scholarly journals Theoretical and Experimental Study on the Functionalization Effect on the SERS Enhancement Factor of SiO2-Ag Composite Films

2021 ◽  
Author(s):  
Paulina De León Portilla ◽  
Ana Lilia González Ronquillo ◽  
Enrique Sánchez Mora
Keyword(s):  
Tannic Acid ◽  
Enhancement Factor ◽  
Composite Films ◽  
Dipole Approximation ◽  
Raman Signal ◽  
Ag Nps ◽  
Dielectric Shell ◽  
Porous Sio2 ◽  
Main Components ◽  
Sio2 Spheres

Herein we addressed a study to determine the enhancement factor (EF) of the Raman signal reached by composite films with two main components, Ag nanoparticles and SiO2 spheres. The study involves the synthesis, structural composition and optical response by using experimental techniques and theoretical-numerical modeling. A colloid with single NPs and agglomerates of them, with a tannic acid layer on its surface, was produced. Separately, porous SiO2 spheres were obtained. A mixture of both, Ag NPs and SiO2 particles was used to produce the films by solvent evaporation method. It is shown that single or agglomerated Ag NPs are preferentially located at the interstices of the SiO2 spheres. Using discrete dipole approximation, the SERS EF has been estimated considering the agglomeration and tannic acid layer. Both, the dielectric spheres and tannic acid layer diminish the electric field intensity and therefore the SERS EF. When a Ag NP with/without a dielectric shell is touching a SiO2 sphere, the EF is as high as 1 × 103, the zones where this value is reached are smaller when the dielectric layer is present. With a cluster of 3 nude Ag NPs surrounded by SiO2 spheres an EF of 2.4 × 103 is obtained.

scholarly journals Single-Step Green Synthesis of Highly Concentrated and Stable Colloidal Dispersion of Core-Shell Silver Nanoparticles and Their Antimicrobial and Ultra-High Catalytic Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 1007
Author(s):  
Azam Ali ◽  
Mariyam Sattar ◽  
Fiaz Hussain ◽  
Muhammad Humble Khalid Tareen ◽  
Jiri Militky ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Green Synthesis ◽  
Tannic Acid ◽  
Rate Constant ◽  
Catalytic Properties ◽  
Colloidal Dispersion ◽  
Alkaline Condition ◽  
Core Shell ◽  
Average Particle ◽  
Ag Nps

The versatile one-pot green synthesis of a highly concentrated and stable colloidal dispersion of silver nanoparticles (Ag NPs) was carried out using the self-assembled tannic acid without using any other hazardous chemicals. Tannic acid (Plant-based polyphenol) was used as a reducing and stabilizing agent for silver nitrate in a mild alkaline condition. The synthesized Ag NPs were characterized for their concentration, capping, size distribution, and shape. The experimental results confirmed the successful synthesis of nearly spherical and highly concentrated (2281 ppm) Ag NPs, capped with poly-tannic acid (Ag NPs-PTA). The average particle size of Ag NPs-PTA was found to be 9.90 ± 1.60 nm. The colloidal dispersion of synthesized nanoparticles was observed to be stable for more than 15 months in the ambient environment (25 °C, 65% relative humidity). The synthesized AgNPs-PTA showed an effective antimicrobial activity against Staphylococcus Aureus (ZOI 3.0 mM) and Escherichia coli (ZOI 3.5 mM). Ag NPs-PTA also exhibited enhanced catalytic properties. It reduces 4-nitrophenol into 4-aminophenol in the presence of NaBH4 with a normalized rate constant (Knor = K/m) of 615.04 mL·s−1·mg−1. For comparison, bare Ag NPs show catalytic activity with a normalized rate constant of 139.78 mL·s−1·mg−1. Furthermore, AgNPs-PTA were stable for more than 15 months under ambient conditions. The ultra-high catalytic and good antimicrobial properties can be attributed to the fine size and good aqueous stability of Ag NPs-PTA. The unique core-shell structure and ease of synthesis render the synthesized nanoparticles superior to others, with potential for large-scale applications, especially in the field of catalysis and medical.

