Volume 6, Issue 12, December 2015

Global Graphene Forum (GGF - 2016), Sweden 

Ashutosh Tiwari

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1025-1025
DOI: 10.5185/amlett.2015.12001

VBRI Press is pleased to announce ‘Global Graphene Forum, during 23 – 25 August 2016, Sweden. It is a three-day international event organised with collaboration of International Association of Advanced Materials (IAAM), and Linkoping University on the Baltic Sea from Stockholm-Helsinki-Stockholm by the Viking Line Cruise, M/S Mariella. The aim of the event is to cover the latest technology developments, applications, commercialization progress, end user requirements and challenges of Graphene and related 2D Materials.

Effect Of Silica Coating On Performance Of Copper-zinc Oxide Based Catalyst For Methanol Synthesis

Tetsuo Umegaki; Yoshiyuki Kojima; Kohji Omata

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1026-1030
DOI: 10.5185/amlett.2015.5558

He present study investigated the effect of silica coating on catalytic activity of copper-zinc oxide based catalyst for methanol synthesis. Silica coated catalysts prepared using ammonia and L(+)-lysine as promoters of silica coating shows almost same specific surface area and pore size distribution compared with pristine commercial copper-zinc oxide based catalyst, while silica coated catalyst prepared using L(+)-arginine shows significantly lower specific surface area than the pristine catalyst and its mesopores and macropores disappear. Silica coated using ammonia and L(+)-lysine weakly bonds to the commercial catalyst without loading into pores of the catalyst, while silica using L(+)-arginine strongly bonds to the catalyst with loading into the pores of the catalyst. Reduction temperature of fine copper species of the silica coated catalysts shifts to the higher temperature than that of the pristine catalyst, and shift temperatures of the silica coated samples prepared using ammonia and L(+)-lysine are lower than that of the sample prepared using L(+)-arginine, indicating that strongly bonding silica prevents reduction of fine copper species in the commercial catalyst. Among the silica coated catalysts, the coated catalyst prepared with ammonia shows highest COx conversion, and the catalytic activity increase with the decrease of weight ratios of silica to catalyst.

A Facile Strategy To Elute Amoxicillin In A Controlled Way From Hydroxyapatite-gelatin Composite

K. Sangeetha; Y. Yokogawa; E.K. Girija

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1031-1036
DOI: 10.5185/amlett.2015.5905

In recent decades bone infection is one of the most challenging issues encountered in biomedical field and local antibiotic delivery is a key strategy to overcome this issue. Hence developing bioactive materials in combination with antibiotics is much focused recently for bone substitutes. Here we report the fabrication of pristine and natural polymer (gelatin) composite matrices of hydroxyapatite (HA) by a facile wet precipitation method and their drug release behavior from directly loaded and in situ loaded matrices using amoxicillin as the model drug. The products thus obtained were analyzed by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry (TG) and scanning electron microscopy (SEM) which confirmed the formation of HA and nanocomposite of HA with gelatin. It was observed that under physiological conditions, for sustained and prolonged release of the drug in situ loading in composite matrix is a favorable approach.

Fabrication Of High Stable Gold Nanofluid By Pulsed Laser Ablation In Liquids

R. Torres-Mendieta; R. Mondrag

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1037-1042
DOI: 10.5185/amlett.2015.6038

Laser ablation in liquids by femtosecond radiation has been used to generate gold nanoparticles in a heat transfer fluid to produce a high stable thermal nanofluid as a heat transfer intensification technique. In oil based fluids, no matter the actual fabrication route, nanoparticles tend to agglomerate. Here, we report a new form to control its stability through the addition of a surfactant that does not degrade at high temperatures. It allow us to produce gold nanoparticles of 58±31 nm in the liquid in situ, avoiding in this way the generation of pollution and reducing the maximum point of nanoparticle agglomeration at 370 nm. The developing of this new nanofluid represents a great opportunity for the harvesting of solar energy industry.

