• 대한화학회지
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• 제40권6호
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• pp.420-426
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• 1996

순수 물에서 Sodium dodecylsulfate(SDS)와 Sodium dodecylbenzenesulfonate(DBS)로 구성된 혼합계면활성제의 임계미셀농도(CMC) 및 반대이온의 결합상수(${\beta}$)값을 15$^{\circ}C$에서 35$^{\circ}C$까지의 온도범위에서 전도도법으로 측정하였으며, 측정된 CMC 및 ${\beta}$값의 온도에 따른 변화로부터 SDS/DBS 혼합계면활성제의 미셀화에 대한 여러가지 열역학 함수값(${\Delta}C_p,\;{\Delta}G_m^{\circ},\;{\Delta}H_m^{\circ}$ 및 ${\Delta}S_m^{\circ}$)들을 계산하였다. 측정한 온도범위 내에서 SDS/DBS 혼합계면활성제의 미셀화로 인한 ${\Delta}G_m^{\circ}$와 ${\Delta}C_p$의 값들은 모두 음의 값을 그리고 ${\Delta}S_m^{\circ}$값은 모두 양의 값을 나타내었다. 이러한 열역학 함수값들의 온도 및 몰분율조성(${\alpha}_{SDS}$)에 따른 변화를 이용하여 SDS/DBS 혼합계면활성제의 미셀화를 분석하였다.

• 한국응용과학기술학회지
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• 제8권2호
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• pp.105-114
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• 1991

In relation to the preparation of Langmuir-Blodgett thin film, four kinds of N-alkylpyridiniurn bromide were synthesized. The values of surface tensions of these materials, measured with a Traube stalagmometer, gave the relationship between the critical micells hydrophobic radical and between CMC and temperature. Values of thermodynamic properties(${\Delta}H^0_m,\;{\Delta}S^0_m,\;{\Delta}G^0_m,$) for the formatoin of micelle were also obtained. Experiments gave the following results; at the temperature range between 40 and 60$^{\circ}C, CMC of Hexadecyl-, Octadecyl-, Eicosyl-, and Docosyl-Pyridinium Bromide were $7.64{\times}10^{-4}{\sim}9.13{\times}10^{-4},\;3.85{\times}10^{-4}{\sim}4.60{\times}10^{-4},\;2.00{\times}10^{-4}{\sim}2.39{\times}10^{-4},\;and\;1.07{\times}10^{-4}{\sim}1.28{\times}10^{-4}$ mol/l, respectively. Surface tension, ${\Gamma}_{CMC}$, of those were 33.49${\sim}$36.00, 34.78${\sim}$37.61, 35.49${\sim}$37.61 and 38.76${\sim}$55.80 dyne/cm, respectively, The relationship between CMC and the mumber of carbon atoms in the hydrophobic radical, N was expressed as follows : Log(CMC)=A-BN where A and B are constants. At the temperature range between 40 and 60$^{\circ}C$, the change of Gibbs evergy (${\Delta}G_m$) for one methylene group ($-CH_2-$) were -0.65RT, respectively, The minus values of enthalpy change (${\Delta}H_m$) suggest that the formation of micelle is exothermic. Additionally, the overall increase in the entropy change (${\Delta}S_m$) with respect to the temperature increase suggests that the formation of micelle is attained by a exothermic enthalpy directed process.

• 분석과학
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• 제11권3호
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• pp.151-155
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• 1998

100 mM NaCl+27 mM $MgCl_2$ 용액에서, 도데실황산나트륨 (SDS)의 유무에 따른 1.0 mM 메틸비올로겐 ($MV^{2+}$)의 전기화학적 거동을 연구하였다. ${\Delta}E_p$(산화와 환원 봉우리전위 값의 차이) 대 - log[SDS]로 도시한 그림에서 두 선의 교차점을 임계미셀농도 (CMC)로 결정하였다. $Mg^{2+}$가 첨가되면, 유리탄소전극에 대한 효과적인 $MV{\cdot}^+$의 접근이 가능해지고 미셀형성도 지연되었다.

