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Nanometer-sized α-Fe 2 O 3 particles have been prepared by a simple solvothermal method using ferric acetylacetonate as a precursor. The products were characterized by X-ray diffraction (XRD), energy dispersive X-ray microanalysis (EDAX), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transition electron microscopy (TEM), infrared spectroscopy (IR) and thermal analysis (TG-DTA). XRD indicates that the product is single-phase α-Fe 2 O 3 with rhombohedral structure. Bundles of acicular shaped nanoparticles are seen in TEM images with an aspect ratio ~ 12; typically 8-12 nm wide and over 150 nm long. The α-Fe 2 O 3 nanoparticles posses a high thermal stability, as observed on thermal analysis traces.

Polyaniline (Pani) and Polyaniline-silver nanocomposites (Pani-Ag) were prepared by employing interfacial polymerization using ammonium persulphate as an oxidizing agent. During the polymerization, the Ag þ is reduced to Ag 0 , and the formations of regular nanocomposite materials were studied by Fourier transform infrared spectroscopy and UV-visible spectroscopy techniques. Scanning electron microscopy and transmission electron microscopy images were conducted to characterize the morphology. Thermogravimetric and differential thermal analysis were carried out to study the thermal stability of the resulting composites. Formation of conducting emeraldine salt form was concluded by electrical conductivity.

Microwave-assisted rapid extracellular biosynthesis of silver nanoparticles was carried out by using carom seed (Trachyspermum copticum) extract as the reducing agent. The reaction mixture containing AgNO 3 and carom seed extract when exposed to microwave irradiation resulted in reducing silver ions to bio-functionalized silver nanoparticles of size 6-50 nm. The AgNP were characterized by UV-vis spectroscopy (UV-vis), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Themogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FTIR) are used to understand the possible mechanism of biosynthesis. In this study, we have also investigated the antimicrobial and antioxidant activities of bio-functionalized AgNP. The antibacterial activity is investigated by measuring the zone of inhibition and antioxidant study is done using 1,1-diphenyl-2-picryl hydrazyl (DPPH) method.

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