Advanced Materials Research Vol. 678

Abstract: Nanomaterials research has become a major attraction in the field of advanced materials research in the area of Physics, Chemistry, and Materials Science. Biocompatible and chemically stable magnetic metal oxide nanoparticles have biomedical applications that includes drug delivery, cell and DNA separation, gene cloning, magnetic resonance imaging (MRI). This research is aimed at the fabrication of magnetic cobalt oxide nanoparticles using a safe, cost effective, and easy to handle technique that is capable of producing nanoparticles free of any contamination. Nanostructured Cobalt oxide powder was prepared by sonication method using ultrasonicator. Effect of sonication for different time intervals, on the morphology of cobalt oxide nanostructures was extensively studied. The morphology of the nanorods were very much affected by the sonication time, it was found that with an increase in sonication time, the length of the nanorods seem to considerably increase at the same time an agglomeration effect comes in to action and the rods form bundle like structures. These cobalt oxide nanorods were characterized using X-ray Diffraction characterization (XRD) and it revealed a cubic structure. Weight percentage of cobalt oxide was confirmed by thermo gravimetric analysis (TGA).

Abstract: Abstract The Chemical bath deposition method was used for the preparation of ZnO nanorods and their optical and structural properties were studied. ZnO seed layer thin films were prepared by chemical bath deposition technique on to well cleaned glass substrates. ZnO seed-coated glass substrates were immersed in aqueous solution of zinc nitrate and hexamethylenetetramine (HMT) on 1:10 molar concentration at 90°C for 4 hours and annealed at different temperatures. The effect of annealing temperatures on the surface morphology and optical properties of the films was studied. The structure of the ZnO nano rod was studied by X-ray diffractometer and scanning electron microscopy. The optical property was studied by UV-Vis spectroscopy and photoluminescence spectroscopy. Experimental results have shown that prepared ZnO nanorods by this method have higher photoluminescence

Abstract: ABSTRACT Silver nanowires have been synthesized by polyol process with ethylene glycol as solvent and PVP as capping agent. The silver nanowires have been characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), and Transmission electron microscope (TEM) techniques. The prepared silver nanowires were found to exhibit face-centered cubic (fcc) structure. The diameter of the prepared silver nanowires have been found to lie in the range of 60 - 80 nm and the length of the wires have been observed to be in the range of 10-20 µm. The I-V characteristics have been carried out to study the conducting behavior of the prepared silver nanowires.

Abstract: ZnO microtubes were synthesized by two step process, (i) synthesis of ZnO microrods and (ii) etching the microrods to form microtubes. The ZnO microrods are synthesized by the simple solution growth method using the zinc chloride and hexamine as a precursors at around 95 °C. Using the KOH as the etchant the ZnO microrods have etched into ZnO microtubes. ZnO micro-tube formation was studied as a function of KOH concentration and etching time. At low KOH concentration the tubes were not completely etched whereas at higher concentration the tube walls were damaged. ZnO tubes were characterized by X-ray diffraction, scanning electron microscopy, UV-vis spectrophotometer and room temperature photoluminescence (PL) measurement. From the UV absorption spectra and PL spectra reveals the presence (Oxygen vacancies related) of defect states due to KOH etching. The as-synthesized Zinc Oxide micro tubes have a diameter of ~600 nm, wall thickness of 30–40 nm, and length of ~7 μm. ZnO microtubes were tested as the catalyst for the photo degradation of the methylene blue (MB) dye. The result shows the photo degradation efficiency of the tubes are twice faster compared to that of rods, this is due to high surface area associated with the tubes.

Abstract: Low-dimension materials such as nanobelts, nanowires and nanorods are being investigated for their superior properties and numerous applications. Among them, one-dimensional semiconductor ZnO, representing one of the most important low dimensional materials, finds its applications in many different fields such as sensors, solar cells, IR detectors, microelectronics, etc. Synthesis of nanostructures without any catalytic template, or using the self-catalytic behavior of the material would be of interest. In this work, ZnO nanorods have been synthesized by simple two step process without using any catalyst. This method provides an easy way to produce nanostructured metal oxides under normal conditions. The prepared samples were characterized by studying their structural, optical and morphological properties using X-Ray Diffraction, Photoluminescence and Scanning Electron Microscopy. The diameter of the prepared nanorods were around 20-30 nm¬. The room temperature Photoluminescence spectra of the ZnO nanorods shows a broad visible emission around 450–530 nm.

