• Journal of the Korean Applied Science and Technology
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• v.37 no.2
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• pp.250-259
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• 2020

The solubilization constant (K_s) was determined by the UV-Vis method to investigate the interaction between organic matter (solubilized substance) and surfactant in solubilization. Solubilization constants and thermodynamic functions, according to the hydrophobic interaction between organic mater (4-alkylanilines with different alkyl substituent length) and cationic surfactants (DTAB, TTAB, and CTAB, having different hydrophobic lengths), were measured and calculated at various temperatures and compared with each other. As a result, the hydrophobic interactions between organic matters and cationic micelles increased with increasing the chain length of solute's substituent as well as surfactant's hydrophobe. However, the hydrophobic effect by the alkyl substituent of organic matter was greater than the hydrophobic effect by the surfactant. In addition, the results of the calculated thermodynamic functions showed that 4-alkylaniline was solubilized at the deep place in the micelle and its solubilization was greatly dependent on both the hydrophobic effects of organic matter and surfactant. At the calculated iso-structural temperature, the difference between the maximum and minimum values was less than 1K within the experimental conditions.

• Journal of the Korean Electrochemical Society
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• v.26 no.4
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• pp.71-79
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• 2023

In this study, we employed anionic, cationic, and nonionic surfactants for the hydrophilization of porous substrates used in the fabrication of pore-filling membranes. We investigated the extent of hydrophilization based on the type of surfactant, its concentration, and immersion time. Furthermore, we used the hydrophilized substrates to produce pore-filling anion exchange membranes and compared their ion conductivity to determine the optimal hydrophilization conditions. For the ionic surfactants used in this study, we observed that hydrophilization progressed rapidly from the beginning of immersion when the applied concentration was 3.0 wt%, compared to lower concentrations (0.05, 0.5, and 1.0 wt%). In contrast, for the relatively larger molecular weight non-ionic surfactants, smooth hydrophilization was not observed. There was no apparent correlation between the degree of hydrophilization and the ion conductivity of the anion exchange membrane. This discrepancy suggests that an excessive hydrophilization process during the treatment of porous substrates leads to excessive adsorption of the surfactant on the sparse surfaces of the porous substrate, resulting in a significant reduction in porosity and subsequently decreasing the content of polymer electrolyte capable of ion exchange, thereby greatly increasing the electrical resistance of the membrane.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.343-344
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• 2016

• Clean Technology
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• v.11 no.1
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• pp.1-12
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• 2005

In these studies, semibatch emulsion copolymerization of n-butyl acrylate (n-BA) as adhesive component and methyl metacrylate (MMA) as coagulant component was carried out in order to investigate the role of surfactant in aqueous phase for polymer cement. It was found that the particle size and concentration of final polymer are affected by surfactant type used. The effect of nonionic surfactants was shown in the decrease of polymer emulsion concentration and small emulsion particle in order of LE-50, NP-50 > CE-50, Tween 20 > TX-405 > Brij 35. In LE and NP (n=7-50) as nonionic surfactant, it could be obtained the stable polymer emulsion of 40% in aqueous phase with average particle size of 250-320 nm using over n=30. On the other hand, the effect of surfactant type in initial reactor charge was shown that when SDS as ionic surfactant was used, the polymer emulsion concentration was constant irrespective of the amount used, whereas CTAB as cationic surfactant and HN-100 as reactive surfactant were shown a tendency to the decrease of that. The effect surfactant type on final polymer particle size was shown in decrease by the order of SDS > CTAB > HN-100.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.112-118
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• 2012

In this study, physical properties of synthesized DE7-OSA82-AO and DEP52-OSA82-AOQ82 zwitterionic surfactants were measured such as critical micelle concentration, surface tension, interfacial tension, contact angle and viscosity. Phase behavior study was also performed. The dual function characteristics of a zwitterionic surfactant were investigated by determining an isoelectric point, which was attained using zeta potential measurements and QCM (quartz crystal microbalance) experiments. The isoelectric point of DE7-OSA82-AO surfactant determined by the zeta potential measurement and QCM experiment was about 7.2 and 7.4, respectively. On the other hand, the isoelectric point of DEP52-OSA82-AOQ82 surfactant determined by the zeta potential measurement and QCM experiment was about 10.9 and 11.0, respectively. The frictional property measured using an automated mildness tester showed that DE7-OSA82-AO surfactant can provide a good softening effect at an acidic or neutral condition. On the other hand, DEP52-OSA82-AOQ82 was found to provide a good softening effect to a fabric surface at a pH below its isoelectric point of 11.

