Keywords : nano

Novel Green Chemistry Synthesis of Nano-Hydroxyapatite using Soya Milk as a Natural Stabiliser

Sreedevi Nimishakavi; V. Madhusudhan Rao; Tarun Babu M; A. K. Singh

Advanced Materials Letters, 2021, Volume 12, Issue 7, Pages 1-6
DOI: 10.5185/amlett.2021.071649

Present work describes a novel green chemistry synthesis of Nano – Hydroxyapatite (HAP) using Soya Milk (SM) as a Natural Stabiliser. The HAP is a biocompatible material and widely used in orthopaedic and dental applications. Nano-HAP powders are characterized using XRD, SEM, EDS and FTIR. These results show that the nano- HAP powders obtained by Green Chemistry Synthesis using Soya Milk (SM) as a Natural Stabiliser (NS) appear to be quite promising due to optimized pH and Ca/P ratio values that can be adapted for future research and development.

Green Chemistry Synthesis of Nano-Hydroxyapatite using Natural Stabilisers

Sreedevi Nimishakavi; V. Madhusudhan Rao; A. K. Singh

Advanced Materials Letters, 2021, Volume 12, Issue 3, Pages 1-6
DOI: 10.5185/amlett.2021.031610

Present work describes the synthesis and characterization of Nano- Hydroxyapatite (nano-HAP) powders through green chemistry route, using Natural Stabilizers (NS) as precursors. The synthesized powders possess crystallite and particles of sizes in nano range. The nature of the powder is poly dispersive. The morphology of synthesized powders is near spherical and the pH value is greater than the ten. The powder possesses similar dielectric constant value of 100 Hz at room temperature, as reported in literature. The corresponding wave numbers of the nano-HAP powder match with the reported functional groups.  

Substrate integrated circular cavity resonator filled with nano-fibrillated cellulose for humidity detection

Majid Ndoye; Benoit Bideau; Aina Heritiana Rasolomboahanginjatovo; Éric Loranger; Dominic Deslandes; Frédéric Domingue

Advanced Materials Letters, 2019, Volume 10, Issue 6, Pages 400-404
DOI: 10.5185/amlett.2019.1927

In this work, a novel microwave sensor fully based on Substrate Integrated Waveguide (SIW) technology filled with nano-fibrillated cellulose for humidity detection is presented for the very first time. The proposed structure consists of a circular SIW cavity resonator perturbed by the inclusion of nano-fibrillated cellulose inside the cavity. Due to the presence of humidity, the relative permittivity of the eco-friendly dielectric, which is known as a humidity sensitive material, changes, leading to a shift of the resonance frequency of the Substrate Integrate Cavity Circular Resonator (SICCR). The proposed humidity sensor structure operates between 4.28 to 4.32 GHz and exhibits a frequency shift of around 20 MHz for relative humidity in the range of 11.7% to 91% RH. The proposed sensing device operates with very low-cost sustainable and renewable material, is simple to manufacture, co-integrates with existing microwave planar circuits and has the advantage of demonstrating high sensitivity performance.

Applications of nano-scale Cirrus DopantTM to improve existing coatings

See Leng Tay; Chris Goode; Wei Gao

Advanced Materials Letters, 2019, Volume 10, Issue 6, Pages 421-424
DOI: 10.5185/amlett.2019.2219

The use of ceramic nano-powders to create composite coatings is well known but is neither simple to industrialize nor environmentally friendly. Patented Cirrus Dopant™ technology from Cirrus Materials Science offers the performance advantages of nano-composite coatings without the implementation and process drawbacks. Cirrus Dopant™ technology is applicable to commercial baths for a large variety of electrolytic and electroless deposited coatings including Ni, Ni-P, Ni-B, Co-P, Au, Ag, Sn, and Zn-Ni. Successful application of the technology simply requires optimization of a specialized Dopant™ to the bath. This paper discusses the process and results for nano-doping commercially important coating baths.

