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Franklin D.S.,Manonmaniam Sundaranar University | Guhanathan S.,Muthurangam Government Arts College
Journal of Applied Polymer Science | Year: 2015

Synthesis of pH-sensitive hydrogels of citric acid with varying diol units viz., 1,2 Ethane diol, 1,4 butane diol, and 1,6 hexane diol along with methacrylic acid towards the solventless green approach. The formations of the hydrogels were identified using FTIR spectroscopy. Thermal characterization (thermo gravimetric analysis, differential thermal analysis (DTA), and differential scanning calorimetry) and morphology of the synthesized hydrogels have been investigated. Swelling studies of hydrogels in various pH ranging from 4.0 to 10.0 have been investigated. The results of the swelling studies implied that percentage of swelling comparatively higher at neutral pH (7.4) than at acidic and alkaline pH. The inverse relationship was noticed, where ascending the diol units of hydrogel in swelling equilibrium. The hydrogels with the increasing chain length show a noticeable pH sensitivity and which could be considered as smart hydrogel. © 2014 Wiley Periodicals, Inc.

Sakthivel M.,Bharathiar University | Guhanathan S.,Muthurangam Government Arts College
Ecotoxicology and Environmental Safety | Year: 2015

A series of Itaconic Acid (IA) based pH-sensitive polymeric hydrogels were synthesized by condensation polymerization of Itaconic Acid (IA) with Ethylene Glycol (EG) in the presence of an acid medium resulted into pre-polymer. Further, pre-polymer were co-polymerized with Acrylic Acid (AA) through free radical polymerization using Potassium persulphate (KPS). The structural and surface morphological characterizations of the synthesized hydrogels were studied using FT-IR spectroscopy and Scanning Electron Microscope (SEM) respectively. The swelling and swelling equilibrium were performed at varies pH (4.0-10.0). Further, the effects of IA, EG and AA on swelling properties have also been investigated. Thermal stability of synthesized hydrogels have been investigated by TGA, DTA and DSC. The synthesized hydrogels have shown good ability to uptake a Cationic dye. The Methylene blue has been chosen as a model cationic dye. The results of dye removal using IA hydrogels found to have excellent dye removal capacity. Such kind of IA based hydrogels may be recommended for eco-friendly environmental application. viz., removal of dyes and metal ions and sewage water treatment, purification of water etc. © 2015 Elsevier Inc.

Prabukanthan P.,Muthurangam Government Arts College | Harichandran G.,University of Madras
Journal of the Electrochemical Society | Year: 2014

Zinc selenide thin films on ITO glass substrate have been grown by an electrochemical deposition technique at a low temperature of 50°C. The bath solution was maintained at three different pH values and the effect of pH on the nature of the deposited films studied. Profilometer studies showed the roughness of ZnSe thin films obtained from the bath in which SeO2 was the Se source is lower than that of the films obtained from the bath in which SeCl4 was the Se source. The atomic percentage ratio for zinc and selenium of the ZnSe thin films obtained from the bath in which SeO2 was the Se source was found to be 49.7:50.3. GAXRD studies confirmed that the as-deposited ZnSe thin films belong to the cubic system with (111) plane as the dominant peak. When SeCl4 was used as Se source the thin films showed peaks due to the cubic system along with hexagonal (100) reflection indicating a mixed phase. The absorption coefficient's fall is sharper for the films obtained from the bath in which SeO2 was the Se source than those films obtained from the bath in which SeCl4 was the Se source due to the presence of hexagonal phase. © 2014 The Electrochemical Society.

Prabukanthan P.,Muthurangam Government Arts College | Harichandran G.,University of Madras
Materials Science in Semiconductor Processing | Year: 2013

Zinc oxide (ZnO) thin films were deposited on sapphire substrates at room temperature by radio frequency (RF) magnetron sputtering. These films were irradiated with 100 MeV O7+ ions of the fluencies 5×10 13 ions/cm2 at room temperature (RT) and at liquid nitrogen temperature (LNT). Profilometer studies showed that the roughness of pristine and LNT irradiated ZnO thin films were higher than that of the RT irradiated ZnO thin film. The glancing angle X-ray diffraction analysis reveals a reduced intensity and increased full width at half maximum (FWHM) of the (002) diffraction peak in the case of LNT irradiated film indicating disorder. However, the intensity and FWHM of the (002) diffraction peak in the case of RT irradiated ZnO thin films are comparable to those of the pristine film. UV-visible transmission spectra show that the percentage of transmission and band gap energy are different for RT and LNT irradiated films. While the pristine ZnO thin film exhibits two emissions - a broad emission at 403 nm and a sharp emission at 472 nm in its photoluminescence spectrum; the emission at 472 nm was absent for the irradiated films. The atomic concentrations of zinc and oxygen during the irradiation process were obtained using auger electron spectroscopy. © 2012 Elsevier Ltd.