• Applied Chemistry for Engineering
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• v.20 no.2
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• pp.140-144
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• 2009

Triethanolamine-type cationic surfactants were synthesized and their applications were established. The production of mono-, di-, and tri-TEA-EQ (triethanol-amine-esterquater) were dependent on the molar ratio of fatty acid and triethanolamine under the controlled reaction temperature. The structures were elucidated by $H^{1}$ NMR. Long-term stability was dependent on the amount of mono- and tri-TEA-EQ. When the amount of mono-TEA-EQ was increased, long-term stability was increased. However, the more tri-TEA-EQ made long-term stability decreased. Softening was dependent on the amount of saturated fatty acid, and re-wettability was counted on the amount of unsaturated fatty acid. Softening was measured by the method of sense estimation e.g. touching to home-towel. Absorption was determined to calculate the height of water on a towel after treatment.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.521-528
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• 2012

In this study, we analyzed the physical properties of an ethylene oxide adducted amphoteric surfactant such as critical micelle concentration, surface tension, interfacial tension, contact angle, viscosity and phase behavior. The dual function characteristics of an amphoteric surfactant were investigated by determining an isoelectric point, which were attained using zeta potential measurements and quartz crystal microbalance (QCM) experiments. The isoelectric points of DE3-OSA82-AO, DE5-OSA82-AO and DE9-OSA82-AO surfactant systems determined by zeta potential measurements were 6.97, 6.93 and 7.10 respectively and they are in good agreement with the isoelectric point values measured by QCM experiments. The frictional property measured using an automated mildness tester showed that the DE-OSA82-AO surfactant could provide a good softening effect at neutral condition.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.2
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• pp.103-108
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• 1997

A series of batch tests were conducted to evaluate the design parameters for the application of soil washing techniques to the hydrophobic organic compounds (HOCs)-contaminated soil using mixed surfactants. Because the mixed surfactants form different structures of molecular aggregates from single surfactant, they were applied to improve the washing efficiency. Kinds of surfactants added, mixing ratio, and total concentration of mixed surfactants were evaluated. The uncontaminated soil was obtained from a country hill near Nock-Chun Station in Seoul. The portion of soil passing #4 (4.75 mm) sieve was used. The pH, organic contents and cation exchange capacity were 4.4, 1.6% and 4.08 meq/100 g, respectively The soil was artificially contaminated by n-dodecane. The 5% solution of OA-5 and OA-14 (1:1) showed 86% washing efficency. The 4% solution of SDS and OA-5 (1:1) showed 95% washing efficiency.

• Clean Technology
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• v.14 no.3
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• pp.193-203
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• 2008

A surfactant is used to assist the effect of cleaning, dispersibility and adhesion during leather manufacturing process. Existing surfactant for that process includes many hydrophilic groups that may cause problem such as stain, bad water resistance and poor durability, etc. It is potential problem to make high-performance property for future leather market. In this study, we have synthesized the fluorinated surfactant of which property decreases surface tension, increases dispersion, cleaning effect and the better chrome absorption by the high bond energy of C-F to complement weakness that the present alkyl derivative surfactants have. Using fluorinated surfactant, we can confirm that dispersion is increased, chrome absorption ratio is augmented with high osmosis and coherence, chrome content in the tanning waste water is reduced, BOD and COD contents are diminished and physical characteristics are improved.

• Clean Technology
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• v.7 no.4
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• pp.291-297
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• 2001

In this study, the stability of concentrated colloidal liquid aphrons (CLAs) containing Aliquat 336 was measured. CLAs in the continuous phase are stabilized by water-soluble surfactant and oil-soluble surfactant. To compare the stability of CLAs, half-life was introduced. According to the change of state of solution, the rate of break-up of concentrated CLAs changed rigorously at critical coagulation concentration. Critical coagulation concentration was measured with changing pH. The effects of ionic strength and concentration of Sodium Dodecyl Benzene Sulfonate (SDBS) on the stability of concentrated CLAs in the continuous phase were also investigated.