Volume 9, Issue 8, August 2018

Polypyrrole/MnO2 nanocomposites as potential electrodes for supercapacitor

Ritu P. Mahore; Devendra K. Burghate; Subhash B. Kondawar; Ashish P.Mahajan; Deoram V. Nandanwar

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 538-543
DOI: 10.5185/amlett.2018.1573

Due to the ever growing demand of energy for various applications attention of researchers is aroused by Supercapacitors due to its superior power, energy density and cyclic life. Electrode material mainly determines the performance of Supercapacitors. Conducting polymers, metal oxides and carbon based materials are mainly used as electrode materials in Supercapacitors. Among these three categories of materials, Conducting polymers and metal oxides shows pseudo-capacitance. This paper reported the synthesis of Pure Polypyrrole (PPy) and Polypyrrole/Manganese dioxide (PPy/MnO2) nanocomposites by in-situ chemical oxidative polymerization. The synthesized materials were tested as potential candidates for the electrodes of supercapacitor. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) revealed that nanoparticles of MnO2 are well incorporated into PPy matrix. Cyclic Voltammetry (CV) indicated that PPy/MnO2 nanocomposites have an ideal capacitive behaviour and an excellent cyclibility. Electrochemical impedance spectroscopy (EIS) and Galvanostatic charge-discharge (GCD) measurements proved that nanocomposite electrode with 10% MnO2 composition showed the smallest charge transfer resistance and highest specific capacitance compared to other compositions. The electrochemical studies of PPy/MnO2 nanocomposites showed that PPy/MnO2 nanocomposites are suitable advanced materials for electrodes of the supercapacitors. Copyright © 2018 VBRI Press.

Experimental investigation on the bending response of multilayered Ag-ionic polymer-metal composite actuator for robotic application

Dillip Kumar Biswal; Payodhar Padhi

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 544-548
DOI: 10.5185/amlett.2018.1753

Ionic polymer-metal composites (IPMCs) are electro-active polymers that undergo bending deformation with the stimulus of a relatively small electric field. In this research we fabricate multilayered structure of IPMC actuator using chemical decomposition method and investigate the influence of bending response on applied input voltage. The experimentally obtained results had been compared to single layered IPMC actuator. The result shows that the increment of layer on base material (Nafion-117) had increased the actuation capability of IPMC actuator. The tip displacement increases up to 20% for three layered and around 30% for four layered compared to single layered IPMC actuator under the application of 1.0V. This finding would be useful for the application where higher bending displacement is required i.e., in the robotic and biomimetic application with a very small input voltage. 

Investigation on stability and photocatalysis of perovskites 

Yidi Wang; Pui Fai NG; Bin Fei

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 549-552
DOI: 10.5185/amlett.2018.1911

Hybrid organic–inorganic perovskite materials have attracted a lot of attention with their facile synthesis process and high efficiency of light absorption. However, poor stability is always a big barrier to commercial development. In this study, a new kind of organic perovskites MA0.6(AA)0.4PbBr3 (AM-PE), which harnesses aniline as a replacement of conventionally used methylamine, was synthesized to increase the stability of MAPbBr3 (M-PE). The decomposition process of MAPbBr3 in acetone was investigated. Smaller PbBr2 particles were formed in the decomposition process, causing the change of photoluminescence emission wavelength from 540 nm to 610 nm. The photocatalysis and photoluminescence properties of M-PE and AM-PE were also compared. As a result, the introduction of aniline reduced the decomposition rate of AM-PE significantly and showed twice the catalysis efficiency of M-PE in the degradation of organic dye - malachite green.

Evaluation of use of bottom ash in cement masonry and concrete regarding their mechanical properties

Rajiv Gupta; Ayub Ahmed; Sasidhar Kumar Reddy Ithepalli

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 553-558
DOI: 10.5185/amlett.2018.1942

Large quantities of ash are generated every year by the various manufacturing industries as a waste by-product. This study aims to utilize waste by-product in concrete and to reduce its cost by replacing cement in parts with bottom ash. This research presents the results of the experimental investigations to study the use of bottom ash as partial replacement for cement in concrete and masonry units. Bottom ash is the coarser material, which falls into furnace bottom and constitutes about 20% of total ash content. The strength development for various percentage replacements (5-15%) of cement with bottom ash has been compared to control specimens of concrete and masonry.

