• Bulletin of the Korean Chemical Society
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• v.22 no.1
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• pp.84-86
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• 2001

• Bulletin of the Korean Chemical Society
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• v.20 no.7
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• pp.838-840
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• 1999

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1616-1622
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• 2002

If the surfaces of vesicles are chemically modified so that they can be dispersed in organic solvents, the application of vesicular colloids may be expanded. A polymerizable surfactant (BDAC) and nonpolymerizable bipolar surfactant (BPAS) were synthesized in multi-steps. Large vesicles composed of BDAC and BPAS with embedded a cross-linking agent (divinylbenzene) underwent a radical polymerization. BPAS was extracted out using methanol (skeletonization). The headgroup of BDAC was cleaved off via hydrolysis in an acidic condition to yield vesicles where surfaces were covered with -COOH groups. There was no significant change in the overall shape. The skeletonized vesicles appear to have many holes with diameters up to about 25 nm. The holes retained even after hydrolysis. The hydrolyzed vesicles were not dispersed in water and most organic solvents such as tetrahydrofuran and chloroform, but dispersed in methanol.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.123-128
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• 2006

Enzymatic deinking method can avoids the alkaline environment as usual required in chemical deinking, which consequently cuts chemical costs and reduced the white water pollution. The electrostatic wastepaper was dinked with commercial cellulolytic enzymes and surfactant in neutral pH and the effectiveness of deinking and the physical properties of deinked pulp were evaluated. The disintegrating efficiency of the electrostatic wastepaper in neutral pH was enhanced with enzyme treatments. Although the freeness of deinked pulp with enzymes was higher than that of deinked pulp with chemical deinking agents, the brightness of the enzymatic deinked pulp was slightly lower than that of the chemical deinked pulp. But, by additions of nonionic surfactants, the brightness of deinked pulp was increased with less residual ink particles and mechanical properties of enzymatic deinked pulp was improved compared to the deinked pulp of conventional alkaline method.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.12-19
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• 2007

Enzymatic deinking method can avoids the alkaline environment as usual required in chemical deinking, which consequently cuts chemical costs and reduced the white water pollution. The electrostatic wastepaper was dinked with commercial cellulolytic enzymes and surfactant in neutral pH and the effectiveness of deinking and the physical properties of deinked pulp were evaluated. The disintegrating efficiency of the electrostatic wastepaper in neutral pH was enhanced with enzyme treatments. Although the freeness of deinked pulp with enzymes was higher than that of deinked pulp with chemical de inking agents, the brightness of the enzymatic deinked pulp was slightly lower than that of the chemical deinked pulp. But, by additions of nonionic surfactants, the brightness of deinked pulp was increased with less residual ink particles and mechanical properties of enzymatic deinked pulp was improved compared to the deinked pulp of conventional alkaline method.

• Journal of the Korean Applied Science and Technology
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• v.17 no.3
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• pp.167-173
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• 2000

The process variables for the manufacture of translucent microemulsion prepared with 2-octyl dodecanol, 12-hydroxy stearic acid cholesteryl , POE(40)HCO and 1,3-butandiol were examined initially (primary emulsion) and following aging for three months. The techniques empolyed in this study were particle size, turbidity, interfacial tension and microfluidizer. Particle size analysis and turbidity measurement to evaluate the emulsion stability were used. It was concluded that the process of the emulsification was an important indicator of the stability of the translucent microemulsion. From the particle size and and turbidity measurement of translucent microemulsion, adding the surfactant to the oil phase before the emulsification was found to be the most important factor for the stability of emulsions. We found that interfacial tension of the adding the surfactant to the oil phase is lower than that of the adding the surfactant to aqueous phase. In spite of hydrophilic surfactant, adding the surfactant to aqueous phase produced inferior emulsion to that to oil phase.

• 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.

• Proceedings of the Korean Vacuum Society Conference
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• 2004.02a
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• pp.49-50
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• 2004

• Applied Chemistry for Engineering
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• v.10 no.6
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• pp.876-880
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• 1999

The surfactant self-diffusion coefficients of mixed micellar solutions of ionic and nonionic surfactants have been measured by the NMR pulsed field gradient spin echo(FT-PGSE) method. In addition, the line widths of $^1H$ NMR signal have been monitored. The system investgated are $C_{12}EO_5/SDS/D_2O$, $C_{12}EO_5/DTAC/D_2O$, and $C_{12}EO_8/SDS/D_2O$. In the sample series, the molar ratios of $D_2O$ to surfactant(ionic+nonionic) were kept constant while the surfactant mixing ratio was varied. For the $C_{12}EO_5$ system, the surfactant self-diffusion coefficient indicates minimum when the surfactant mixing ratio is about 20% ionic surfactant. The observed decrease in self-diffusion coefficients as nonionic surfactant was replaced by ionic surfactant is interpreted to mainly be due to an increased micelle-micelle repulsion. The increase in self-diffusion coefficients occurring at higher fraction of ionic surfactant is shown to be due to a decrease in micelle size. For the $C_{12}EO_8$ system, the effect of the surfactant mixing ratio is much weaker which can be understood by considering the molecular geometry and large headgroup area. The proton NMR line widths correlate well with the self-diffusion coefficients and broadening of the alkyl chain methylene signals is found when the self-diffusion coefficients is low.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.799-805
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• 2008

In general, anionic and cationic surfactants are incompatible because their mixtures form insoluble complexes and precipitate in the water. There are, however, some equimolar complexes of anionic and cationic surfactant that are soluble and behave like regular surfactants, specifically like nonionic surfactants, thus named pseudo-nonionic surfactant complexes. Pseudo-nonionic complexes are more effective and efficient in surface activities than their ionic surfactant components as shown by their equilibrium and dynamic surface tensions. They pack at the interface more than their ionic components. When a novel cationic surfactant, diglyceryl dodecyl dimethyl ammonium chloride(DGDAC), having the polyhydroxyl group at the hydrophilic head group, was mixed with a conventional anionic surfactant (sodium dodecyl sulfate; SDS) at equimolar ratio, we found that the aqueous equimolar mixture showed strong positive synergism in which molecular interaction parameter ${\beta}^M$ was very low, -17.2. According to the studies of equilibrium phase behavior and microscopy, this mixed system could form homogenous solutions containing vesicles.