Fabrication and characterization of nano-bridge Josephson junction based on Fe0.94Te0.45Se0.55 thin film

Jia Lu; Wen Zhang; Zheng Wang; Xiaoming Ma; Shicai Shi; Lei Yan; Hong Ding

Advanced Materials Letters, 2019, Volume 10, Issue 5, Pages 319-323
DOI: 10.5185/amlett.2019.2270

Nano-bridge Josephson junction has been fabricated with Fe0.94Te0.45Se0.55 (FTS) thin films by using focused ion beam etching (FIB). Electrical properties of the Josephson effects of the nano-bridge have been deeply studied. Current-voltage (I-V) characteristics of the junction exhibit resistively and capacitively shunted junction-like (RCSJ) behaviors. Critical current of the junction is 16.1 mA at 4.2 K. The product of the critical current and normal state resistance (IcRn) is higher than those reported in the literatures. Thermal conductance of the nano-bridge increases with increasing resistance, which suggests that the thermal transfer has been enhanced. Noise equivalent power of the nano-bridge is at the order of magnitude of 10-12 WHz-1/2, which is comparable to that of the NbN bolometer. With these unique electrical characteristics, the FTS based nano-bridge could have various potential applications.

Effect of electrode material on piezoelectric output of PVDF sensor with electrospun nanofiber web

Hu Jiyong; Gu Yuanyuan; Zhang Hele; Zhu Yinda; Yang Xudong

Advanced Materials Letters, 2018, Volume 9, Issue 5, Pages 363-368
DOI: 10.5185/amlett.2018.1958

The electrospun PVDF (Polyvinylidene Fluoride) nanofiber web is commonly agreed on a kind of new sensitive materials for the sensor testing the dynamic pressure and energy harvesting, and has the characteristics of fast response and high sensitivity of pressure. As a result of the nanofiber web, it must be packaged to collect piezoelectric charge and bear strong mechanical behavior before industrial practice. The packaging of PVDF nanofiber web is usually sandwiched by incorporating a pair of flexible electrode. However, the effects of the surface and mechanical properties of electrodes such as morphology, roughness and compressibility have not been well investigated yet. This work will introduce three common types of packaging electrode materials (adhesive copper foil tape, indium tin oxide (ITO) thin film, adhesive conductive cloth.) in previously published literatures, compares the piezoelectric output of their sensor prototypes under a periodic impact, and discusses the effect of surface morphology, electrical resistance, and compressibility. The results showed that it has higher output of PVDF piezoelectric sensor packaged by electrode materials with the smooth surface and low mechanical compressibility. This result provides a guideline for designing the textile electrode material for the PVDF nanofiber web.

Porous hydroxyapatite scaffolds fabricated from nano-sized powder via honeycomb extrusion

Mohammed Elbadawi; James Meredith; Mosalagae Mosalagae; Ian M. Reaney

Advanced Materials Letters, 2017, Volume 8, Issue 4, Pages 377-385
DOI: 10.5185/amlett.2017.7063

In this study, we have developed hydroxyapatite (HA) scaffolds for synthetic bone graft from nano-sized HA particles using ceramic extrusion. We also demonstrate that these HA scaffolds show enhanced compressive strength (29.4 MPa), whilst possessing large pore sizes (> 600 µm) that are suitable for bone grafting. The extrusion process involved forming a ceramic paste by mixing the HA powder with a binder and distilled water. The ceramic paste was then fabricated using a ram extruder that was fitted with a honeycomb die to impart large, structured pores. Several green bodies were extruded and then subjected to the same drying and thermal debinding treatment. The samples underwent three different sintering temperatures and two varied dwell times, in order to determine the optimum sintering parameters. The scaffolds were then analysed for their chemical, physical, mechanical and biological properties to elucidate the effects of the sintering parameters on extruded HA scaffolds. The results revealed that the nano-sized particles exhibited a high sinterability, and XRD analysis showed phase purity until 1300 o C. At 1300 o C, trace amounts of phase impurities were detected, however, scaffolds sintered at this temperature exhibited the highest mean compressive strength. The findings demonstrated that traces of phase impurities were not detrimental to the scaffold’s compressive strength. In addition, scanning electron microscopy and density measurements revealed a highly densified solid phase was attained.

Chemically Synthesized Ag/PPy-PVA Polymer Nanocomposite Films As Potential EMI Shielding Material In X-band

Jyoti Srivastava; Pawan Kumar Khanna; Priyesh V More; Neha Singh

Advanced Materials Letters, 2017, Volume 8, Issue 1, Pages 42-48
DOI: 10.5185/amlett.2017.6486

Silver/Polypyrrole/Polyvinylalcohol polymer nanocomposite films were prepared by in-situ polymerization of pyrrole with variable loading of silver nanoparticles from 0.5-10%.  The conducting films prepared from the nanocomposite solution were flexible, light weight, thermally stable and showed high hydrophobicity/hydrophilicity ratio. X-Ray diffraction measurement showed formation of fcc silver nanoparticles with particle size in the range of about 20-40 nm. UV-visible spectroscopy revealed the characteristic bands of Ag nanoparticles and polypyrrole in the so obtained co-polymer nanocomposites. The SEM studies of the nanocomposite films showed that the filler material was well conjugated in the Polymer matrix. Vector Network Analyser showed Electromagnetic shielding efficiency (EMI) efficiency as high as -35 dB in the X band (8-12GHz).