Natural polyphenol tannic acid reinforced poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) composite films with enhanced tensile strength and fracture toughness

2014 ◽  
Vol 36 (12) ◽  
pp. 2303-2308 ◽  
Author(s):  
Hengxue Xiang ◽  
Lili Li ◽  
Shichao Wang ◽  
Renlin Wang ◽  
Yanhua Cheng ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Tannic Acid ◽  
Composite Films ◽  
Natural Polyphenol

Tannic acid: A versatile and effective modifier for gelatin/zein composite films

2020 ◽  
Vol 23 ◽  
pp. 100440
Author(s):  
Dajian Huang ◽  
Zhuo Zhang ◽  
Qiling Quan ◽  
Yuting Zheng
Keyword(s):  
Tannic Acid ◽  
Composite Films

scholarly journals The surface-enhanced resonance Raman scattering of dye molecules adsorbed on two-dimensional titanium carbide Ti3C2Tx (MXene) film

2020 ◽  
Vol 1 (2) ◽  
pp. 146-152 ◽  
Author(s):  
Satheeshkumar Elumalai ◽  
John R. Lombardi ◽  
Masahiro Yoshimura
Keyword(s):  
Raman Scattering ◽  
Titanium Carbide ◽  
Crystal Violet ◽  
Enhancement Factor ◽  
Resonance Raman ◽  
Raman Signal ◽  
Two Dimensional ◽  
Dye Molecules ◽  
Resonance Raman Scattering ◽  
Surface Enhanced

The resonance Raman signal enhancement of crystal violet dyes onto the two-dimensional MXene–Ti3C2Tx film, so called MXenes-enhanced resonance Raman scattering (MERRS), is reported with a calculated enhancement factor of 3.42 × 109.

Fabrication of Silver Nanoparticle Decorated AFM Tips for Tip-Enhanced Raman Scattering Applications

2013 ◽  
Vol 643 ◽  
pp. 195-198 ◽  
Author(s):  
Yu Hua Li ◽  
Chang Hui Xu ◽  
Min Han
Keyword(s):  
Gas Phase ◽  
Silver Nanoparticle ◽  
Enhancement Factor ◽  
High Yield ◽  
Raman Signal ◽  
Simple Method ◽  
Atomic Force ◽  
Afm Tips ◽  
Enhanced Raman Scattering ◽  
Tip Enhanced Raman Spectroscopy

We report on a simple method for the fabrication of metalized tips by depositing gas-phase synthesized silver nanoparticles onto atomic force microscope (AFM) tips. The method enables fabricating tips suitable for AFM based tip-enhanced Raman spectroscopy (TERS) with high yield. The performance of the fabricated silver nanoparticle decorated tips is examined by detecting low concentration BPE molecules using a transmission mode TERS setup. An 30-fold enhancement of the Raman signal is shown. The net TERS enhancement factor is calculated to be about 1000.

scholarly journals Monitoring of the morphologic reconstruction of deposited ablation products in laser irradiation of silicon

2008 ◽  
Vol 40 (1) ◽  
pp. 69-78 ◽  
Author(s):  
M. Vlasova ◽  
Márquez Aguilar ◽  
M.C. Reséndiz-González ◽  
M. Kakazey ◽  
V. Stetsenko ◽  
...  
Keyword(s):  
Laser Irradiation ◽  
Heating Temperature ◽  
Composite Films ◽  
Target Surface ◽  
Oxygen Impurity ◽  
Irradiation Channel ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gaseous Atmospheres ◽  
Main Components

Using electron microscopy, atomic force microscopy, X-ray microanalysis, and IR spectroscopy, it was established that, in the regime of continuous laser irradiation of silicon at P = 170 W in different gaseous atmospheres with an oxygen impurity, SiOx composite films with a complex morphology form. The main components of ablation products are clusters that form during flight of ablation products and as a result of separation of SiOx-clusters from the zone of the irradiation channel. The roughness and density of the films depend on the heating temperature of the target surface and the type of deposited clusters.

scholarly journals Anticorrosion Property of Alcohol Amine Modified Phosphoric and Tannic Acid Based Rust Converter and Its Waterborne Polymer-Based Paint for Carbon Steel

Coatings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1091
Author(s):  
Yang Chen ◽  
Shiyu Li ◽  
Zhiyong Liu ◽  
Zixiao Wang
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Tannic Acid ◽  
Iron Phosphate ◽  
Anticorrosion Property ◽  
Rust Layer ◽  
Passivation Film ◽  
Film Layer ◽  
Main Components

