International Journal of Nano and Biomaterials (11 papers in press)
Silver Nanoparticles from Methanolic Stem Extract of Gymnema Sylvestre and its Characterization Studies
by Sathyaa R, Subha V, Ernest Ravindran R S, Renganathan S
Abstract: In this approach silver nanoparticles (AgNPs) were synthesized from Gymnema sylvestre stem extract. Gymnema sylvestre herb exhibits wide range of therapeutic properties. Phytochemical studies of this plant extract revealed the presence of alkaloids, flavonoids, tannins and glycosides. These phyto constituents were responsible for the reduction of silver ions to silver nanoparticles. The bioreduced silver nanoparticles were characterized by UV-visible spectroscopy, Fourier Transform Infrared spectroscopy (FTIR), X-Ray powder Diffraction (XRD) and High Resolution Transmission Electron microscopy (HR-TEM). The free radical scavenging activity of stem extract of Gymnema sylvestre was also evaluated using DPPH assay. DPPH radical scavenging ability of Gymnema sylvestre stem extract was found to be 56.25 %. Antimicrobial activity of these silver nanoparticles was examined through disc diffusion method. Zone of inhibition formed against silver nanoparticles at different concentrations 30, 60, 100
Keywords: Phytochemical; Antimicrobial activity; Gymnema sylvestre; Silver Nanoparticles.
Analytical modelling of sensing performance of carbon nanotubes for gas sensing
by Geoffrey Ijeomah, Fahmi Samsuri, Mohamad Adzhar Md Zawawi
Abstract: Carbon nanotubes as a new variety of quasi one-dimensional (1D) materials belong to the family of carbon-based nanostructures, which have recently ignited tremendous research interest. The latest discoveries of the outstanding properties of carbon nanotubes (CNTs) in terms of their electronic and structural behaviours such as, large surface-to-volume ratio, tunable band gap, high mechanical strength, high mobility and extreme sensing capability make them a great candidate for nanoelectronic devices of the future. Due to the importance of nanoscale sensors and biosensors in various areas of our lives, using promising materials such as carbon nanotubes has widely captured the attention of researchers to achieve better sensitivity and accuracy in these devices. Up until now, the majority of investigations have focused on experimental studies for sensors. Therefore, there is a lack of analytical models in comparison to experimental investigations. In order to model the transport parameters of a CNT-based gas sensor, the field effect transistor (FET)-based structure has been employed as a primary model for a gas detection sensor. The conductance of the carbon nanotube has been affected under exposure to the target analyte NH3 gas molecules. The absorption of NH3 gas concentration on the CNT surface follows a chemical reaction between CNTs and the NH3 gas. Therefore, it modulates the current-voltage (I-V) characteristics and conductance of the proposed CNT-based gas sensor. The I-V characteristics of the CNT-based sensors have been proposed as a criterion to detect the effect of gas absorption. Finally, the accuracy of the proposed models were validated by benchmarking them on existing experimental works.
Keywords: carbon nanotubes; sensors; I-V characteristics; conductance.
Modifications of optical properties in doped germanene nanosheet
by Namrata Dhar, Debnarayan Jana
Abstract: Optical properties, like complex dielectric constant, absorption
coefficient, refractive index and reflectivity have been analyzed via density
functional theory (DFT) of As and Ga doped free standing (FS) germanium (Ge)
nanosheet. Position dependent (same or different sub-lattice positions) doping
mechanism of foreign elements along with concentration variation upto 6.25%,
in pristine germanene layer has been adopted for the whole work. Interesting
modifications in optical anisotropy than pristine layer have been observed as
a consequence of doping. Such modifications, like enhancement or reduction
of peak intensity or shifting of peak positions may be useful to design smart
germanene based opto-electronics devices in upcoming future.
Keywords: Germanene; Density functional theory; Optical properties.
Thin film of Yttria stabilized Zirconia on NiO using vacuum cold spraying process for solid oxide fuel cell
by Debabrata Pradhan, Lala Behari Sukla
Abstract: Yttria stabilized zirconia (YSZ) was fabricated on a glass and NiO-YSZ anode support substrate using the vacuum cold spraying (VCS) technique at room temperature. The field emission scanning electrode microscope (FESEM) analysis revealed a dense microstructure and several vertical cracks within 0.1 μm width of the YSZ film. The transmission electron microscopy (TEM) was used to analyze the grain size and it was found to be 20 nm which was finer size compared to the average particle size of the starting YSZ powder. The x-ray diffraction (XRD) analysis showed lacking of phase transformation during the VCS process. The YSZ film fabricated by VCS technique showed better gas tightness compared to that fabricated by atmospheric plasma spray process. The Youngs modulus of the YSZ film was found to be 172 GPa.