Non-isothermal crystallization of PCL/CLAY nanocomposites

Matias R. Lanfranconi; Vera A. Alvarez;Leandro N. Ludue

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 559-566
DOI: 10.5185/amlett.2018.1976

In this work, Differential Scanning Calorimetry (DSC) was used to study the crystallization behavior of nanocomposites based on polycaprolactone (PCL) reinforced with organo-montmorillonite (C20A) and organo-bentonite (B-THBP) under non-isothermal conditions. The effect of clay content (0.0, 2.5, 5.0 and 7.5 wt.%) was analysed. Linear and non-linear regression methods were used to calculate theoretical kinetic parameters. The study was focused on the correlation between the non-isothermal crystallization process and the morphology of the clay inside the PCL matrix. Continuous cooling transformation diagrams were obtained by means of a mathematical model that involves both induction and growth of the crystal during cooling. For the construction of these diagrams, both crystallization steps, crystals induction (analysed by the induction time equation) and growing (studied by a crystal growth model), were considered.

Fibre-optic trapping and manipulation at the nanoscale

Yuchao Li; Hongbao Xin; Xiaohao Xu; Xiaoshuai Liu; Baojun Li

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 567-577
DOI: 10.5185/amlett.2018.1994

With the initial design based on Ashkin’s pioneering work in 1970, optical trapping and manipulation of micron-size particles and cells has been extensively applied in the fields of physical science and technology as well as cellular and molecular biology. However, due to the fundamental diffraction limit of light, it is difficult to extend these techniques to the nanometre range that includes nanomaterials such as nanotubes, nanowires, nanoparticles and biomolecules, which are crucial for nanoscience and nanotechnology. Recently, several approaches based on optical fibre nanoprobes have been developed and demonstrated for trapping and manipulation of nanostructures. Here, starting from basic theories of optical forces, we review the state-of-the-art in fibre-optic trapping and manipulation of different nanostructures, with an emphasis on carbon nanotubes, silver and semiconductor nanowires, upconversion and polystyrene nanoparticles, and DNA molecules. Finally, we discuss the future perspectives of nano-optical manipulation, which has considerable potential applications in a variety of scientific fields.

The effect of growth time and oxygen flow on the properties of electrochromic WO3 thin layers grown by LPCVD 

D. Louloudakis; D. Vernardou; G. Papadimitropoulos; D. Davazoglou; E. Koudoumas

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 578-584
DOI: 10.5185/amlett.2018.2013

Results are presented regarding the development of functional electrochromic WO3 thin layers, using a simple, one step and fast process without the need of template or seed layers or even post-annealing, factors favoring large scale industrial deposition. In particular, low-pressure chemical vapor deposition (LPCVD) was employed to develop gama-monoclinic WO3 crystalline phase of granular agglomerations structure, with a thickness from 60 nm up to 160 nm onto FTO coated glass substrates. The effect of growth time and oxygen flow on the structural, morphological and electrochemical properties of WO3 thin layers was investigated. It was found that a deposition time of 15min and an O2 flow rate through the reactor of 0.1 l/min result in a more stable behavior during the interchange charge circles. 

Synthesis of α-MoO3 nanofibers for enhanced field-emission properties

Sandeep Kumar Singh Patel; Khemchand Dewangan; Simant Kumar Srivastav; Narendra Kumar Verma; Paramananda Jena; Ashish Kumar Singh; N. S. Gajbhiye

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 585-589
DOI: 10.5185/amlett.2018.2022

One-dimensional α-MoO3 nanofibers of 280–320 nm diameters were synthesized by a hydrothermal method. The morphologies and compositions of as-synthesized α-MoO3 nanofibers have been characterized by X-ray powder diffraction, Raman spectroscopy, and field-emission scanning electron microscopy. X-ray photoelectron spectroscopy showed the predominantly 6+ oxidation state with a small percentage of reduced δ+ (5 < δ < 6) oxidation state. The field-emission properties of α-MoO3 nanofibers show a lower turn-on electric field of 2.48 V µm -1 and threshold electric field of 3.10 V µm -1 . The results suggest that the α-MoO3 nanofibers are promising candidate for efficient and high-performance field-emission devices. 