Four kinds of alcohol amines were tested to improve the anticorrosion performance of the phosphoric and tannic acid (PTA)-based rust converter. The alcohol amine modified PTA rust converters with the optimum mechanical and functional performances were used to prepare the homogeneous single-component waterborne rust conversion-based paint. The mechanical properties and the long-term corrosion resistance of the synthesized rust converter-based paint were investigated. The results show that alcohol amine modified PTA rust converter can convert the rust layer into a thick passivation film with iron tannate and iron phosphate as the main components, significantly improving the corrosion resistance of the carbon steel. The alcohol amine D modified PTA rust converter (RC-D) showed the best anticorrosion and rust conversion performances. The waterborne rust conversion-based paint can convert the rust layer of steel into a blue-black and relatively flat passivation film layer. The waterborne polymer-based paint containing 10 wt.% RC-D significantly improves the long-term corrosion resistance of the rusty steel and the mechanical property of paint.

Far Field Optical Properties of a Monolayer of SiO2 Spheres and Small Au Nanoparticles

MRS Advances ◽  
2018 ◽  
Vol 3 (64) ◽  
pp. 3917-3923 ◽  
Author(s):  
A. Santos Gómez ◽  
A. L. González
Keyword(s):  
Numerical Study ◽  
Normal Incidence ◽  
Dipole Approximation ◽  
Silica Spheres ◽  
Far Field ◽  
Approximation Model ◽  
Au Nps ◽  
Transmission And Absorption ◽  
Sio2 Spheres ◽  
Hexagonal Closed Packed

ABSTRACTHere, we present a numerical study of the far field optical response of a monolayer composed by an hexagonal closed packed array of SiO2 spheres with a single Au NP at each interstitial position. The Optical Efficiencies, Reflection, Transmission and Absorption at normal incidence, were calculated using Discrete Dipole Approximation model extended to periodic targets. In order to consider different amounts of loads of Au NPs per unit of area in the monolayer, we have fixed the diameter of Au NPs (9 nm) and varied the diameter of the SiO2 spheres. The numerical calculations indicate that Au-SiO2 composite monolayers can absorb and scatter the incident electromagnetic wave, as the load of Au NPs increases the monolayer becomes less transparent to light and the spectra are red-shifted. The profile of the absorption spectrum of the Au-SiO2 composite monolayer is very similar to that of a Au NPs monolayer (composite monolayer without the Silica spheres) but less intense, presumably because the Silica spheres screen the coupling of the Localized Surface Plasmons of Au NPs.

scholarly journals Leachates of Thermally Modified Pine (Pinus sylvestris L.) Wood

2015 ◽  
Vol 34 (329) ◽  
pp. 26-31 ◽  
Author(s):  
Anete Meija-Feldmane
Keyword(s):  
Pinus Sylvestris ◽  
Mass Loss ◽  
Tannic Acid ◽  
Environmentally Friendly ◽  
Hazardous Substances ◽  
Environmental Aspects ◽  
Treatment Technology ◽  
Thermally Modified Wood ◽  
Main Components ◽  
Modified Wood

Abstract During the last decades, thermally modified wood has become an object of interest among the wood scientists as an environmentally friendly material, because nowadays environmental aspects of materials have become more and more significant. Leaching is one of the processes that occurs in outdoor use. The aim of this study was to evaluate concentration of potentially hazardous substances in leachates of thermally modified pine wood. Scots pine (Pinus sylvestris L.) wood was thermally modified using Wood Treatment Technology (WTT) company device at 170 °C for 1 hour (TMP170/1) and at 160 °C for 3 hours (TMP160/3) and the mass loss was calculated. Material preparation and leaching procedure was made according to standard LVS EN 84:2000. In obtained leachates, the content of sugars, acetic acid, furfural and tannic acid were determined. Results showed that the total wood mass loss was 7.1 ± 1.4% (n=20) for TMP170/1 and 4.0 ± 1.6% (n=20) for TMP160/3. The initial leaching velocity differs between both modes and is higher for TMP160/3. The velocity decreases exponentially with immersion time and reaches plateau after 7th (5 days) immersion, but leaching still continues after the 9th immersion (14 days). The main components in leachates were tannic acid and pentoses. Among all studied compounds furfural is the hardest leachable one. Thermally modified wood treated at TMP170/1 is more environmentally friendly due to less water leachable substances. It is worth looking forward by investigating volatile organic compounds emissions in the air as it also could give high impact on human health.

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