On the Influence of Silver Nanoparticles Size in the Electrical Conductivity of PEDOT: PSS

2010 ◽  
Vol 644 ◽  
pp. 85-90 ◽  
Author(s):  
Rebeca G. Melendez ◽  
Karla J. Moreno ◽  
Ivana Moggio ◽  
Eduardo Arias ◽  
Arturo Ponce ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Reducing Agent ◽  
Molar Ratio ◽  
Plasmon Band ◽  
Vis Spectroscopy

In this paper, we studied the influence of the silver nanoparticles size on the electrical conductivity of PEDOT:PSS in Ag(PEDOT:PSS) films. The silver nanoparticles were synthesized in presence of PEDOT:PSS by varying the molar ratio between AgNO3 and the reducing agent (NaBH4). Both the particle size determined by TEM and the plasmon band obtained by UV-Vis spectroscopy were found to be strongly dependent on the reducing agent concentration. The electrical conductivity increases inversely with the concentration of reducing agent from 5.24 x 10-4 up to 1.63 S/cm; three orders of magnitude higher than pristine PEDOT:PSS.

Green Synthesis of Silver Nanoparticles by Tannic Acid with Improved Catalytic Performance Towards the Reduction of Methylene Blue

NANO ◽  
2018 ◽  
Vol 13 (01) ◽  
pp. 1850003 ◽  
Author(s):  
Yueyue Hao ◽  
Nan Zhang ◽  
Jing Luo ◽  
Xiaoya Liu
Keyword(s):  
Methylene Blue ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Tannic Acid ◽  
Molar Ratio ◽  
High Catalytic Activity ◽  
Ag Nps ◽  
Environmental Friendly ◽  
Vis Spectroscopy

In this work, a facile, environmental-friendly and cost-effective method was developed to prepare silver nanoparticles (Ag NPs) in aqueous solution at room temperature. In our approach, tannic acid was employed as the reducing agent and stabilizer simultaneously, avoiding the usage of any toxic agent. The tannic acid derived silver nanoparticles (TA-Ag NPs) were fully characterized by UV-Vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analyzer (TGA). The particle size of the synthesized TA-Ag NPs is tunable from 6.5[Formula: see text]nm to 19.2[Formula: see text]nm with narrow distribution by varying the molar ratio of TA to silver precursor. Efficient reduction of methylene blue (MB) catalyzed by TA-Ag NPs was observed, which was dependent upon the particle size of TA-Ag NPs or the TA concentration used for synthesis. By optimizing the TA concentration, complete reduction of MB was accomplished by TA-Ag NPs within 8[Formula: see text]min. The high catalytic activity of TA-Ag NPs was attributed to their nanosize and good dispersity as well as the electrostatic interaction between TA and MB which induces rapid enrichment of MB towards TA-Ag NPs, creating a locally concentrated layer of MB. Considering the facile and environmental-friendly preparation procedure and excellent catalytic activity, TA-Ag NPs are green, efficient and highly economical candidates for the catalysis of organic dyes and extendable of other reducible contaminants as well.

scholarly journals Eco-friendly microwave-enhanced green synthesis of silver nanoparticles using Aloe vera leaf extract and their physico-chemical and antibacterial studies

2018 ◽  
Vol 7 (3) ◽  
pp. 231-240 ◽  
Author(s):  
Omid Ahmadi ◽  
Hoda Jafarizadeh-Malmiri ◽  
Naeimeh Jodeiri
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Exposure Time ◽  
Leaf Extract ◽  
Aloe Vera ◽  
Synthesis Conditions ◽  
Stabilizing Agents ◽  
Microwave Exposure ◽  
Mean Particle Size ◽  
Vis Spectroscopy

Abstract Silver nanoparticles (AgNPs) were synthesized using Aloe vera leaf extract as both reducing and stabilizing agents via microwave irradiation method. The effects of the microwave exposure time and the amount of AgNO3 solution on the mean particle size and concentration of the synthesized AgNPs solution were investigated using response surface methodology. The synthesized AgNPs were characterized by transmission electron microscopy, UV-Vis spectroscopy, and dynamic light scattering. Well-dispersed and spherically fabricated AgNPs with mean particle size (46 nm) and maximum concentration (64 ppm) and zeta potential (+15.5 mV), were obtained at optimal synthesis conditions, using 9 ml of AgNO3 (1 mm) and 0.1 ml of Aloe vera extract during microwave exposure time of 360 s. The antibacterial activity of the synthesized AgNPs was tested using Escherichia coli and Staphylococcus aureus bacteria and the obtained results indicated their significant inhibitory effects against these two Gram-negative and Gram-positive bacteria.

