Volume 8, Issue 7, July 2017

Microfluidics and Nanofluidics Conference Series

Ashutosh Tiwari

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 752-753
DOI: 10.5185/amlett.2017/7001

International Association of Advanced Materials (IAAM, www.iaamonline.org) is pleased to announce Microfluidics and Nanofluidics Conference Series in Asia, Europe and America with collaboration of VBRI Press AB, Sweden (www.vbripress.com). The conference aims to provide a forum to promote scientific exchanges including fundamental understandings and technological developments, discuss the most recent innovations and to foster global networks and collaborative ties between leading international micro and nano- fluidics researchers across various disciplines from engineering, physics, chemistry, biology, medicine, material science and biotechnology.  

Low temperature rf-sputtered thermochromic VO2 films on flexible glass substrates

Emmanouil Gagaoudakis; Giannis Michail; Elias Aperathitis; Ioannis Kortidis; Vassilios Binas; Marianthi Panagopoulou; Yannis S. Raptis; Dimitris Tsoukalas; George Kiriakidis

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 757-761
DOI: 10.5185/amlett.2017.6934

The high deposition temperature of the order of 400 o C and more is requirement for the growth of the thermochromic phase of vanadium dioxide (VO2), limits the type of substrates that one may grow them on only to rigid ones. In this work, thermochromic VO2 films were successfully deposited on flexible Corning® Willow® glass substrates, without the use of a buffer layer, by rf sputtering at a substrate temperature of 300 o C, one of the lowest for this technique ever reported. The critical transition temperature of 80 nm thin films was Tc = 50.7 o C, transmittance hysteresis width was ΔT = 12.1 o C, while the modulation of the transmittance at λ = 2000 nm measured at 25 o C and 90 o C was around 36%, leading to a solar modulation of ΔTrsol = 5%. In addition, an increase in transmittance at λ = 600nm (visible region) of 4% was observed before and after heating, while integrated luminous transmittance remained almost constant at Trlum = 34%. The thermochromic and luminous characteristics of the VO2 films deposited on flexible glass are comparable to those deposited on rigid glass substrates. The deposition of thermochromic VO2 film on flexible glass substrates by sputtering technique opens up a new window for thermochromic applications on flexible substrates.

Polypyrrole-Pd nanocomposites modified gold electrode for electrochemical detection of ascorbic acid

Nitin R. Dighore; Suresh T. Gaikwad; Anjali S. Rajbhoj

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 762-767
DOI: 10.5185/amlett.2017.6987

The fabrication of an electrochemical sensor based on polypyrrole-Pd nanocomposites modified gold electrode (PPy-Pd-AuE) and its electrodetection of ascorbic acid is described. The PPy-Pd nanocomposites were synthesized by chemical method and characterized by different techniques. The Pd nanoparticles incorporated with PPy were confirmed by x-ray diffraction, scanning electron microscope, elemental dispersive spectroscopy and transmission electron microscopy analysis. The electrochemical behavior of polypyrrole-Pd nanocomposites towards the electro catalytic oxidation of ascorbic acid was investigated by cyclic voltammetry, differential pulse voltammetry and square wave voltammetry. The observed cyclic voltammetry, differential pulse voltammetry and square wave voltammetry response depended linearly on concentration of ascorbic acid in the range of 100-1000 mM with correlation coefficients of R 2 =0.977, R 2 =0.980, R 2 = 0.990 and sensitivity 7.96 mA/mM.cm 2 , 0.70 mA/mM.cm 2 and 2.10 mA/mM.cm 2 respectively. The reproducibility of PPy-Pd-AuE electrode from CV, DPV and SWV were found to be 3.9%, 4.69% and 2.98 % respectively. These results indicate the PPy-Pd-AuE exhibited excellent platform and could be used for electrochemical determination of ascorbic acid. 

