Advanced Materials Letters

Abstract The supervision of conducting a doctorate degree in interdisciplinary science and technology such as healthcare nanotechnology, a strategic supervisory role is essential. Supervision of such doctor of philosophy (PhD) students immerses in an internationally leading education, research environment and provide a wide range of scientific and complementary training, executed both inter and intra university-private sectors joint supervisions. The focus of this editorial is to bring the criteria to produce trained, highly competent, enthusiastic and creative PhDs by the public and private sectors partnership. The interdisciplinary PhD supervision approach would make significant contributions to designed, constructed and commercialized new technology including personalized healthcare and medical nanodevices.

Abstract A health monitoring system (HMS) involving a blood extraction device with a new type of hybrid biosensor comprising an enzyme and a semiconductor has recently been developed. A MOSFET was used as the transducer. The gate electrode was extracted from the MOSFET using a cable. Gold (Au)-plate-immobilized glucose oxidase (Go) was used as a biosensor and attached to the gate electrode. Go was immobilized on a self-assembled spacer combined with an Au electrode by the cross-link method using BSA as an additional bonding material. The electrode could be used to detect electrons generated by the oxidization of hydrogen peroxide produced by the reaction between Go and glucose using the constant electric current measurement system of the MOSFET-type hybrid biosensor. The sensitivities for the diluted whole blood and blood plasma were 61.4 and 171.2 V/(mol/L), respectively. The hybrid biosensor was useful for HMS.

Abstract A series of star–shaped poly(acrylamide–co–[2–(acryloyloxy)ethyl] trimethyl ammonium chloride) were prepared by inverse microemulsion polymerization. The growth of side chains in the arms of the precursor has been carried out using different compositions of the comonomers acrylamide and [2–(acryloyloxy)ethyl] trimethyl ammonium chloride) (Q9). The characterization and star structure were determined by nuclear magnetic resonance, FTIR, MALDI–TOF and DSC. The dimensions of the particles were determined by quasielastic light scattering and transmission electron microscopy. Quasi–spherical particles of star polymers in the nanozise range were obtained which might be useful for the controlled transport and release of several biologically active drugs.

Abstract Mesoporous titania adapted chromium-niobate nanocatalysts CrxNbxTi1-2xO2-x/2 (x = 0.01-0.2) were synthesized by a new synthetic approach, using N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (edteH4) precursors and their photocatalytic activities were investigated. TiO2 nanomaterials have continued to be highly active in photocatalytic applications because these are useful to break down the organic molecules in water for endorsing the diffusion of reactants and products. CrxNbxTi1-2xO2-x/2 (x = 0.01)(CNT1) nanoparticles with the smaller particle sizes 12±1 nm and have mesoporous characteristics (SBET = 162 m 2 g −1 ). The energy band gap of CNT1 was found 1.85 eV obtained from optical emission spectrum. The XRD peaks revealed a mixture of anatase and rutile phases in the synthesized powders. EPR spectroscopy showed the characteristic features of Nb 5+ ions, whose existence was confirmed by XPS. The CNT1 powders display good (2.5 times greater) photocatalytic activity for degradation of Rhodamine B (RhB) as opposed to pure anatase TiO2 and other compositions of CrxNbxTi1-2xO2-x/2.

Abstract Silver nanoparticles have been widely used in consumer products due to their excellent antimicrobial properties. Release of nanosilver into natural waters may induce negative environmental impacts on local microorganism communities. This work evaluated the influence of anions such as sulfate, phosphate, chloride and sulfide on the toxicity of silver nanoparticles. Results revealed that sulfide anion could significantly reduce their toxicity in comparison with other anions, which provides an in-depth investigation on the toxicity control of released silver nanoparticles.

Abstract Nickel oxide (NiO) nanoparticles were prepared by the simple approach of co-precipitation method using nickel carbonate as precursor. Novel electrically conducting composite materials consisting of nickel oxide nanoparticles dispersed in a polyaniline (PANI) are prepared by an in-situ polymerization method in the presence of different weight percentage of  NiO (5, 10, 15 and 20%) at room temperature using ammonium persulphate (NH4)2S2O8 as an oxidant in acidic medium. The synthesized PANI/NiO nanocomposites have been characterized by means of XRD, FTIR, UV-VIS, TEM and VSM for structural and magnetic investigation. NiO has single phase cubic structure with average crystallite size of 23nm and is intercalated to form a core shell of PANI due to which nanocomposites show the peaks of NiO as well as PANI. PANI/NiO nanocomposites showed semiconducting as well as ferromagnetic nature. It was also observed that the conductivity of the PANI/NiO nanocomposites decreased and the magnetization increased with the increase in weight percentage of NiO in PANI. We studied first time the effect of NiO on transport properties of PANI/NiO nanocomposites in terms of transport parameters such as electrical conductivity (s), charge localization length (a-1), most probable hopping distance (R) and charge hopping energy (w) using variable range hoping (VRH) of charge model as described by Ziller   to conducting polymers.Copyright © 2013 VBRI press.

