• Journal of Photoscience
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• v.2 no.2
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• pp.89-93
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• 1995

Solvatochromic effects and hydrogen bonding interactions of 4-hydroxy-4'-nitrostilbene(NSOH) were investigated. Electronic transition energies of NSOH have good correlation with Taft's $\pi$$^*$. The hydrogen bonding interactions can be accounted by analysis with equation of $\Delta$E= $\Delta$E$_0$ + s($\pi$$^*$ + d$\delta$) + a$\alpha$ + b$\beta$. From UV-visible absorption maximum energies, $\Delta$E = 81.2 kcal/mole - 6.66($\pi$$^*$ - 0.20$\delta$) - 0.66$\alpha$ - 1.93$\beta$ (corr.=0.970) was obtained, and from fluorescence intensity maximum energies, $\Delta$E= 70.07 kcal/mole - 21.6($\pi$$^*$ - 0.11d) - 1.74$\alpha$ - 2.73$\beta$ (corr.=0.947) was obtained. The micropolarity estimated at the solubilization sites is close to the polarity of water. The apparent Taft's $\pi$$^*$ values of solubilization sites are close to 1. Howcver, the solubilization sites for the fluorescent NSOH is rather nonpolar. Both NSOH and NSO$^-$ can be solubilized in CTAB and CTAC micelles and NSOH is the only species that can be solubilized in SDS and Brij-35 micelles.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.401-408
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• 1992

The extracellular cholesterol oxidase produced from a soil microorganism HSL613 was purified and partially characterized. Through a series of purification procedures including concentration with CH2 concentrator, DEAE-cellulose column chromatography and gel filtration on Superose12, the purified enzyme was shown to have a specific activity of 108 units/mg protein giving 30.8-fold purification and final yield of 66%. The molecular weight of the enzyme was estimated to be 59,500 daltons by SDS-PAGE. The optimum temperature and pH for this enzyme were $50^{\circ}C$ and 6.0, respectively. The activity of the purified cholesterol oxidase was inhibited by $Ag^{2+}$, $Hg^{2+}$ and SDS.

• Bulletin of the Korean Chemical Society
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• v.24 no.1
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• pp.37-44
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• 2003

We examined the effect of polyether-type nonionic surfactants (Brij 35, Triton X-100, Tween 20 and Tween 80) on the potentiometric properties of sodium-, potassium- and calcium-selective membranes which are prepared with widely used ionophores and four kinds of polymer matrices [poly(vinyl chloride) (PVC), polyurethane (PU), PVC/PU blend, and silicone rubber (SR)]. It was found that the PVC-based membranes, which provide the best performance among all other matrix-based membranes in the absence of nonionic surfactants, exhibited larger change in their potentiometric properties when nonionic surfactants are added to the sample solution. On the other hand, the sodium-selective SR-based membrane with calix[4]arene, potassium-selective PVC/PU- or SR-based membrane with valinomycin, and the calcium-selective SR-based membrane with ETH 1001 provide almost identical analytical performance in the presence and absence of Tween 20 or Tween 80 surfactants. The origin of nonionic surfactants effect was also investigated by interpreting the experimental results obtained with various matrices and ionophores. The results suggest that the nonionic surfactant extracted into the membrane phase unselectively form complexes with the primary and interfering ions, resulting in increased background potential and lower binding ability for the ionophore. Such effects should result in deteriorated detection limits, reduced response slopes and lower selectivity for the primary ions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.166-169
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• 2003

In this study, we evaluated the characteristics by the addition of 3 different kinds of nonionic surfactant to improve the dispersion stability of slurries. Slurry stability is an issue in any industry in which settling of particles can result in poor performance. So we observed the variation of particle size and settling rate when the concentration and addition time of surfactant are changed. When the surfactant is added after milling process, the particle size and pH became low. It is supposed that the particle agglomeration was disturbed by adsorption of surfactant on alumina abrasive. The settling rate was relatively stable when nonionic surfactant is added about 0.1~1.0 wt%. When molecular weight(MW) is too small like Brij 35, it was appeared low effect on dispersion stability. Because it can't prevent coagulation and subsequent settling with too small MW. The proper quality of MW for slurry stability was presented about 500,000. Consequently, the addition of nonionic surfactant to alumina slurry has been shown to have very good effect on slurry stabilization. If we apply this results to copper CMP process, it is thought that we will be able to obtain better yield.

• Journal of the Korean Applied Science and Technology
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• v.33 no.1
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• pp.51-57
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• 2016

In this study, we synthesized reactive surfactant which have functional radical group for effective chemical reaction. Reactive surfactant have been synthesized using synthesis of polyoxyethylene lauryl ether(POE 23) which is nonionic surfactant and methacrylic acid, acrylic acid. benzene was used as the solvent, p-TsOH was used as the catalyst. synthesized surfactant was confirmed by FT-IR, $^1H$-NMR spectra, and elemental analysis. Evaluation of physical properties was measured HLB, cloud point, surface tension, the critical micelle concentration, emulsifying power. HLB number was evaluated 11.62 to 12.09 range. The Critical Micelle Concentration(cmc) values evaluated was $1{\times}10^{-4}{\sim}5{\times}10^{-4}mol/L$ by surface tension method. The cloud point was $35^{\circ}C$, $39^{\circ}C$ each. The emulsifymvcqa ing properties of the synthesized surfactants was lower than polyoxyethylene lauryl ether. In addition, soybean oil was better than benzene. The experimental results confirmed the ester bond, the yield of 93.27%, 94.49% was found.