of ${\Delta}H^0_m$ were positive at inferior temperature, while negative at superior temperature. The negative ${\Delta}H^0_m$ values in urea ($NH_2CONH_2$) medium illustrate exothermic micellization process. The magnitudes of ${\Delta}S^0_m$ were positive in almost all cases. The excess free energy of mixed micelle formation (${\Delta}G_{ex}$) was found to be negative, which indicates the stability of mixed micelle as compared to the individual's components micelles.

• Rapid Communication in Photoscience
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• 제4권3호
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• pp.73-75
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• 2015

Cr(VI) reduction was successfully achieved in the presence of cationic micelles (CMs) under visible light illumination. Micelle formation of cationic surfactants seems to be critical in Cr(VI) reduction. Cr(VI) was reduced very fast above the critical micelle concentration (cmc) of CTAB solutions, but was not reduced at all either below or around the cmc of CTAB. The reduction rate of Cr(VI) was enhanced in the absence of dissolved oxygen, supporting that the removal of Cr(VI) should be achieved via a reductive pathway. When CTAB was substituted by Brij 35 or SDS, the reduction of Cr(VI) was negligible. This indicates that the electrostatic interaction between Cr(VI) and headgroups of surfactants is important in the visible light-induced Cr(VI) reduction in micellar solutions.

• 한국환경과학회지
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• 제1권1호
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• pp.69-76
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• 1992

The effects of $Ca_{2+}$ ion on the formation of micelle colloid of nonionic surfactants, nonylphenol-(ethylene oxide)n [NP-(EO)n: n= 11, 40, 100) were investigated by the iodine solubilization method. The characteristics of spectra depended on the concentration of $Ca_{2+}$ ion and the number of EO unit. Above CMC(critical micelle concentration), the intensity of the CT (charge transfer) band by the addition of $Ca_{2+}$ ion for the NP-(EO)11 and NP-(EO)40 increased and when decreased and for the NP-(EO)In continuously increased. The increase in the intensity of CT band were attributed to the compactness of micelle in the presence of $Ca_{2+}$ ion. These phenomena may be explained by the fact that the linear ethylene oxide (EO) chain, relatively free to assume various configuration in aqueous solution, could form a pseudo-crown ether structures capable of forming complexes with $Ca_{2+}$ ion.

• Archives of Pharmacal Research
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• 제15권2호
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• pp.126-129
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• 1992

The critical micelle concentrations (CMCs) of aqueous solutions of a nonionic surfactant, polyoxyl 23 lauryl ether in the presence of various concentration of urea and its derivatives were measured. The CMC of the surfactant increase in proportion to the concentration of the additives, and the CMC-raising activities increased with more and longer alkyl grups substituted in urea. The CMC shift values were successfully correlated with the cloud point shift values and the protein-denaturing activities of the additives, respectively. These results suggest that the micelle formation, clouding of the surfactant and the protein denaturation are a closely related phenomenon, and a common mechanism is operating which might be the hydrophobic interaction.

• 한국응용과학기술학회지
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• 제36권2호
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• pp.609-622
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• 2019

계면활성제가 수용액 중에 용해되면 용액 내에서 micelle (< 20 nm) 이라는 응집체를 형성하며, micelle은 그 내부에 활성물질을 담지하여 가용화 제형이 형성될 수 있다. Swollen micelle은 50~100 nm 정도로 일반 가용화 제형보다 더 많은 양의 활성물질을 담지할 수 있는 제형이다. Swollen micelle은 고압유화와 같은 별도의 공정이 필요한 liposome이나 nanoemulsion과는 달리 특별한 공정이 필요 없어 생산적인 면에서 좀 더 효율성 있는 가용화 및 입자형성 방법이라고 할 수 있다. 본 연구에서는 Poloxamer 407을 이용하여 swollen micelle 제형에 대한 안정화 실험을 진행한 후, Response Surface Methodology (RSM)을 이용하여 tocopheryl acetate 가용화에 대한 제형 최적화 실험을 진행하였다. 가용화에 영향을 주는 계면활성제와 활성물질인 tocopheryl acetate를 요인(factor)로 설정하고 서로 간의 상관관계를 확인하였다. 평가방법으로서 온도 및 시간에 따른 안정성과 입자 분포 및 크기를 확인하였으며, FIB를 통해 효능 물질을 담지한 swollen micelle의 입자 구조 및 모양을 확인하였다. 이러한 실험 결과들을 통하여 tocopheryl acetate를 안정화시킨 swollen micelle은 poloxamer 407 0.500%, octyldodeceth-16 0.387%, tocopheryl acetate 0.945%일 때 가장 최적화된 처방이라 할 수 있다.