Efficient siRNA delivery using osmotically active and biodegradable poly(ester amine)  

Jadhav N.; Min Hye Ahn; Jaiprakash Sangshetti; Rohidas B. Arote

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 590-593
DOI: 10.5185/amlett.2018.2026

Biodegradable and hyperbranched poly(ester amine) (PEA) was prepared by reaction of glycerol dimethacrylate (GDM) with  low molecular weight polyethylenimine (LMW-PEI) by Michael addition reaction. This novel gene carrier showed excellent physicochemical properties and relatively low cytotoxicity compared with PEI 25K. It showed excellent transfection efficiency and siRNA delivery. The higher silencing efficiency of PEAs could be attributed to the synergistic effect arising from hyperosmotic glycerol and proton sponge active PEI residues in the PEA backbone.

Naphthol bis-indole derivative as an anode material for aqueous rechargeable lithium ion battery

R. Anil Kumar; R. Vijeth Shetty; G. S.Suresh; K. M. Mahadevan

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 594-601
DOI: 10.5185/amlett.2018.2029

Aqueous or non-aqueous rechargeable lithium ion batteries with organic electrodes as a current carrier can perform effectively sensible and affordable energy storage devices due to large accessibility of organic materials. Here we report a high-performance lithium-based energy storage device using 3,3'-(naphthalen-1-ylmethanediyl)bis(1H-indole) (NBI) as anode material for Aqueous Rechargeable Lithium-ion Battery. The active material is synthesized by condensation between indole and naphthaldehyde under stirring in glacial acetic acid, followed by lithiation by ball milling method. The obtained samples have been characterized by the combination of elemental analysis, NMR, FT-IR and powder XRD. The electrochemical measurements show that the cell Li-NBI | Sat. Li2SO4 | LiFePO4 has been delivered an initial discharge capacity of 113 mAh g −1 at lower current density. At the high current density 75 mAh g −1 discharge capacity can be achieved, which represents its high rate capability. Consequently, the as-prepared Li-NBI could be a potential active species as low-cost anode materials for lithium batteries. The kinetics of electrode reactions under saturated Li2SO4 have been studied by Potentiostatic Electrochemical Impedance Spectroscopic method, show the semi-infinite behaviour at peak potentials. These considerations may be rendering the effective rate performance during charge/discharge process.

Structural and mechanical properties of CeO2 reinforced Al matrix nanocomposites

Himyan Mohammed; Matli Penchal Reddy; Fareeha Ubaid; Abdul Shakoor; Adel Mohamed Amer Mohamed

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 602-605
DOI: 10.5185/amlett.2018.2030

In this study, Al-CeO2 nanocomposites containing various concentrations of reinforcement were fabricated by ball milling and microwave sintering process. A comparison of structural and mechanical properties of the developed nanocomposites is presented to elucidate the effect of reinforcement. Different characterizing tools such as X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), surface profilometrer, microhardness tester and universal compression testing machines were employed. XRD and SEM/EDX analyses reveal the presence and uniform distribution of CeO2 nanoparticles into the Al matrix. A significant increase in microhardness and compressive strength is noticed with increasing concentration of CeO2 nanoparticles due to a dispersion hardening effect of the reinforcement. Our study indicates that the concentration of reinforcement has a significant influence of the properties of Al-CeO2 nanocomposites. It is further noticed that Al-2.0 vol.% CeO2 nanocomposite demonstrates the best performance as compared to pure Al and other developed nanocomposites.

Effect of selected cellulosic fibers on the properties of cement based composites

Alena Sicakova; Viola Hospodarova; Nadezda Stevulova; Vojtech Vaclavik; Tomas Dvorsky

Advanced Materials Letters, 2018, Volume 9, Issue 8, Pages 606-609
DOI: 10.5185/amlett.2018.2032

In this paper, the experimental work providing the testing of cement mixture containing two types of cellulosic fibers, namely fibers from bleached wood pulp and recycled waste paper fibers, is given. Fibers are described by selected characteristics such as length, density, and pH. They were applied as additive to the cement composite/plaster while they were dosed in different amounts: 0.2 %, 0.3 % and 0.5 % of the weight of both the filler and binder. Mixtures without fibers were prepared as reference samples. Density, water absorption, thermal conductivity, flexural and compressive strength were studied following by analyses of differences between resulting values. The observed differences in the physical, mechanical and thermal properties were found to be influenced by the properties (such as type, amount and other characteristics) of cellulosic fibers.