• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.45-50
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• 2008

The self assembled silver process and silver coating process after surface reforming for silica particle, were investigated to coat the silver to colloidal silica. The effects of silver amounts and reductant amounts on silver coating efficiencies were investigated. The silver coating process after surface reforming for silica particle using MPTS (3-Mercaptopropyl trimethoxysilane) and APTS (3-Aminopropyl trimethoxysilane), showed the higher coating efficiency and better antibacterial effect than the self assembled silver process.

• Journal of the Korean Ceramic Society
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• v.41 no.9
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• pp.670-676
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• 2004

The synthesis of highly concentrated silver nano sol assisted by polymeric dispersant (polyelectrolytes) for inkjet method was studied. The silver nano sol was prepared with AgNO$_3$, polyelectrolytes (HS5468cf ; polyacrylic ammonium salt), and reducing agent. The polyelectrolytes play an important role in formation of complex composed of Ag$\^$+/ion and carboxyl group (COO$\^$-/), result in preparation of highly dispersed silver nano particles. The optimization of added amount of polyelectrolytes, and concentration of silver nano sol was studied. The silver nanoparticles were evaluated by XRD, particle size/zeta potential analyzer and FE-TEM. The silver nanoparticles with the range of 10 nm in diameter were produced. The concentration of batch-synthesized silver nano sol was possible up to 40 wt%.

• Journal of the Korean Applied Science and Technology
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• v.21 no.1
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• pp.17-23
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• 2004

Silver bromide particles from 50 to 200${\AA}$ in diameter are prepared by mixing two microemulsions contaning the precursor salts $AgNO_3$ and KBr. The microemulsions are composed of AOT(bis(2-ethylhexyl) sodium sulfosuccinate), n-heptane and water. The particle diameters are measured on photomicrographs obtained by transmission electron microscopy. The size of the particles is generally larger than that of the water cores. The influence of both the concentration of precursor salts in the water cores of the microemulsoin and the size of these water cores on the size of the particles has been studied.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.6
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• pp.674-681
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• 2008

Silver as a metal catalyst has been used to remove odorous compounds. In this study, silver particles in nano sizes ($5{\sim}30nm$) were prepared on the surface of $NaHCO_3$, the supporting material, using a sputtering method. The silver nano-particles were dispersed by dissolving $Ag-NaHCO_3$ into water, and the dispersed silver nano-particles in the aqueous phase was applied to remove inorganic odor compounds, $NH_3$ and ${H_2}O$, in a scrubbing reactor. Since ammonia has high solubility, it was removed from the gas phase even by spraying water in the scrubber. However, the concentration of nitrate (${NO_3}^-$) ion increased only in the silver nano-particle solution, implying that the silver nano-particles oxidized ammonia. Hydrogen sulfide in the gas phase was rapidly removed by the silver nano-particles, and the concentration of sulfate (${SO_4}^{2-}$) ion increased with time due to the oxidation reaction by silver. As a result, the silver nano-particles in the aqueous solution can be successfully applied to remove odorous compounds without adding additional energy sources and producing any harmful byproducts.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.862-868
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• 2008

Many studies have been conducted to increase heat transfer in fluid. One of the various heat transfer enhancement techniques is suspending fine metallic or nonmetallic solid powder in traditional fluid. Nanofluid is defined as a new kind of heat transfer fluid containing a very small quantity of nanometer particles that are uniformly and stably suspended in a liquid. This study investigates the effect of nanofluid containing diamond, CuNi and CuAg nanometer particles, and proposes the heat transport mechanism of nanofluid. The test result shows that the thermal conductivity of nanofluid is much higher than that of traditional fluid, and the increasing rate of the conductivity is dependent on the conductivity of the solid metal.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.544-547
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• 2000

Polypyrrole (PPy) was chemically synthesized within the pores of nanoporous polycarbonate (PC) Particle Track-etched Membranes (nano-PTM). Hollow tubules are formed because polypyrrole initially deposits on the surface of the pores walls. By running successive syntheses, we have obtained wires (filled tubules). The redox property of PPy nanotubules was investigated by cyclic voltammetry. The redox potential was lowered as much as 0.5V vs. Ag/AgC1, comparing with electrosynthesized PPy film. It suggests that an electron hopping mechanism of PPy nanotubules was improved. Electric conductivity of PPy nanotubules and nanowire was evaluated. We obtained good electric conductivity of PPy nanotubules even in the neutral state. The conductivity and activation energy were $10^1$ order at the room temperature and 25.3 meV respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.551-552
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• 2006

