Search results for "Silver Nano"
showing 10 items of 135 documents
Silver nanoparticles in resin luting cements: antibacterial and physiochemical properties
2016
Background Silver has a long history of use in medicine as an antimicrobial and anti-inflammatory agent. Silver nanoparticles (NAg) offer the possibility to control the formation oral biofilms through the use of nanoparticles with biocidal, anti-adhesive, and delivery abilities. This study aims to evaluate the antibacterial effect of resin luting cements with and without NAg, and their influence on color, sorption and solubility. Material and methods NAg were incorporated to two dual-cured resin cements (RelyX ARC (RA) color A1 and RelyX U200 (RU) color A2) in two concentrations (0.05% and 0.07%, in weight), obtaining six experimental groups. Disc specimens (1x6mm) were obtained to verify t…
In Situ Synthesis of Polythiophene and Silver Nanoparticles within a PMMA Matrix: A Nanocomposite Approach to Thermoelectrics
2022
The processability of organic thermoelectric materials plays a crucial role due to their clear advantages of applicability in large-scale areas compared to traditional inorganic counterparts. A promising way to process thermoelectric materials based on conductive polymers is through in situ polymerization in an insulating polymer matrix. This work shows an interpenetrating polymeric network based on polythiophene, silver nanoparticles (Ag NPs), and poly(methyl methacrylate) (PMMA) produced by the oxidative polymerization of terthiophene by an oxidizing silver salt in a PMMA matrix. Ag NPs are in situ synthesized simultaneously as a byproduct. The reaction occurs very fast in the solid state…
Monitoring Chemical Reactions with SERS-Active Ag-Loaded Mesoporous TiO2 Films
2020
Monitoring chemical reactions that occur in small spaces or confined environments is challenging. Surface-enhanced Raman scattering (SERS) spectroscopy offers the unique possibility to monitor spectral changes with high sensitivity and time resolution. Herein, we report the application of composite mesoporous TiO2 films loaded with Ag nanoparticles (NPs) to track in situ chemical processes in real time. In particular, the AgNPs@TiO2 system was employed to monitor two chemical reactions: one occurring on the Ag NPs surface and another taking place in the surrounding solution. In the first case, we monitored the decarboxylation reaction of 4-mercaptobenzoic acid on Ag NPs, which allowed us to…
Surface enhanced Raman scattering of silver sensitized cobalt nanoparticles in metal–dielectric nanocomposites
2008
We report the preparation of a new type of nanocomposite containing cobalt and silver nanoparticles organized in parallel layers with a well controlled separation. This arrangement allows the observation of an enhanced low-frequency Raman signal at the vibration frequency of cobalt nanoparticles excited through the surface plasmons of silver nanoparticles. Numerical simulations of the electric field confirm the emergence of hot spots when the separation between silver and cobalt nanoparticles is small enough. © IOP Publishing Ltd.
Optical determination and identification of organic shells around nanoparticles: application to silver nanoparticles
2013
We present a simple method to prove the presence of an organic shell around silver nanoparticles. This method is based on the comparison between optical extinction measurements of isolated nanoparticles and Mie calculations predicting the expected wavelength of the Localized Surface Plasmon Resonance of the nanoparticles with and without the presence of an organic layer. This method was applied to silver nanoparticles which seemed to be well protected from oxidation. Further experimental characterization via Surface Enhanced Raman Spectroscopy (SERS) measurements allowed to identify this protective shell as ethylene glycol. Combining LSPR and SERS measurements could thus give proof of both …
One pot light assisted green synthesis, storage and antimicrobial activity of dextran stabilized silver nanoparticles.
2014
Background Green synthesis of nanomaterials finds the edge over chemical methods due to its environmental compatibility. Herein, we report green synthesis of silver nanoparticles (Ag NPs) mediated with dextran. Dextran was used as a stabilizer and capping agent to synthesize Ag NPs using silver nitrate (AgNO3) under diffused sunlight conditions. Results UV–vis spectra of as synthesized Ag nanoparticles showed characteristic surface plasmon band in the range from ~405-452 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies showed spherical Ag NPs in the size regime of ~50-70 nm. Face centered cubic lattice of Ag NPs was confirmed by powder X-ray diffraction (PXRD…
Solid phase extraction materials as a key for improving the accuracy of silver nanoparticle characterization with single-particle inductively coupled…
2022
The accurate characterization of silver nanoparticles (Ag NPs) in environmental samples is crucial for understanding the potential impact of these materials on the environment and human health. Single-particle inductively coupled plasma mass spectrometry (spICP-MS) is one of the few techniques available for quantifying NPs at environmentally relevant concentrations. However, the spICP-MS detection of Ag NPs can be interfered with coexisting dissolved analyte causing high background signals, which mask NP signals leading to a significant bias in NP characterization. In this paper, a simple sample pre-treatment procedure for efficient removal of dissolved silver in natural waters is proposed …
Cd12Ag32(SePh)36 : Non-Noble Metal Doped Silver Nanoclusters
2019
While there are numerous recent reports on doping of a ligand-protected noble metal nanocluster (e.g., Au and Ag) with another noble metal, non-noble metal (e.g., Cd) doping remains challenging. Here, we design a phosphine-assisted synthetic strategy and synthesize a Cd doped Ag nanocluster, Cd12Ag32(SePh)36 (SePh: selenophenolate), which exhibits characteristic UV–vis absorption features and rare near-infrared (NIR) photoluminescence at ∼1020 nm. The X-ray single crystal structure reveals an asymmetric two-shell Ag4@Ag24 metal kernel protected by four nonplanar Cd3Ag(SePh)9 metal–ligand frameworks. Furthermore, the electronic structure analysis shows that the cluster is a 20-electron “supe…
Alcohol-Selective Oxidation in Water under Mild Conditions via a Novel Approach to Hybrid Composite Photocatalysts
2015
Abstract The oxidation of alcohols to carbonyl compounds in a clean fashion (i.e., with water as a solvent or under solvent‐free conditions, and using O2 or H2O2 as the primary oxidant) is the subject of considerable research efforts. A new approach for the selective oxidation of soluble aromatic alcohols in water under mild conditions via a novel composite photocatalyst has been developed. The catalyst is synthesized by grafting 4‐(4‐(4‐hydroxyphenylimino)cyclohexa‐2,5dienylideneamino)phenol and silver nanoparticles onto the surface of moderately crystalline titanium dioxide. The titanium dioxide‐based composite was first extensively characterized and then employed in the catalytic oxidati…
Rayleigh-instability-driven dewetting of thin Au and Ag films on indium-tin-oxide surface under nanosecond laser irradiations
2013
Investigations have been carried out on laser-beam-induced nanoparticle (NP) formation in thin (5 nm) Au and Ag films on indium-tin-oxide substrate. After the irradiation the films were observed to break-up into NPs through a dewetting mechanism. This mechanism was investigated as a Rayleigh-instability- driven process. In fact, for each used laser fluence, the resulting Au and Ag NPs' mean size and surface-to-surface mean distance were quantified and correlated between them in the framework of the Rayleigh-instability theory showing an excellent agreement. © The Institution of Engineering and Technology 2013.