Govind Umarji

Innovative biofilm inhibition and anti-microbial behavior of molybdenum sulfide nanostructures generated by microwave-assisted solvothermal route

The incessant use of antibiotics against infectious diseases has translated into a vicious circle of developing new antibiotic drug and its resistant strains in short period of time due to inherent nature of micro-organisms to alter their genes. Many researchers have been trying to formulate inorganic nanoparticles-based antiseptics that may be linked to broad-spectrum activity and far lower propensity to induce microbial resistance than antibiotics. The way-out approaches in this direction are nanomaterials based (1) bactericidal and (2) bacteriostatic activities. We, herein, present hitherto unreported observations on microbial abatement using non-cytotoxic molybdenum disulfide nanostructures (MSNs) which are synthesized using microwave assisted solvothermal route. Inhibition of biofilm formation using MSNs is a unique feature of our study. Furthermore, this study evinces antimicrobial mechanism of MSNs by reactive oxygen species (ROS) dependent generation of superoxide anion radical via disruption of cellular functions.

Tuning Magnetic Behavior of Nanoscale Cobalt Sulfide and Its Nanocomposite with an Engineering Thermoplastic

Nanocomposites containing magnetic nanoparticles embedded in a polymer matrix with good thermal stability (up to 200°C) are technologically important. We report an environmentally benign solid–solid approach for synthesis of cobalt sulfide and its nanocomposite using a thermally stable matrix of polyphenylene sulfide. Physicochemical characterizations reveal the formation of nanoclusters of the hexagonal phase CoS. Even though bulk CoS is nonmagnetic, magnetization studies exhibit anomalous magnetic behavior for phase-pure nanoscale CoS and its nanocomposites.

Comparison of optical and photovoltaic properties of ZnO chemically synthesized by using different hydrolyzing agents

AbstractTwo zinc oxide (ZnO) nanoparticles ZS with hexagonal sheet and ZN having nanorod-like morphologies were prepared by precipitation technique using two different hydrolyzing agents viz. water (ZS) and ethanol (ZN). The physicochemical properties of both of the as-synthesized ZnO nanoparticles were investigated by UV–vis, powder X-ray diffraction (pXRD) and field emission scanning microscopy (FESEM). The as-synthesized ZnO nanoparticulates were successfully employed as photoanode material in dye-sensitized solar cells (DSSCs). The photoanode fabricated by using ZN in DSSC showed two times better cell efficiency with enhanced photocurrent and open circuit potential in comparison to the photoanode fabricated using ZS. The improved efficiency of ZN over ZS is due to high active surface area for greater dye loading. Graphical abstractThe enhanced efficiency has been obtained by employing ZnO nanostructures (nanosheets and short rods) as photoanode in dye-sensitized solar cells.

XPS and AFM investigations on silver-based photoimageable thick film systems

Purpose – The purpose of this paper is to ascertain chemical changes occurring at various stages involved in processing of silver‐based photoimageable thick films; and to determine ensuing topographical features which other wise appeared to be hindered in 2D scanning electron microscopy.Design/methodology/approach – Surface sensitive techniques, viz. X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used.Findings – Interfacial adhesion of silver film with substrate (Al2O3) was specifically looked into with respect to role played by photoimaging (before and after exposure to ultra‐violet light). XPS results revealed occurrence of subtle chemical changes in terms of unsaturation to saturation in C−C bonding and also an interesting C−Al bonding which presumably improves mechanical adhesion of unfired film with the alumina substrate. AFM was carried out to examine the surface roughness, particle size, and microstructure of film which are very important from the standpoint of high‐f...