Cu-NiO Nano-composite Formation Through Reactive Milling: Reaction Mechanism

Yasaman Kolvandi; Mohammad Aghagholizadeh; Saeed Sheibani

Advanced Materials Letters, 2017, Volume 8, Issue 1, Pages 82-87
DOI: 10.5185/amlett.2017.6864

In this paper, the possibility of production of Cu matrix nano-composite powder containing 10, 37 and 54 wt.% NiO using mechano-chemical reduction of different copper oxides (CuO and Cu2O) was studied. Structural evolutions were characterized by X-ray diffraction. Also, the microstructure was characterized by scanning electron microscopy and transmission electron microscopy. Particular attention has been paid to the reaction mechanism and kinetics using differential scanning calorimetry. It was found that the reactions completed gradually between 5 to 22h of milling. Formation of Cu2O and Cu(Ni) solid solution, as intermediate phases, were observed during the reaction. It was found that, the initial excess Cu delayed reduction reaction and decreased the final crystallite size up to 18nm. Microstructural results showed that relatively large nano-composite agglomerates powder composed of uniform dispersion of NiO nano-particles in nano-crystalline Cu matrix were obtained. Kinetic study revealed that CuO reduction to Cu through two-steps reaction with lower activation energies in each step had higher rate, compared to one-step reduction of Cu2O. 

Chromium (VI) Ions Adsorption Onto Barium Hexaferrite Magnetic Nano-adsorbent

Aida Mohammadi; Abolghasem Ataie; Saeed Sheibani

Advanced Materials Letters, 2016, Volume 7, Issue 7, Pages 579-586
DOI: 10.5185/amlett.2016.6394

Barium hexaferrite (BaFe12O19) magnetic nano-powder was prepared by co-precipitation method. The effectiveness of different chemical synthesis variables such as solvent and mechanical milling on the adsorption efficiency of barium hexaferrite nano-particles to remove Cr (VI) ions from aqueous solutions was examined. Structural, magnetic, and adsorption properties of the powders are investigated by different techniques. X-ray diffraction analysis revealed that barium hexaferrite formed at a relatively low temperature of 700?C in the sample prepared with a mixture of water/alcohol as a solvent. The FESEM and VSM studies confirmed that all samples had a plate like structure with a particle size in the range of 87-145 nm and high magnetic properties. It was demonstrated that nanometer barium hexaferrite was produced to be an operative adsorbent for removal of Cr (VI) ions from solutions. Different Cr (VI) adsorption experiments were carried out by controlling effective adsorption factors. It was revealed that the sample calcined at a temperature of 700°C and then milled for 5 h (owing themaximum surface area 13 m2/g) showed the highest removal efficiency of 99.5% at pH 3.0, amount of nano adsorbent 1.5 g, initial chromium concentration 133 mg/l, and contact time 1 h. FTIR analysis showed that due to the existence of Cr-O stretching band on the surface of nano-particles, the electrostatic reaction between Cr (VI) ions and nano-adsorbent is possible. The adsorption data were best fitted with the pseudo-second-order kinetic model. Also, the equilibrium adsorption capacity of Cr (VI) calculated from adsorption experiments was found to be 13.25 mg/g. Adsorption studies indicated that the potential use of barium hexaferrite nano-adsorbents for the removal of the other heavy metal ions without sacrificing adsorption capacity can be practical.

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. 

