QUENCHING OF SURFACE PLASMON MODES IN COLLOIDAL SILVER NANOPARTICLES ON OZONIZATION

NANO ◽  
2006 ◽  
Vol 01 (03) ◽  
pp. 229-234
Author(s):  
R. K. RAKSHIT ◽  
SAYANTANI BHATTACHARYA ◽  
R. C. BUDHANI

Oxidation characteristics of colloidal silver nanoparticles produced by pulsed laser ablation in pure and chemically treated water are studied as a function of the degree of ozonization. The bright yellow colloidal solution of silver characterized by a sharp surface plasmon mode at ~400 nm, becomes colorless in the initial stages of O 3 flow, and then acquires a brown hue with a broad plasmon peak centered at ~440 to ~450 nm on further ozonization. The solution again becomes colorless in a few days once the O 3 flow is stopped. We present a qualitative model for the reaction dynamics and analyze the optical absorption in the framework of an effective medium theory. The aqueous phase laser ablation chemistry described here provides a unique means to produce ionic silver for enhanced antimicrobial effects.

2012 ◽  
Vol 488-489 ◽  
pp. 1409-1413
Author(s):  
Adeleh Granmayeh Rad ◽  
Hamed Abbasi

In this work we report the preparation of colloidal silver nanoparticles. In order to prepare the silver nanoparticles laser ablation method has been used.A silver coin as a target (purity 99.9 %) was ablated by a Q-Switched Nd:YAG laser with a fluence of about 91 mJ/cm2 at a repetition rate of 10 Hz at room temperature. In order to evaluate these particles transmission electron microscopy (TEM) and spectrophotometry (from UV to NIR) have been used. The average size of prepared nanoparticles is ~ 20 nm. The importance of morphology of nanoparticles has been investigated. Developed applications of silver nanoparticles have been studied,silver nanoparticles are considered as biocompatible and low in toxicity and have good potential for biological applications. Lately silver nanoparticles have found a novel approach in different fields of medicine, biology and industry.


MOMENTO ◽  
2021 ◽  
pp. 1-11
Author(s):  
Miguel A. Valverde-Alva ◽  
Jhenry F. Agreda-Delgado ◽  
Juan A. Vega-González ◽  
Juan C. Rodríguez-Soto ◽  
Julio C. Idrogo-Córdova ◽  
...  

The effect of magnetic field of 0.3 T on the concentration, distribution of sizes in suspension and zeta potential of colloidal gold and colloidal silver nanoparticles, obtained by considering the pulsed laser ablation in double distilled water was studied. The magnetic field was transverse to the direction of incidence of the laser radiation and parallel to the surface of a submerged target. An Nd: YAG laser was used (1064 nm in wavelength, 10 ns in duration, repetition rate of 10 Hz and 37 mJ of energy) to ablate targets. The colloids were characterized by inductively coupled plasma optical emission spectroscopy, ultraviolet-visible spectroscopy, dynamic light scattering and zeta potential. Concentration analysis suggested that applying magnetic field of 0.3 T during nanoparticle synthesis leads to higher concentration. Applying magnetic field led to an eleven percent increase in the concentration of the colloid with gold nanoparticles and a five percent increase in the concentration of the colloidal silver nanoparticles. The absorption spectra suggested the presence of spherical nanoparticles. When analyzing the effect of the magnetic field on the hydrodynamic size distribution of the nanoparticles and the zeta potential of the colloids, no significant changes were evidenced. The magnetic confinement of the plasma induced by laser ablation caused changes in the characteristics of the colloids.


2021 ◽  
Vol 21 (3) ◽  
pp. 761
Author(s):  
Syifa Avicenna ◽  
Iis Nurhasanah ◽  
Ali Khumaeni

The silver nanoparticles (AgNPs) have been applied as an antibacterial agent in consumer products, cosmetics, and food industries. In this present work, AgNPs were synthesized in various mediums of polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and chitosan using the pulse laser ablation synthesis method. Experimentally, a pulse Nd:YAG laser beam (1064 nm, 7 ns, 30 mJ) was directed using a silver mirror and focused using a quartz lens with a focal length of 30 mm on a silver metal plate placed in a petri dish containing liquid mediums for 120 min to produce colloidal silver nanoparticles. The results certified that All AgNPs have a spherical shape with polydisperse size in all media, including PVP, PEG, and chitosan. The smallest AgNPs have been produced in PVP medium with an averaged smallest size of 11.62 nm. Based on this result, PVP is the preferred medium to produce AgNPs with the smallest size and good stability. The produced silver nanoparticles have been successfully employed as an antibacterial agent, which is experimentally demonstrated by using Escherichia coli and Staphylococcus aureus. The result certified that the produced silver nanoparticles could effectively kill the bacteria with a killing percentage of 99.6 to 100%.


2013 ◽  
Vol 11 (1) ◽  
pp. 44-51 ◽  
Author(s):  
Ruixue Wang ◽  
Shasha Zuo ◽  
Weidong Zhu ◽  
Shan Wu ◽  
Weifeng Nian ◽  
...  

2010 ◽  
Vol 79 (12) ◽  
pp. 1203-1208 ◽  
Author(s):  
Kazem Naghavi ◽  
Elias Saion ◽  
Khadijeh Rezaee ◽  
Wan Mahmood Mat Yunus

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