Potential of Silver Nanoparticles Functionalized Polyaniline as an Electrochemical Transducer

2016 ◽  
Vol 44 ◽  
pp. 21-34 ◽  
Author(s):  
Malefetsane Khesuoe ◽  
Mangaka Matoetoe ◽  
Fredrick Okumu
Keyword(s):  
Silver Nanoparticles ◽  
Diffusion Coefficient ◽  
Surface Coverage ◽  
Current Response ◽  
Ag Nps ◽  
One Dimensional ◽  
Transmission Electron ◽  
Doped Polyaniline ◽  
And Diffusion ◽  
Electrochemical Transducer

Modification of commercial platinum (Pt) and glassy carbon (GC) electrodes with polyaniline (PANI) and silver nanoparticles doped polyaniline (PANI/Ag NPs) through electropolymerization of aniline in the absence and presence of Ag NPs in 1 M hydrochloric acid (HCl) was interrogated. Fourier transform infrared (FTIR) and transmission electron microscope (TEM) techniques were used for structural, compositional and morphological elucidation. FTIR spectra for PANI and PANI/Ag NPs had the characteristic PANI functional groups as well as desired bands for the conducting emeraldine (EM) form. The predominance of the PANI pattern in the spectra is indicative of the intact PANI structure in the presence of Ag NPs while the slight band shifts are signify interfacial interactions between PANI and Ag NPs. TEM micrograms depicts different size one dimensional nanofibric tubes of the supramolecular structures of PANI. Ag NPs functionalized PANI had larger smoother tubes, suggesting organized morphology arrangement. An increased energy dispersive spectroscopy (EDS)-TEM count from 256 to 277 confirms incorporation of Ag NPs in PANI. GC/PANI/Ag NPs exhibited outstanding electroactivity (higher conductivity and rate of electron transfer).This might be a result of the large surface coverage, film thickness and diffusion coefficient as a result of the large GC surface area. Possibly, the improvement might be due to the GC electrode properties. The electroactivity of the electrodes increased in the order: Pt < GC < Pt/PANI < Pt/PANI/Ag NPs < GC/PANI < GC/PANI/Ag NPs. The effect of Ag NPs in the polymer was demonstrated by ultimate band gap reduction of PANI and enhanced magnitudes of current response per electrode.

scholarly journals Size Control of Synthesized Silver Nanoparticles by Simultaneous Chemical Reduction and Laser Fragmentation in Origanum majorana Extract: Antibacterial Application

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2326
Author(s):  
Entesar Ali Ganash ◽  
Reem Mohammad Altuwirqi
Keyword(s):  
Silver Nanoparticles ◽  
Irradiation Time ◽  
Chemical Reduction ◽  
Size Control ◽  
Reduction Process ◽  
Laser Wavelength ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
Transmission Electron ◽  
Origanum Majorana

In this work, silver nanoparticles (Ag NPs) were synthesized using a chemical reduction approach and a pulsed laser fragmentation in liquid (PLFL) technique, simultaneously. A laser wavelength of 532 nm was focused on the as produced Ag NPs, suspended in an Origanum majorana extract solution, with the aim of controlling their size. The effect of liquid medium concentration and irradiation time on the properties of the fabricated NPs was studied. While the X-ray diffraction (XRD) pattern confirmed the existence of Ag NPs, the UV–Vis spectrophotometry showed a significant absorption peak at about 420 nm, which is attributed to the characteristic surface plasmon resonance (SPR) peak of the obtained Ag NPs. By increasing the irradiation time and the Origanum majora extract concentration, the SPR peak shifted toward a shorter wavelength. This shift indicates a reduction in the NPs’ size. The effect of PLFL on size reduction was clearly revealed from the transmission electron microscopy images. The PLFL technique, depending on experimental parameters, reduced the size of the obtained Ag NPs to less than 10 nm. The mean zeta potential of the fabricated Ag NPs was found to be greater than −30 mV, signifying their stability. The Ag NPs were also found to effectively inhibit bacterial activity. The PLFL technique has proved to be a powerful method for controlling the size of NPs when it is simultaneously associated with a chemical reduction process.

Preparation of Triangular Silver Nanoparticles Using Polyvinyl Pyrrolidone with Different Concentration

2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Driving Force ◽  
Ostwald Ripening ◽  
Polyvinyl Pyrrolidone ◽  
Protective Agent ◽  
Ag Nps ◽  
Transmission Electron ◽  
Uv Visible

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.

scholarly journals Microwave-Assisted Green Synthesis of Silver Nanoparticles Using Juglans regia Leaf Extract and Evaluation of Their Physico-Chemical and Antibacterial Properties

