Issue 4

American Advanced Materials Congress  (AAMC - 2016), Miami, USA

Ashutosh Tiwari

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 253-253
DOI: 10.5185/amlett.2016.4001

VBRI Press is pleased to announce ‘American Advanced Materials Congress (AAMC - 2016), USA during 04 – 09 December 2016, USA. It is a six-day international event organised with the collaboration of International Association of Advanced Materials (IAAM), VBRI Press AB cruising from Miami-Bahamas-Mexico-Miami with the Royal Caribbean Cruise Ship Navigator of the Seas. The goal of congress is to provide a global platform for researchers and engineers coming from academia and industry to present their research results and activities in the field of fundamental and interdisciplinary research of materials science and technology.  

Magnetically Responsive Biological Materials And Their Applications

Ivo Safarik; Kristyna Pospiskova; Eva Baldikova; Mirka Safarikova

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 254-261
DOI: 10.5185/amlett.2016.6176

Diamagnetic biological materials of various origins (e.g., prokaryotic and eukaryotic microbial cells, lignocellulosic materials, food wastes, soluble and insoluble biopolymers etc.) can be magnetically modified in order to obtain smart biomaterials exhibiting an appropriate response to external magnetic field. Magnetic modification of originally nonmagnetic biological materials is usually based on the attachment of magnetic iron oxides nano- and microparticles on the surface or within the pores of the treated material, or by their entrapment in the gel structure. Magnetic modification can be performed using different procedures, e.g., by magnetic fluid treatment, mechanochemical synthesis and by direct or indirect microwave assisted synthesis. This short review will summarize magnetic modification procedures developed by the authors and applications of advanced magnetically modified biomaterials as adsorbents of both organic and inorganic xenobiotics and radionuclides, affinity adsorbents for isolation of target biomolecules, carriers for various affinity ligands, biologically active compounds and cells or whole-cell biocatalysts. The potential of magnetically responsive biomaterials will increase in the near future. 

Investigation Of Single Wall Nanotube Gas Sensor Recovery Behavior In The Presence Of UV

Deepak Kumar; R. P. Tandon ;Partap K Chaudhury; Poornendu Chaturvedi; Abhilasha Chouksey

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 262-266
DOI: 10.5185/amlett.2016.5938

The recovery of single wall nanotube (SWNT) based gas sensors have been investigated in the presence of Ultraviolet (UV) light at ambient conditions by real time monitoring. The rate of recovery is same for low concentration upto 5 ppm, but decreases with increase in concentration of NO2. It is observed that the response of thick film resistor (CNT-TFR) remains 7.5 and 25.4 % with multiple exposures of 5 ppm and 20 ppm NO2 concentration, respectively. But the recovery rate decreases with multiple exposures. Both the response and recovery rate changes in case of micro resistor (CNT-µR). To study the significant effect of absorbed O2 in recovery behavior, the analyte is exposed to gas sensor with and without regeneration in the presence of UV light. The gas sensor response increases 1.5 times but it does not recover to its base line when regenerated in the presence of UV light. 

Synthesis Of High Purity ϒ-lithium Aluminate By Freeze Drying

A. C. Nascimento; M. E. Queiroz;N. D. S. Mohallem

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 267-270
DOI: 10.5185/amlett.2016.6126

γ-LiAlO2 plate-like nanostructures have been synthesized by lyophilization of a gel precursor prepared by coprecipitation process. Aqueous solutions of Al(NO3)3.9H2O and LiNO3 were used as precursors, and NaOH was used as precipitant agent. After freeze-drying, the samples were calcined at several temperatures for characterization. The lyophilization process allowed the preparation of γ-LiAlO2 phase at 750 °C, which remained stable until temperatures about 1150 ºC, without the formation of other undesired phases as LiAl5O8. 

Green Route Synthesis Of Silicon/silicon Oxide From Bamboo

Vinay Kumar; Pranjala Tiwari; Lucky Krishnia; Reetu Kumari; Anshika Singh; Arnab Ghosh; Pawan K. Tyagi

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 271-276
DOI: 10.5185/amlett.2016.6151

Silica, generally known as silicon dioxide is insulating in nature whereas silicon is semiconducting. These two materials are widely used in sensing and electronic devices. In order to full-fill demand of silicon, sources other than sand, have to explore for silicon extraction. In this report, bamboo culms have been subjected to thermo chemical decomposition at high temperature (1250 °C) in an inert atmosphere. After pyrolysis, contents in residual of bamboo culms have been characterized by using scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Nanosized, pure crystalline Si has been formed. Si as well as charcoal is found to be crystalline in nature. No silicon carbide formation observed. 