Abstract The polycrystalline sample of 0.7(BiFeO3)-0.3(PbTiO3) [0.7(BFO)-0.3(PT)] was prepared by a high temperature solid state reaction technique. Studies of structural analysis confirm the formation of the compound with rhombohedral structure at room temperature. The electrical properties (impedance, modulus and conductivity) of the material were analyzed using a complex impedance spectroscopy technique in a wide temperature (225-300 o C) and frequency (10 2 -10 6 Hz) range. The studied material exhibits a significant contribution of grain (bulk) effect and non-Debye of relaxation process. The bulk resistance decreases with rise in temperature which exhibits negative temperature coefficient of resistance (NTCR) behavior. Electrical modulus study confirms the presence of bulk effect in the material. This compound also exhibits the temperature dependence of relaxation phenomena. The ac and dc conductivity of the materials were found to be increase with increase in temperature. The activation energy of the compound is found to be less than 1eV and suggests the conduction process is of mixed type (ionic-polaronic and singly-ionized oxygen ion vacancies).

Abstract The Gibbs–Bogoliubov (GB) inequality is applied to investigate the thermodynamic properties of some equiatomic noble metal alloys in liquid phase such as Au-Cu, Ag-Cu and Ag-Au using well known pseudopotential formalism. For description of the structure, well known Percus-Yevick (PY) hard sphere model is used as a reference system. With this procedure the thermodynamic properties such as entropy and heat of mixing have been computed. The influence of local field correction functions viz; Hartree (HR), Taylor (TY), Ichimaru-Utsumi (IU), Farid et al. (FD) and Sarkar et al. (SS) is also investigated and found successful. The computed results of the excess entropy and the heats of mixing compares are found in qualitative agreement with the available experimental or theoretical data in the literature.

Abstract The quasi-lattice model based on pairwise interactions has been used to study the large deviation from the ideal mixture and the concentration dependent asymmetry in the thermodynamic properties of Mg-Bi liquid alloy. This has been utilised to extract microscopic information such as concentration-concentration structure factor in long wavelength limit [Scc(o)] and warren-cowley short range order parameter a1 of Mg-Bi liquid alloy at 975K. The analysis suggests that heterocoordination leading to the formation of complex Mg3Bi2 is likely to exist in the melt, and is of strongly interacting nature. The theoretical analysis reveals that the pairwise interaction energies between the species depend considerably on temperature and the alloy is chemically more ordered in Mg-rich region of the phase diagram. The alloy behaves like a segregating system in Bi-rich region.

Abstract Leaf-like Fe-Ni alloy have been synthesized via a facile hydrothermal approach without any soft and hard template. The structure of the leaf-like Fe-Ni alloy was characterized by Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray energy-dispersive spectroscopy (EDX). The dendrite trunks lengths of the leaf-like Fe-Ni alloy were about 2.0μm-8.5 μm, and those of the branch trunk ranged from 850.0 nm to 4.0 μm. Furthermore, it was founded that the formation of leaf-like Fe-Ni alloy strongly depended on the reaction temperature. Moreover, the magnetic and microwave absorption properties of products with various morphologies were also compared, and the result showed that the leaf-like Fe-Ni alloy had higher ferromagnetic and microwave absorption properties compared with spherical Fe-Ni alloy.

Abstract Aluminium powder metallurgy (Al-PM) alloys are finding promising applications in many areas such as household appliances, automotive vehicles and many other allied sections where reduction in weight is the primary constraint. In the proposed research, two binary alloy systems Al-X were studied by mixing elemental powders of Aluminium (Al), Tin (Sn) and Magnesium (Mg). Two types of mixing techniques were followed. In one case, elemental powders were blended in a mechanical mixer without any mixing media (A) and another case powders were blended with ball to powder ratio of 10:1 (B). The content in binary premix was varied from 0.4 to 0.8 % Sn (by wt.) and 0.5 to 2 % Mg (by wt.) with base of Aluminium. The blended powders was compacted at 450 MPa followed by sintering in ultra high purity nitrogen atmosphere in tubular sintering furnace at 600oC. The mixing technique B showed significant influence on increase in hardness by two-fold and reduction in dimensional growth.

Abstract The powder of ZnS nanoparticles were prepared by using chemical deposition technique and characterized by electroluminescence techniques are reported in this paper. The estimated size of ZnS:Cu nanocrystals with change in capping agent concentration and ZnS:Cu/PVA nanocomposites and no effect of doping has been observed on the absorption spectra. Electroluminescence (EL) investigations of nanocrystalline powder as well as nanocomposites, it is seen that Log B vs. 1/V curve is a straight line with negative slope. This indicates that EL is produced by acceleration-collision mechanism. The detail EL characterization and application in display devices of these materials are reported in this paper.