scholarly journals Stabilization of Silver Nanoparticles by Cationic Aminoethyl Methacrylate Copolymers in Aqueous Media—Effects of Component Ratios and Molar Masses of Copolymers

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1647 ◽  
Author(s):  
Mikhailova ◽  
Senchukova ◽  
Lezov ◽  
Gubarev ◽  
Trützschler ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Analytical Ultracentrifugation ◽  
Silver Salt ◽  
Aqueous Media ◽  
Reducing Agent ◽  
Methacrylate Copolymers ◽  
Vis Spectroscopy ◽  
Cationic Copolymers ◽  
Consistent Information ◽  
Scanning Electron

The ability of aminoethyl methacrylate cationic copolymers to stabilize silver nanoparticles in water was investigated. Sodium borohydride (NaBH4) was employed as a reducing agent for the preparation of silver nanoparticles. The objects were studied by ultraviolet-visible (UV-vis) spectroscopy, dynamic light scattering (DLS), analytical ultracentrifugation (AUC) and scanning electron microscopy (SEM). Formation of nanoparticles in different conditions was investigated by varying ratios between components (silver salt, reducing agent and polymer) and molar masses of copolymers. As a result, we were successful in obtaining nanoparticles with a relatively narrow size distribution that were stable for more than six months. Consistent information on nanoparticle size was obtained. The holding capacity of the copolymer was studied.

Electrolytic Behavior Silver Microphases and Nanophases on the Graphite Electrode Surface

2016 ◽  
Vol 712 ◽  
pp. 117-122 ◽  
Author(s):  
Daria O. Perevezentseva ◽  
Eduard Gorchakov ◽  
Yulia A. Oskina
Keyword(s):  
Silver Nanoparticles ◽  
Silver Oxide ◽  
Graphite Electrode ◽  
Reducing Agent ◽  
Molar Ratio ◽  
Graphite Electrodes ◽  
Stepwise Mechanism ◽  
Voltage Curve ◽  
Current Voltage ◽  
Current Voltage Curve

The stepwise mechanism of electrooxidation and reduction of silver nanophases and microphases is proposed on the graphite electrodes surface in alkaline medium. The electrochemical splitting of silver nanophases peak is observed on the anodic branch of the cyclic current-voltage curve. There is the shoulder at E = 0.2 V on the he anodic branch of cyclic current-voltage curve. The appearance of additional cathodic wave at E = -0.08 V is observed on the cathodic branch of the cyclic current-voltage curve that is caused by the reduction of silver nanoparticles. The additional cathode maximum is represented at 0.3 V on the cathodic branch of the cylic current-voltage curves of only silver nanophases. This effect is associated the catalytic process of decomposition of hydrogen peroxide on silver nanoparticles surface. The offset of the cathodic maxima of current-voltage curves of silver nanophases obtained with an excess of a reducing agent are observed to more negative potentials. There is a significant decrease of the all currents maxima compared to silver nanophases obtained with an equal molar ratio of reactants. These results may be connected with the formation of silver oxide monolayers in the different oxidation in the presence of large amounts a reducing agent. The excess of the reducing agent required for the preparation of silver nanoparticles leads to decrease of the cathodic maximum of silver nanoparticles

The Aggregation Study and Characterization of Silver Nanoparticles

2017 ◽  
Vol 263 ◽  
pp. 165-169
Author(s):  
Silvia Chowdhury ◽  
Faridah Yusof ◽  
Nadzril Sulaiman ◽  
Mohammad Omer Faruck
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Absorption Spectrum ◽  
Average Particle Size ◽  
Average Particle ◽  
Transmission Electron ◽  
Vis Spectroscopy

In this article, we have studied the process of silver nanoparticles (AgNPs) aggregation and to stop aggregation 0.3% Polyvinylpyrrolidone (PVP) was used. Aggregation study carried out via UV-vis spectroscopy and it is reported that the absorption spectrum of spherical silver nanoparticles were found a maximum peak at 420 nm wavelength. Furthermore, Transmission Electron Microscopy (TEM) were used to characterized the size and shape of AgNPs, where the average particle size is around 10 to 25 nm in diameter and the AgNPs shape is spherical. Next, Dynamic Light Scattering (DLS) were used, owing to observed size distribution and self-correlation of AgNPs.