Gopinathan H.,Thiruvalluvar University | Komathi N.,Muthurangam Government Arts College | Arumugham M.N.,Thiruvalluvar University
Inorganica Chimica Acta | Year: 2014

The cobalt (III) complexes, [Co(trien)(phen)] (ClO4) 2Cl, (1), [Co(trien)(phen)](NO3)3, (2) (where trien = triethylenetetramine, phen = 1,10-phenanthroline) has been synthesized and characterized by Infra-red, UV-Vis, ESI-MS and elemental analysis methods. Complex 1 was structurally characterized by single crystal X-ray crystallography. It was crystallized in a triclinic system with space group P1̄, a = 7.797(10) Å, b = 10.6584(2) Å, c = 14.889(3) Å, α = 96.83(10)°, β = 96.16(10)°, and γ = 98.88(10)°. The cobalt atom assumes a distorted octahedral geometry by coordinating to 6 nitrogen atoms from four triethylenetetramine and two 1,10-phenanthroline ligands. The binding of this cobalt (III) complex with calf thymus DNA (CT-DNA) was investigated by UV-Vis absorption, fluorescence spectroscopic, cyclic voltammetric and viscosity techniques. Also, the interactions of pBR322 DNA with these cobalt (III) complexes were studied using the gel electrophoresis method. The thermal denaturation and viscosity binding data advocates that the cobalt (III) complexes interact with DNA by groove binding. When compared to complex 2 complex 1 has more potential to the kill human liver cancer cell as revealed by the MTT assay. The cobalt (III) complexes screened for their activities in vitro on common bacteria and fungi and exhibit antimicrobial activities. © 2014 Elsevier B.V. All rights reserved.

Ravichandran C.,Anna University | Ravichandran C.,Dhanalakshmi College of Engineering | Srinivasan G.,Muthurangam Government Arts College | Lennon C.,University of Illinois at Chicago | And 2 more authors.
Superlattices and Microstructures | Year: 2011

Lithium (Li) and magnesium (Mg) co-doped zinc oxide (ZnO) thin films were deposited by sol-gel method using spin coating technique. The films were deposited on glass substrates and annealed at different temperatures. The effects of annealing temperature on the structural, optical and electrical properties of the deposited films were investigated using X-ray diffraction (XRD), Ultraviolet-Visible absorption spectra (UV-VIS), photoluminescence spectra (PL), X-ray photo electron spectroscopy (XPS) and Hall measurements. XRD patterns indicated that the deposited films had a polycrystalline hexagonal wurtzite structure with preferred (0 0 0 2) orientation. All films were found to exhibit a good transparency in the visible range. Analysis of the absorption edge revealed that the optical band gap energies of the films annealed at different temperatures varies between 3.49 eV and 3.69 eV. Room temperature PL spectra of the deposited films annealed at various temperatures consist of a near band edge emission and visible emission due to the electronic defects, which are related to deep level emissions, such as oxide antisite (O Zn), interstitial zinc (Zni), interstitial oxygen (O i) and zinc vacancy (VZn) which are generated during annealing process. The influence of annealing temperature on the chemical state of the dopants in the film was analysed by XPS spectra. Ion beam analysis (Rutherford back scattering) experiments were performed to evaluate the content of Li and Mg in the films. Hall measurements confirmed the p-type nature of the deposited films. © 2011 Elsevier Ltd. All rights reserved.

