• Title, Summary, Keyword: Ag nanoparticles

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Synthesis of Well-Distributed SnO2-Sn-Ag3Sn Nanoparticles in Carbon Nanofibers Using Co-Electrospinning (이중 전기방사법을 이용하여 SnO2-Sn-Ag3Sn 나노 입자가 균일하게 내재된 탄소 나노섬유의 합성)

  • An, Geon-Hyoung;Ahn, Hyo-Jin
    • Korean Journal of Materials Research
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    • v.23 no.2
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    • pp.143-148
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    • 2013
  • Well-distributed $SnO_2$-Sn-$Ag_3Sn$ nanoparticles embedded in carbon nanofibers were fabricated using a co-electrospinning method, which is set up with two coaxial capillaries. Their formation mechanisms were successfully demonstrated. The structural, morphological, and chemical compositional properties were investigated by field-emission scanning electron spectroscopy (FESEM), bright-field transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In particular, to obtain well-distributed $SnO_2$ and Sn and $Ag_3Sn$ nanoparticles in carbon nanofibers, the relative molar ratios of the Ag precursor to the Sn precursor including 7 wt% polyacrylonitrile (PAN) were controlled at 0.1, 0.2, and 0.3. The FESEM, bright-field TEM, XRD, and XPS results show that the nanoparticles consisting of $SnO_2$-Sn-$Ag_3Sn$ phases were in the range of ~4 nm-6 nm for sample A, ~5 nm-15 nm for sample B, ~9 nm-22 nm for sample C. In particular, for sample A, the nanoparticles were uniformly grown in the carbon nanofibers. Furthermore, when the amount of the Ag precursor and the Sn precursor was increased, the inorganic nanofibers consisting of the $SnO_2$-Sn-$Ag_3Sn$ nanoparticles were formed due to the decreased amount of the carbon nanofibers. Thus, well-distributed nanoparticles embedded in the carbon nanofibers were successfully synthesized at the optimum molar ratio (0.1) of the Ag precursor to the Sn precursor after calcination of $800^{\circ}C$.

Preparation and Characterization of Core/Shell-type Ag/Chitosan Nanoparticles with Antibacterial Activity

  • Lin, Yue;Jing, Wang;Kang, Pan;Xiaoming, Zhang;Zhouping, Wang;Wenshui, Xia
    • Bulletin of the Korean Chemical Society
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    • v.32 no.4
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    • pp.1277-1281
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    • 2011
  • Making use of chitosan (CS) and ethylenediaminetetraacetic acid (EDTA) as a reaction system, CS-EDTA nanoparticles were synthesized through a facile counterion complex coacervation method. $Ag^+$ could enter porous CS nanoparticles synthesized with this method, allowing Ag nanoparticles within chitosan nanoparticles were synthesized by reducing silver nitrate with chitosan. Because of the noncovalent interaction between CS and EDTA, the EDTA could be easily removed via dialysis against water, and pure core/shell-type Ag/CS nanoparticles could be obtained. The nanoparticles showed higher antibacterial activity toward E. coli than the active precursor Ag nanoparticles and CS.

Nelumbo nucifera extracts mediated synthesis of silver nanoparticles for the potential applications in medicine and environmental remediation

  • Supraja, N.;Avinash, B.;Prasad, T.N.V.K.V.
    • Advances in nano research
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    • v.5 no.4
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    • pp.373-392
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    • 2017
  • Silver nanoparticles (AgNPs) were successfully synthesized through a simple green route using the Nelumbo nucifera leaf, stem and flower extracts. These nanoparticles showed characteristic UV-Vis absorption peaks between 410-450 nm which arises due to the plasmon resonance of silver nanoparticles. The Fourier transform infrared spectroscopy (FT-IR) confirmed the presence of amides and which acted as the stabilizing agent. X-ray diffraction spectrum of the nanoparticles confirmed the Face centered cubic (FCC) structure of the formed AgNPs. Dynamic light scattering technique was used to measure hydrodynamic diameter (68.6 nm to 88.1 nm) and zeta potential (-55.4 mV, -57.9 mV and 98.9 mV) of prepared AgNPs. The scanning electron micrographs of dislodged nanoparticles in aqueous solution showed the production of reasonably monodispersed silver nanoparticles (1-100 nm). The antimicrobial activity of prepared AgNPs was evaluated against fungi, Gram-positive and Gram-negative bacteria using disc diffusion method. Anti-corrosion studies were carried out using coupon method (mild steel and iron) and dye degradation studies were carried out by assessing photo-catalytic activity of Nelumbo nucifera extracts mediated AgNPs.