Synthesis of Silver Nanoparticles Using o-Hydroxybenzoic, p-Hydroxybenzoic, and o,p-Dihydroxybenzoic Acids as Reducing Agents

2017 ◽  
Vol 901 ◽  
pp. 26-31 ◽  
Author(s):  
Dian Susanthy ◽  
Fadliah ◽  
Endang Tri Wahyuni ◽  
Sri Juari Santosa
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Reducing Agents ◽  
Reducing Agent ◽  
Para Position ◽  
Hydroxyl Groups ◽  
Hydroxybenzoic Acid ◽  
Dihydroxybenzoic Acid ◽  
Transmission Electron ◽  
Shape And Size

Synthesis of silver nanoparticles (AgNPs) by reduction of AgNO3 with o-hydroxybenzoic, p-hydroxybenzoic and o,p-dihydroxybenzoic acids as reducing agents was investigated. This research was conducted to determine the effect of the position and number of hydroxyl groups towards the size, shape and stability of the resulted AgNPs. Surface Plasmon Resonance (SPR) of AgNPs was characterized by UV/Vis spectrophotometer, the shape and size of AgNPs was determined by Transmission Electron Microscope (TEM). The results showed that the reducing agent that has substituents in the para position (p-hydroxybenzoic acid) has the higher reduction ability than the others. AgNPs were yielded by all types of reducing agents in alkaline system. Reducing agents which have greater number of substituents (o,p-dihydroxybenzoic acid) could produce AgNPs with smaller concentration of AgNO3 than the others. AgNPs that was produced by reducing agent having substituents on the para position (p-hydroxybenzoic acid) was more stable and smaller particle size, i.e. 34 ± 1.78 nm than reducing agent that has substituent on the ortho para positions (with particle size 45 + 3.67 nm) and ortho positions (with particle size 70 ± 4.96 nm).

scholarly journals Green Synthesis, Characterization, Antioxidant, Antibacterial and Dye Degradation of Silver Nanoparticles using Combretum indicum Leaf Extract

2021 ◽  
Vol 34 (1) ◽  
pp. 216-222
Author(s):  
Arnannit Kuyyogsuy ◽  
Paweena Porrawatkul ◽  
Rungnapa Pimsen ◽  
Prawit Nuengmatcha ◽  
Benjawan Ninwong ◽  
...  
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Dye Degradation ◽  
Sunlight Irradiation ◽  
Particle Size Analyzer ◽  
Vis Spectroscopy ◽  
Edx Analyses ◽  
Aqueous Leaf Extract ◽  
And Staphylococcus Aureus

Silver nanoparticles were synthesized by bioreduction of silver nitrate using the aqueous leaf extract of Combretum indicum (CI-AgNPs). The synthesized CI-AgNPs exhibited a distinct absorption peak at 414 nm in UV-vis spectroscopy. Various parameters such as pH, temperature and time were optimized using spectrophotometry. The particle size of the CI-AgNPs was 48 nm as evaluated from the laser particle size analyzer. The XRD and EDX analyses confirmed the presence of silver in silver nanoparticles. Synthesized CI-AgNPs revealed significant antioxidant, antimicrobial (against Escherichia coli and Staphylococcus aureus) and photocatalytic (against methylene blue under sunlight irradiation) activities. Thus, an eco-friendly method was developed to synthesize silver nanoparticles using the C. indicum leaf extract.

scholarly journals Green Synthesis of Antileishmanial and Antifungal Silver Nanoparticles Using Corn Cob Xylan as a Reducing and Stabilizing Agent

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1235 ◽  
Author(s):  
Rony Lucas Silva Viana ◽  
Gabriel Pereira Fidelis ◽  
Mayara Jane Campos Medeiros ◽  
Marcelo Antonio Morgano ◽  
Monique Gabriela Chagas Faustino Alves ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Synthesis Method ◽  
Optical Emission ◽  
Molar Ratio ◽  
Emission Spectrometry ◽  
Corn Cob ◽  
Ultrasound Technique ◽  
Force Microscopy ◽  
Vis Spectroscopy ◽  
Agricultural Byproduct