Time Resolved Emission Spectra And Electron Paramagnetic Resonance Studies Of Gd3+ Doped Calcium Phosphate Glasses

Sooraj H. Nandyala; Graham Hungerford; S. Babu; J. L. Rao; Isabel B. Leonor; Ricardo Pires; Rui L. Reis

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 277-281
DOI: 10.5185/amlett.2016.6243

Gadolinium, Gd 3+ (4f 7 ), containing glasses are particularly interesting owing to their magnetic and optical properties. Gd 3+ has an electron paramagnetic resonance (EPR) centre, which is often used as the EPR probe in different matrices. Another important feature of Gd 3+ is that emits ultraviolet radiation (UVR) at around 310 – 313 nm from the 6 P < sub>7/2 à 8 S7/2 transition and is suitable for the treatment of skin disease.  Here, we report on Gd 3+ doped calcium phosphate host glasses with four different concentrations; 0.5 - 4 mol % and labelled as 0.5Gd, 1Gd, 2Gd and 4Gd. A strong emission peak at 310 nm was observed in the reported glasses with excitation at 274 nm. The emission spectra can also be obtained at specific times during the decay. The time resolved emission data was analyzed with three different approaches namely, simple exponential, NED distribution and stretched exponential. The other approaches confirm the single exponential behaviour for all samples with deviation for the 0.5 Gd. The decay associated spectra (DAS) for the 0.5 Gd indicate that both decays have the same origin. The EPR spectrum exhibits several resonance signals characteristic of Gd 3+ ions. The stimulated emission cross sections (σ P < /sup > E×10 −21  cm 2 ) of the UV emission transition 6 P < sub>7/2 à 8 S7/2 were also reported in the above three approaches. 

Influence Of Conducting Polymer On Mechanical, Thermal And Shape Memory Properties Of Polyurethane/polythiophene Blends And Nanocomposite

Rabia Sattar; Ayesha Kausar; Muhammad Siddiq

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 282-288
DOI: 10.5185/amlett.2016.6198

Polyurethane/polythiophene (PU/PTh) blends and nanocomposites were prepared by solution mixing and in situ polymerization, respectively and were investigated for mechanical, thermal, electrical and shape memory properties. Formation of blends and composites was supported by FTIR analysis. Surface morphology of prepared samples was clarified by scanning electron microscopy (SEM). Homogeneous morphology of the composites was observed compared to blends due to well dispersion of NH2 functionalized MWCNTs attributed to introduction of urea linkages between the functionalized nanotubes and the NCO-terminated PU. Smooth morphology of the composites resulted for the significant improvement of the mechanical properties. Thermal stability of the blends and composites was found increased with PTh content. According to differential scanning calorimetry (DSC), an increase in glass transition, melting and crystallization temperature was observed for composites with PTh addition. Maximum shape recoverability (92 %) was exhibited by the PU/PTh composite with 1 wt. % PTh loading. 

Multifunctional Inorganic-organic Hybrid Resins With Polymerizable Methacrylate Groups For Biomedical Applications; Effects Of Synthesis Parameters On Polymerisation Shrinkage And Molecular Weight

C. Vibha; P. P. Lizymol

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 289-295
DOI: 10.5185/amlett.2016.6046

Inorganic-organic hybrid resins revolutionarize the biomedical field by virtue of its versatility. In this work, bioactive inorganic-organic hybrid resins containing mixture of alkoxides of calcium/magnesium/zinc with polymerizable tetramethacrylate groups was synthesized using 1,3-bis methacryloxy 2-(trimethoxy silyl propoxy) propane as the precursor. We optimised the processing parameters by investigating the influence of pH of the medium used for the hydrolysis of silane on molecular weight of the resultant resin obtained. Physico-mechanical properties including polymerisation shrinkage of photocured composites prepared from novel inorganic-organic hybrid resins were evaluated and compared. The resin hydrolysed at pH 2 have low molecular weight with high filler loading capacity (325 phr) than the one hydrolysed at pH 10.  Photocured polymeric composite fabricated from resin hydrolysed at pH 2 showed lower polymerisation shrinkage, better depth of cure, good diametral tensile strength, non-cytoxic to L929 fibroblasts with good cell viability and cell adhesion. This new biocompatible polymer with low polymerisation shrinkage stands as a potent candidate in biomedical applications, especially in the field of dental, orthopaedic and coating applications. 

