• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.259-264
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• 2015

For the enhanced oil recovery, one of the most important factors is to determine the surfactant formulation in chemical flood. The objective of this study is to analyze the microemulsion formed between the alkali-surfactant (AS) solution and A crude oil for screening surfactants. The alkali-surfactant solution was manufactured by using the surfactant purchased from AK ChemTech. $C_{16}-PO_7-SO_4$ and sodium carbonate solution were used as surfactant and alkaline, respectively. Both TEGBE and IBA were used as a co-solvent. The AS solution and A crude oil can form a Type III middle phase microemulsion at the salinity from 0.0 wt%~3.6 wt%. Increasing the salinity causes the phase transition of microemulsion from the lower (Type I) to middle (Type III) to upper (Type II) phase. Interfacial tension (IFT) values calculated by Huh's equation were in good agreement with ultralow IFT. According to this characteristic, the surfactant purchased from a domestic company can be applied to the enhanced oil recovery.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.74.1-74.1
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• 2010

단결정 실리콘 태양전지 공정에서 이방성 습식 식각 용액을 이용하여 기판 표면에 피라미드 구조를 형성하는 것을 텍스쳐링이라고 한다. 실리콘 기판의 표면을 식각하여 요철구조를 만들어줌으로써 셀 내부로 입사되는 광량을 증가시켜 태양전지의 단락 전류 및 효율 향상 효과를 얻을 수 있다. 일반적인 태양전지 공정에서는 요철구조를 형성할 시 따로 마스크를 사용하지 않으며, 태양전지 급 웨이퍼를 절삭손상층 식각 한 후, 강염기성 용액과 알코올의 혼합용액에 담가서 이방성 식각을 실시하여 요철 구조를 형성한다. 본 연구는 기존의 텍스쳐링 공정에서 사용되는 대표적인 용액인 수산화칼륨(potassium hydroxide, KOH)과 알코올의 혼합용액과 사메틸수산화암모늄(Tetramethylammonium Hydroxide, TMAH)과 알코올의 혼합용액에 Triton X-100 계면활성제를 각각 첨가하여 실험을 진행하였다. 식각된 태양전지용 실리콘 기판의 표면은 주사전자현미경(Scanning Electron Microscope)을 통하여 관찰하였고, 분광광도계(UV/VIS/NIR Spectrophotometer)로 반사도 값을 측정하여 기판의 특성을 평가하였다.

• Analytical Science and Technology
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• v.11 no.6
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• pp.413-420
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• 1998

The hydrophobic interaction has been studied on sodium naphthalene derivatives such as sodium 1-naphthaleneacetate (S1NA), sodium 1-naphthalenemalonate (SINM), sodium 2-naphthaleneacetate (S2NA), and sodium 2-naphthalenepropionate (S2NP) in $H_2O$-MeOH mixture solutions and in surfactant solutions. In $H_2O$-MeOH mixture solutions, the hydrophobic interaction was measured, and resulted in the red shift in emission spectra. In cationic surfactant, cetyltrimethylamonium bromide (CTAB) solution, the hydrophobic interaction was also observed by the red shift in absorption and emission spectra.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.519-520
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• 2006

계면활성제의 종류로 OA-n계열에서 분자량이 낮은 OA 300이 가장 우수한 세척력을 보였고 계면활성제의 함량은 3 wt.%일 때 가장 좋았다. 이는 평균입경이 작고 접촉각이 낮은 것으로 분석되어지며 세척력은 우수하지만 저장안정성은 떨어졌다. 그러나 OA 600의 경우 세척력은 떨어지나 저장안정성이 우수하여 이를 혼합한 계면활성제를 사용하여 저장안정성을 높였다.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.602-611
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• 2014

The critical micelle concentration (CMC) of the zwitterionic surfactant of dodecyldimethyl(3-sulfopropyl)ammonium hydroxide(LSB, $CH_3(CH_2)_{11}N^+(CH_3)_2(CH_2)_3SO{_3}^-$) and LSB/Tween-20, LSB/Tween-40, LSB/Tween-80 and LSB/DTAB, LSB/TTAB, LSB/CTAB mixed surfactant systems were determined by using the UV/Vis absorbance method from 284 K to 312 K. And the effects of temperature on the micellization have been measured for the thermodynamic study. The results show that the measured values of gibbs free energy are all negative in the whole measured. The values of enthalpy are positive Tween-20, And negative other surfactants. but the values of entropy are positive in the whole measured temperature region. The results show that all of the thermodynamic parameters are dependent on temperature and alkyl-group's length.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.93-106
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• 2000

One phase liquid crystal formula was developed by using of nonionic surfactants, polyols, water and oils and its physical property was investigated. At the system oft to 1 ratio of POE octyldodecyl ether series, which have Y type (branch type) hydrophobic group, and POE glyceryl monostearate series, Y type hydrophilic group, it was examined that the formula at 7:3, 6:4, and 5:5 ratio of nonionic surfactant : polyols, shows L$\alpha$ , a pattern which is a typical characteristic of liquid crystal structure under the cross microscope polarized film. As results of L$\alpha$ phase diagram study, the formula which had high hydrophilic nonionic surfactant and the 7:3 ratio of nonionic surfactant : polyol appeared to increase the amount of oil containment and to be capable of the lamella formation. Besides it was examined that lamellar liquid crystal formula could contain about 25-40% water between lamella layers and it was transformed into w/o emulsion following as water content increased. When the lamella gel was applied into a human skin, it was investigated that it had effectiveness in increasing transepidermal water content of the skin.