Tannic Acid: A Natural Source To Tailor Nano Crystalline Silver Particles Of Different Morphologies As Antibacterial Agent

Henam Premananda Singh; Sarbjeet Singh Gujral; Surinder Kumar Sharma; Rakesh Kumar Sharma

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1043-1049
DOI: 10.5185/amlett.2015.5946

In this work we have successfully prepared spherical and chain type silver nanoparticles of excellent size’s homogeneity, reproducibility and stability using tannic acid. The synthesized nanometallic structures were characterized for their shape, size, thermal stability and crystalline nature. The mechanism for the formation of Ag NPs and shape evolution of the chain structure has been vividly explained. Further, these NPs were found to exhibit significant antibacterial activity against gram negative Escherichia coli bacteria but to different extend indicating the influence of particles morphology on their antibacterial behaviours.

Biosynthesis Of Bimetallic Au-Ag Nanoparticles Using Ocimum Basilicum (L.) With Antidiabetic And Antimicrobial Properties

V. Malapermal; J.N. Mbatha; R.M. Gengan; K. Anand

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1050-1057
DOI: 10.5185/amlett.2015.5997

This study was aimed at developing a simple, eco-friendly and cost effective green chemistry method for the synthesis of bimetallic Au-Ag nanoparticles using Ocimum basilicum aqueous leaf and flower extracts, respectively as the natural reducing agents. The successive reduction of chloroauric acid and silver nitrate led to the formation of Au-Ag nanoparticles within 10 min at room temperature, suggesting a higher reaction rate than chemical methods involved in the synthesis. Stable, spherical nanoparticles with well-defined dimensions of average size of 3-25 nm was confirmed by UV-Visible spectroscopy, TEM, SEM-EDX, DLS, and zeta potential, whilst, FTIR in combination with GC-MS analyzed the functional groups adhered to the surface of the nanoparticles The colloidal suspension displayed enhanced antihyperglycemic activity at 69.97 ± 3.42% (leaf) against α-amylase (from porcine) and at 85.77 ± 5.82% (flower) against Bacillus stearothermophilus α-glucosidase than that of acarbose and their respective crude extracts. Furthermore, revealed good antibacterial activity against bacterial species Staphylococcus aureus, Escherichia coli, Bacillus subtilis and Pseudomonas aeruginosa.

Electrical Conductivity, Mechanical Stability, Antibacterial And Anticancer Activities Of Ethyl Cellulose-tin(ll) Hydrogen Phosphate

Tanvir Arfin; Faruq Mohammad

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1058-1065
DOI: 10.5185/amlett.2015.5896

In the present study, a very prominent cost effective sol-gel method was used to amalgate the ethyl cellulose-tin(II) hydrogen phosphate (EC-SnHPO4), an organic–inorganic composite material with certain acidic condition practiced in a conductivity system. The physical characterization of the material was described by the UV-Vis and FTIR study. The different monovalent electrolytes such as KCl (aq) and NaCl (aq) at diverse temperature range was employed to measure the conductivity of EC-SnHPO4 and also for the concentration to explore between affinity of conductivity and electrochemical properties of the material. From the study, the conductivity was established to be less for K + than Na + . For such process in addition, the different parameters such as ionization potential, oscillator strength, transition dipole moment, resonance energy, and transition energy were investigated. Finally, the anticancer effect against the MCF-7 breast cancer cell line and the antibacterial activity against two different bacterial strains show the potential pharmacological activity of the EC-SnHPO4 towards medical applications.

Liquid-assisted Pulsed Laser Ablation Synthesized Titanium Ferrite Nanoparticles: Structural, Optical And Magnetic Properties

Abhishek Shukla; S.C. Singh; B.K. Pandey; K.N. Uttam; J. Shah; R.K. Kotnala; R. Gopal

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1066-1072
DOI: 10.5185/amlett.2015.5930

Titanium ferrite nanoparticles (NPs) with controlled titanium to iron ratios (Ti/Fe) were synthesized using liquid-assisted pulsed laser ablation (LA-PLA) technique. Present manuscript describes effect of variation of Ti/Fe ratio in the target and the effect of laser pulse energy on size, shape, optical band gap, crystalline phase and magnetic properties of as-synthesized titanium ferrite NPs.  UV-visible absorption, TEM and XRD investigations reveal that size of as-produced NPs decreases with the increase of Ti in the Ti/Fe targets used for ablation. Variation in laser pulse energy at a given Ti/Fe ratio has lesser dependence on size, shape and magnetic properties of produced NPs. Higher ferromagnetism with larger sized particles demonstrates dominance of bulk phenomenon over surface defects for the generation of ferromagnetic responsible spins. As-produced titanium ferrite nanomaterials may be used as promising magnetic recovery catalysts (MRCs).