Magnetic, thermal and magnetocaloric properties of Ni50Mn35In14.5B0.5 ribbons

Sudip Pandey; Abdiel Quetz; P. J. Ibarra-Gaytan; C. F. Sanchez-Valdes; Anil Aryal; Igor Dubenko; Dipanjan Mazumdar; J.L. Sanchez Llamazares; Shane Stadler; Naushad Ali

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 768-772
DOI: 10.5185/amlett.2017.1452

The structural, thermal, magnetic, and magnetocaloric properties of Ni50Mn35In14.5B0.5 melt-spun ribbons have been investigated using room-temperature x-ray diffraction (XRD), differential scanning calorimetry (DSC), and magnetization measurements. Magnetic and structural transitions were found to coincide in temperature leading to large magnetocaloric effects associated with the first-order magnetostructural phase transition. In comparison to the bulk Ni50Mn35In14.5B0.5 alloys, both the martensitic transition temperature (TM) and Curie temperature (TC) shifted to lower temperatures. The MCE parameters were found to be comparable to those reported for bulk Ni50Mn35In14.5B0.5 Heusler alloys and Ni48Mn39In13-xBx ribbons. A comparison of magnetic properties and magnetocaloric effects in Ni50Mn35In14.5B0.5 alloys as a ribbon and in their bulk form has been shown in detail. The roles of the magnetic and structural changes on the transition the temperatures of the ribbons are discussed. 

Microwave-assisted: Boron nitride nanomaterials based sulfonic acid catalyst for the synthesis of biologically active ethylpiperazinyl-quinolinyl fused acridine derivatives

Arul Murugesan; Robert M Gengan; Kandasamy G Moodley; Gerhard Gericke

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 773-782
DOI: 10.5185/amlett.2017.1495

Boron nitride nanomaterial based solid acid catalyst is an efficient and reusable sulfonic acid catalyst for the one-pot synthesis of 9-(2-(4-ethylpiperazin-1-yl)quinolin-3-yl)-3,3-dimethyl-3,4,9,10-tetrahydroacridin-1(2H)-one derivatives under microwave irradiation conditionsvia. The Knoevenagel and Michael type reactions. The catalyst was prepared by simply mixing boron nitride and 3-amino-4-methoxybenzenesulfonic acid in a safe method. The morphological properties of the catalyst was determined by using FT-IR, XRD, TEM, SEM and Raman spectroscopy. The synthesised catalyst was employed in a Knoevenagel and Michael type reaction to synthesise novel ethylpiperazinyl-quinolinyl based acridine derivatives. Furthermore, the newly-synthesised compounds was used for molecular docking in Hsp90 protein studies. The method developed in this study has the advantages of good yield, simplicity coupled with safety and short reaction time. Most importantly it was found that the solid acid catalyst can be recycled with minimal loss of activity over five cycles. 

A high energy 3V lithium-ion capacitor synthesized via electrostatic spray deposition

Richa Agrawal; Chunhui Chen; Samantha Dages; Chunlei Wang

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 783-790
DOI: 10.5185/amlett.2017.7098

Reduced graphene oxide-carbon nanotube (rGO-CNT) and anatase TiO2-Li4Ti5O12 (ATO-LTO) composite electrodes were synthesized via electrostatic spray deposition (ESD) and analyzed as cathode and anode vs. lithium, respectively.  The rGO-CNT and ATO-LTO electrodes were able to deliver discharge capacities of ca. 63 mAhg -1 and 95 mAhg -1 , respectively for a current rate of 0.1 Ag -1 with superior rate capability and cycle stability. Post electrode analyses, lithium-ion hybrid electrochemical capacitors (Li-HEC) were constructed comprising a prelithiated ATO-LTO anode and an activated rGO-CNT cathode in a carbonate based 1M LiPF6 salt electrolyte. The Li-HEC cells were stable for a cell potential of  0.05-3V and were able to deliver a maximum gravimetric energy density of 33.35 Whkg -1 and a maximum power density of 1207.4 Wkg -1 , where the cell parameters were normalized with the total mass of the anode and cathode active materials. Furthermore the Li-HEC cells were able to retain ~77% of the initial capacity after 100 cycles. The superior Li-HEC performance is attributed to the utilization of a prelithiated lithium-intercalating anode and a double layer cathode in an asymmetric configuration. The feasibility of using a low-cost, facile process like ESD was therefore shown to produce high performance Li-HECs.