Green Synthesis And Antimicrobial Activity Of Silver Nanoparticles Onto Cotton Fabric: An Amenable Option For Textile Industries 

Anal K. Jha;Kamal Prasad

Advanced Materials Letters, 2016, Volume 7, Issue 1, Pages 42-46
DOI: 10.5185/amlett.2016.6083

Biosynthesis, characterizations and applications of nanoparticles have become an important branch of nanotechnology nowadays. In this paper, green synthesis of silver nanoparticles (AgNPs) using the alcoholic extract of Clerodendron infortunatum as a reducing and stabilizing agent, has been discussed. This biosynthetic method is simple, cost-effective and reproducible. Formation of AgNPs was established by X-ray diffraction, scanning and transmission electron microscopy, UV-visible spectroscopy techniques. The phytochemicals responsible for nano-transformation were principally phenolics, tannins and organic acids present in the leaves. Further, AgNPs were used for antibacterial treatment of cotton fabrics which was tested by antibacterial activity assessment of textile material by agar diffusion method against Staphylococcus aureus. The colloidal AgNPs have been soaked onto cotton fabrics and studied for their effective antibacterial activity toward Staphylococcus aureus which showed remarkable antibacterial activity.

Aqueous Phase Photodegradation Of Rhodamine B And P-nitrophenol Desctruction Using Titania Based Nanocomposites

Suranjan Sikdar; Sayantan Pathak; Tanmay K Ghorai

Advanced Materials Letters, 2015, Volume 6, Issue 10, Pages 867-873
DOI: 10.5185/amlett.2015.5858

Heterogeneous photocatalysts offer great potential for converting photon energy into chemical energy for decomposition and destruction of organic contaminants from organic molecules i.e. Rhodamine B (RhB) and p-nitophenol (p-NP) under UV light. The titania based novel MxNbxTi1-2xO2-x/2 (M = Cr, Fe; x = 0.01-0.2) was prepared by tetra and tri-podal amine type binder with iron or chromium support using sol–gel method followed by calcination at 150 o C in an auto generated pressure. The photodegradation performance of the optimized catalyst was compared with synthesized nano-compositions, P-25 titania with RhB and p-NP. The particle sizes, surface area, mesopore sizes of CrxNbxTi1-2xO2-x/2 (x = 0.01) (CNT1) and FexNbxTi1-2xO2-x/2 (x = 0.01) (FNT1) are 12±1 and 10±2 nm, SBET=162 and 145 m 2 g −1 , 4.9 and 4-5 nm, respectively. The energy band gap of CNT1, FNT1 and NT was found to be 1.85, 2.06 and 2.1 eV, respectively. The importance of CNT1 powders is that it shows good photocatalytic activity for the degradation of Rhodamine B (RhB) within only 180 min and the importance of FNT1 powders is that it reduces the p-NP to p-aminophenol using a little bit of NaBH4 (0.054 g) within 10 min as compared to pure anatase TiO2 and other compositions of MxNbxTi1-2xO2-x/2 (M = Cr, Fe).

Green Syntheis Of Silver Nanoparticles And Its Activity On SiHa Cervical Cancer Cell Line

Anal K. Jha; K. Prasad

Advanced Materials Letters, 2014, Volume 5, Issue 9, Pages 501-505
DOI: 10.5185/amlett.2014.4563

 Biosynthesis and characterizations of nanoparticles has become an important branch of nanotechnology nowadays. In this paper, green synthesis of silver nanoparticles (AgNPs) using the alcoholic extract of Argemone mexicana Linn. as a reducing and stabilizing agent, has been discussed. This biosynthetic method is simple, cost-effective and reproducible. Formation of AgNPs was established by X-ray diffraction, transmission electron microscopy and UV-Visible spectroscopic techniques. Nanoparticles almost spherical in shape having a size of 2-6 nm are found. UV-visible study revealed the surface plasmon resonance at 414 nm. A possible involved mechanism for the biosynthesis of silver nanoparticles has also been proposed.  Further, it was found that AgNPs sol when applied to the SiHa cancer cell line was found to inhibit the growth by 70-80%. It is cumulative effect of the unutilized plant extract and nanosilver. The work signifies the importance of medicinal plants in synthesis of nanomaterials as it bestows double benefit in terms of drug delivery as well as safety. It may open a fresh avenue in future cancer therapeutics.

Characterization Of Nano-structured Magnesiumchromium ferrites Synthesized By Citrate-gel auto Combustion Method

M. Raghasudha; D. Ravinder; P. Veerasomaiah

Advanced Materials Letters, 2013, Volume 4, Issue 12, Pages 910-916
DOI: 10.5185/amlett.2013.5479