Antifungal Effects of Silver Nanoparticles (AgNPs) against Various Plant Pathogenic Fungi

  • Kim, Sang-Woo;Jung, Jin-Hee;Lamsal, Kabir;Kim, Yun-Seok;Min, Ji-Seon;Lee, Youn-Su
    • Mycobiology
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    • v.40 no.1
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    • pp.53-58
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    • 2012
  • This research is concerned with the fungicidal properties of nano-size silver colloidal solution used as an agent for antifungal treatment of various plant pathogens. We used WA-CV-WA13B, WA-AT-WB13R, and WA-PR-WB13R silver nanoparticles (AgNPs) at concentrations of 10, 25, 50, and 100 ppm. Eighteen different plant pathogenic fungi were treated with these AgNPs on potato dextrose agar (PDA), malt extract agar, and corn meal agar plates. We calculated fungal inhibition in order to evaluate the antifungal efficacy of silver nanoparticles against pathogens. The results indicated that AgNPs possess antifungal properties against these plant pathogens at various levels. Treatment with WA-CV-WB13R AgNPs resulted in maximum inhibition of most fungi. Results also showed that the most significant inhibition of plant pathogenic fungi was observed on PDA and 100 ppm of AgNPs.

Study on the Recovery Silver and Nanoparticles Synthesis from LTCC By-products of Lowly Concentrated Silver (저농도 은이 함유된 LTCC 전극공정부산물로부터 은 회수 및 나노입자 제조 연구)

  • Joo, Soyeong;Ahn, Nak-Kyoon;Lee, Chan Gi;Yoon, Jin-Ho
    • Journal of Korean Powder Metallurgy Institute
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    • v.25 no.3
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    • pp.232-239
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    • 2018
  • In this paper, the recovery and nanoparticle synthesis of Ag from low temperature co-fired ceramic (LTCC) by-products are studied. The effect of reaction behavior on Ag leaching conditions from the LTCC by-products is confirmed. The optimum leaching conditions are determined to be: 5 M $HNO_3$, a reaction temperature of $75^{\circ}C$, and a pulp density of 50 g/L at 60 min. For the selective recovery of Ag, the [Cl]/[Ag] equivalence ratio experiment is performed using added HCl; most of the Ag (more than 99%) is recovered. The XRD and MP-AES results confirm that the powder is AgCl and that impurities are at less than 1%. Ag nanoparticles are synthesized using a chemical reduction process for recycling, $NaBH_4$ and PVP are used as reducing agents and dispersion stabilizers. UV-vis and FE-SEM results show that AgCl powder is precipitated and that Ag nanoparticles are synthesized. Ag nanoparticles of 100% Ag are obtained under the chemical reaction conditions.

Geno- and Ecotoxicity Evaluation of Silver Nanoparticles in Freshwater Crustacean Daphnia magna

  • Park, Sun-Young;Choi, Jin-Hee
    • Environmental Engineering Research
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    • v.15 no.1
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    • pp.23-27
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    • 2010
  • Genotoxic- and ecotoxic assessments of silver nanoparticles (AgNPs) were conducted on the freshwater crustacean Daphnia magna. AgNPs may have genotoxic effects on D. magna, given that the DNA strand breaks increased when exposed to this nanoparticle. Increased mortality was concomitantly observed with DNA damage in the AgNPs-exposed D. magna, which suggests AgNPs-induced DNA damage might provoke higher-level consequences. The results of the comparative toxicities of AgNPs and Ag ions suggest that AgNPs are slightly more toxic than Ag ions. Overall, these results suggest that AgNPs may be genotoxic toward D. magna, which may contribute to the knowledge relating to the aquatic toxicity of AgNPs on aquatic ecosystems, for which little data are available.

Synthesis of Highly Dispersible Metal Nanoparticles in P3HT:PCBM Layers and Their Effects on the Performance of Polymer Solar Cells (P3HT:PCBM 층 내 분산 가능한 금속 나노입자의 제조 및 이를 포함한 고분자 태양전지 소자의 특성에 관한 연구)