Synthesis and performance of La0.5Sr0.5CoO3 cathode for solid oxide fuel cells

Pankaj K. Tiwari; Suddhasatwa Basu

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 791-798
DOI: 10.5185/amlett.2017.6895

In the present work, different synthesis methods i.e., sol-gel method, glycine-nitrate method and solid state route have been used to synthesize lanthanum strontium cobaltite (LSCO), which is utilized as cathode in low and intermediate temperature solid oxide fuel cell (SOFC). Calcination temperature for LSCO has been determined by TGA. XRD, SEM, EDX and TEM have been used to assess the phase purity, crystallite size, morphology, distribution of constituent elements and particle size of synthesized LSCO material. Two-probe AC conductivity method has been used to calculate the ionic conductivity of LSCO in air environment between 400-800 °C. LSCO synthesized by sol-gel method provided highest ionic conductivity of 0.42 S/cm at 700 °C and lowest activation energy of 31.60 kJ/mol between 500 to 700 °C among all the methods. LSCO synthesized by sol-gel method gives lowest area specific resistance (ASR) of 3.52 Ω cm 2 at 800 °C for half-cell (LSCO/YDC). High ionic conductivity and low polarization resistance established LSCO synthesized by sol-gel method, as the potential cathode material. 

Preparation of dense BaxSr1-xCo0.8Fe0.2O3 membranes: Effect of Ba2+ substituents and sintering method to the density, hardness and thermal expansion coefficient of the membranes  

Hamzah Fansuri; Muhammad I. Syafi

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 799-806
DOI: 10.5185/amlett.2017.6948

The aims of this research are to study the sintering technique during the production of BaxSr1-xCo0.8Fe0.2O3-δ (BSCF) membranes and to obtain information about the correlation between Ba 2+ substituent with membrane’s density, hardness and thermal expansion coefficient. BSCF with x = 0.5, 0.6 and 0.7 (BSCF 5582, 6482 and 7382) were synthesized by the solid state method. X-ray diffraction analysis revealed that the three oxides possessed a cubic structure with high purity and crystallinity. BSCF membranes were made by dry pressing method from their respective powders which passed through 400 mesh sieves at 1050 o C and 1150 o C. Membranes with high density were obtained from phased sintering technique at 1150 °C. SEM analysis results showed that the surface of the membranes is dense, albeit pores can still be found in the cross section of the membranes. The density of the membranes decreased as the amount of Ba 2+ substituent increases indicated by the increase in pore size. A similar pattern was also found in the membrane hardness which decreased as the amount of Ba 2+ content increased. Thermal expansion coefficient of BSCF 5582 was 18.28 ppm which was the highest one followed by BSCF 6482 and BSCF 7382.

Tape casting and lost carbonate sintering processes for production of heat sinks for portable electronics   

Mosalagae Mosalagae; Russell Goodall; Mohammed Elbadawi

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 807-812
DOI: 10.5185/amlett.2017.7074

Porous copper was fabricated by means of a powder metallurgy process applied to tape casting. Lost Carbonate Sintering (LCS) was employed to control porosity within the component during processing. The weight ratio of the potassium carbonate introduced into the matrix ranged from 30-40 wt%. Additives such as; plasticizers, binders, dispersant and solvents were utilized to control the properties throughout the processes and ease fabrication. The component was debinded and sintered at 400 °C and 900 °C respectively, under vacuum. The potassium carbonate was removed from the sintered component via dissolution in water. By using X-ray Florescence (XRF) and Energy Dispersive X-ray Spectrometry (EDS) techniques, the effectiveness of the dissolution route at removing the space holder was investigated. The results show that porous copper produced in this way has porosity ranging from 75-85 % and pore size from 500-766 mm. The component produced has thickness ranging from 1300 -1800 mm. 

Synthesis, characterization and photovoltaics studies of 3-alkylthienyl thiophene based polymers prepared via direct arylation polymerization

Geeta Saini; Vandna Luthra;R. P. Tandon; Vishal Sharma

Advanced Materials Letters, 2017, Volume 8, Issue 7, Pages 813-818
DOI: 10.5185/amlett.2017.1483

The synthesis and characterization of two novel 3-thienyl based polythiophene derivatives PT and BT have been presented. These polymers have been synthesized by convenient and ecofriendly Pd catalyzed direct arylation polymerization method. In these polymers the alkyl side chain has been replaced by alkylthienyl side chain and polymer PT analogous to regioregular poly(3-hexylthiophene) (rr-P3HT) has been synthesized. These polymers have been characterized by 1 H NMR, GPC, TGA and UV vis absorption spectroscopy. The absorption maxima of these polymers are comparable to the rr-P3HT. The polymers have very good solubility in common organic solvents and therefore the solution processing of these materials has been easily done. Solar cells of these polymers have been fabricated by using PT and BT as donor materials and PC61BM as acceptor material. It was observed that both the materials showed almost same photovoltaic characteristics. Solar cell performance of these materials has been found to be low and we are working on the optimization and improvement of power conversion efficiency of these materials.