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Polyaniline-Nd2O3:Al2O3 nanocomposites were prepared by in situ oxidative polymerization method using different weight percentages of oxide powders. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy and X-ray diffraction for molecular and crystal structures. Scanning electron microscopy and transmission electron microscopy images show the tubular structure of polyaniline nanocomposite with embedded metal oxides. The electrical conductivity of the nanocomposites increases with increase in temperature as well as with concentration of Nd2O3:Al2O3 particles in polyaniline. This is because of the hopping of charge polarons and extended chain length of the nanocomposites as evidenced by the negative thermal coefficient (NTC) characteristic. A high NTC value of 2.67 was found in nanocomposites with 15 wt% of oxide particles. These nanocomposites show low dielectric constant and dielectric loss; the electrical conductivity is higher than 0.3 S/cm as confirmed by Cole-Cole plot that indicates a decrease in both grain resistance and bulk resistance of the nanocomposites. The current-voltage and capacitance-voltage measurements were also carried out. The carrier mobility μ values of pure polyaniline and nanocomposites were found to be 4.27 × 10−3 and 1.45 × 10-2 H.M−1, respectively. A significant enhancement in carrier mobility was observed in comparison with the literature. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A facile synthesis method was adapted to prepare Ortho-chloropolyaniline/graphite oxide (OPANI/GO) composites. The properties of these composites have been discussed based on different characterizations such as scanning electron microscopy, FTIR, and dielectric studies. The important peaks of benzenoid and quinoid rings in the spectrum confirm the formation of composites. Scanning electron microscopic studies indicate that the morphology of the prepared composites was influenced by different weight ratios of GO in OPANI and the resulting micrographs of these composites exhibited flaky and folded structures. The electrical conductivity study was carried out and found that 6 wt% of GO in PANI shows high conductivity value of 20 × 10−2 S/cm. The obtained results suggest an easy approach to prepare such novel nanocomposites with excellent dielectric properties which can be used in many technological applications. [ABSTRACT FROM AUTHOR]

This article highlights the microwave absorption and dielectric attributes of synthesized polyaniline (PAni)-yttrium trioxide (Y2O3) composites. Temperature-dependent conductivity measurements were carried out in the temperature range of 300-473 K, which indicates the presence of hopping conduction. The PAni-Y2O3 composites showed semiconductor behavior with the exponential variation of inverse temperature dependence of electrical conductivity. Microwave measurements were carried out in the X-band (8-12 GHz) frequency; the composites exhibit absorption-dominated shielding effectiveness (SEA) in the range -33 to -35 dB (>99% microwave attenuation) and minimum electromagnetic reflection. The ε′ and ε″ values of the composites are in the range of 81.5-97.5 and 80-118.5, respectively. The PAni-Y2O3 composites showed significant improvement in microwave SE and complex permittivity of the composites, indicating the influence of Y2O3 in PAni. [ABSTRACT FROM AUTHOR]

Conducting polyaniline/ γ-FeO (PANI/FE) composites have been synthesized using an in situ deposition technique by placing fine-graded γ-FeO in a polymerization mixture of aniline. The composites are characterized by using scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared (IR) spectroscopy. The electrical properties such as d.c. and a.c. conductivities are studied by sandwitching the pellets of these composites between the silver electrodes. It is observed that the conductivity increases up to a composition of 20 wt.% of γ-FeO in polyaniline and decreases thereafter. The initial increase in conductivity is attributed to the extended chain length of polyaniline, where polarons possess sufficient energy to hop between favourable sites. Beyond 20 wt.% of γ-FeO in polyaniline, the blocking of charge carrier hop occurs, reducing conductivity values. The magnetic properties such as hysteresis characteristics and normalized a.c. susceptibility are also measured, which show a strong dependence on content of γ-FeO in polyaniline. Because of superparamagnetic behaviour of these composites, they may find extensive technological applications, especially for absorbing and shielding applications in microwave frequencies. [ABSTRACT FROM AUTHOR]

Organic electronic devices with low cost, wearable and flexible electrodes have become forefront of scientific and technological development of optoelectronic research. Electrode fabrication techniques with superior multi-functionalities such as conductivity, optical transparency, and mechanical flexibility remains a biggest challenge for research community. Herein, we present a strategy to develop highly conductive, transparent and flexible electrodes based on post-treated Poly (3,4-ethylenedioxythiophene): Poly (styrene sulfonate) (PEDOT: PSS) films on a Polyethylene terephthalate (PET) substrate for possible optoelectronic and energy storage applications. Commercially available PEDOT-PSS doped with secondary solvent such as N,N- Dimethylformamide (DMF) was spin coated onto PET substrate followed by camphor sulphonic acid (CSA) post-treatment. Doping of DMF followed by CSA post-treatment significantly enhances the conductivity of PEDOT-PSS films from 1.5 S cm−1 to 1826 S cm−1. Optical transmittance of 87% was achieved in the post-treated PEDOT-PSS films in comparison to 92% for PET substrate. The influence of rotation speed, rotation time of coating unit, and number of fabricated layers on opto-electronic properties of post-treated PEDOT-PSS films were investigated in detail. Improved electrical conductivity, optical conductivity, dielectric constant, and refractive index associated with photon energies suggests significant removal of insulating PSS segments and formation of localized energy states within energy band gap of post-treated films. The post-treated flexible PEDOT-PSS films exhibit excellent stability interms of conductivity and optical transmittance for a period of 30 days under ambient conditions. Furthermore, the post-treated PEDOT-PSS films show improved electrochemical performance to be used as flexible electrode in supercapacitors. This study demonstrates an efficient strategy to fabricate highly conductive, flexible electrodes based on PEDOT-PSS films with superior optical and electrochemical properties for a possible optoelectronic and energy storage applications. • Highly conductive, transparent and flexible electrodes based on post-treated (PEDOT: PSS films on (PET) substrate for possible optoelectronic and energy storage applications. • Doping of DMF followed by CSA post-treatment significantly enhances the conductivity of PEDOT-PSS films from 1.5 S cm−1 to 1826 S cm−1. • Optical transmittance of 87% was achieved in the post-treated PEDOT-PSS films in comparison to 92% of PET substrate. • The post-treated flexible PEDOT-PSS films exhibit excellent stability interms of conductivity and optical transmittance for a period of 30 days under ambient conditions. • Furthermore, the post-treated PEDOT-PSS films shows improved electrochemical performance to be used as flexible electrode in supercapacitors. [ABSTRACT FROM AUTHOR]

Conducting polyaniline/BaTiO 3 (PANI/BT) composites have been synthesized by ‘in situ’ deposition technique by placing fine graded BaTiO 3 in polymerization mixture of aniline. The composites are characterized using various techniques such as SEM, XRD and IR spectroscopy. The electrical properties such dc conductivity and ac conductivity are studied by sandwitching the pellets of these composites between the silver electrodes. It is observed that in both the cases the values of conductivities increases up to 30 weight % of BaTiO 3 in polyaniline and decreases thereafter. Initial increment in conductivity is due to extended chain length of polyaniline where polarons possess sufficient energy to hop between favorable sites. Beyond 30 weight % of BaTiO 3 in polyaniline, the blocking of charge carriers takes place reducing the conductivity values. The polyaniline/ BaTiO 3 composites are poled by applying constant voltage for a fixed time to study their electrical hysteresis characteristics. It is observed that the area under the curve depends on the content of BaTiO 3 in polyaniline. [ABSTRACT FROM AUTHOR]