  • Kim, Min-Ji;Choi, Gyu-Chae;Kim, Young-Kuk;Kim, Yang-Do;Baek, Youn-Kyoung
    • Journal of Korean Powder Metallurgy Institute
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    • v.21 no.3
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    • pp.179-184
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    • 2014
  • In this study, we prepare polymer solar cells incorporating organic ligand-modified Ag nanoparticles (O-AgNPs) highly dispersed in the P3HT:PCBM layer. Ag nanoparticles decorated with water-dispersible ligands (WAgNPs) were also utilized as a control sample. The existence of the ligands on the Ag surface was confirmed by FT-IR spectra. Metal nanoparticles with different surface chemistries exhibited different dispersion tendencies. O-AgNPs were highly dispersed even at high concentrations, whereas W-AgNPs exhibited significant aggregation in the polymer layer. Both dispersion and blending concentration of the Ag nanoparticles in P3HT:PCBM matrix had critical effects on the device performance as well as light absorption. The significant changes in short-circuit current density ($J_{SC}$) of the solar cells seemed to be related to the change in the polymer morphology according to the concentration of AgNPs introduced. These findings suggested the importance of uniform dispersion of plasmonic metal nanoparticles and their blending concentration conditions in order to boost the solar cell performance.

Phyto-synthesized silver nanoparticles for biological applications

  • Salunke, Bipinchandra K.;Sathiyamoorthi, Ezhaveni;Tran, Tuan Kiet;Kim, Beom Soo
    • The Korean Journal of Chemical Engineering
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    • v.34 no.4
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    • pp.943-951
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    • 2017
  • Silver nanoparticles (AgNPs) are valuable metal nanoparticles that exhibit exceptional properties compared to their bulk materials. Pronounced surface area, quantum confinement effect complemented by small particle dimension, and many other extraordinary characteristics make AgNPs suitable in a variety of applications. Different methods have been adopted to synthesize AgNPs. Biological methods can formulate AgNPs in an environmentally friendly manner without producing toxic waste. Among the biological methods, plants are simple and attractive sources for AgNP synthesis. Compared to AgNPs produced via other modes of synthesis, phyto-synthesized AgNPs, due to their safety features, have been found to be advantageous for a variety of applications, especially biological applications. Strong research efforts have investigated the utility of phyto-synthesized AgNPs for different applications. Investigators are coming up with innovative applications of phyto-synthesized AgNPs for the development of science and technology and to benefit humankind. The present article focuses on phyto-synthesized AgNPs for biological applications, with a brief review of their synthesis, mechanism, and size/shape control.

Formation of Size-controllable Ag Nanoparticles on Si Substrate by Annealing (크기 조절이 가능한 은 나노입자 형성을 위한 박막의 열처리 효과)

  • Lee, Sang Hoon;Lee, Tae Il;Moon, Kyeong-Ju;Myoung, Jae Min
    • Korean Journal of Materials Research
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    • v.23 no.7
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    • pp.379-384
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    • 2013
  • In order to produce size-controllable Ag nanoparticles and a nanomesh-patterned Si substrate, we introduce a rapid thermal annealing(RTA) method and a metal assisted chemical etching(MCE) process. Ag nanoparticles were self-organized from a thin Ag film on a Si substrate through the RTA process. The mean diameter of the nanoparticles was modulated by changing the thickness of the Ag film. Furthermore, we controlled the surface energy of the Si substrate by changing the Ar or $H_2$ ambient gas during the RTA process, and the modified surface energy was evaluated through water contact angle test. A smaller mean diameter of Ag nanoparticles was obtained under $H_2$ gas at RTA, compared to that under Ar, from the same thickness of Ag thin film. This result was observed by SEM and summarized by statistical analysis. The mechanism of this result was determined by the surface energy change caused by the chemical reaction between the Si substrate and $H_2$. The change of the surface energy affected on uniformity in the MCE process using Ag nanoparticles as catalyst. The nanoparticles formed under ambient Ar, having high surface energy, randomly moved in the lateral direction on the substrate even though the etching solution consisting of 10 % HF and 0.12 % $H_2O_2$ was cooled down to $-20^{\circ}C$ to minimize thermal energy, which could act as the driving force of movement. On the other hand, the nanoparticles thermally treated under ambient $H_2$ had low surface energy as the surface of the Si substrate reacted with $H_2$. That's why the Ag nanoparticles could keep their pattern and vertically etch the Si substrate during MCE.

Synthesis of Concentrated Cu-Ag Nano Sol for Ink-Jet Method

  • Park, Han-Sung;Choi, Young-Min;Ryu, Beyong-Hwan
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1370-1373
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    • 2006
  • The Cu-Ag nanoparticles have been synthesized in aqueous medium using a hydrazine reduction method. The assisted role of polymeric dispersant on synthesis of highly concentrated Cu-Ag nanoparticles was studied. The 30wt% of Cu-Ag nanoparticles with the range of 10 nm in diameter was prepared.

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