Nano-ferrites of the composition Mg Crx Fe2-xO4 (where x=0.0, 0.1, 0.3, 0.5, 0.7, 0.9 and 1.0) were synthesized at a very low temperature (180°C) by Citrate-gel auto combustion method. The as synthesized powders were sintered at 500 0 C for four hours in an air and were characterized by X-ray diffraction (XRD) which confirmed the formation of cubic spinel structure of ferrites. The crystallite size was in the range of 7 to 23nm for different compositions with the significant decrease of ~16nm in response to the increase in Cr substitution. Such low nano sized ferrites are desirable for variety of applications like, in magnetic data storage and in targeted drug delivery, etc. Morphological studies by Scanning Electron Microscopy (SEM) revealed formation of largely agglomerated, well defined nano particles of the sample. Elemental composition characterizations of the prepared samples were performed by Energy Dispersive Spectroscopy (EDS) which shows the presence of Mg, Cr, Fe and O without precipitating cations. The FTIR spectral studies at room temperature in the range of 400 to 800cm-1 showed two strong absorption bands. The high frequency band (ν1) around 600 cm -1 is attributed to the intrinsic vibrations of tetrahedral complexes and the low frequency band (ν2) around 400 cm -1 is due to octahedral complexes. The spectra showed the characteristic peaks of ferrite sample. The observed results can be explained on the basis of composition and crystal size.

Effect Of Morphology On Thermal Stability Of Core-shell Polyaniline/TiO2 Nanocomposites

Ameena Parveen; Aashis S. Roy

Advanced Materials Letters, 2013, Volume 4, Issue 9, Pages 696-701
DOI: 10.5185/amlett.2012.12481

Polyaniline/TiO2 nanocomposites have been prepared by sol-gel technique using citric acid and saturated solution of α-dextrose as a surfactant in presence of hydroxyl group at an anomeric position in sugar chain. The FTIR spectrum indicates the benzenoid, quinoid and MO peaks confirm the formation of PANI/TiO2 nanocomposites. The XRD studies show the monoclinic structure and the TEM study of nano TiO2 reveals that the average particles size is 9 ±2 nm whereas the composite size is 13 ± 2 nm and further it is observed that the TiO2 nanoparticles are intercalated to form a core shell of PANI. The formation of core shell is significant up to 30wt% observed from the SEM. The TGA-DSC curves show the thermal stability of polyaniline and its nanocomposites at 660 °C of temperature.

New Synthetic Approach, Mesoporous properties And Photocatalytic Activity Of Titania adapted Chromium-niobate Nanocatalysts

Tanmay K. Ghorai; Prasanta Dhak

Advanced Materials Letters, 2013, Volume 4, Issue 2, Pages 121-130
DOI: 10.5185/amlett.2012.7382

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.

Solution Combustion Preparation Of Fe2O3- Nano-flakes: Synthesis And Characterization 

Pooja Dhiman; Amit Kumar;M. Singh

Advanced Materials Letters, 2012, Volume 3, Issue 4, Pages 330-333
DOI: 10.5185/amlett.2012.4337

This paper outlines synthesis of iron oxide nano-flakes and their magnetic properties. Fe2O3–Nano-flakes were synthesized by simple, non-expensive solution combustion method using glycine as fuel. XRD confirmed the phase purity of the sample. Surface morphology and elemental composition were determined by SEM and EDX analysis. Mössbauer studies revealed the sextet at room temperature indicating ordered crystalline long range ferromagnetism. M-H measurements showed the saturated hysteresis curve with noticeable coercivity of 300 Oe. UV-vis spectra revealed the good optical absorbance in the visible region.

Surface Patterning On Indium Phosphide With Low Energy Ar Atoms Bombardment: An Evolution From Nanodots To Nanoripples

Indra Sulania; Ambuj Tripathi; D. Kabiraj; Matthieu Lequeux; Devesh Avasthi

Advanced Materials Letters, 2010, Volume 1, Issue 2, Pages 118-122
DOI: 10.5185/amlett.2010.5128

In the present study, Indium Phosphide (InP) (100) samples with a thickness of ~ 0.5 mm have been bombarded with 1.5 keV Argon atoms for a fixed fluence of 8 × 10 16 atoms/cm 2 . The angle of incidence of the atom beam has been varied from normal incidence to 76° with respect to surface normal. The bombarded surface shows the nanostructures as analysed by Atomic Force Microscopy (AFM). For normal and near normal incident angles of the beam, nanodots pattern have been observed and after a critical angle of incidence, the dots begin to align and with further increase of angle, nanostructures elongate along the beam direction. At 63° incidence, a well ordered ripple pattern has been reported. The evolution of nanostructures from nanodots to nanoripples has been analysed in terms of their size, shape and roughness by means of AFM imaging.