scholarly journals CdS Nanoparticles with a Thermoresponsive Polymer: Synthesis and Properties

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Aslam Khan

This paper describes the synthesis of thermoresponsive colloidal nanocomposites based on CdS and poly(N-isopropylacrylamide). The CdS nanoparticles were prepared at room temperature from cadmium chloride and sodium sulfide salts in the presence of an organic ligand, 3-mercaptopropionic acid (MPA). The as-prepared MPA-bound CdS nanoparticles were stable for more than 30 days and exhibited good optical properties. The effect of various ratios of MPA/Cd2+and H2O/DMF (dimethylformamide) on the particle size of the CdS nanoparticles was investigated using UV-vis absorption measurements. Transmission electron microscopy studies showed that the particle sizes were approximately 4 nm in diameter, which is consistent with the size obtained using UV-vis spectroscopy. The CdS nanocomposite showed a temperature-responsive phenomenon as its temperature increased from 20 to 45°C.

2009 ◽  
Vol 7 (3) ◽  
pp. 555-559 ◽  
Author(s):  
Zehra Durmus ◽  
Hüseyin Kavas ◽  
Abdulhadi Baykal ◽  
Muhammet Toprak

AbstractA novel environmental friendly, room temperature route using an ionic liquid 1-n-butyl-3-methylimidazolium hydroxide ([BMIM]OH) for the synthesis of Mn3O4 nanoparticles is presented. The product was characterized using Fourier transform infrared spectroscopy, X-ray powder diffraction, and transmission electron microscopy. Phase purity was confirmed by XRD, and X-ray line profile fitting determined a crystallite size of 42 ± 11 nm. TEM analysis revealed various morphologies. EPR measurements have indicated the existence of long-range interactions, due to the wide range of particle sizes and morphologies observed.


2014 ◽  
Vol 5 ◽  
pp. 380-385 ◽  
Author(s):  
Arkadius Maciollek ◽  
Helmut Ritter

A facile and one pot synthesis of silver nanoparticles with narrow size distributions using silver nitrate and a copolymer 1 from N-isopropylacrylamide (NIPAM) and mono-(1H-triazolylmethyl)-2-methylacryl-β-cyclodextrin acting as reductant and stabilizer without using any additional reducing agent is reported. The reduction was carried out in aqueous solution under pH neutral conditions at room temperature. The results of dynamic light scattering analysis and transmission electron microscopy show adjustable particle sizes from 30–100 nm, due to variation of silver nitrate concentration, the polymeric reducing and stabilisation agent concentration or reaction time. The spherical structure of the silver nanoparticles has been confirmed by UV–vis spectroscopy and transmission electron microscopy. The optical properties of the nanoparticles have also been characterized by fluorescence spectroscopy. The formed spherical particles are stable in aqueous medium at room temperature over a period of several weeks. Furthermore the changes in the optical properties of the nanoparticles due to thermo induced volume phase transition behavior of the thermoresponsive cyclodextrin containing polymer 1 have been characterized by UV–vis spectroscopy.


Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 909 ◽  
Author(s):  
Federico Tasca ◽  
Riccarda Antiochia

The development of new nanomaterials is gaining increasing attention due to their extensive applications in fields ranging from medicine to food and cultural heritage. Green nanoparticles provide advantages compared to conventional nanoparticles as their synthesis is environmentally-friendly and does not require the use of high temperatures, pressure, or toxic chemicals. In this paper, green silver nanoparticles (AgNPs) have been synthesized according to a new method using quercetin as a reducing agent at room temperature. The synthesized AgNPs were characterized using UV-Vis spectroscopy, transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and dynamic light scattering (DLS) techniques and successively tested for biocide activity by studying their effects in the inhibition of bacterial growth. The results demonstrated that the smaller the AgNPs size, the greater their biocide activity. In particular, AgNPs with a diameter of 8 nm showed a minimum inhibitory concentration (MIC) value of 1.0 μg/mL against Streptococcus sp., Escherichia coli and Candida sp. microorganisms, while AgNPs with a larger diameter of about 20 nm were able to inhibit microbial of all selected pathogens at a higher MIC value of 2.5 μg/mL.


Author(s):  
AJI JOVITHA AT ◽  
DEIVASIGAMANI B

Objective: The present study attempted to synthesize AgNPs from mangrove bark Rhizophora mucronata and analyze characteristics. The synthesized AgNPs analyzed with UV–vis spectroscopy, high-resolution transmission electron microscopy (HRTEM), and energy-dispersive X-ray (EDX) for confirming the nanoparticles. Methods: The dried R. mucronata bark was powdered and kept in at 55°C for 15 min in a water bath and cooled at room temperature to get the extract. The R. mucronata bark extract was treated with silver nitrate and kept overnight in the dark environment which will turn the solution to dark brown color. The silver nanoparticles were characterized using UV–visible absorption at room temperature. Further characterization was also done with X-ray diffraction, high-resolution transmission electron microscope measurements, and DLS analysis. Results: The synthesized AgNPs were analyzed with various analytical methods that revealed the abundant presence of silver nanoparticles. The UV–vis spectroscopy analysis exposed the surface plasmon resonance peak of 422 nm. High-resolution transmission electron microscopy (HRTEM) analysis indicated the size ranging from 10 nm to 200 nm in diameter and a spherical shaped poly dispersal of the particles. The energy-dispersive X-ray (EDX) and DLS also confirmed the presence of silver atoms. Conclusion: Silver nanoparticles of Rhizophora mucronata bark revealed a well-defined structure and may be used in antimicrobial function in further researches.