SERS Studies Of Explosive Molecules With Diverse Copper Nanostructures Fabricated Using Ultrafast Laser Ablation

Hamad Syed; G. Krishna Podagatlapalli; M. A. Mohiddon; Venugopal Rao Soma

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1073-1080
DOI: 10.5185/amlett.2015.6007

We report the fabrication and application of ultra-short pulse laser induced nanostructures (NSs) on copper surface accomplished with different pulse energies and number of pulses. The shapes and sizes of NSs have been evaluated from the field emission scanning electron microscopy (FESEM) data which illustrated different ablation mechanisms in picosecond (ps) and femtosecond (fs) domains. The Cu NSs generated with ps pulses demonstrated Raman enhancements upto ~10 5 -10 8 in the case of the explosive molecules of 1,1-diamino-2,2-dinitroethene (FOX-7), 5 Amino, 3-nitro,1,3,5-nitrozole (ANTA) and 2,4,6,8,10,12-Hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20). The SERS studies were repeated two more times on the same substrate following a simple cleaning procedure.  We achieved considerable enhancement factors (of >10 5 ) for the Raman modes of an explosive molecule of FOX-7 on fs laser fabricated Cu NSs.

Correlative Exploration Of Structural, Optical And Electric Properties Of Colossal Dielectric Ni Doped Sm Orthoferrites

Sajad Ahmad Mir; M. Ikram; K. Sultan; Z. Habib; H. Kausar; K. Asokan

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1081-1087
DOI: 10.5185/amlett.2015.5959

Structural, optical and dielectric properties of polycrystalline SmFe1-xNixO3 (x=0.0, 0.3 and 0.5) samples prepared by ceramic method is presented. Lattice parameters, unit cell volume and porosity were calculated and found decreasing with an increase in Ni concentration. SEM shows an increase in grain size (0.2 μm to 0.3 μm) with an increase in Ni doping. The influences of Ni doping on optical energy band gap are investigated in the wavelength range of 200-800 nm. Dielectric properties (dielectric constant and loss) for SmFe1-xNixO3 were studied in the temperature range 100-400K and in the frequency range 20 kHz-1MHz. AC conductivity of pristine sample is found to be less than Ni doped samples. Various possibilities were explored to explain the observed dielectric and electric behavior of Ni doped SmFeO3 ceramics.

Gamma Radiation Assisted Biosynthesis Of Silver Nanoparticles And Their Characterization

R. Madhu Kumar; B. Lakshmeesha Rao; S. Asha; B. Narayana; K. Byrappa; Youjiang Wang; Donggang Yao; Y. Sangappa

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1088-1093
DOI: 10.5185/amlett.2015.6002

Silver nanoparticles (AgNPs) were synthesized in situ under gamma radiation environment at room temperature using aqueous silk fibroin (SF) solution obtained from Bombyx mori silk. The formation of the Ag NPs was confirmed by its characteristic surface plasmon resonance (SPR) band at around 424 nm in UV-visible spectra. The strength of the photoluminescence (PL) spectra decreases with increasing dosage reveals the optimum dose required for the synthesis of silver nanoparticles. Dynamic light scattering (DLS) measurement indicated the dose dependent size of the Ag NPs formed in the solution. The transmission electron microscopy (TEM) images showed that the formed nanoparticles are roughly spherical in shape. Further the X-ray diffraction (XRD) analysis confirms the nanocrystalline phase of silver with FCC crystal structure. From this study, it was found that the increasing the radiation dose increases the rate of reduction and decreases the particle size. The size of the Ag NPs can be tuned by controlling the radiation dose.

Economic Growth Of Vertically Aligned Multiwalled Carbon Nanotubes In Nitrogen Atmosphere

Abhishek Kumar Arya; Bhanu Pratap Singh; Jeevan Jyoti; Santwana Pati; S.R. Dhakate

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1094-1097
DOI: 10.5185/amlett.2015.6082

Vertically aligned carbon nanotube (VACNT) arrays are widely studied because of their immense potential in a wide range of applications.  In order to tailor the properties of carbon nanotubes (CNTs) for a particular application, vertical alignment in the form of sheet is a major breakthrough. Herein we report an economic and effective strategy developed to synthesise aligned multiwalled carbon nanotube sheets using Al powder as buffer layer. We achieved easy growth of VACNTs sheets using toluene/ferrocene solution in a two-zone furnace by chemical vapor deposition method. First zone was set at temperature 200 ° C and other zone was set at temperature 750 ° C for the synthesis of VACNTs. Almost 500 µm long VACNT sheet was grown. We observed the significant growth of VACNT sheet on Al powdered quartz substrate in nitrogen medium. Uniform length of CNTs was maintained all over the sheet and additionally nitrogen is an economical alternative rather than other inert gases.