Keywords: Yttria stabilized zirconia; vacuum cold spraying; solid oxide fuel cell; thin film; gas permeability; conductivity; mechanical properties.
Synthesis and Characterization of Lanthanum Complex Bis (5-Choloro-8hydroxy quinoline)(2-2bipyridine) Lanthanum La(Bpy)(5-Clq)2
by Rahul Kumar, Ankur Soam, Parag Bhargava
Abstract: Lanthanum complex Bis (5-Choloro-8hydroxyquinoline) (2-2bipyridine) lanthanum La(Bpy) (5-Clq)2 has been synthesised and characterized for its structural, thermal and photoluminescence analysis. Structure analysis of the complex was performed by Fourier transformed infrared spectroscopy (FTIR). Thermal analysis of the lanthanum complex was done by thermal gravimetric analysis (TGA) and complex is stable up to 370 oC. Absorption and emission spectra of the complex was measured by UV-visible spectroscopy and photoluminescence spectroscopy, respectively. Solution of this complex in ethanol showed two absorption peaks at 402 and 334 nm, which may be attributed due to (π π*) transitions. The photoluminescence spectra of La(Bpy)(5-Clq)2 in ethanol solution showed intense peak at 510 nm.
Keywords: Organometallic compounds; Lanthanum complex; Chemical Synthesis; Thermal stability; Photoluminescence.
Effect of annealing on the physical properties of WO3 thin films
by Madhuri Kalapala
Abstract: Tungsten trioxide (WO3) thin films have considerable interest due to its wide variety of properties, and extensively studied for various applications such as chromogenic devices, switching mirrors, optoelectronic devices and gas sensors. In this view, our present investigations are aimed at electron beam evaporated thin films of WO3. The films were deposited at an oxygen partial pressure of 2x10-4 mbar and at different substrate temperatures ranging from room temperature (RT) to 4500C. The films were annealed at 4000C about 2 hours and the properties were studied systematically. The X-ray Diffraction studies show the diffraction peak of (320) at 2θ = 44.070 which indicate the Orthorhombic phase of WO3 and also the other peaks represent the hexagonal phase of WO3. Due to annealing of the films, the monoclinic phase is also observed. The surface morphology of WO3 thin films was investigated by using Atomic Force Microscopy and Scanning Electron Microscopy, which supports the above data. The Energy Dispersive X-ray (EDX) compositional analysis confirmed the presence of W and O. The optical properties were studied by UV-VIS Spectrophotometry and hence the bandgap values are calculated.
Keywords: Tungsten trioxide thin films; annealed; structural; morphological; optical and compositional.
ALTERNATING CURRENT CONDUCTION STUDIES OF HYBRID NANOCOMPOSITE AT ROOM TEMPERATURE
by T. Chandrasekhar, Y.T. Ravi Kiran, C.H. V. V. Ramana, D.K. Mishra
Abstract: Polyaniline (PANI) and Polyaniline-Yttrium oxide (PANI-Y2O3) hybrid nanocomposite were synthesized separately by simple chemical polymerisation method and then they were structurally characterised by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning electron microscopy (SEM) techniques. The alternate current (AC) conduction parameters of PANI and the composite were comparatively studied in the frequency range 100Hz-1MHz at room temperature. The AC conduction results were interpreted as power law of frequency and the frequency exponent s and was found to lie in the range 0
Keywords: Polyaniline; Yttrium oxide; Polymer composites; AC conductivity; Correlated barrier hopping;.
Adsorption of Ni(II) ions from waste water by -MnO2-MCM-41: Isotherm, kinetics and thermodynamics
by Suresh Kumar Dash
Abstract: δ-MnO2 modified MCM-41 adsorbent was prepared by loading different amounts of δ-MnO2 (5, 10, 15 and 20 weight %) onto MCM-41 by direct-synthesis or in situ method. The synthesized materials were characterized by UV-vis diffused reflectance spectra, Fourier Transform Infrared spectra and BET surface area. The adsorbent (δ-MnO2-MCM-41) showed very high efficiency and sensitivity for removing Ni(II). By varying different parameters like initial Ni(II) concentration, pH of solution and temperature, it was concluded that highest adsorption took place for (5) δ-MnO2-MCM-41 at 323 K, and at a pH 3.0. The equilibrium isotherms fitted well to Langmuir and Freundlich models explaining modest adsorbate-adsorbent interactions. From kinetic studies the adsorption was found to follow the pseudo-second-order kinetics. The thermodynamic studies indicated endothermic nature with chemisorption mode.
