M. L. Singla

Synthesis, Characterization and Application of Silica‐Gold Nano‐Composites

Present work deals with the synthesis of silica‐gold shell nanocomposite and their characterization using UV‐Visible spectroscopy, SEM and XRD. Gold nanoparticles were prepared using hydrazine hydrate as reducing agent. Synthesis of Silica‐gold nano‐composites (silica@AuNPs), was achieved using Tetra Ethyl Ortho Silicate (TEOS) as silane reagent. Surface Plasmon Resonance (SPR) of synthesized AuNPs and silica@AuNPs was observed at 525 nm which corresponds to the approximate size of ±12u2009nm. The SPR intensity of Si@AuNPs was however reduced, which confirmed the formation of silica shell around AuNPs. SEM of nanoparticles showed spherical shape and are stable for about 4 weeks. XRD of AuNPs showed fcc lattice structure. Further, silica@AuNPs have been explored for their application in nitrobenzene detection, using UV‐Visible spectroscopy. As the varied concentration of nitrobenzene was added, the SPR of silica@AuNPs showed decrease in the intensity, confirming the adsorption of nitrobenzene on NP surface. Th...

Thermal stability and electrical characteristics of poly(2-ethyleaniline)-Au nanocomposite

The Present work reports the synthesis of poly2-ethyleaniline (PEANI) by oxidative polymerization of 2-ethyleaniline and its composite with gold nanoparticles (AuNPs) via in situ chemical synthesis route (simultaneous polymerization and precipitation). PEANI and its nanocomposite were characterized by thermogravimetric analysis-differential Scanning Calorimetry, X-ray diffraction and Fourier transform-infrared. The structural confirmation of the polymer was confirmed by FT-IR which shows strong absorption starting at ~1,600xa0cm−1 and extended to near-IR, Attributed to the presence of free carrier in the polymer. XRD of Polymer shows large X-rays peaks indicating that the material is rather amorphous with a certain degree of crystallinity where as XRD of PEANI-Au nanocomposite confirms the incorporation of AuNPs in composite. The TEM image showed the formation of PEANI-AuNPs core shell nanostructure. From TGA–DSC studies it was confirmed that the decomposition of the polymer in the composite is lowered by 254xa0°C as compare to PEANI alone, resulting in weak structure. Whereas I–V characteristics’ shows that the composite has about 10xa0% lower conductance values than the polymer alone.

An intrinsic fiber optic H2S gas sensor

The sensor involves application of a chemical agent on an unclad portion of a multimode optical fiber which produces brown stains due to the presence of H2S gas resulting in anenuation of the light signal propagating in the fiber. The paper discusses the salient technical features and experimental details of the sensor.

Chemical phase analysis of seed mediated synthesized anisotropic silver nanoparticles

Noble-metal nanoparticles are of great interest because of its broad applications almost in every stream (i.e. biology, chemistry and engineering) due to their unique size/shape dependant properties. In this paper, chemical phase of seed mediated synthesized anisotropic silver nanoparticle (AgNPs) has been investigated via fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). These nanaoparticles were synthesized by seed-growth method controlled by urea and dextrose results to highly stable 12-20u2005nm particle size revealed by zeta potential and transmission electron microscopy (TEM).