Thermal Conductivities Of Silica Aerogel Composite Insulating Material

Ehsan Rezaei; Jafarsadegh Moghaddas

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 296-301
DOI: 10.5185/amlett.2016.6178

Silica aerogels have interesting physical properties such as hydrophobicity and low thermal conductivity are advantageous for a wide variety of actual applications, such as super thermal insulators. Poor mechanical properties prevented to use silica aerogel directly. In this study, nano silica aerogel and its composite with cotton were synthesized using a water glass precursor by ambient pressure drying method .To modify silica aerogel use trimethyl chlorosilane (TMCS) diluted in n-hexane (1:5 volume ratio). By adding TMCS, –OR groups in silica aerogel structure replaced –OH and silica aerogel became hydrophobic. Thermal conductivity and hydrophobicity of synthesized samples were measured by needle probe method and contact angle meter respectively. Pure silica aerogel contact angel is 166 o and it shows silica aerogel is super hydrophobic. Silica aerogel added to cotton structure in 20 %, 40 %, 60 % and 80 % wt. Silica aerogel particles attached cotton fibers and changed hydrophobicity properties. Contact angels of composites are 115°, 120°, 128° and 129° respectively. Cotton is hydrophilic and its ability to absorb moisture causes decreasing contact angel in composites. Silica aerogel and cotton thermal conductivities are 0.0134 Wm-1K-1and 0.0308 Wm-1K-1respectively. Having low thermal conductivity, pure silica aerogel is known as super thermal. Thermal conductivity of composites was measured 0.0251, 0.0227, 0.0216 and 0.0171 Wm-1K-1 respectively. By increasing silica aerogel ratio, thermal conductivity decreased. In silica aerogel- cotton composite improved structural strength and the thermal conductivity and hydrophobicity were acceptable. 

Synthesis And Characterization Of Eu3+ Doped α-Al2O3 Nanocrystalline Powder For Novel Application in Latent Fingerprint Development

Amrita Das; Vishal Shama

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 302-306
DOI: 10.5185/amlett.2016.6310

In the present study, we investigate upon the synthesis and characterization of inorganic Eu 3+ doped Al2O3 nanophosphor for its structural and luminescent properties. The luminescent nanopowder was prepared using a combustion method in which the stoichiometric ratio of oxidizers and fuel was fixed to one, with varying concentration of Eu 3+ ions acting as an activator. The prepared powder showed excellent thermal stability. For the identification of the phase and structure of the powder synthesized, X-ray diffractometer was used. From the XRD analysis, it is revealed that the rhombohedral crystallite phase of α-alumina was formed. The type of morphology and particle size was ascertained by Filed Emission-Scanning Electron Microscope (FE-SEM) and it was found that particles were having irregular spherical shape. A qualitative analysis of these nanophosphor particles was made using an Energy dispersive X-ray detector (EDS) and it was found that the samples were composed of Al, O and Eu ions. Photo-luminescence (PL) spectra were obtained using Spectrofluorometer absorption. The intense band position was observed at 618 nm and other less intense bands were also seen at 592 nm, 601 nm, 631 nm, while two weak bands were observed at 660 nm and 718 nm, when excited at 226 nm. The CIE color space chromaticity diagram was calculated from the CIE Calculator program using obtained PL spectra. The prepared nanophosphor powder was tested for latent fingerprint detection in forensic applications. The synthesized nanophosphor was successfully used as a latent fingerprint developing powder on various non-porous surfaces for forensic application. 

Correlation Selection Of Perovskites With Optimal Parameters

N. Mykytenko; A. Kiv; D. Fuks

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 307-311
DOI: 10.5185/amlett.2016.5918

A descriptor is constructed to predict the composition of ABO3 perovskites that do not contain transition metals and have a high level of ionic conductivity (s). The descriptor consists of two parts: the ratio of ionic radii, RA/RB and the ratio of ionization potentials, VB/VA for A- and B- cations. Parameters for 100 perovskite compounds were considered to find the correlation dependences between the descriptor and the magnitude of s. Correlation selection approach is proposed to reveal a suitable correlation series. This approach allows determining the composition of perovskites that has a desirable ionic conductivity. 