Abstract: The effect of electron beam irradiation on electrical, thermal, mechanical and morphological properties of plasticized polymer electrolytes was investigated. A significant improvement in the mechanical strength without reduction in ionic conductivity was observed for the irradiated polymer electrolytes. DSC studies showed that the thermal behavior of the polymer electrolytes was improved by the addition of filler and by irradiation. SEM studies revealed a significant improvement in surface morphology of the polymer electrolyte after irradiation. The results are presented herein.

Abstract: Nanosized Mn doped ZnO samples were synthesized by co-precipitation method using Polyethylene glycol (PEG) as a capping agent. X- ray diffraction patterns confirm that the pure and Mn doped ZnO nanocrystals have wurtzite structure without any seconadary phases. Lattice parameters of pure and Mn doped ZnO nanocrystals increase slightly with increasing Mn concentration. The average crystalline size of pure and Mn doped ZnO nanocrystals are in the range of 14-18 nm. The X-ray density for pure and Mn doped ZnO sample is calculated using lattice parameters. It is found that almost static for Mn doped ZnO samples. In the Zn1-xMnx samples, room temperature magnetic hysteresis is observed and the saturation magnetization increases with increasing Mn content. However, these samples show room temperature ferromagnetic in nature. Result of the present investigation compared without PEG.

Abstract: Electroactive copolymer of o-anisidine and ethyl 4-aminobenzoate were synthesized in 1 M HClO4 using cyclic voltammetry on glassy carbon electrode. The copolymer was characterized by FT-IR spectral data. The surface morphology was studied using SEM analysis. The grain size of the copolymer was measured using XRD studies and was found to be 70 nm. The electrical conductivity of the copolymer was 3.14 ×10−3 S cm−1, as determined using a four-probe conductivity meter.

Abstract: Nano size Polypyrrole (PPY) was synthesized electrochemically in presence of three different surfactants namely CTAB, CSA and TTX-100. Cyclic voltammetric studies showed an irreversible oxidation of pyrrole in the presence of surfactants. The currents of the broad peak were 4.26mA, 5.3mA and 8.6mA for PPY/CTAB, PPY/CSA and PPY/TTY-100 respectively. The FT IR spectra of electrochemically synthesized PPY in presence and absence of surfactants were analyzed and the prominent peaks were assigned properly. The presence of N-H group in both cases suggests the presence of pyrrole units in the polymer. From the XRD results the particle sizes of all the four PPYs were determined and the values are as follows: PPY (34 nm), PPY/CSA (31 nm), PPY/CTAB (30nm), PPY/TTX-100 (29 nm). The PPY/TTX-100 exhibited highest electrical conductivity (2.04 ×10−3 S/cm) among other PPY synthesized (PPY/CTAB - 1.13 ×10−3 S/cm, PPY/CSA - 1.09×10−3 S/cm and PPY - 1.27 ×10−3 S/cm). SEM images of PPY/CSA showed agglomerated small polymeric fragments whereas PPY/CTAB showed large sized polymeric plates. Interestingly PPY/TTX–100 showed uniform hollow structure. The presence of surfactants has resulted in uniform polymer formation.

Abstract: Bismuth sulfide (Bi2S3) and Polyvinyl pyrrolidone (PVP) encapsulated Bi2S3 Nanoparticles are synthesized from aqueous solutions at room temperature. Synthesized samples are subjected to UV-Visible Spectroscopy, X-Ray Diffraction (XRD), Scanning electron microscopy (SEM), Energy Dispersive Analysis of X-ray (EDAX), Transmission Electron Microscopy (TEM) and FT-IR studies and their results are compared. X-ray diffraction spectrum reveals the crystalline nature of the synthesized samples. Grain size value of PVP/ Bi2S3 nanoparticles show a decrease when compared to Bi2S3 nanoparticles and this ensures the good encapsulant effect of PVP on Bi2S3 nanoparticles. SEM images show that all the particles in the synthesized sample are nearly equal in size. From the TEM image we conclude that the particle size lies between 30nm to 70nm. Finally the samples are subjected to EDAX studies for determining their composition.