Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Centre for Nanotechnology Research

PVDF + BaZrO3 electroactive nanocomposite thin film has been prepared by solution casting method. The structural analysis was carried out by using x-ray diffraction pattern and atomic force microscopy (AFM). Generally, the performance of dielectric capacitors toward higher energy density and higher operating temperatures has been drawing increased interest. In this regard, the present study was focussed on the fabrication and characterization of PVDF + BaZrO3 electroactive nanocomposites in view of enhancing the energy density at elevated temperature. Cole-Cole plot is an agreement with multiple relaxation process in electroactive nanocomposites. Dielectric energy storage performance is assessed for PVDF nanocomposites with different wt% of BaZrO3 at different frequencies and temperature. It has been observed that with increase of temperature, the permittivity increased while the energy density slightly decreased but significantly higher than pure polymer PVDF. A high energy density of 6.88 J/cm3 was obtained for BaZrO3 electroactive nanocomposites at 50 °C and 5.06 J/cm3 at 70 °C. Overall, the testing results indicate that using nanocomposites of PVDF and BaZrO3 as a dielectric component is promising for implementation to preserve high energy density values up to temperatures of 70 °C.The enhancement of dielectric permittivity and the energy density is attributed due to increase of interracial charge density. The effect of BaZrO3 nanoparticles in energy density of PVDF is first time reported. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

World University root node

VIT Unitversity

Vellore Campus

Ionics

Enhanced energy storage in polyvinylidenefluoride (PVDF) + BaZrO3 electroactive nanocomposites

The present study focuses on the development of a chitosan functionalized nanobiocomposite for the co-delivery of two anti-cancer drugs camptothecin (CPT) and 3,3′‑Diindolylmethane (DIM). The difference in the mechanism of action of the two drugs makes them a promising candidate to produce a synergistic effect against breast cancer. Herein a nanobiocomposite was developed by functionalizing a natural polymer chitosan to graphene oxide nanoparticles and decorated with folic acid. The nanobiocomposite thus synthesized was loaded with camptothecin and 3,3′‑Diindolylmethane and characterized by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV–visible spectroscopy (UV) and atomic force microscopy (AFM).Biocompatibility was assayed by hemolysis and anti-inflammatory assay. The cellular toxicity was measured by 3‑(4,5‑Dimethylthiazol‑2‑yl)‑2,5‑Diphenyltetrazolium Bromide (MTT), Sulforhodamine B (SRB) and cell death assay against MCF-7 cell lines. Further in vivo studies were carried out to analyze the biodistribution of the drug, blood biochemical analysis and bioavailability of the drug. The data revealed a significant increase in anticancer activity after co-loading of CPT and DIM to the nanocarrier. Also in-vivo studies revealed that DIM successfully masked the toxic effects produced by CPT. © 2018 Elsevier B.V.

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

International Journal of Biological Macromolecules

Natural polymer functionalized graphene oxide for co-delivery of anticancer drugs: In-vitro and in-vivo

In this work, we report the fabrication of a high performance multi-layer varistor (MLV) via water based tape casting method using novel compositions of nanomaterials. Bi2O3, CaO and Co3O4 doped ZnO nanopowders were prepared by solution combustion synthesis (SCS) route, calcined at different temperatures (550, 650, 750 and 850 °C) and characterized by TEM, XRD, SEM and AFM. The nanopowder (crystallite size ~30 nm) calcined at 650 °C for 1 h was used as the starting material for MLV fabrication. Compositions of the slurry containing doped ZnO nanopowders, binder and plasticizer in water solvent were optimized for the fabrication of thick film. The rheological properties of the slurries having different solid loadings were analysed and thick films of various thicknesses (50–500 µm) were prepared by varying the feeding rate of tape casting. The film roughness of 38.3 nm for the thick film made from 40 wt% solid slurry was found to be superior compared to other samples due to the presence of reduced crack and shrinkage. MLV fired at 950 °C for 1.5 h exhibited a coefficient of nonlinearity of 18 and breakdown voltage of 291.5 V that yields superior properties compared to commercial MLVs. © 2018 Elsevier Ltd and Techna Group S.r.l.

Ceramics International

High performance multi-layer varistor (MLV) from doped ZnO nanopowders by water based tape casting: Rheology, sintering, microstructure and properties

IET Nanobiotechnology

Guest Editorial: 1st International Conference on Nanoscience and Nanotechnology (ICNAN 2016)

Department of Communication Engineering

School of Electronics Engineering

Journal of Computational Electronics

Negative VCC in MIM capacitors: modeling and experiments

In this report, a novel wound dressing material has been woven by electrospinning technique and tested for its various properties. For the nanofibre mat, a mixture of polyurethane (PU) and soy protein isolate (SPI) was electrospun in conjugation with zinc oxide nanoparticles (ZnO Nps) and ciprofloxacin hydrochloride (CipHCl) to produce fibrous mats viz. PU/SPI/ZnO and PU/SPI/CipHCl. An optimum ratio (1: 1) of PU/SPI was used as suitable polymeric ratio in order to produce homogenous nanofibres without beads having an average diameter in the range of 300–350 nm. The electrospun nanofibre-based mats were characterised using X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis and scanning electron microscope. The mechanical properties of the nanofibrous mats were tested using universal testing machine. The wettability analysis was done using the contact angle measurement based on the sessile drop test. This study revealed that the electrospun PU/SPI-based nanofibres are non-sensitizing, non-allergic and non-toxic and that it can be used as a peculiar wound healing material. © The Institution of Engineering and Technology 2017.