Electrical And Dielectric Properties Of Carbon Nanotube Containing Se85Te10Ag5 Glassy Composites

A. N. Upadhyay; R. S.Tiwari; Kedar Singh

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1098-1103
DOI: 10.5185/amlett.2015.5978

The electrical and dielectric properties of 3 and 5 wt. % of multi-walled carbon nanotube (MWCNT) containing Se85Te10Ag5 glassy composites have been investigated in the frequency range 20 Hz to 2 MHz from room temperature to 387 K. It has been found that the electrical conductivity is enhanced by 6 to 9 orders of magnitude up to 5 wt. % of MWCNT content resulting in transition for insulating to conducting behaviour. The activation energies for all samples have also been evaluated from the Arrhenius plot of the DC conductivity which shows a decreasing trend up to 5 wt. % MWCNT content. The largest dielectric constant of 142 (almost 10 times greater than pristine Se85Te10Ag5 glassy alloy) has been observed for 5 wt. % of MWCNT content at room temperature in low frequency range. Therefore it can be inferred that the electrical and dielectric properties of the chalcogenide glasses can be altered by the admixing or doping of carbon nanotubes (CNTs). The enhanced dielectric constant and electrical conductivity can be attributed to interface effect between MWCNT and the glassy matrix.

Effects Of Solvent On Structural, Optical And Photocatalytic Properties Of ZnO Nanostructures

Sini Kuriakose; Biswarup Satpati; Satyabrata Mohapatra

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1104-1110
DOI: 10.5185/amlett.2015.6088

ZnO nanostructures were synthesized by a facile wet chemical method using water, ethanol and propanol as solvents. X-ray diffraction, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) have been used to study the structural properties of the synthesized ZnO nanostructures, while their optical properties have been studied using UV-visible absorption spectroscopy and Raman spectroscopy. The photocatalytic activities of the as-synthesized ZnO nanostructures were evaluated by monitoring sunlight driven photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes in water and it was observed that ZnO nanostructures prepared using propanol as a solvent exhibit highly enhanced photocatalytic activity as compared to those prepared using other solvents. The mechanism underlying the photocatalytic activity of ZnO nanostructures towards photocatalytic degradation of dyes is proposed. We attribute the highly enhanced photocatalytic activity of ZnO nanostructures prepared in propanol to the high surface area of nanosheets-like structures formed, which lead to enhanced adsorption of dye molecules resulting in efficient photocatalytic degradation of dyes upon sunlight irradiation.

Photoluminescence And Decay Properties Of Sm3+ And Dy3+ In SrAl4O7 Phosphor    

Atul N. Yerpude; Sanjay Janrao Dhoble; B. Ramesh; Borelli Deva Prasad Raju

Advanced Materials Letters, 2015, Volume 6, Issue 12, Pages 1111-1115
DOI: 10.5185/amlett.2015.5919

In this study, Sm 3+ - and Dy 3 -doped SrAl4O7 phosphors were synthesized by combustion method. X-ray diffraction (XRD) measurement confirmed the monoclinic crystal structure of SrAl4O7. Sr-O and Al-O bonds were identified by Fourier transform infrared (FTIR) spectroscopy. Under 352 nm excitation, the SrAl4O7: Dy 3+ phosphor shown emission bands at 475 nm (blue) and 574 nm (yellow) that are due to 4 F9/2→ 6 H15/2, 6 H13/2 transitions, respectively. Photoluminescence spectra (PL) of SrAl4O7: Sm 3+ phosphor has shown bright orange red emission at 598 nm with an excitation wavelength of 405 nm. The decay curve of Sm 3+ and Dy 3+ single doped SrAl4O7 phosphors were well fitted to a bi-exponential function. The obtained results show that the prepared phosphors may be applicable in the field of eco-friendly solid state lighting technology.