• 폴리머
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• 제24권6호
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• pp.854-859
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• 2000

N,N-dimethylamino ethyl methacrylate(DMAEMA)와 poly(ethylene glycol) (PEG)로 이루어진 블록 공중합체를 합성하였고, 그 구조를 FT-IR, DSC, 및 $^1$H-NMR로 확인하였다. 준비된 poly(DMAEMA))-PEG 블록 공중합체 수용액에 poly(ethyl acrylamide)(PEAAm)를 첨가하면 블록 공중합체의 DMAEMA와 poly(EAAm) 사이에서 일어나는 수소결합에 의해 나노복합체가 형성되었다. 나노복합체는 임계미셀농도 이상의 농도에서 이루어졌다.

• Bulletin of the Korean Chemical Society
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• 제5권5호
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• pp.182-187
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• 1984

The polarographic and conductometric studies of methyl viologen $(MV^{++})$ solutions with varying concentration of sodium dodecyl sulfate (SDS) showed strong association of $MV^{++}$ and its cationic radical, $MV^+$., with SDS below the critical micelle concentration. The stoichiometries of these associations were found to be their electric charge ratios. Both electrostatic and hydrophobic interactions were found to contribute to the associations. The formation constant of$MV^+.DS^-$ in 0.1 M NaCl was $7{\times}10^3M$. The $MV^{++}$-SDS association was observed to be cooperative leading to formation of large aggregates. In the presence of $MV^{++}$, the micellization of SDS was formation of SDS homo-micelle without direct involvement of $MV^{++}$.

• 대한화학회지
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• 제16권4호
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• pp.201-204
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• 1972

Decylpyridinium Chloride 수용액의 c.m.c를 $10^{\circ}$부터 $50^{\circ}$사이의 온도에서 전기전도도법으로 결정하였던바 온도에 따른 c.m.c. 변화는 $15^{\circ}$근처에서 최소값을 보였다. Clausius-Clapeyron형의 식과 log(c.m.c)의 온도방법식으로 부터 micelle화 과정에 따른 ${\Delta}Hm$, ${\Delta}$Fm^{\circ}$, ${\Delta}$Sm, ${\Delta}Sm^{\circ}$ 및 ${\Delta}$Cpm을 얻어 dodecylpyridinium chloride와 dodecylpyridinium bromide의 값들과 비교 검토하였다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 봄 학술발표회 논문집
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• pp.291-292
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• 2003

Amphiphilic block copolymer는 self-assembly특성을 가지고 있기 때문에 선택된 용매 속에서 nanoscale-domain 즉 micelle을 형성할 수 있다. 이러한 특성은 기타 불용성 물질을 가용화하고 colloidal particle을 안정화시키거나 micro-emulsion을 형성할 수 있어 pharmaceutics, drug delivery system등 영역, 그리고 emulsion stabilizer, thickener, dispersion agent등으로 사용될 수 있다. (중략)

• Bulletin of the Korean Chemical Society
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• 제31권3호
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• pp.639-644
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• 2010

Amphiphilic porphyrin derivatives have been synthesized and characterized by $^1H$ NMR and MALDI-TOF-MS. All porphyrin derivatives showed very high solubility to aqueous medium as well as hydrophobic organic solvent. The UV-vis absorption of the porphyrin derivatives showed significant broadness and decrease of maximum intensity of absorption in aqueous solution. SEM experiment showed the formation of spherical micellar structure. The $T_1$ relaxation time of aqueous medium was drastically decreased in the presence of Mn(III)-porphyrin derivative, indicating that the supramolecular micelle has strong possibility to use as a $T_1$ contrast agent.