Department of Physics

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Physics

Poly(ε-caprolactone) (PCL)-containing rosin nanofibers were prepared via electrospinning technique for biomedical applications. To improve the biocompatibility properties, rosin was blended into PCL to prepare nanofibers. Nanofibers mats were prepared with different concentrations of rosin. The morphology, structure, and thermal properties of the resultant PCL/rosin nanofibers were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and thermogravimetry (TGA) analysis. SEM images revealed that the nanofibers were well-oriented and had good incorporation of rosin. FTIR results indicated the various bonding groups of PCL/rosin nanofibers with stable structure. TGA analysis revealed that the onset degradation temperature was decreased with increasing rosin content in the nanofibers. The bactericidal activity of PCL/rosin nanofibers was also investigated. These results indicate that the PCL blended with rosin nanofibers can be utilized as a promising candidate material for many biomedical applications. [Figure not available: see fulltext.] © 2014 The Polymer Society of Korea and Springer Sciene+Business Media Dordrecht.

World University root node

School of Advanced Sciences

Chennai Campus

Macromolecular Research

Bactericidal efficacy of electrospun rosin/poly(ε-caprolactone) nanofibers

The nonlinear optical single crystals of diglycine barium chloride monohydrate were grown by slow evaporation solution growth technique from the mixture of an aqueous solution of glycine and barium chloride in the ratio 2:1 at room temperature. The grown crystals were characterized by various techniques such as single crystals X-ray diffraction, FTIR, UV-Vis-NIR spectra, Vickers hardness studies, thermogravimetric analysis, and fluorescence spectra. Its second harmonic generation efficiency was measured by Kurtz and Perry powder technique using Nd :YAG laser.

Centre for Bio-Separation and Technology

Vellore Campus

Journal of Nonlinear Optical Physics & Materials

OPTICAL, THERMAL AND MECHANICAL STUDIES ON NONLINEAR OPTICAL MATERIAL DIGLYCINE BARIUM CHLORIDE MONOHYDRATE (DGBCM) SINGLE CRYSTAL

In this article, we report the synthesis of silver nanospheres (Ag NS) by a simple microwave irradiation method using Triton X 100 (TX 100) as a capping agent. TX 100 was also observed to act as a reducing agent in the presence of microwave radiation. From the ultraviolet-visible spectrum, the formation of Ag NS was confirmed by observing surface plasmon resonance band at 414 nm. The emission band of Ag NS was observed at 482 nm from the photoluminescence (PL) spectrum. High-resolution transmission electron microscopy (HR TEM) was used to investigate the morphology of the synthesized sample. It shows that the synthesized sample has sphere-like morphology with an average diameter of 5 nm. Further, the elemental composition of the Ag NS was determined by energy dispersive x-ray analysis (EDX). Selected area electron diffraction (SAED) was used to find the crystalline nature of the Ag NS. The interaction between Ag NS and TX 100 was established by Raman spectroscopy. The electrochemical behaviour of the synthesized Ag NS was analyzed by cyclic voltammetry (CV). © 2013 Copyright Taylor and Francis Group, LLC.

Journal of Dispersion Science and Technology

Microwave-Assisted Synthesis and Characterization of Triton X 100 Capped Silver Nanospheres

A novel self-assembled pure and Mg doped ZnO nano-particles (NPs) were successfully synthesized by a simple low temperature co-precipitation method. The prepared photocatalysts were characterized by X-ray diffraction, high resolution scanning electron microscopy, high resolution transmission electron microscopy, diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy. The results indicated that the prepared photocatalysts showed high crystallinity with a uniform size distribution of the NPS. The degradation of cholorphenols is highly mandatory in today's scenario as they are affecting the environment adversely. Thus, the photocatalytic degradation of 4-chlorophenol (4-CP), a potent endocrine disrupting chemical in aqueous medium was investigated by both pure and Mg-doped ZnO NPs under UV-light irradiation in the present study. The influence of the Mg content on the structure, morphology, PL character and photocatalytic activity of ZnO NPs were investigated systematically. Furthermore, the effect of different parameters such as 4-CP concentration, photocatalyst amount, pH and UV-light wavelength on the resulting photocatalytic activity was investigated.

Department of Manufacturing Engineering

School of Mechanical Engineering

Journal of Environmental Sciences

Pure and Mg-doped self-assembled ZnO nano-particles for the enhanced photocatalytic degradation of 4-chlorophenol

Activated carbon composite was prepared from sugarcane bagasse. The X-ray diffraction revealed the evolution of crystallites of carbon and silica during activation at higher temperature. FTIR spectrum shows the presence of functional groups and silica in the carbon composite. The morphology of the carbon sample was determined by SEM. The surface area, pore volume and pore size distribution of carbon composites were measured. The dc conductivity was determined and conductivity at room temperature was found to increase from 10.22×10-3 to 25.131×10-3Scm-1. The samples show good electrochemical property and the specific capacitance in the range of 92-340Fg-1. © 2013 The Korean Society of Industrial and Engineering Chemistry.

