Progress in preparation, processing and applications of polyaniline

A unique nanostructured polyaniline (PANI)/mesoporous TiO(2) composite was synthesized and explored as an anode in Escherichia coli microbial fuel cells (MFCs). The results of X-ray diffraction, morphology, and nitrogen adsorption-desorption studies demonstrate a networked nanostructure with uniform nanopore distribution and high specific surface area of the composite. The composite MFC anode was fabricated and its catalytic behavior investigated. Optimization of the anode shows that the composite with 30 wt % PANI gives the best bio- and electrocatalytic performance. A possible mechanism to explain the excellent performance is proposed. In comparison to previously reported work with E. coli MFCs, the composite anode delivers 2-fold higher power density (1495 mW/m(2)). Thus, it has great potential to be used as the anode for a high-power MFC and may also provide a new universal approach for improving different types of MFCs.

Nanostructured polyaniline/titanium dioxide composite anode for microbial fuel cells

The comparative study on the effect of different type of dopants on the properties of polyaniline (PANI) is relative less although dopant has profound effect of the properties of PANI. So, the aim of the present work is to study the effect of different type of dopant, namely strong inorganic hydrochloric acid (HCl), organic and aromatic acids containing different aromatic substitution, namely p-toluene sulfonic acid (PTSA), dodecylbenzenesulfonic acid (DBSA), organic and aliphatic acids having long hydrocarbon chain, namely lauric acid (LA), on the properties of PANI. The PANI was prepared through oxidative polymerization methods and doped with HCl, PTSA, DBSA, and LA and then characterized through different methods like conductivity measurement, UV, X-ray, DSC, TGA, and SEM. It was found that the properties of doped PANI depend on the type and molecular size of the dopant. With the increase in dopant chain length, the crystallinity is decreased, whereas the d-spacing, interchain separation, and solubility are increased. The bond formation of water molecules with the backbone nitrogen of the polymers is much less in presence of aromatic dopants when compared with those of inorganic or aliphatic dopants. All the doped polyanilines under investigation do not decompose up to 500°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Effect of Dopant Type on the Properties of Polyaniline

The conductive polypyrrole (PPy) polymer nanocomposites (PNCs) reinforced with different magnetite (Fe3O4) nanoparticle loadings have been successfully synthesized by using a facile surface initiated polymerization (SIP) method. The scanning electron microscope (SEM) is used to characterize the surface morphology of the as-received Fe3O4 nanoparticles (NPs), pure PPy and Fe3O4/PPy PNCs. The high-resolution transmission electron microscope (HRTEM) is used to observe the nanoparticle dispersion within the polymer matrix. The chemical structure of the PNCs is characterized by Fourier transform infrared (FT-IR) spectroscopy. The thermal stability of the Fe3O4/PPy PNCs is assessed by thermogravimetric analysis (TGA). X-ray diffraction (XRD) results reveal that the addition of NPs has a significant effect on the crystallization of PPy. The switching frequency, at which the permittivity switches from negative to positive, is observed in the synthesized pure PPy and Fe3O4/PPy PNCs. The optical band gap of Fe3O4/P...

Magnetite−Polypyrrole Metacomposites: Dielectric Properties and Magnetoresistance Behavior

The electrical and magnetic properties PVA/PEO films incorporated with different weight percentage of MnCl 2 prepared by casting technique were studied. The Magnetic properties were investigated by electron spin resonance (ESR) and vibrating sample magnetometer (VSM). The electrical conductivity was enhanced depends on both frequencies and temperatures indicate the existence of charge carriers transported by hopping through defect sites attributed to increase in the number of mobile charge carriers of Mn +2 . The AC conduction mechanism and conduction parameters have been calculated according to the Correlated barrier hopping (CBH) model. ESR spectra reveals aggregated forms of Mn 2+ ions are formed at higher concentration and isolated forms at lower concentration. VSM shows paramagnetic nature for pure MnCl 2 and anti-ferromagnetic nature for doped samples due to overlapping of Mn d-states with valence band.

Modification and development of electrical and magnetic properties of PVA/PEO incorporated with MnCl2

Electrical transport properties of cobalt doped polyaniline in an aqueous ethanol medium were investigated in the temperature range 77 ≤ T ≤ 300 K, applying magnetic fields up to 1 T in the frequency range 20 Hz–1 MHz. The room temperature dc resistivity increases with increase in Co content. The dc resistivity and magnetoresistivity of these samples have been interpreted in terms of the variable range hopping theory. The frequency dependence of conductivity has been described by a power law σ(ω) ∝ ωS. The value of s is found to be temperature dependent, which shows a decreasing trend with temperature. The correlated barrier hopping model is the most likely mechanism for the electron transport. The different physical parameters were calculated from the experimental data.

Electron transport properties of cobalt doped polyaniline

We investigated the electrical-transport properties of hydroiodic acid doped polyaniline in the temperature range 77–300 K, applying magnetic field strength to a maximum of 1 T in the frequency range 20 Hz–1 MHz. The direct-current conductivity was explained by variable range hopping theory, and the direct-current magnetoconductivity, which was positive, was interpreted by orbital magnetoconductivity theory. The alternating-current (ac) conductivity was found to follow the universal dielectric response σ′(f) ∝ fs, where σ′(f) is the frequency-dependent real part of the complex ac conductivity, f is the frequency, and s is the frequency exponent. The trend in the variation of s, the temperature dependence of the frequency exponent, corroborated the fact that the correlated barrier hopping was the dominating charge-transport mechanism. The ac conductivity also showed a positive variation with magnetic field, which could be interpreted by this theory. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Electrical-transport properties of iodine-doped conducting polyaniline

Direct and alternate current conductivity and magnetoconductivity of oxalic acid doped polyaniline

A low temperature study of electron transport properties of tantalum nitride thin films prepared by ion beam assisted deposition

The electrical transport properties of hydroiodic acid doped polyaniline in the temperature range 77 ≤ T < 300 K were studied. The magnetic field strength was varied to a maximum of 1T in the frequency range of 20 Hz-1 MHz. The ac conductivity followed the universal dielectric response σ'(f) ∝ f s . The trend in the variation of 's', the temperature dependence of the frequency exponent, indicated that correlated barrier hopping is the dominating charge transport mechanism. The ac conductivity also shows a positive variation with magnetic field, which can be interpreted by Maxwell-Wagner capacitor model.

P. Ghosh

Papers

Electron transport properties of cobalt doped polyaniline

Electrical-transport properties of iodine-doped conducting polyaniline

Direct and alternate current conductivity and magnetoconductivity of oxalic acid doped polyaniline

A low temperature study of electron transport properties of tantalum nitride thin films prepared by ion beam assisted deposition

Frequency‐dependent resistivity and magnetoresistivity of iodine doped conducting polyaniline