Keywords: δ-MnO2-MCM-41; adsorption of Ni(II); Equilibrium isotherms; kinetic and thermodynamic studies.
Preparation and Characterization of graphene Oxide Nanofluid and its Electrical conductivity
by Md. Zaved Hossain Khan, M. Abu Naser Shatez, K.Y. N Ritee
Abstract: Recently, two dimensional honeycomb lattice structural graphene grants unique properties that are currently being pursued for conductive composites, advanced electronics, membranes etc. In this work, we report the preparation of graphene oxides (GO) nanofluids by dispersion of GO nanosheets in base fluid. Firstly, GO sheets were synthesized in controlled size using improved Hummer method by simply oxidation and facile exfoliation procedure. As prepared samples are characterized by UV-vis spectrometer, Fourier transform infrared spectroscopy (FTIR) spectrometer, scanning electron microscopy (SEM), and X-ray powder diffraction (XRD). The XRD pattern revels that GO were form in nanoscale with crystalline structure. SEM image confirmed that GO were form in ultra small sheet state with smooth surface. UV-vis absorption spectrum reveals that GO nanosheets disperse well in the base fluid. FTIR result reveals the presence of functional group in the lattice which helps the graphene sheets to interact with water molecules and good dispersion. In terminology of electrical conductivity, the result suggests that the samples with 0.1% volume of GO had the highest conductivity with the value of 5310 µS/cm.
Keywords: Graphene oxide, nonofluids, electrical conductivity, crystalline structure, nanosheets
Special Issue on: ICONAN 2016 Recent Advances in Nanomedicine Delivery, Diagnosis and Therapy
Collagen/Chitosan Hybrid 3D-Scaffolds as Potential Biomaterials for Tissue Engineering
by Hilary Urena-Saborio, Emilia Alfaro-Viquez, Daniel Esquivel-Alvarado, Marianelly Esquivel, Sergio Madrigal-Carballo
Abstract: Chitosan (CHT) has been reported to be biocompatible, bio-absorbable and particularly, is considered a good wound-healing accelerator. On the other hand, collagen (CGN) is one of the most widely used matrix biomaterial in tissue engineering. Highly porous CGN single 3D-scaffolds have been used to support in vitro growth of many types of tissues. We fabricated hybrid 3D-scaffold biomaterials by mixing CHT from native shrimp waste streams and CGN from tilapia aquaculture waste by-products, applying previously developed methodologies involving solvent casting and freeze-drying. CGN/CHT hybrid 3D-scaffolds were characterized according to its water uptake capacity, mechanical properties, thermal behavior (TGA), and morphology (SEM). Hybrid 3D-scaffolds showed improved stability, greater porosity, increased thermal stability, and mechanical properties, as well higher biodegradation as compared to single 3D-scaffolds. Cell culture incubation with adipose tissue-derived stem cell (ADSC) and SEM imaging showed that CGN/CHT hybrid 3D-scaffolds allowed ADSC adhering, spreading, and growing in vitro.
Keywords: Collagen; chitosan; scaffolds; tissue engineering.
Special Issue on: ISMA 2016 Smart Materials and Applications
Development of Defects in Nanocrystalline Zirconia: Studied through Photoluminescence Spectroscopy
by Shreenu Pattanaik, Sushanta Kamilla, Dilip Mishra
Abstract: Zirconium dioxide (zirconia) nanoparticle with monoclinic structure is successfully synthesized by chemical route i.e. pyrophoric method from aqueous solution of ZrOCl2.8H2O and triethanol amine. The structural and optical properties of the annealed samples have been investigated by using X-ray diffractometer, photoluminescence spectroscopy and UV-visible spectrometer. It is observed that the variations of annealing temperature from 650°C to 950°C do not change the structure. However, the crystallite size of zirconia varies from 18 nm to 27 nm and particle size from 10 to 70 nm by annealing the samples. The optical bandgap of all the annealed zirconia samples does not vary a lot by the temperature variation in the monoclinic structural phase of zirconia because the crystallite size changes in nanoscale range. The photoluminescence studies clearly states the presence of interstitial and vacancy related defects in nanocrystalline ZrO2. This informs that point defects in form of oxygen vacancies and zirconia vacancies can be introduced in nanocrystalline ZrO2 which is necessary for making these samples efficient for sensor applications.
Keywords: Zirconia; X-ray diffraction, Photoluminescence, Defects.