• 한국응용과학기술학회지
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• 제18권2호
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• pp.118-126
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• 2001

Micelle formation and adsorption at the $Ti0_{2}$ interface of a series of polystyrene-polythylene oxide(PS-PEO) block copolymer in aqueous solution was studied using fluorescence probing and small-angle X-ray methods. Further, the stability of aqueous $Ti0_{2}$ dispersion in the presence of copolymer was investigated by microelectrophoresis, optical density and sedimentation measurements. The dissolution of pyrene as fluorescent probe in aqueous surfactant solution leads to a slow decrease of the $I_{1}/I_{3}$ ratio, as the copolymer concentration increase; $I_{1}$ and $I_{3}$ are respectively the intensities of the first and third vibrionic peaks in the pyrene fluorescence emission. The behaviour was due to the characteristics of the copolymers and/or to the copolymer association efficiency in water. Moreover, the adsorption at the plateau level increases with decreasing PEO until chain length. The zeta potential of $TiO_{2}$ particles decreases with increasing copolymer concentration and reaches a plateau value. Finally, stabilization using block copolymers was more effective with samples having higher weight fractions of PS block.

• 대한화학회지
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• 제37권9호
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• pp.781-786
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• 1993

$Mg^{2+}$ 존재하에서 비이온성 계면활성제 $nonylphenol-(ethylene oxide)_n$[NP-nEO; n = 12, 40, 100]와 요오드간의 상호작용을 UV-visible spectrophotometer를 이용하여 수용액 중에서 조사하였다. CMC (Critical micelle concentration)는 $Mg^{2+}$ 농도 증가에 따라 감소하였으며, 그 감소폭은 EO(ethylene oxide) 수에 크게 의존하였다. CMC 이상에서 $Mg^{2+}$ 첨가에 따른 상호작용 피크와 강도는 증가하다가 감소하는 변곡점을 보였다. 상호작용 피크의 강도 증가는 $Mg^{2+}$ 존재하에서 미셀구조가 더욱 조밀해진데 따른 요오드와의 전자주게-받게 겹침증가로 볼 수 있다. 이러한 현상들은 비이온성 계면활성제 미셀표면에 노출된 EO 사슬이 유사크라운에테르 구조를 형성하여 $Mg^{2+}$ 의 착물을 형성할 수 있는 가능성을 보여준다.

• 한국재료학회지
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• 제22권4호
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• pp.207-210
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• 2012

The preparation of $Sm_2O_3$ doped $CeO_2$ in Igepal CO-520/cyclohexane reverse micelle solutions has been studied. In the present work, we synthesized nanosized $Sm_2O_3$ doped $CeO_2$ powders by reverse micelle process using aqueous ammonia as the precipitant; hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of a micro emulsion consisting of cyclohexane as the oil phase, and poly (xoyethylene) nonylphenylether (Igepal CO-520) as the non-ionic surfactant. The synthesized and calcined powders were characterized by Thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), and Transmission electron microscopy (TEM). The crystallite size was found to increase with increase in water to surfactant (R) molar ratio. Average particle size and distribution of the synthesized $Sm_2O_3$ doped $CeO_2$ were below 10 nm and narrow, respectively. TG-DTA analysis shows that phase of $Sm_2O_3$ doped $CeO_2$ nanoparticles changed from monoclinic to tetragonal at approximately $560^{\circ}C$. The phase of the synthesized $Sm_2O_3$ doped $CeO_2$ with heating to $600^{\circ}C$ for 30 min was tetragonal $CeO_2$. This study revealed that the particle formation process in reverse micelles is based on a two step model. The rapid first step is the complete reduction of the metal to the zero valence state. The second step is growth, via reagent exchanges between micelles through the inter-micellar exchange.