Karpagam S.,Vellore Institute of Technology | Guhanathan S.,Muthurangam Government Arts College
Journal of Luminescence | Year: 2014

Dichloro quinoline substituted phenylene vinylene oligomer (QUI-OPV) was synthesized via Wittig route. Formation of the oligomer was characterized by spectral (FTIR, 1H and 13C NMR), elemental and gel permeation chromatography analysis. The oligomer possesses excellent thermal stability (decomposition temperature 470 C), solubility in common organic solvents and high glass transition temperature (61 C). The morphology of the oligomer film of one dimensional (1D) and three dimensional (3D) architectures was observed using atomic force microscopy (AFM). In CHCl3 solution, the oligomer showed the absorption maxima at 382 nm and also observed excellent photoluminescence (PL) with bluish green emission maxima at shorter wavelengths of 477 nm. The introduction of quinoline to the main chain resulted in a slight decrease of effective conjugation length and exhibited the blue shift in both the absorption and emission spectra. © 2013 Elsevier B.V.

Karpagam S.,Vellore Institute of Technology | Guhanathan S.,Muthurangam Government Arts College
International Polymer Processing | Year: 2015

Core-shell hyperbranched polyesters (HBPE) of third generation prepared from 2,2ʹ-bis (hydroxymethyl) propionic acid (Bis-MPA) as an ABx monomer and N-heterocyclic (indole, piperidine and piperazine) phosphoryl dichloride as a core molecule by melt condensation process. These polymers were characterized by FT-IR, 1H NMR, 13C NMR, 31P NMR, elemental analysis, and MALDI spectroscopy. The thermal behavior of the polymers has been investigated by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC). There is no weight loss observed until 250 ˚C under nitrogen atmosphere. DSC showed that the glass transition temperatures was about –14 and –30 ˚C for the prepared core-shell HBPE. The dielectric properties such as dielectric constant and loss factor for these polyesters were also studied with respect to change of frequency (50 Hz to 5 MHz). © 2015 Carl Hanser Verlag GmbH & Co. KG.

Karpagam S.,Vellore Institute of Technology | Guhanathan S.,Muthurangam Government Arts College
Journal of Applied Polymer Science | Year: 2013

The functional modification of poly (vinyl alcohol) (PVA) was conducted through phosphorus containing nitrogen heterocycles. This has been believed to have extensive thermal stability and heavy metal ion adsorption in the area of polymers. The heterocyclic modified polymers were characterized by Infra red (FTIR), Nuclear magnetic resonance spectroscopy, and elemental analysis. Thermogravimetric analysis studies displayed that phosphorus-containing five membered and fused heterocyclic based PVA were less thermally stable than six membered compounds. Differential scanning calorimetric studies reported that the glass transition and melting point temperature of the heterocyclic modified PVA was higher than the pure PVA. X-ray diffraction studies were done to analyze the structure of the modified polymer. Atomic force microscopy surface scans showed that the modified polymeric surface was found to have rough in micrometer scale. Modified PVA showed improved thermal stability, flame retardance, organosolubility, and surface roughness. The adsorption capacities of the modified PVA were determined for several heavy metal ions with the variation of pH. The adsorption capacity was found as 289 mg Pd2+/g of imidazole modified PVA and exhibited higher than other modified PVA. © 2013 Wiley Periodicals, Inc.

Karpagam S.,Vellore Institute of Technology | Guhanathan S.,Muthurangam Government Arts College
Progress in Organic Coatings | Year: 2014

Third generation of hyperbranched polyester (HP) synthesized via melt condensation and end-capped with bis indole and imidazole phosphoryl chloride. The modified polyesters subjected to different characterization viz., FTIR, 1H and 13C NMR, GPC and elemental analysis. NMR analysis was used for the determination of OH conversion that demonstrates linear units had a lower reactivity as compared to terminal OH groups in HP. The thermogravimetric analysis (TGA) and differential scanning calorimetric (DSC) studies indicated that the HP was stable up to 276 °C and the glass transition temperature was 79.6 °C. After modification of HP, thermal stability was increased for indole modified HP, but the glass transition temperature was decreased. The flame retardance of the hyperbranched polyester was also evaluated with the help of TGA analysis and showed higher value of limiting oxygen index (LOI) for modified polyesters. Morphology of the modified polyester showed more roughness than unmodified HP and this nature positive correlated with bacterial zone of inhibition value. Biological studies showed that the HP and modified HP are able to inhibit the reproduction of gram-positive and gram-negative bacteria. Indole modified HP is showed good activity compared to imidazole modified HP. © 2014 Elsevier B.V.

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