2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Jejenija Osuntokun ◽  
Peter A. Ajibade

We report the synthesis and structural studies of ZnS and CdS nanoparticles in polyvinylpyrrolidone (PVP), poly(vinyl alcohol) (PVA), and poly(methyl methacrylate) (PMMA) matrices. The metal sulfides/polymer nanocomposites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, electronic spectroscopy (UV-Vis), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The particle sizes as calculated from the absorption spectra were in agreement with the results obtained from TEM and XRD data. They showed metal sulfides nanoparticles in the polymers matrices with average crystallite sizes of 1.5–6.9 nm. The TGA results indicate that incorporation of the nanoparticles significantly altered the thermal properties of the respective polymers with ZnS/PVA and CdS/PVA nanocomposites displaying higher thermal stability than the other polymer nanocomposites.


2011 ◽  
Vol 284-286 ◽  
pp. 697-702
Author(s):  
Zhen Li ◽  
Li Wei Peng ◽  
Fei Gao ◽  
Deng Yu Pan ◽  
Ming Hong Wu

In this paper, a rapid, facile and green strategy — electron beam irradiation has been developed to prepare CdSe nanoparticles. 10 mA GJ-2-II electronic accelerator was applied as radiation resource. CdSe nanoparticles were synthesized using NH3 as complexing agent by electron beam method in a colloid system, which used Cd(Ac)2 and Na2SeO3 as raw materials. Nanocrystalline CdSe was prepared rapidly at room temperature under atmospheric pressure. The structure and morphology of prepared CdSe nanoparticles were analyzed by X-ray diffraction and transmission electron microscopy. UV–vis spectroscopy (U-3010, Japan Hitachi) and photoluminescence spectroscopy (PL, F-7000, Japan Hitachi) were used to investigate the optical properties of the CdSe nanoparticles. The effects of radiation dose on the formation of CdSe nanocrystallines were discussed. The possible mechanism of the CdSe grain growth by electron beam irradiation method was proposed.


2021 ◽  
Author(s):  
Babak Kaboudin ◽  
Meysam Kyomarzi ◽  
Foad Kazemi

Abstract Different size and shapes of CdS and ZnS nanoparticles have been synthesized, characterized and studied for photodegradation of organic dyes. In this study, effect of alkyl chain of dithiocarbamates was investigated for the size and shaped controlled CdS and ZnS nanoparticles. A thorough structural characterization of nanoparticles has been carried out by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM) images, EDS, XRD, and UV/vis spectroscopy. Results showed that the alkyl chain in dithiocarbamate complexes of zinc and cadmium systems plays a significant role in the final morphology of the CdS and ZnS nanoparticles. A photocatalytic degradation of UV-irradiated Methylene Blue solutions in the presence of ZnS and CdS nanoparticles was studied in order to examine the nanoparticles influence on photodegradation rates.


In this paper an attempt has been made to synthesize undoped and 1wt% Cu doped CdS nanoparticles through chemical co-precipitation method. Prepared particles were characterized to explore their structural and thermoluminescence properties. The X-ray diffraction analysis reveals a hexagonal crystal structure at room temperature. The particle sizes are determined by Scherer formula for both undoped and doped CdS nanoparticles of various concentrations. The average grain size of undoped and Cu doped nanoparticles is found to be 32.81nm and 22.3nm respectively. The thermoluminescence studies of these above samples show TL peaks occurring at temperatures 379,428,471,510 and 550 Kelvin corresponding to activation energy 0.7 eV, 0.9eV, 1.2 eV, 1.4 eV and 1.3eV respectively.


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4094
Author(s):  
Piya Roychoudhury ◽  
Przemysław Dąbek ◽  
Michał Gloc ◽  
Aleksandra Golubeva ◽  
Renata Dobrucka ◽  
...  

In the present investigation, fucoxanthin—one of the major pigments in diatoms—has been extracted from Nanofrustulum shiloi SZCZM1342, and its reducing efficiency in the biogenesis of gold nanoparticles (GNPs) was checked. Fucoxanthin extracted from golden-brown cells of N. shiloi was compared to the healthy, growing biomass of N. shiloi and standard fucoxanthin after separate exposure to 25 mg L−1 aqueous hydrogen tetrachloroaurate solutions at room temperature. Isolated and standard fucoxanthin were found to be able to reduce gold ions within 12 h whereas, the whole biomass turned pink in color after 72 h of reaction. The synthesized particles were characterized by UV-vis spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). UV–vis spectroscopy of purple-colored suspensions showed the absorption band at approximately 520–545 nm, indicating a strong positive signal for GNP synthesis. The SEM study revealed the deposition of GNPs on siliceous frustules of metal-treated diatom cells. The TEM analysis confirmed the GNPs synthesized by whole biomass are triangular, spherical and hexagonal in nature, whereas the particles produced by extracted and standard fucoxanthin are all spherical in nature. This study demonstrates the involvement of fucoxanthin in the reduction of gold ions and subsequent production of gold nanospheres.


Author(s):  
Joseph J. Comer

Domains visible by transmission electron microscopy, believed to be Dauphiné inversion twins, were found in some specimens of synthetic quartz heated to 680°C and cooled to room temperature. With the electron beam close to parallel to the [0001] direction the domain boundaries appeared as straight lines normal to <100> and <410> or <510> directions. In the selected area diffraction mode, a shift of the Kikuchi lines was observed when the electron beam was made to traverse the specimen across a boundary. This shift indicates a change in orientation which accounts for the visibility of the domain by diffraction contrast when the specimen is tilted. Upon exposure to a 100 KV electron beam with a flux of 5x 1018 electrons/cm2sec the boundaries are rapidly decorated by radiation damage centers appearing as black spots. Similar crystallographio boundaries were sometimes found in unannealed (0001) quartz damaged by electrons.


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