• 분석과학
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• 제8권2호
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• pp.107-116
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• 1995

양이온 계면활성제인 cetyltrimethyl ammonium bromide(CTAB)를 첨가함에 따라 4-biphenyl acetate ($BPA^-$) 음이온의 202nm band의 흡광도 변화를 측정하여 CTAB의 CMC를 구하였다. 또한 $30^{\circ}C{\sim}70^{\circ}C$의 온도범위에서 CTAB의 미셀화 과정에 수반되는 열역학적 파라미터를 구하였다. 이 온도범위에서 CTAB의 미셀화 자유에너지는 음의 값을 나타내며 미셀화 엔트로피(${\Delta}S^{\circ}m$)는 큰 양의 값을 나타내고 있다. CTAB의 미셀화 과정은 자발적인 상전이(phase transition) 현상임을 알 수 있었다. $300MHz\;H^1-NMR$ 자료로부터 $BPA^-$ 음이온의 CTAB 미셀내의 배향을 알 수 있었다. $BPA^-$ 음이온의 방향족 기가 CTAB 미셀내의 palisade layer까지 침투하여 혼합 미셀을 형성함을 알 수 있었다.

• 한국식품과학회지
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• 제34권5호
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• pp.770-774
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• 2002

대두유 수중유적형 유화액의 산화에 미치는 surfactant micelle의 영향을 규명하기 위하여 수중유적형 유화액에서 continuous phase로 전이되는 ferric iron의 양을 측정하였다. Continuous phase로 전이된 ferric iron의 양은 첨가한 잉여의 surfactant micelle의 농도를 $0.5{\sim}2.0%$로 증가시킬수록, 저장기간이 길어질수록 증가하였다. pH 3.0에서 continuous phase로 전이된 ferric iron의 양은 pH 7.0에서 보다 높게 나타났다. Ferric iron을 함유한 대두유 수중유적형 유화액의 지방산화정도는 hydroperoxide와 headspace hexanal을 측정하여 살펴본 결과 첨가된 계면활성제의 양이 증가할수록 산화는 감소하였다. 이상의 결과로 첨가된 계면활성제에 의해 수중유적형 유화액에서 prooxidant로 작용하는 ferric iron의 위치가 변화되어 산화를 줄일 수 있을 것으로 판단하였다.

• 한국응용과학기술학회지
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• 제15권3호
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• pp.39-45
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• 1998

In recent years, there has been considerable interest in the development of new functional surfactant including new type of anionic surfactants. Anionic surfactants, ${\alpha}-sulfo$ fatty acids that straight long chain alkyl group having from 12 to 18 carbon atoms, were synthesized with sulfur trioxide-dioxane complex to good yield. Xylitol ${\alpha}-sulfo$ fatty acid esters were obtained by reaction that the acetification and esterification of xylitol, by addition reaction with sodium chloride and hydrolysis respectively. These compounds were a new group of destructible surfactants which readily hydrolyzed and oxidized in natural water reservoirs. Physical properties of these new compounds involved surface tension, critical micelle concentration(cmc), foaming power, emulsion power, and hydrolysis properties, were measured. The cmc values of the compounds by ring method were assumed to $7.0{\times}10^{-3}{\sim}3.0{\times}10^{-2}mol/{\ell}$ range and surface tensions at cmc were $25{\sim}31dyne/cm$ respectively.

• 한국고분자학회:학술대회논문집
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• 한국고분자학회 2006년도 IUPAC International Symposium on Advanced Polymers for Emerging Technologies
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• pp.310-310
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• 2006

We have demonstrated the formation of highly nanoporous films composed of two different BCMs through layer-by-layer (LbL) assembly on substrates. The films thus prepared showed tunable optical properties, with strong antireflective properties with light transmission above 99%. Considering the wide application areas of both LbL multilayers and block copolymer thin films, the approaches introduced in present study are likely to open up new possibilities for devices with multifunctional properties.