S. Raghu

Surfactant assisted surface morphology and thermal properties of polythiophene composites

Conducting polythiophene (PTH)/aluminium oxide (Al2O3) composites was prepared with camphor sulphonic acid (CSA) as s anionic surfactant by means of in situ chemical oxidation polymerization. The morphology and material phase of PTH/Al2O3 (PTHA) composites were investigated by Field-Emission Scanning Electron Microscopy (FESEM) and Energy-dispersive X-ray spectroscopy (EDX). The FESEM image shows alter the size of grain and EDX results consistent with the presence of Al2O3 and CSA chemical composition. Thermal stability of composites was characterized using TGA/DSC, the results indicate that the PTP/Al2O3 composites have higher thermal stability than that of PTP and decompose at higher temperatures due to addition of anionic surfactant.

Optical and electrical studies of vanadium pentoxide doped polyaniline composite

Polyaniline and its composites at different compositions of Vanadium pentoxide (PCV3 and PCV5) were prepared by simple in-situ chemical polymerization method. The composites were characterized using UV/Vis spectrophotometer and impedance analyzer of frequency range from 20Hz to 1MHz at room temperature. The UV-Vis absorption exhibits the red shift in the visible region and direct optical band gap was found to decrease from 2.72eV to 2.65eV with increasing the V2O5 concentration. The electrical conductivity and dielectric constant results vary with frequency. The maximum electrical conductivity obtained is for PCV5 and these polymer composites are prominent candidates for super capacitor and optoelectronics display etc.

Structure, morphology and optical studies of Li+ doped polyaniline composite

Conjugating Polyaniline (PANI) composites have many interesting optical property useful in optical device applications. The pure PANI and PANI-Lithium perchlorate composites (PL1 & PL10) were prepared by chemical reaction method. The composites are characterized with the help of FT-IR, SEM and UV-Vis to confirm the chemical interactions, change in surface morphology and optical changes respectively. The direct optical band gap was found decreased from 3.89 to 2.97eV with increasing the LiClO4. The obtained results suggesting these polymer composites are suitable candidates for optoelectronics display, electrode material and electrochromic devices.Conjugating Polyaniline (PANI) composites have many interesting optical property useful in optical device applications. The pure PANI and PANI-Lithium perchlorate composites (PL1 & PL10) were prepared by chemical reaction method. The composites are characterized with the help of FT-IR, SEM and UV-Vis to confirm the chemical interactions, change in surface morphology and optical changes respectively. The direct optical band gap was found decreased from 3.89 to 2.97eV with increasing the LiClO4. The obtained results suggesting these polymer composites are suitable candidates for optoelectronics display, electrode material and electrochromic devices.

Thermochromism and fluorescence in dyed PEO films

The optical absorbance spectra of solution casted pure & methyl blue (MB) dyed polyethylene oxide (PEO) films were recorded in a wavelength range from 190-1100nm at different temperatures. The absorbance was found to increases with increasing temperature. Fluorescence micrographs confirmed the interaction between polymer and dye and also revealed decreased crystallinity of the sample. Fluorescence quantum yield has been calculated with the help of fluorescence spectra.

Electrical transport and thermochromic properties of polyaniline/chitosan/Co3O4 ternary nano composite

A new Polyaniline/ chitosan/ Co3O4 (CPAESCO) ternary nanocomposite is prepared by in situ oxidation polymerization of aniline in the presence of (NH4)2S2O8, chitosan and Co3O4. The Structural, Thermal, Optical and Electrical features of Polyaniline (PANI), Polyaniline/ chitosan (CPANI) and CPAESCO were analyzed using FT-IR, TGA, UV-vis analysis and Impedance spectroscopy by varying temperature. The results show that the introduction of the Co3O4 nanoparticles into CPANI matrix enhanced its properties. Mott’s parameters show 3D -VRH Type conduction in it.

Conductivity and optical band gaps of polyethylene oxide doped with Li2SO4 salt

The conductivity and optical properties of Li2SO4 doped polyethylene oxide (PEO) films were studied. The polymer electrolyte films are prepared using solution casting technique. The material phase change was confirmed by X-ray diffraction (XRD) technique. Optical absorption study was conducted using UV- Vis. Spectroscopy in the wavelength range 190–1100nm on pure and doped PEO films. The direct and indirect optical band gaps were found decreased from 5.81–4.51eV and 4.84–3.43eV respectively with increasing the Li2SO4. The conductivity found to increases with increasing the dopant concentration due to strong hopping mechanism at room temperature.