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Polyaniline nanostructures have been synthesized by self‐assembly method by varying the dopant to monomer molar ratio. High resolution transmission electron micrographs show how the dopant to monomer molar ratio influences on the morphology and structure. The temperature dependence of dc conductivity study shows semiconducting behavior. From dc conductivity study it has been observed that conductivity increases with increasing dopant concentration and maximum conductivity is attained at dopant to monomer molar ratio of 3:4. From the slope of the reduced activation energy versus temperature plot it is confirmed that the charge transport in polyaniline nanostructures is in insulating regime and dominated by variable range hopping mechanism. In particular, a crossover from 1D to 3D variable range hopping conduction is observed by changing the dopant to monomer molar ratio. With increasing the dopant concentration the 680 nm absorption peak shifted towards higher wavelength range. The red shifting of this peak indicates the increased extent of π‐conjugation length. The enhancement of characteristic band intensity at 1336 cm−1 in Micro‐Raman spectra indicates the increase of delocalization degree. Temperature profiles of the degradation processes have been mapped using thermogravimetry analyzer and it is observed three‐step weight losses for all the samples. POLYM. ENG. SCI., 55:995–1002, 2015. © 2014 Society of Plastics Engineers

The charge carriers relaxation dynamics in synthesized poly(3,4‐ethylenedioxythiophene) nanotubes has been investigated as a function of frequency and temperature through the framework of dielectric permittivity, modulus formalism and impedance formalism. The fitting of experimental data of real part of dielectric permittivity and imaginary part of modulus with Havriliak‐Negami equation and Bergman modified Kohlrausch‐Williams‐Watts function indicates the presence of non‐Debye type relaxation process in the synthesized poly(3,4‐ethylenedioxythiophene) nanotubes. The scaling of imaginary part of modulus and impedance formalisms have been performed to understand the charge carrier relaxation dynamics in the synthesized samples, which suggests the presence of time temperature superposition principle in the nanotubes. The red shifting of the band from 1440 cm−1 to 1430 cm−1 in micro‐Raman spectra indicates the conformational transition from benzenoid to quinoid structure with increasing dopant concentration. The linear increase of imaginary part of dielectric permittivity with decreasing frequency is ascribed to the higher contribution from dc conductivity as compared to that from the electrode polarization effects. POLYM. ENG. SCI., 56:448–457, 2016. © 2016 Society of Plastics Engineers

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The electrical conductivity and carrier relaxation in poly (3, 4-ethylenedioxythiophene) (PEDOT) nanofibers have been studied over a wide range of frequency and temperature by means of impedance spectroscopy. High resolution transmission electron micrographs confirm the formation of nanofibers with average diameter of 14 nm. The linear increase of imaginary permittivity with decreasing frequency in the loglog plot of ε″ versus ω is attributed to the higher contribution of dc conductivity than that of the electrode polarization. The presence of single semicircle in the complex impedance ColeCole plot indicates the presence of single charge carrier relaxation mechanism. The perfect matching of the relaxation peak in Z″ and M″ vs. frequency at different temperature confirms the presence of Debye type relaxation. From the temperature dependent behavior of frequency exponent study it is confirmed that the charge transport takes place through correlated barrier hopping mechanism. Decrease of barrier height and increase of density of states with increasing dopant concentration can be corroborated with the conductivity enhancement.