• Journal of Energy Engineering
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• v.9 no.2
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• pp.102-108
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• 2000

난류상태로 유동중인 고분자 수용액은 순수 용매만의 경우에 비교할 때 동일유량에서 초기에 높은 마찰 저항감소효과를 보이며, 이러한 마찰저항감소효과는 펌프의 펌핑능력 증대로 큰 경제적 이익을 가져다준다. 그러나, 고분자 수용액은 그 극적인 마찰저항감소효과에도 불구하고 유동중에 가해지는 기계적 에너지, 열에너지 등에 의해서 초기의 높은 마찰저항감소효과를 점차적으로 상실하게 되기 때문에, 고분자 수용액의 퇴화를 완화시키기위한 연구가 필요하다. 따라서 본 연구에서는 기계적 퇴화특성이 비교적 강한 합성고분자와 계면활성제의 농도합계를 100wpm 으로 고정하고 비율을 11가지로 세분화하여 , 1$0^{\circ}C$의 온도에서 유속 1.5m/sec , 3.0m/sec 및 4.5m/sec 에 대한 퇴화경향을 알아보는 실험을 수행하였으며, 각 조건에서 합성고분자와 계면활성제의 적정비율을 관찰하였다. 실험 결과, 각 속도에서 시간에 따른 퇴화경향은 고속에서 기계적 에너지에 대한 퇴화를 볼 수 있었고, 계면활성제와 합성고분자를 혼합하여 첨가했을 경우 저온에서도 퇴화완화효과가 있음을 확인하였다.

• Journal of the Korean Applied Science and Technology
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• v.31 no.2
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• pp.244-254
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• 2014

The interactions of 4-chlorobenzoic acid with the micellar system of various cationic, nonionic, and mixed surfactant systems were studied by the UV/Vis spectrophotometric method. The solubilization constants ($K_s$) of 4-chlorobenzoic acid into those micellar systems have been measured at various temperatures and various thermodynamic parameters for the solubilization of 4-chlorobenzoic acid have been calculated and analyzed from those changes. The results show that the values of ${\Delta}G^o_s$ are all negative within the measured temperature range and that the values of ${\Delta}H^o_s$ and ${\Delta}S^o_s$ are all positive. The effects of alkyl-group's length of surfactant molecules on the solubilization of 4-chlorobenzoic acid have been also measured. The values of $K_s$ were dependent simultaneously on the alkyl-group's length and the kind of head-group in surfactant molecules. From these changes we can postulate the solubilization site and the degree of interaction of 4-chlorobenzoic acid with the micellar systems.

• Journal of the Korean Chemical Society
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• v.41 no.6
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• pp.284-291
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• 1997

The critical micelle concentrations($CMC^*$) of a cationic surfactant cetylpyridinium chloride (CPC) and a nonionic surfactant triton X-100(TX-100) in aqueous solutions of n-alcohols(methanol, ethanol, 1-propanol, 1-butanol and 1-pentanol) were determined by UV spectroscopic method at 25$^{\circ}C$. The various thermodynamic values in 0.1 M n-alcohols were calculated by means of the equation derived from the pseudo-phase separation model and compared with the values in the absence of n-alcohols. The results were a good agreement with the nonideal mixed micelle model, and they showed negative deviation from the ideal behavior.

• Journal of the Korean Chemical Society
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• v.56 no.5
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• pp.556-562
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• 2012

The critical micelle concentration (CMC) and the counter-ion binding constant (B) for the mixed micellizations of TTAB (tetradecyltrimethylammonium bromide) with other surfactants (DTAB, CTAB, Tween-20, Tween-40, and Tween-80) in aqueous solution of 4-chlorobenzoic acid (0.5 mM) at $25^{\circ}C$ were determined as a function of ${\alpha}_1$ (the overall mole fraction of TTAB) by using the spectrophotometric method and the conductivity method. Various thermodynamic parameters ($X_i$, ${\gamma}_i$, $C_i$, $a_i^M$, ${\beta}$, and ${\Delta}H_{mix}$) were calculated for each mixed surfactant system and compared with the other mixed surfactant systems by means of the equations derived from the nonideal mixed micellar model. The results show that TTAB/DTAB mixed system has a great positive deviation from the ideal mixed micellar model and the other mixed systems have great negative deviations from the ideal mixed model.