• Journal of ILASS-Korea
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• v.8 no.1
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• pp.16-22
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• 2003

Zeta potential measurements of colloid particles suspended in a liquid are performed by a Zeta Meter developed. There are many applications of colloid stability in spray technology, paints, wastewater treatment, and pharmaceuticalse. Zeta potentials of charged particles are obtained by measuring the electrophoretic velocities of the particles using video enhanced microscopy and image analysis program. The values of zeta potential of polystyrene latex(PSL), $silica(SiO_2)$M, polyvinylidence difluoride(PVDF), silicon nitride, and alumina particles in deionized (DI) water were measured to be -40.5, -31.9, -25.2, -15.1 and -10.1mV, respectively. The particles having high zeta potential less than -20 mV are stable in DI water, because the double layers of them have strong repulsive forces mutually, and the particles having low zeta potential over -20mV are unstable due to Van Der Waals forces. Silica(>20nm), PSL, aluminum and PVDF particles were found to be stable that would remain separate and well disperse, while silicon nitride and alumina particles were found to be unstable that would gradually agglomerate in DI water.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.561-562
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• 2006

The purpose of this study was to investigate the root cause of adhesion of silica and ceria particles during Poly-Si, TEOS, and SiN CMP process, respectively. The zeta-potentials of abrasive particles and wafers were observed negative surface charges in the alkaline solutions. SAC and STI patterned wafers have intermediate values of their composition surface's zeta potentials. The theoretical interaction force and adhesion force of silica and ceria particle were calculated in solution with acidic, neutral and alkaline pH. A stronger attractive force was calculated for silica and ceria particles on wafers in acidic solutions than in alkaline solutions. The theoretical interaction forces of the SAC and STI patterned wafers have intermediate values of their constitution wafer's values. The adhesion forces is observed lower values in alkaline solutions than in acidic solutions. And the ceria particle has lower adhesion than that of the silica particle.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.12 no.1
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• pp.17-33
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• 1986

The interfacial Properties of ferrosoferric oxide suspended in aqueous KNO3 solution are investigated by studying the zeta potentials and surface charge densities at $25^{\circ}C$. The zeta potentials are obtained by measuring the electrophoretic mobility and the surface charge densities by potentiometric titrations in the aqueous KNO3 solutions of different concentrations from 10-3 to 10-1M. The data are interpreted by the surface dissociation and complexation model of Davis, et als. and the modified model.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.262-262
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• 2005

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.53-60
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• 2007

LbL multilayering technology introduced by Decher is a nano technique that a substrate surface is layered by the successive deposition of polyelectrolytes with positive and negative charge. We investigated the electrochemical properties of LbL multilayered pulp fibers with poly-DADMAC and PSS. Three types of pulp-Hw-BKP, BCTMP and KOCC- were treated with polyelectrolytes. Zeta potentials of multilayered fibers ranged from +30 mV to +40 mV, depending on the intial zeta potential of pulp fibers and fines content. All kinds of pulp which were examined in this study, however, showed a similar zeta potential of -35 mV after layering with PSS. To obtain pulp fiber with a uniform and stable zeta potential, BCTMP and KOCC pulp fibers should be multilayered above 5 times. The addition level of polyelectrolytes had little influence on the zeta potential of pulp fibers.

• Journal of Astronomy and Space Sciences
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• v.35 no.1
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• pp.1-6
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• 2018

The reanalysis of the previously published abundance pattern of mild barium star HD202109 (${\zeta}$ Cyg) and the chemical compositions of 129 thin disk barium stars facilitated the search for possible correlations of different stellar parameters with second ionization potentials of chemical elements. Results show that three valuable correlations exist in the atmospheres of barium stars. The first is the relationship between relative abundances and second ionization potentials. The second is the age dependence of mean correlation coefficients of relative abundances vs. second ionization potentials, and the third one is the changes in correlation coefficients of relative abundances vs. second ionization potentials as a function of stellar spatial velocities and overabundances of s-process elements. These findings demonstrate the possibility of hydrogen and helium accretion from the interstellar medium on the atmospheres of barium stars.

• Journal of the Korean Ceramic Society
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• v.29 no.7
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• pp.551-557
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• 1992

X-ray diffraction patterns, IR spectra and zeta-potentials of silicon nitride and $\beta$-Sialon powders were investigated before and after surface manipulations. $\beta$-Sialon powder was produced from Hadong Kaolin by the carbothermic reduction and simulataneous nitridation. Isoelectric points of as-prepared Si3N4 and $\beta$-Sialon powders were 8.4 and 7.4, respectively. After both silicon nitride and $\beta$-Sialon powders were oxidized at 80$0^{\circ}C$ for 24 h in air, the isoelectric points of these powders corresponded to that of silica (pH=3). I case of the addition of Darvan C as deflocculant, its isoelectric point was 3 and zeta-potential was nearly constant in the range of pH 5~12. When SN 7347 was used as deflocculant, its isoelectric point was 8.3 and zeta-potential over -156 mV was measured above pH 11.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.969-971
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• 2007

The black/white electronic ink containing high mobility white nano particles and the organic black pigment particles dispersed in dielectric fluid were prepared. A charge control agent affects the electrophoretic zeta potentials of white particle, which show the maximum value in zeta potential. The electronic ink panel fabricated with the charged white particles and the black particles exhibits more than 15:1 contrast ratio at 10V.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.10
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• pp.1209-1215
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• 1988

A space charge effect at the doped silicon semiconductor/organic solvent ($C_6H_6$, $CH_3OH$, $C_2H_5OH$) interfaces and a mechanism for two reversals of zeta potentials at the undoped polycrystalline gallium arsenide semiconductor/electrolyte (NaCl, KCl, KI solution) interfaces has been qualitatively analyzed using microelectrophoresis measurements. It has been found that the space charge effect in the organic solvents can be neglected and the two reversals of zeta potentials depend on surface states, specific adsorption, electronegativity and size of specifically adsorbed ions at the undoped polycrystalline gallium arsenide/electrolyte interfaces. The position of shear plane of colloidal semiconductors is a fixed distance from the surface and is almost or exactly coincides with the outer Helmholtz plane (OHP).

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.667-674
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• 2007

Phase behavior for the mixed aqueous surfactant systems of cationic octadecyl trimethyl ammonium chloride (OTAC)/anionic ammonium dodecyl sulfate (ADS)/water was examined. Below the total surfactant concentrations of 1.5 m molal, mixed micelles were formed. At the total surfactant concentrations higher than 1.5 m molal, there appeared a region where mixed micelles and vesicles coexist. As the surfactant concentration increased, the systems looked very turbid and much more vesicles were observed. The vesicles were spontaneously formed in this system and their existence was observed by negative-staining transmission electron microscopy (TEM), small-angle neutron scattering (SANS) and encapsulation efficiency of dye. The vesicle region was where the molar fraction α of ADS to the total mixed surfactant was from 0.1 to 0.7 and the total surfactant concentration was above 5 × 10-4 molality. The size and structure of the vesicles were determined from the TEM microphotographs and the SANS data. Their diameter ranged from 450 nm to 120μm and decreased with increasing total surfactant concentration. The lamellar thickness also decreased from 15 nm to 5 nm with increasing surfactant concentration and this may be responsible for the decrease in vesicle size with the surfactant concentration. The stability of vesicles was examined by UV spectroscopy and zeta potentiometry. The vesicles displayed long-term stability, as UV absorbance spectra remained unchanged over two months. The zeta potentials of the vesicles were large in magnitude (40-70 mV) and the observed longterm stability of the vesicles may be attributed to such high ζ potentials.