This study was attended to demonstrate synthesis of silver nanoparticles stabilized with polymer and their applicability to printed electronics. Silver nanoparticles were synthesized by reduction of silver nitrate in aqueous solution in the presence of polyvinyl pyrrolidone (PVP) as a stabilizer. The ink used here is composed of 50 wt% Ag NP, 15 wt% humectant and then were printed on polyimide film. Particle deposit morphologies were controlled by varying the ink compositions. Printed silver patterns and dots were cured on a convection oven in air at $300^{\circ}C$ for 60 min. The printed patterns show good shape definition and the resistivity of the printed films is about $5{\mu}{\Omega}{\cdot}cm$.

• Fashion & Textile Research Journal
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• v.6 no.6
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• pp.810-814
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• 2004

This study is one of the fundamental researches for the development of future smart clothing and textile products using silver(Ag) nano powder. Our study was focused on the blocking or insulating effects of nano-processed textiles from electromagnetic waves. Also, for the surveying of the actual effect to human body, we measure the variation of electroencephalogram which is an indication of human physical symptoms. Among various textiles in this experiment, nano silver processed case has shown the best blocking performance from the electromagnetic waves, which decreases depending on the distance. As a reference model of working environment, we setup the visual stimuli object on the computer that is a source of electromagnetic wave. The power spectrum distribution and the incidence of electroencephalogram was measured. The analysed data has shown that, with nano-processed textiles, ${\beta}$ wave does not appear very often where ${\beta}$ wave appears only to illustrate the stable states of human's body. However, as for the materials without nano processing, the ratio of ${\gamma}$ waves in the total level of electroencephalogram becomes higher in spite of short exposure to visual stimuli in work environment, which shows that the worker becomes stressed. The ${\beta}$ wave electroencephalogram of all materials is drawn in calcarine fissure of occipital lobe to show the convergent distribution, and stronger with block-processed Nano Silver Silk(NSS). The study based on the potential risks of human diseases such as physical fatigue by electromagnetic waves, and has shown that the application of Nano Silver textile for human uses require a proper particle size of it which would not penetrate cellular tissues, and a proper binder and binding treatment for it. However, it is highly required for back-up researches to verify various aspects in applying nano silver to textile products.

• Journal of Powder Materials
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• v.19 no.1
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• pp.60-66
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• 2012

In this study, Platinum(Pt) nanoparticles were synthesized by using polyol process which is one of the liquid phase reduction methods. Dihydrogen hexachloroplatinate (IV) hexahydrate $(H_2PtCl_6{\cdot}6H_2O)$, as a precursor, was dissolved in ethylene glycol and silver nitrate ($AgNO_3$) was added as metal salt for shape control of Pt particle. Also, polyvinylpyrrolidone (PVP), as capping agent, was added to reduce the size of particle and to separate the particles. The size of Pt nanoparticles was evaluated particle size analyzer (PSA). The size and morphology of Pt nanoparticles were observed by transmission electron microscopy (TEM) and high resolution TEM (HRTEM). Synthesized Pt nanoparticles were studied with varying time and temperature of polyol process. Pt nanoparticles have been successfully synthesized with controlled sizes in the range 5-10 and 20-40 nm with cube and multiple-cube shapes.

• Advances in nano research
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• v.4 no.2
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• pp.129-143
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• 2016

The present work reports a facile, rapid and an eco-friendly method for the synthesis of silver nanoparticles using Luffa acutangula (L. acutangula) leaves extract and their antibacterial and cytotoxic effects. The synthesized silver nanoparticles (AgNPs) were characterized by UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction analysis (XRD). Additionally the topography, morphology and the elemental composition of the particles were determined by Scanning Electron Microscopy (SEM) and Energy dispersive spectrophotometric (EDS) technique and the measured particle sizes from SEM micrographs are in the range of 12.5 to 24.5nm. The in-vitro antimicrobial activity of the synthesized nanoparticles was high against gram positive Staphylococcus aureus and moderate against gram negative Escherichia coli and Pseudomonas aeruginosa strains. Further, the cytotoxic effects of synthesized AgNPs were evaluated against Human Breast Cancer (MCF 7) cell line.