• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.2
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• pp.242-247
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• 1987

Electrophysical phenomena at the silicon semiconductor-electrolyte solution interfaces were analyzed based on the zeta potential of the electrical double layer and microelectrophoresis. The suspensions were composed of the p or n-type silicon particles suspended in the KCI or pH buffer solutions. The approximate diameter of the prepared and sampled sioicon semiconductor pardticles was 1.5\ulcorner. The sign of the zeta poetntials of the p and n-type silicon particles in the KCl and pH buffer solution was positive. A range of electrophoretic mobilities of the p and n-type silicons in the KCl solutions was 5.5-8.9x10**-4 cm\ulcornerV-sec and 4.2-7.9x10**-4cm\ulcornerV-sec, respectively. The range of zeta potentials corresponding to the electrophoretic mobilities is 70.4-114.0mV nad 53.9-101.2mV, respectively. On the other hand, a range of electrophoretic mobilities of the p and n-type silicons in the pH buffer solutions was 1.1x10**-4-2.2x10**-3cm\ulcornerV-sec and 0-2.1x10**-3cm\ulcornerV-sec, respectively. The range of zeta potentials corresponding to the electrophoretic mobilities is 14.1-281.6mV and 0-268.8mV, respectively. The zeta potentials and electrical double layers of the doped silicon semiconductors are decisively influenced by the positively charged ions in the solutions. The maximum values of the zeta potentials in the KCl solutions appeared at a concentration of about 10-\ulcorner. The isoelectric point of the n-type silicon semiconductors appeared at about a pH 7. The effect of the space charge of the doped silicon semiconductors can be neglected compare with the effect of the surface charge.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.33 no.2
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• pp.105-110
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• 2007

The stability of titanium dioxide dispersion was evaluated by zeta ($\zeta$) potential and we intended to apply it for improvement of dispersion stability. Both theories related to $\zeta$ potential (electric double layer, electrophoresis, isoelectric point and electroosmosis) and a method to measure $\zeta$ potential were explained in this study. The change in $\zeta$ potential of $TiO_2$ dispersion was measured by means of Henry's function of Helmholtz-Smoluchowski's equation (H-S equation). The $\zeta$ potentials of $TiO_2$ dispersion were negative in all measured pH values ($3.0{\sim}9.0$), and absolute values of $\zeta$ potentials of $TiO_2$ increased as pH values increased. $TiO_2$ dispersion was maintained in pH 8.0 and 9.0 respectively. From these results, we suggest that $\zeta$ potentials have an effect on $TiO_2$ dispersion and absolute value of $\zeta$ potentials played an important role in the stability of $TiO_2$ dispersion in aqeous medium.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.960-968
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• 2012

In this study, the measurement of physical properties of 3 different ethylene oxide adducted zwitterionic surfactants were measured such as critical micelle concentration, surface tension, interfacial tension, contact angle, viscosity and foam stability. Also, the dual function characteristics of the zwitterionic surfactants were investigated by determining an isoelectric point, which were obtained using zeta potential measurement and QCM (quartz crystal microbalance) experiments. The isoelectric point of the synthesized zwitterionic surfactant determined by zeta potential measurement was close to that obtained by QCM experiment and both results have shown almost the same trend as that determined by the frictional property measured using an automated mildness tester. In particular, it has been observed that all three surfactants used during this study provide better softening effect at a pH of neutral condition than at an acidic or an alkaline condition. This result indicates that the synthesized surfactants act as a cationic surfactant at a pH of neutral condition and thus provide good softening effect during a rinsing cycle in the detergency process.

• Korean Journal of Materials Research
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• v.15 no.2
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• pp.112-114
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• 2005

Dispersion stability of the $Sm_xCe_{1-x}O_{2-2/x}$ nanoparticles, which was produced by hydrothermal process, was studied in aqueous suspension using ESA (Eletrokinetic Sonic Amplitude). The average particle size of the synthesized $Sm_xCe_{1-x}O_{2-2/x}$ at nanoparticles was about $5{\pm}2nm$. The dispersion and rheological behavior of the $Sm_xCe_{1-x}O_{2-2/x}$ nanoparticles aqueous suspension was investigated using $NH_4OH\;and\;HNO_3$ as a disperse agent. The colloidal stability of aqueous suspensions with $Sm_xCe_{1-x}O_{2-2/x}$ nanoparticles at different pH values has been investigated by means of zeta potential, average particle size, and the distribution of synthesized $Sm_xCe_{1-x}O_{2-2/x}$ nanoparticles. The isoelectric point of the $Sm_xCe_{1-x}O_{2-2/x}$ nanoparticles was at pH around 11 and the value of zeta potential was at its maximum near pH 6.5.