Antibiotics ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 68 ◽  
Author(s):  
Mahsa Eshghi ◽  
Hamideh Vaghari ◽  
Yahya Najian ◽  
Mohammad Najian ◽  
Hoda Jafarizadeh-Malmiri ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Leaf Extract ◽  
Juglans Regia ◽  
Antibacterial Properties ◽  
Infrared Analysis ◽  
Ag Nps ◽  
Stabilizing Agents ◽  
Agno3 Solution ◽  
Transmission Electron ◽  
Vis Spectroscopy

Silver nanoparticles (Ag NPs) were synthesized using Juglans regia (J. regia) leaf extract, as both reducing and stabilizing agents through microwave irradiation method. The effects of a 1% (w/v) amount of leaf extract (0.1–0.9 mL) and an amount of 1 mM AgNO3 solution (15–25 mL) on the broad emission peak (λmax) and concentration of the synthesized Ag NPs solution were investigated using response surface methodology (RSM). Fourier transform infrared analysis indicated the main functional groups existing in the J. regia leaf extract. Dynamic light scattering, UV-Vis spectroscopy and transmission electron microscopy were used to characterize the synthesized Ag NPs. Fabricated Ag NPs with the mean particle size and polydispersity index and maximum concentration and zeta potential of 168 nm, 0.419, 135.16 ppm and −15.6 mV, respectively, were obtained using 0.1 mL of J. regia leaf extract and 15 mL of AgNO3. The antibacterial activity of the fabricated Ag NPs was assessed against both Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria and was found to possess high bactericidal effects.

Synthesis and Characterization of Bone Cement (Hydroxyapatite Base) Calcinated at 900°C and Loading the Silver Nanoparticles on it

2012 ◽  
Vol 622-623 ◽  
pp. 893-896
Author(s):  
H.R. Ebrahimi ◽  
M. Eslami
Keyword(s):  
Silver Nanoparticles ◽  
Bone Cancer ◽  
Calcium Hydroxyapatite ◽  
Chemical Precipitation ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
X Ray ◽  
Agno3 Solution ◽  
Transmission Electron

The bioceramics, calcium hydroxyapatite (HA), is a material which is biocompatible to the human body and is well suited to be used in hyperthermia applications for the treatment of bone cancer. We synthesis hydroxyapatite in modified synthetic body fluid (SBF) solutions at 37°C and pH of 7.4 using a novel chemical precipitation technique. Then after heat operation, on filtered precipitated result HA were produced. For loading the silver nanoparticles (Ag NPs) on the hydroxyapatite we use AgNO3 solution. And for reducing Ag+ ions apply sodium borohydrate solution. The formations of the silver nanoparticles on the HAP structure were confirmed by X-ray diffraction, transmission electron microscopy (TEM). TEM image show the nanostructure of silver particles, being formed on hydroxyapatite texture.

scholarly journals Carbene modification and reversible crosslinking of silver nanoparticles for controlled antibacterial activity

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Liling Jing ◽  
Mark G. Moloney ◽  
Hao Xu ◽  
Lian Liu ◽  
Wenqiang Sun ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Photoelectron Spectroscopy ◽  
Inhibition Zone ◽  
Insertion Reaction ◽  
Ag Nps ◽  
Zone Method ◽  
Transmission Electron

Abstract Silver nanoparticles (Ag NPs) system capable of exhibiting different particle size at different temperature was developed, which depended on the extent of Diels–Alder (DA) reaction of bismaleimide with furan. Thus, Ag NPs were functionalized on the surface by a furyl-substituted carbene through an insertion reaction. Subsequent reversible DA crosslinking achieved a controlled aggregation with different particle size, which gives a series of different antibacterial activity. These Ag NPs were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Nanoparticle Size Analyzer. The aggregation of the Ag NPs could be reliably adjusted by varying the temperature of DA/reverse-DA reaction. The antibacterial activity was assessed using the inhibition zone method against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which decreased first and then increased in agreement with the size evolution of Ag NPs. This approach opens a new horizon for the carbene chemistry to modify silver nanoparticles with variable size and give controlled antibacterial activity.

scholarly journals Alginate-Mediated Synthesis of Hetero-Shaped Silver Nanoparticles and Their Hydrogen Peroxide Sensing Ability

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 435 ◽  
Author(s):  
Sneha Bhagyaraj ◽  
Igor Krupa
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Linear Response ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Range ◽  
Pollution Detection

A new method for the simple synthesis of stable heterostructured biopolymer (sodium alginate)-capped silver nanoparticles (Ag-NPs) based on green chemistry is reported. The as-prepared nanoparticles were characterized using the ultraviolet-visible (UV-Vis) absorption spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and dynamic light scattering (DLS) techniques. The results showed that the as-prepared Ag-NPs have a heterostructured morphology with particle size in the range 30 ± 18–60 ± 25 nm, showing a zeta potential of −62 mV. The silver nanoparticle formation was confirmed from UV-Vis spectra showing 424 nm as maximum absorption. The particle size and crystallinity of the as-synthesized nanoparticles were analyzed using TEM and XRD measurements, respectively. FTIR spectra confirmed the presence of alginate as capping agent to stabilize the nanoparticles. The Ag-NPs also showed excellent sensing capability, with a linear response to hydrogen peroxide spanning a wide range of concentrations from 10−1 to 10−7 M, which indicates their high potential for water treatment applications, such as pollution detection and nanofiltration composites.