Corn cob is an agricultural byproduct that produces an estimated waste burden in the thousands of tons annually, but it is also a good source of xylan, an important bioactive polysaccharide. Silver nanoparticles containing xylan (nanoxylan) were produced using an environmentally friendly synthesis method. To do this, we extracted xylan from corn cobs using an ultrasound technique, which was confirmed by both chemical and NMR analyses. This xylan contained xylose, glucose, arabinose, galactose, mannose, and glucuronic acid in a molar ratio of 50:21:14:9:2.5:2.5, respectively. Nanoxylan synthesis was analyzed using UV–vis spectroscopy at kmax = 469 nm and Fourier transform infrared spectroscopy (FT-IR), which confirmed the presence of both silver and xylan in the nanoxylan product. Dynamic light scattering (DLS) and atomic force microscopy (AFM) revealed that the nanoxylan particles were ~102.0 nm in size and spherical in shape, respectively. DLS also demonstrated that nanoxylan was stable for 12 months and coupled plasma optical emission spectrometry (ICP-OES) showed that the nanoxylan particles were 19% silver. Nanoxylan reduced Leishmania amazonensis promastigote viability with a half maximal inhibitory concentration (IC50) value of 25 μg/mL, while xylan alone showed no effective. Additionally, nanoxylan exhibited antifungal activity against Candida albicans (MIC = 7.5 μg/mL), C. parapsilosis (MIC = 7.5 μg/mL), and Cryptococcus neoformans (MIC = 7.5 μg/mL). Taken together, these data suggest that it is possible to synthesize silver nanoparticles using xylan and that these nanoxylan exert improved antileishmanial and antifungal activities when compared to the untreated polysaccharide or silver nitrate used for their synthesis. Thus, nanoxylan may represent a promising new class of antiparasitic agents for use in the treatment of these microorganisms.

Synthesis and characterization of silver nanoparticles using as a reducing agent plant extract of Dandelion (Taraxacun officianale)

2019 ◽  
pp. 11-17
Author(s):  
Lidia Meléndez-Balbuena ◽  
Eric Reyes-Cervantes ◽  
Blanca Martha Cabrera-Vivas ◽  
Maribel Arroyo
Keyword(s):  
Silver Nanoparticles ◽  
Plant Extract ◽  
Plant Extracts ◽  
Low Cost ◽  
Coli Strain ◽  
Reducing Agent ◽  
Force Microscopy ◽  
Yellow Color ◽  
Golden Yellow ◽  
Vis Spectroscopy

The objective of this work was to synthesize the synthesis of silver nanoparticles using as a reducing agent of ionic silver the plant extract of Dandelion (Taraxacun officianale), vegetable of high availability and low cost, as an alternative to the processes conventional, based on the antioxidant capacity of plant extracts that reduce metals in solution. The nanoparticles prepared by this method were characterized by the golden yellow color characteristic of silver nanoparticle solutions. Measurements with UV-Vis spectroscopy of aqueous solutions of Ag1 + ions after coming into contact with plant extracts of Dandelion at different pHs showed an intense absorption band around 400-450 nm, characteristic of the resonance of the Plasmon of silver nanoparticles. Through the scanning of the samples by means of AFM (atomic force microscopy), morphological information of the nanoparticles is obtained, from 3D topographic images of them, such as distribution, size and shape of the silver nanoparticles. Finally, its antibacterial activity was tested against the Escherichia coli strain.

Green Synthesis of Silver Nanoparticles Using a Vitamin C Rich Phyllanthus emblica Extract

2012 ◽  
Vol 622-623 ◽  
pp. 864-868
Author(s):  
Sirirat Mookriang ◽  
Ampa Jimtaisong ◽  
Nisakorn Saewan ◽  
Krisada Kittigowittana ◽  
Pornchai Rachtanapun ◽  
...  
Keyword(s):  
Particle Size ◽  
Silver Nanoparticles ◽  
Silver Nitrate ◽  
Heating Temperature ◽  
Average Diameter ◽  
Reducing Agent ◽  
Deionized Water ◽  
Phyllanthus Emblica ◽  
High Concentration ◽  
Shape And Size

Silver nanoparticles were prepared by treating a solution of AgNO3 dissolved in deionized water with Emblica (Phyllanthus emblica) extract as reducing agent. The factors that affect the synthesis of silver nanoparticles (time, temperature and concentration of silver nitrate and reducing agent) were investigated. The high concentration of silver nitrate and reducing agent showed the higher in concentration of silver nanoparticles. The heating temperature help increase the yield of silver nanoparticles at shorter reaction time. Their structure, shape and size distribution were characterized by UV-vis spectrophotometer, SEM and TEM technique. The UV-vis spectrophotometer show peaks located of silver-Emblica nanoparticle at 430 nm and the particle size of silver-Emblica is 41.2 nm in average diameter determined by TEM.

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