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This article addresses the synthesis and characterization of polyaniline (PANI) both in pure and doped forms with various levels of CuCl 2 and ZnCl 2 in HCl medium where ammonium persulphate was used as an oxidant. Synthesized polymeric materials were characterized spectroscopically (UV-visible spectroscopy, Fourier transform infrared spectroscopy, and Atomic absorption spectroscopy), thermally (Differential scanning calorimetry), and morphologically (Scanning electron microscopy). Free adsorption energy was calculated via Langmuir adsorption isotherm based on the quantities of Cu 2þ and Zn 2þ cations in both pre-and post-polymerization process where it was found that Cu 2þ and Zn 2þ are adsorbed physically on PANI surface. The dielectric measurements as a function of frequency and temperature showed that conductivity decreased with increasing doping levels of metal cations at high temperatures.

Purpose -The purpose of this paper is to understand corrosion behavior of different Cu-containing Al-Si-x% Cu alloys (x: 1 wt% Cu, 2 wt% Cu, 3 wt% Cu, 4 wt% Cu, and 5 wt% Cu) in 0.1 M HCl and 0.1 M H 2 SO 4 . Design/methodology/approach -Potentiodynamic, chronoamperometric and impedance measurements were applied to specimens to obtain their electrochemical characteristics. For the long-term analyses, hydrogen evolution with immersion time (V-t) was measured. The corroded surfaces of the alloys were investigated using scanning electron microscopy (SEM) to understand the corrosion mechanism. Findings -All experimental investigations showed that the corrosion resistance of alloys increased with increasing Cu content in the alloys. Research limitations/implications -Cu-containing aluminum alloys are age-hardenable alloys. The corrosion behaviour of these alloys can be changed by heat treatment. Corrosion test results for the heat treated and aged alloys will be discussed in another study. Originality/value -Al-Si-Cu alloys are widely used in the automobile industry and the corrosion behaviour of these alloys has a great importance on the service life of these materials. Understanding the effect of copper and the corrosion mechanism of these alloys will be helpful in predicting and prolonging the service life of these materials.

This article reports synthesis of polypyrrole (PPy) and its composites having various amounts of selenium (Se) in the presence of nitric acid in aqueous medium via chemical oxidative polymerization. Samples were spectroscopically characterized using Fourier transform infrared spectroscopy, ultraviolet‐visible spectroscopy, and atomic absorption spectroscopy. Although morphology of the samples was examined by using scanning electron microscopy (SEM), their thermal properties were studied via differential scanning calorimetry (DSC). The alternating current (ac) conductivity and dielectric properties were investigated as a function of temperature. Variation of adsorption free energy obtained from Langmuir adsorption isotherm showed that metal cations were physically adsorbed onto the polymer surface. SEM images showed that filling process significantly changes the morphology of PPy. DSC results indicated that cold crystallization temperature (Tcc) of unfilled PPy decreases with increasing filling level. Dielectric measurements showed that relaxation times for PPy and its composites have decreased linearly with increasing temperature. The conductivity of the PPy, when filled with 1 g of Se, increased ∼ four times at room temperature for 1 kHz. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers

This paper reports structural, thermal, and temperature‐dependent dielectric properties of polyindole–cadmium selenide (PIN–CdSe) nanocomposites. PIN and its nanocomposites were synthesized via in situ chemical oxidative polymerization method. Samples were characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), scanning electron microscopy with energy dispersive X‐ray (SEM/EDX), atomic force microscope, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Dielectric properties were analyzed as a function of temperature. FT‐IR spectroscopy indicated that both NH and aromatic CC bonds were affected more by doping process. Significant structural differences were observed in XRD and SEM analyses of PIN and its nanocomposites. Both XRD and DSC measurements revealed that crystallinity of the PIN increases to a certain degree with increasing doping level. Thermogravimetric analysis showed that addition of CdSe decreased degradation temperature of the PIN. Conductivity measurements investigated by universal power law indicated that the charge transport mechanism of all the samples is consistent with correlated barrier hopping model. POLYM. COMPOS., 37:3057–3065, 2016. © 2015 Society of Plastics Engineers

This study reports structural and thermal properties and temperature-dependent alternating current (AC) conductivity of polyaniline/selenium (PANI/Se) composites in emeraldine salt form prepared by a chemical polymerization method. Fourier transform infrared spectroscopy showed that the doping process significantly affected the N-H bond in PANI chain. The free energy change, which was calculated from the Langmuir adsorption isotherm, showed that Se was electrostatically adsorbed on PANI molecules. From the scanning electron microscopy images it was determined that morphological changes caused by the doping process on PANI surface could affect conductivity. Thermal analysis, which was performed with differential scanning calorimetry, showed that the addition of Se increased the degradation temperature of PANI. Depending on the doping level, significant increase was observed in the AC conductivity of PANI, approximately 11, 13, and 17 times for 300, 350, and 400 K temperatures respectively.

Polyaniline/chloroplatinic acid (PANI/H 2 PtCl 6 .H 2 O) composite is synthesized via in situ oxidative polymerization method. Fourier transform infrared, ultraviolet-visible, energy-dispersive X-ray, and Thermogravimetric techniques are used for the characterization studies. The surface morphology of the samples is investigated by scanning electron microscopy and atomic force microscopy. Dielectric measurements are carried out depending on the temperature. The dispersion process increases the thermal degradation temperature of PANI by about 608C, while reducing the optical energy gap of PANI from 1.99 to 1.76 eV. Chloroplatinic acid significantly increases the agglomeration and grain size (up to 10 lm) on the surface of the PANI. Gas sensor measurements show that Polyaniline/chloroplatinic acid composite can be a candidate for ethanol detection. With the dispersion process, the electrical conductivity of PANI increases almost 2.5 times. The charge transport mechanism of the samples is consistent with electron tunneling model up to 978C and with small polaron tunneling model at higher temperatures. The hopping distance of the charge carriers reduced to 4.82 from 5.30 nm with dispersion process. Experimental results reveal that PANI/chloroplatinic acid composite can be a rather suitable multifunctional material for various applications such as gas sensors, optoelectronic and semiconductor devices. POLYM. ENG. SCI., 00:000-000, 2018.

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