Electrospun polyurethane and soy protein nanofibres for wound dressing applications

A series of SnS/Graphene (SnS/G) nanocomposites at various concentrations of graphene were synthesized by a wet chemical route and the prepared composites were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), High Resolution Transmission Electron Microscopy (HRTEM) for its structural and morphological investigation. Results show that the prepared SnS nanoparticles in the composite are [Formula: see text]30[Formula: see text]nm sized and uniformly dispersed on graphene sheets. To test the supercapacitance behavior, electrochemical measurements were carried out in 6[Formula: see text]M KOH electrolyte. A maximum specific capacitance of 984[Formula: see text]F/g was observed for SnS/G-c at 5[Formula: see text]mVs[Formula: see text] scan rate. Galvanostatic charge/discharge curves showed an excellent cyclic stability with higher charge/discharge duration, and hence could be used for high performance supercapacitor applications.

International Journal of Nanoscience

Wet Chemical Synthesis of SnS/Graphene Nanocomposites for High Performance Supercapacitor Electrodes

The aim of this work is to synthesize nickel sulfide–graphene (NiS/G) nanocomposites with different compositions and to analyze the structural and electrochemical capacity and compatibility for their application as supercapacitor material with enhanced charge storage capacity and reduced impedance. NiS nanoparticles (NPs) loaded on graphene were synthesized at various concentrations of graphene by a simple hydrothermal route from nickel sulphate and graphene oxide as precursors in the presence of PVP as surfactant and thioacetamide (TAA) as sulfur source. The composites structural, morphological and physical properties were analyzed by X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier Transform-infrared (FT-IR) analysis. SEM measurements showed the presence of surface attachment of the NiS NPs onto the graphene sheets. To assess the properties of the nanocomposites for their applicability in supercapacitors, electrochemical analysis was carried out in 6[Formula: see text]M KOH electrolyte. Three different samples with different graphene contents — GNiS-10 with 10 wt.%, GNiS-20 with 20 wt.% and GNiS-40 with 40 wt.% were prepared. The specific capacitances obtained for the nanocomposites were calculated to be 84.33[Formula: see text]F/g, 129.66[Formula: see text]F/g, 187.53[Formula: see text]F/g at 10[Formula: see text]mV/s scan rate, respectively. The EIS data showed that the loading of NiS NPs on graphene caused the reduction in impedance at high frequency and has a long cycle life (over 1000 cycles).

Synthesis of NiS–Graphene Nanocomposites and its Electrochemical Performance for Supercapacitors

Cobalt and Nickel ferrite based graphene nanocomposites with increased electrochemical performances were successfully prepared by solvothermal process. To know the structure and morphology of the as-synthesized nanocomposite, the material was investigated by X-ray diffraction and electron microscopy techniques. Further, the material was tested for hydrogen production through electrochemical route. HER activity of nanocomposites was tested for hydrogen evolution at an applied potential of −1.2 to 0.8 V in acidic electrolyte. It shows good exchange current density of 47.9 mAcm−2 and 41.2 mAcm−2 at over potential of 248.3 mV and 259 mV and a Tafel slope of 116.6 mVdec−1 and 121.4 mVdec−1 for CFG and NFG nanocomposite respectively. The experimental results revealed that cobalt and nickel ferrites based graphene nanocomposites is a good electrocatalyst towards hydrogen production. © 2017 Elsevier B.V.

Fulltext

Journal of Magnetism and Magnetic Materials

Cobalt and nickel ferrites based graphene nanocomposites for electrochemical hydrogen evolution

Incessant streak of unsuccessful attempts to synthesize low cost graphene with larger flake size and purity is frequently reported. Any reported methods that result in few layers of graphene with minimal contamination are definitive to exist. In this work, graphene was prepared economically from source of “paper” and detailed investigation was done on the effect of synthesizing parameters like paper source, temperature and amount of urea in the formation of graphene. This is a cost effective method, in which the paper that we use in our daily life was carbonized with the help of urea at a temperature of 850[Formula: see text]C under N2 atmosphere. The paper source was varied, shape of the paper was altered and the graphene paper with large surface area was synthesized without smudging and the prepared graphene paper was analyzed by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) for its structural, morphological investigation. To test the supercapacitance performance, electrochemical behavior was investigated in 6[Formula: see text]M KOH electrolyte. The specific capacitance of 1122[Formula: see text]F/g was obtained at 5[Formula: see text]mV/s scan rate. Chronopotentiometry curves showed an excellent cyclic stability with higher charge/discharge duration and hence could be used for electrochemical supercapacitor applications.