Journal of Industrial and Engineering Chemistry

Studies on structural, morphological, electrical and electrochemical properties of activated carbon prepared from sugarcane bagasse

The effect of ethylenediamine addition in the sol-gel method for the preparation of pure and Sr(II)- added nano copper aluminate (CuAl2O4) composites for the enhancement in their structural, electrical, and alcohol sensing properties were investigated. The effect of addition of Sr(II) to pure CuAl2O4 in both the methods were also discussed. X-ray diffraction, scanning electron microscopy, nitrogen adsorption/desorption isotherms, temperature dependant conductance measurements and thermoelectric power measurements were used to characterize the composites prepared. Among the composites, 0.8 molar ratio strontium added copper aluminate composite prepared by modified sol-gel method showed the highest sensitivity towards alcohols. The stability, response and recovery of MS-CuSA5 were also discussed. The response and recovery characteristics showed that the order of sensing alcohols by the composites was butanol isopropanol ethanol methanol, which could be explained on the basis of oxidation of alcohols. Copyright © 2013 American Scientific Publishers All rights reserved.

Journal of Nanoscience and Nanotechnology

Pure and Sr(II)-Added Copper Aluminate Nanocomposites: Structural, Electrical and Alcohol Sensing Studies

Pure and Ni-doped ZnFe2O4 nanoparticles, Zn1-xNixFe2O4 (x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5) were synthesized by microwave combustion method (MCM). The structural, morphological and magnetic properties of the products were determined by X-ray diffraction (XRD), high resolution scanning electron microscopy (HR-SEM) and vibrating sample magnetometer (VSM). X-ray analysis showed that all the compositions crystallize with cubic spinel structure. The broadband visible emission is observed in the entire photoluminescence (PL) spectrum and the estimated energy band gap is about 2.1 eV. VSM measurements shows superparamagnetic behavior for lower concentration of Ni (x ≤ 0.2), whereas for higher concentration (x ≥ 0.2), it becomes ferromagnetic. The saturation magnetization (Ms) varies considerably with Ni content to reach a maximum value for Ni0.5Zn0.5Fe2O4 composition, i.e. 57.89 emu/g.

Advanced Materials Research

Comparative Study of Pure and Ni-Doped ZnFe2O4 Nanoparticles for Structural, Optical and Magnetic Properties

Porous Zn1-xCuxAl2O4 (x = 0,0.1,0.2,0.3,0.4,0.5) spinel nanostructures were synthesized by onepot microwave combustion technique. All the samples were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and scanning electron microscopy (SEM). The XRD patterns confirm the formation of single phase ZnAl2O4 without any impurities. The results of XRD indicated the average crystallite size in the range of 12.44-22.86 nm. FT-IR spectra show the vibrational stretching frequencies corresponding to the zinc aluminate spinel structure. The estimated band gap of undoped ZnAl 2O4 was 4.96 eV indicating the quantum confinement phenomenon. DRS spectra also indicated the band gap narrowing effect with increase in copper ion concentrations. The defect centers acting as trap levels were obtained from photoluminescence studies responsible for the emission spectra. SEM images showed the features of well created pore structures in all the matrices. The percentage porosity of zinc aluminate matrices decreased with increasing copper doping. Copyright © 2013 American Scientific Publishers.

VIT Unitversity

One-Pot Microwave Combustion Synthesis of Porous Zn1–xCuxAl2O4 (0 ≤ x ≤ 0.5) Spinel Nanostructures

The hexagonal ZnO nanorods supported activated carbon (ZSAC) was successfully prepared using zinc nitrate hexahydrate and urea through microwave irradiation. The method of preparation is simple and cost effective. The activated carbon (AC) with high surface area (446.44 m2/g), pore volume (00.21 cm3/g) and average pore diameter (01.89 nm) was employed as a matrix support for the growth of ZnO nanorods. The XRD results affirm the formation of wurtzite ZnO nanostructures. The FT-IR studies disclose the presence of varied functional groups present in ZSAC. The HR-SEM images reveal the pore morphology of AC and hexagonal shape of ZnO nanorods formed. The E(g) value obtained from Kubelka-Munk transformed reflectance spectra is about 3.43 eV. The photoluminescence emissions reveal the defects in the crystal lattice. The ZSAC thus prepared would perform substantial role in the area of catalysis.

Fabrication of Hexagonal ZnO Nanorods on Porous Carbon Matrix by Microwave Irradiation

A series of Sr(II)-added nickel aluminate nanocatalysts with different molar ratios of Ni:Sr (1.0:0.0, 0.9:0.1, 0.8:0.2, 0.7:0.3, 0.6:0.4 and 0.5:0.5) keeping the molar ratio of aluminum constant were synthesized by modified sol-gel method using ethylenediamine and sintered at 900 °C. The samples were labeled as NiSA1-900, NiSA2-900, NiSA3-900, NiSA4-900, NiSA5-900, NiSA6-900, respectively. The catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), nitrogen adsorption/desorption isotherms and tested for the catalytic oxidation of benzyl alcohol. Influence of the reaction parameters (molar ratio of Sr(II) added to nickel aluminate nanocatalyst, reaction time, reaction temperature and solvent effect) on the catalytic oxidation of benzyl alcohol were studied. It was observed that the addition of Sr(II) improves the performance of the nickel aluminate nanocatalysts towards the selective oxidation of benzyl alcohol and decreases the grain size. Higher activity was obtained for the conversion of benzyl alcohol to benzaldehyde for 0.3 molar percentage Sr(II) added nickel aluminate catalyst (NiSA4-900). Stability and reusability of the catalyst was also investigated. Copyright © 2013 American Scientific Publishers.