Preparation And Photocatalytic Activity Of Hydroxyapatite Supported BiOCl Nanocomposite For Oxytetracyline Removal

Pankaj Raizda; Sourav Gautam; Bhanu Priya; Pardeep Singh

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 312-318
DOI: 10.5185/amlett.2016.5847

The study investigates photocatalytic activity of hydroxyapatite supported BiOCl (BiOCl/HA) in the presence of H2O2. BiOCl/HA was prepared by simple hydrolysis method. BiOCl/HA was characterized using scanning electron microscopy (SEM), tunneling electron microscopy (TEM), X- ray diffraction (XRD), energy diffraction X-ray (EDX), Fourier transform infrared spectroscopy (FTIR) and UV-visible (UV-vis)analysis. SEM results confirmed the dispersion of BiOCl onto hydroxyapatite. BiOCl/HA exhibited irregular pleats-like structure having average size of 80 nm. The band gap of BiOCl/HA was found to be 3.42 eV.  The solar light was used as radiation source during photocatalysis. Both H2O2 and BiOCl/HA had synergistic effect on oxytetracycline removal. The simultaneous adsorption and photocatalysis (A+P) was most efficient process for OTC removal. The photocatalytic degradation of oxytetracycline obeyed pseudo first order kinetics. The effect of process parameters catalyst loading, H2O2 concentration, pH and OTC concentration was investigated on photocatalysis. The oxidative removal occurred through hydroxyl radical formation. BiOCl exhibited significant recycle efficiency due to easier separation and stability in reaction solution. Solar/H2O2/BiOCl/HA displayed excellent photocatalytic property for degradation of OTC from aqueous solution. 

Tunable Structural, Optical And Electrical Properties Of Annealed ZnO-SnO2 Composite Thin Films deposited By Pulsed Laser Deposition

Sudip. K. Sinha

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 319-324
DOI: 10.5185/amlett.2016.6155

We report the thermal annealing effect of ZnO-SnO2 composite thin films deposited by pulsed laser deposition on its structural, electrical, and optical properties. The results present a consistent portrayal of the evolution of ZnO-SnO2 composite oxide films phase formation in post-annealed condition and its subsequent effect on various physical properties. X-ray diffraction confirms that the films transform from nearly amorphous to fully crystalline state on thermal annealing at 600 °C. X-ray photoelectron spectroscopy reveals a small shift in Sn-3d peak towards lower energy and O-1s and Zn-2p < /em> peaks towards higher binding energy with increasing ZnO concentration and confirms the formation of combined oxides of ZnO and SnO2. The average optical transmission is greater than 80 % in the visible region of the annealed ZnO-SnO2 composite films. The lowest electrical resistivity of 9.8 × 10 -4 Ωcm has been obtained in the film containing 25 wt % ZnO. Our results suggest that annealed ZnO-SnO2 composite films with improved electrical and optical properties could find potential use in thin film solar cells or touch pad control panels. 

A Prototype Synthesis And Characterization Of Hydroxyapatite Bioceramics Nanocrystallites

Pramod N. Jagadale; Pramod P. Jagtap; Meghnad G. Joshi; Sambhaji R. Bamane

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 325-329
DOI: 10.5185/amlett.2016.5837

Novel porous bioactive hydroxyapatite (HAP) nanocrystallites were synthesized by auto-combustion technique. The texture properties of the HAP nanopowder were determined through series of characterization techniques. The thermal decomposition behaviour and required sintering temperature of citrate precursor to phase formation of the sample was checked by thermogravimetric analysis (TG-DTA). The hexagonal structure and porous nature of the material were estimated by using X-ray diffraction (XRD) and electron microscopy scanned with different magnifications. Phase formation of HAP was determined by FTIR technique. Transmission electron microscopic (TEM) study indicated the nanostructure of the ceramics, particle size was found to be 30 - 35 nm. These nanoparticles were evaluated for the qualitative and quantitative determination of different elements by energy-dispersive X-ray spectroscopy. In vitro MTT assays showed HAP nanopowder have good biocompatibility and promotes cell proliferation. This nanostructured HAP powder with enhanced biocompatibility can be potentially used as a material for bone tissue engineering.

Classification And Study Of Near-surface Region Of Active Material For Gas Detection Using X-ray Photoelectron Spectroscopy

Pravin S. More; Dattatray J. Late; Subhash B. Kondawar

Advanced Materials Letters, 2016, Volume 7, Issue 4, Pages 330-336
DOI: 10.5185/amlett.2016.6137

We report investigations on resistive material SnO2: Cu (9 wt. %) evaluated and optimized for the application of gas sensor. SnO2: Cu has been thoroughly characterized by using X-ray photoelectron spectroscopy (XPS). The deconvolution of XPS spectra confirms the existing surface reactive species in the form of states of the metal orbital and the presence of multiple pathways for the detection of CO vis-à-vis sintering temperature effect. Enhanced CO pickup at the sintering temperature of   650 0 C (wide range and low sensitivity) and 750 0 C (short range and high sensitivity) has been observed. The CO sensing and XPS data correlates well along with the nonconventional use of variation in average XPS background intensity of general scan seems to be related to optimized sensitivity conditions of various gases.