D. K. Kanchan

Conductivity relaxation in Ag + ion conducting PEO-PMMA-PEG polymer blends

In this paper, the electrical conductivity and relaxation studies in two different temperature regions (T < Tm and T > Tm) on plasticized PEO–PMMA blend polymer electrolyte system with AgNO3 salt are reported. The polymer electrolyte system has been prepared by solution cast technique and characterized by X-ray diffraction and differential scanning calorimetry. The conduction and relaxation processes at various temperatures have been investigated in the framework of modulus formalism. The distribution of relaxation times is discussed using Argand plot. Variation in ionic conductivity of polymer blends is discussed with the increase of PEO as well as with temperature.

Conducting and Antimicrobial Properties of Silver Nanowire–Waxy Starch Nanocomposites

ABSTRACT Silver nanowires were prepared on a waxy corn starch matix by a simple and green hydrothermal route. Infrared (IR) spectroscopy and X-ray diffraction (XRD) confirmed the presence of nanostructured cubic silver embedded in waxy starch matrix. The particle size by Scherrer’s equation is calculated to be about 32 nm. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) revealed a uniform morphology, indicating intimate association of the metal-polysaccharide composite. The nanocomposites exhibited bactericidal effect and electrical conductivity, which was observed to be a function of temperature and metal concentration. The eco-friendly nanocomposites could be of potential biomedical application.

Effect of ethylene carbonate concentration on structural and electrical properties of PEO–PMMA polymer blends

Polyethylene oxide–polymethyl methacrylate (PEO–PMMA) polymer blend electrolyte system complexed with silver salt having different ethylene carbonate (EC) concentrations was prepared using solution cast technique. Complex formation and change in structural and microstructural properties have been studied by X-ray diffraction, Fourier transform infrared, and scanning electron microscopy analysis. The thermal properties of polymer films have been examined by the differential scanning calorimetry technique. Addition of plasticizer is observed to lower melting temperature. Electrical response of polymer films has been measured as a function of EC concentration and temperature using complex impedance spectroscopy. Complex impedance data are used to analyze the conductivity, permittivity, and modulus formalism to understand the conduction mechanism. The temperature dependence of electrical conductivity of polymer electrolytes shows a sudden rise at the melting temperature of PEO.

Conductivity and Dielectric Behavior of AgCF3SO3 Doped PEO Polymer Films

PEO containing AgCF3SO3 polymer films have been prepared by the hot press technique. The effect of salt concentration on the frequency-dependent conductivity properties of PEO: AgCF3SO3 complexes are investigated by impedance spectroscopy in the temperature range from 303 K to 328 K. The ac conductivity and dielectric properties of the prepared samples have been analyzed. The ac conductivity obeyes the universal power law and as the temperature increases, the feature of σ(ω) α ωn is more predominant. The dielectric permittivity is found to increase with temperature of the prepared samples. The imaginary part of electrical modulus, M” shows the formation of dispersion peak. Relaxation times for the ionic charges carriers were extracted from the peak maxima of imaginary part of modulus at various temperatures. The plot of relaxation times as a function of temperature shows Arrhenius type behavior.

Conductivity Studies on Filler Free and Filler Doped PVA-PEO Based Blend Polymer Electrolytes

The present study deals with the investigation of conduction behavior of filler free and filler based blend electrolyte system. The polymer blend films consisting of PVA and PEO doped with silver salt and PEG plasticizer, are prepared using solution cast technique. The filler free system is prepared for varying ratios of host polymers (PVA: PEO); whereas the filler based system is prepared with various Al2O3 concentrations in the blend films. The conductivity studies of prepared samples are carried out using impedance spectroscopic analysis. The conductivity for the filler free blend system is found to increase with increasing amount of PEO in all the blend specimens. On the other hand, the filler based system shows the conductivity enhancement upto 6wt% which mitigates with further addition of filler into the electrolytes. The DSC scans are found to support the conductivity results.

Dielectric properties of Pure and Strontium doped Nano- Hydroxyapatite

Hydroxyapatite (Ca10(PO4)6(OH)2-HAp), is an excellent inorganic biomaterial and finds various applications. As it is similar to inorganic matrix of human bone and dental enamel, pure and doped HAps are widely studied. In the present study, pure nano-HAp and Strontium doped nano-HAp (Sr-HAp) with different concentrations were synthesized by surfactant mediated approach. The doping of strontium was confirmed by EDAX. The powder XRD study was carried out and it suggested nano-crystalline nature of the sample and the extra peaks observed other than HAp were due to the presence of brushite phase for higher concentration of Sr. TEM study revealed the needle type morphology for all the samples with size ranging from 23 nm to 78 nm. The dielectric study was carried out at room temperature within the frequency range from 102 Hz to 107 Hz and the variations of dielectric constant with frequency of applied field as well as with the concentration of strontium were studied. The results are discussed.

Dielectric relaxation, protonic defect, conductivity mechanisms, complex impedance and modulus spectroscopic studies of pure and L-threonine-doped ammonium dihydrogen phosphate

Ammonium dihydrogen phosphate (ADP) has a wide range of applications in integrated and nonlinear optics. The dopant-like L-threonine has hydrogen-bonded side chain that causes defects in ADP. The pure and L-threonine-doped ADP crystals are grown using slow evaporation technique. The powder XRD patterns show the single-phase nature of pure and doped ADP. The dielectric constant and dielectric loss have shown the usual behaviour with respect to frequency and temperature. The protonic conduction is prevailing for electric transport, and from Jonscher’s plot, the correlation barrier hopping (CBH) and non-overlapping small polaron tunnelling (NSPT) conduction mechanism is confirmed. The Nyquist plot and modulus spectra show the presence of grain and grain boundary. The stretch exponent exhibits non-Debye-type relaxation. The activation energy of relaxation time for all samples is calculated. The modulus master curve and variation of Z″ and M″ versus angular frequency confirmed the proposed conduction. The nonlinear optical counterpart is in accordance with dielectric results.

Effect of sintering on electrical properties of yttrium doped Li-based NASICON compounds

Electrical properties of Lithium based Li1.3Al0.3-xYxTi1.7(PO4)3 (LAYTP) system was prepared using solid state reaction route. The samples were subjected to differing duration of sintering. X-ray diffraction was used to investigate the microstructure while density measurement was performed to determine the effect of sintering on the density of the prepared samples. Electrical properties of the material were studied using impedance spectroscopy, in frequency range 20 MHz to 1 Hz and in temperature range 303 K to 423 K. It was found that sample with least amount of yttrium and which was sintered for least duration had superior conductivity over other samples. It was also found that grain boundary conductivity improved marginally for sample with higher proportion of yttrium heat treated for longer duration.

Characterization studies of plasticized PEO-PMMA nano-composite polymer electrolyte system

Present study reports the characterization studies on silver based PEO-PMMA-PEG nano composite polymer electrolyte system, prepared by solution cast technique. The complexation among various constituents of polymer samples was carried by XRD and FTIR analysis. Thermal analysis of the samples was carried out by DSC study.

Dielectric And Conductivity In Silver‐Poly (ethylene oxide) Solid Polymer Electrolytes Dispersed With SiO2 Nanoparticles

Thin solid polymer electrolytes based on poly‐ethylene oxide (PEO) and silver triflate (AgCF3SO3) dispersed with nanoparticles (SiO2) have been prepared by solution casting technique. Electrical properties of PEO—AgCF3SO3‐SiO2 system were investigated by impedance spectroscopy. Further from impedance spectroscopy quantity such as complex dielectric constant and loss tangent were computed. Conductivity was studied for prepared films and the results are discussed.