• KSBB Journal
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• v.25 no.1
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• pp.41-46
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• 2010

In this study, we found that dewatering properties were related with physico-chemical properties such as sludge concentration, pH, and zeta potential with sewage sludge, Ionic contents in digested sludge were in the order of $Ca^{2+}$ (14.2 mg/g) > $Mg^{2+}$ (1.9 mg/g) > $Na^+$ (1.4 mg/g) > $K^+$ (1.0 mg/g). Divalent ion more than monovalent have influenced on physico-chemical and dewatering properties. Floc size distribution in activated (AS) and digested sludge (DS) increased on lower pH range to be near isoelectric point and than specific resistance to filtration (SRF) decreased. A linear increase in SRF ($5.25\times10^{13}\sim2.86\times10^{14}$ m/kg in AS and $6.89\times10^{14}\sim1.09\times10^{15}$ m/kg in DS) was observed throughout low concentration range of 1230~9960 mg/L in AS and 2700~5400 mg/L in DS.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.366-367
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• 2005

The effect of benzotriazole (BTA) on the adhesion force of silica and pad particle on Cu/TEOS wafer surfaces was investigated with and without the addition of BTA. Cu-BTA had the isoelectric point (IEP) at around pH 4$\sim$8. Pad particles were more positive zeta potentials than silica. The adhesion force initially decreased of silica and pad particle on Cu surfaces when BTA was added. However, the more BTA was added, the more adhesion force gradually increased with the increase of BTA concentrations. Then the adhesion force of pad particle was higher than silica. And TEOS didn't resulted increasing adhesion force like Cu when BTA was added in DI water.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.1
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• pp.46-55
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• 2014

In this study, we modified the surface of nanofibrillated cellulose (NFC) through LbL (Layer-by-Layer) multilayering process with polyelectrolytes and investigated the effects of the NFC modification on the charge of NFC surface and the dewatering ability of NFC suspension. The multilayering process was done onto NFC fibers using polydiallyldimethylammonium chloride (PDADMAC) and poly-sodium 4-styrene sulfonate (PSS) under different dosage and washing conditions. When the washing was carried out in every adsorption stage, the modified NFC had strong cationic or anionic charge depending on the type of polyelectrolyte in the outermost layer and the dewatering ability was not affected. In the case of no washing treatment or washing in the final adsorption stage, however, the zeta potential of NFC was close to an isoelectric point so that the dewatering ability increased remarkably. Low addition level of polyelectrolytes also showed the similar results. The mixing of NFC suspensions with opposite charge resulted in higher network strength and improved dewatering ability due to the flocculation.

• Applied Chemistry for Engineering
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• v.27 no.3
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• pp.291-298
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• 2016

In this study, zwitterionic surfactants were added to liposome systems at different pH conditions to understand the effect of surfactants on liposome characteristics. For this purpose, amine oxide surfactants having different hydrocarbon chain lengths were synthesized and the structure of the resulting product was elucidated by using $^1H$ NMR, $^{13}C$ NMR, and FT-IR. In addition, the physical properties of newly synthesized surfactants such as critical micelle concentration (CMC), surface tension and isoelectric point were measured. The stability characteristics of liposome systems including average particle sizes and zeta potentials were measured by varying pH and hydrocarbon chain lengths of an amine oxide surfactant. Effects of the pH and hydrocarbon chain length of an amine oxide surfactant on fluidity of a liposome membrane were also examined by measuring the deformability and the binding degree between the surfactant and liposome.

• Journal of Powder Materials
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• v.11 no.6 s.47
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• pp.503-509
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• 2004

Dispersion stabilities and photocatalytic activities of rutile $TiO_{2}$ powders with unique nano-structure synthesized by homogeneous precipitation process at low temperature(HPPLT) have been investigated in the acrylic resin containing fluorostyrene in the range of 0~0.16 mole. Isoelectric point of $TiO_{2}$ in the acrylic resin placed in the neutral region whereas that of $TiO_{2}$ in the water placed in the acidic region, indicating that zeta potential and agglomeration of $TiO_{2}$ powder is strongly dependent on the pH and the type of solvent. To prepare an adhesion, an acrylic resin containing fluorostyrene was synthesized by a radical polymerization. The adhesion of coating layer was increased with increasing fluorostyrene's contents without changing the dispersion stabilities and degrading photocatalytic properties.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1127-1137
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• 2000

Applications of lanthanum ion and crude rare earth chloride to the phosphate wastewater and fluorine wastewater, respectively, as treatment agents were studied. For the investigation of phosphate removal characteristics according to the amount of lanthanum ion, initial phosphate content was decreased by about 50% when molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] was 0.25 and nearly all of phosphate was removed when the molar ratio of [$La^{3+}$]:[$PO_4{^{3-}}-P$] to be doubled. The removal of phosphate by $La^{3+}$ appeared to reach equilibrium state rapidly, and it was exothermic reaction since the removed amount of phosphate was diminished somewhat when the reaction temperature was increased. The zeta potential of combined particulate compound of lanthanum ion and phosphate was located for its isoelectric point at pH 5.5 and the turbidity of treated wastewater was found to vary according to the pH in a similar manner as the absolute value of zeta potential of the combined particulate compound did. For the treatment of fluorine wastewater by crude rare earth chloride, the remaining fluorine content after treatment decreased as the dosage of crude rare earth chloride increased. Whereas, the turbidity of treated wastewater and the amount of sludge generated were shown to increase as more crude rare earth chloride was added. The remaining fluorine content and the turbidity of treated wastewater were decreased and the amount of sludge generated was observed to increase according the increase of coagulant dosage under the condition of constant input of crude rare earth chloride.