Fabrication and Characterization of Cellulose Acetate Ultrafine Fiber Containing Silver Nanoparticles by Electrospinning

2011 ◽  
Vol 337 ◽  
pp. 116-119 ◽  
Author(s):  
Dong Mei Zhao ◽  
Qing Mao Feng ◽  
Li Li Lv ◽  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Silver Nanoparticles ◽  
Cellulose Acetate ◽  
Average Diameter ◽  
Xrd Analysis ◽  
Water Soluble ◽  
Ag Nps ◽  
Ultrafine Fibers ◽  
Transmission Electron ◽  
Electrospinning Method

Silver nanoparticles (Ag NPs)/cellulose acetate (CA) composite ultrafine fibers were successfully prepared by the electrospinning method. Water-soluble Ag NPs were directly mixed into CA polymer fibers to form organic–inorganic composite ultrafine fibers. The optical property of Ag NPs was measured by ultraviolet-visble spectrometer (UV-vis). The presence and identification of crystalline of Ag NPs were confirmed by XRD analysis. Transmission electron microscopy (TEM) images showed that silver nanoparticles (Ag NPs) with an average diameter of 5–15 nm were obtained and were well distributed in the CA ultrafine fibers. The morphologies of the as-prepared electrospun Ag NPs/CA composite ultrafine fibers were characterized by scanning electron microscopy (SEM) and TEM. The composition of fibers was characterized by FTIR spectrometer.

scholarly journals Photo-induced chemical reduction of silver bromide to silver nanoparticles

2011 ◽  
Vol 9 (6) ◽  
pp. 982-989 ◽  
Author(s):  
Agnieszka Król-Gracz ◽  
Ewa Michalak ◽  
Piotr Nowak ◽  
Agnieszka Dyonizy
Keyword(s):  
Silver Nanoparticles ◽  
Chemical Reduction ◽  
Silver Bromide ◽  
Molar Ratio ◽  
Efficient Production ◽  
Ag Nps ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Nanoparticle Suspensions ◽  
Actinic Radiation

AbstractThis paper discusses the experimental results of the production of nanocolloidal silver using photoreduction method. Ultrafine crystalline gelatine-stabilised aqueous suspensions of silver bromide were used as a substrate for the synthesis of silver nanoparticles (Ag NPs). The influences of the reductant to substrate molar ratio, the medium’s pH, the type of the source of actinic radiation and the time of exposure to the efficient production of the Ag NPs were studied. A typical reaction was suggested, which involves the photo-induced reduction of silver bromide nanocrystals in the presence of ascorbic acid under specified physicochemical conditions. The properties of resultant silver particles were examined using UV-Vis spectroscopy and Dynamic Light Scattering (DLS). In addition, Transmission Electron Microscopy (TEM) was used for imaging the silver nanoparticle suspensions.

scholarly journals Alginate-Mediated Synthesis of Hetero-Shaped Silver Nanoparticles and their Hydrogen Peroxide Sensing ability

2020 ◽  
Author(s):  
Sneha Bhagyaraj ◽  
Igor Krupa
Keyword(s):  
Hydrogen Peroxide ◽  
Particle Size ◽  
Silver Nanoparticles ◽  
Environmentally Benign ◽  
X Ray Diffraction ◽  
Ag Nps ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Range ◽  
Pollution Detection

Silver nanoparticles have been the focus of extensive research for many decades due to their unique physical, chemical and electrical properties. Introducing new environmentally benign methods for the synthesis of silver nanoparticles is of great interest in the research community. In this work we propose a new method for the simple synthesis of stable heterostructured biopolymer (sodium alginate)-capped silver nanoparticles (Ag-NPs) based on green chemistry.The as-prepared nanoparticles were characterized using the ultraviolet–visible (UV–Vis) absorption spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and Dynamic light scattering (DLS) techniques. The results showed that the as-prepared Ag-NPs have a heterostructured morphology with particle size in the range 30 ± 18 – 60 ± 25 nm, showing a zeta potential of -62 mV. The silver nanoparticle formation was confirmed from UV-Vis spectra showing 424 nm as maximum absorption. The particle size and crystallinity of the as- synthesized nanoparticles were analyzed using TEM and XRD measurements respectively. FTIR spectra confirmed the presence of alginate as capping agent to stabilize the nanoparticles. The Ag-NPs also showed excellent sensing capability, with a linear response to hydrogen peroxide spanning a wide range of concentrations from 10-1 – 10-7 M, which indicates their high potential for water treatment applications, such as pollution detection and nanofiltration composites.

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