Amorphous Polyaniline Research Articles

Development of ternary PANI/GO-Fe3O4@AgNps nanocomposites for photocatalytic remediation of toxic dye effluent under energy-efficient system

The environmental toxicity of effluents contaminated with synthetic industrial dyes and their resistance to conventional treatments drive the need for developing innovative treatment technologies such as visible photoactive catalysts in a photocatalytic system. In this study, novel nanocomposite photocatalysts were synthesized for photocatalytic remediation of toxic dye effluent under energy-efficient Light Emitting Diode (LED) irradiation. Concise instrumental analysis was used to investigate the morphological, functional, particle size, thermal and optoelectronic features of the developed photocatalytic nanocomposites. Their performance was tested with cationic (methylene blue) and anionic (methyl orange) model dyes. The instrumental elucidation reveals the coating of amorphous polyaniline with other composites, giving the blend rapid reactivity, which promotes photocatalyst-dye interaction. The composites exhibit lowered bandgap (2.66 eV, 2.85 eV and 2.27 eV) when compared to polyaniline (3.34 eV) used as macromolecular support via in situ coupling. This accounts for the efficiency of 95 % and 98 % reported for methylene blue and methylene orange, respectively, at optimal experimental conditions of 90 min irradiation time, pH of 5 and dosage of 20 mg/100 mL dye effluent. The study also proposed a Z-scheme mechanism with the vital role of •O2 –, •OH and h+ reactive species in the photodegradation of the dye molecules.

Sensitive Electrochemical Sensing Properties for Cyanide Detection Using Polyaniline/Cu-Vanadate Nanobelt-modified Electrode

Background: Cyanide is a toxic anion and may be discarded into the water environment, which is a serious threat to human beings and the environment. Hence, it is essential to explore a facile, sensitive method for cyanide detection. Polyaniline/Cu vanadate nanobelts serve as electrode materials for sensitive cyanide determination. Methods: Polyaniline/Cu vanadate nanobelts were obtained by a simple route using polyaniline, Cu vanadate nanobelts. The polyaniline/Cu vanadate nanobelts were measured via electron microscopy, diffraction, infrared spectrum, and electrochemical methods. Results: Amorphous polyaniline nanoparticles with a particle size of about 100 nm were attached firmly to the surface of Cu vanadate nanobelts. Electrochemical sensing properties for cyanide detection were analyzed using a cyclic voltammetry technique using the nanobelts-modified electrode. The cyclic voltammograms (CV) peaks centered at +0.64 V and +0.54 V were observed using the polyaniline/Cu vanadate nanobelts in 0.1 M KCl solution with 2 mM cyanide. The proposed composite nanobelt-modified electrode possessed the detection range and detection limit of 0.001-2 mM and 0.22 μM, respectively. Conclusion: Polyaniline greatly enhances the electro-catalytic performance of the Cu vanadate nanobelt-modified electrode for cyanide detection.

Fabrication of Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell and improvement of its photocatalyst properties

Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell structures were made by a two-step method, first, bismuth ferrite nanoparticles by hydrothermal method and then, aniline core-shell by co-precipitation method. The bismuth ferrite (BFO) XRD pattern showed no impurities of Sm, Cr, or their compounds in the samples, indicating that Sm+3 and Cr+3 had been replaced in the BFO structure. The XRD pattern of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell shows all peaks of Bi0.90Sm0.1Fe0.97Cr0.03O3 composition with lower intensity, as a result, the Bi0.90Sm0.1Fe0.97Cr0.03O3 composition is phase single. This lower intensity is attributed to the presence of amorphous polyaniline in the core-shell structure. Since there is in the FT-IR spectrum of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell, characteristic peaks of both polyaniline and bismuth ferrite simultaneously so, the FT-IR spectrum of the Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell is a perovskite structure. The synthesized samples exhibit weak magnetic properties and behave as a paramagnetic material. The absorption capability of core-shell compared to core nanoparticles has increased in the visible region, and this enhancement is attributed to the influence of the presence of polyaniline. All the peaks in the UV–visible absorption spectrum characterize the nano-sized bismuth ferrite and polyaniline in the UV–visible spectrum of the core-shell. The intensity of the photoluminescence spectrum in the doped sample is significantly higher compared to the core-shell sample. This indicates a much faster recombination rate in the doped nanoparticles compared to the core-shell nanocomposite. The doping of the core with Cr and Sm elements, as well as the coating of the core with a polymeric shell, has led to an increase in the degradation rate of the red dye. We also found that shell thickness plays a vital role in dye degradation efficiency and photocatalytic performance. The Bi0.90Sm0.1Fe0.97Cr0.03O3@PANI core-shell exhibits significant photocatalytic activity under visible light. The photocatalytic studies show that the best sample is Bi0.9Sm0.1Fe0.97Cr0.03O3@PANI core-shell with aniline concentration of 0.2 mL and a pH = 2 which was able to destroy 100 % of Congo red dye molecules.

A New Method to Prepare Stable Polyaniline Dispersions for Highly Loaded Cathodes of All-Polymer Li-Ion Batteries.

A new method for the preparation of polyaniline (PANI) films that have a 2D structure and can record high active mass loading (up to 30 mg cm-2) via acid-assisted polymerization in the presence of concentrated formic acid was developed. This new approach represents a simple reaction pathway that proceeds quickly at room temperature in quantitative isolated yield with the absence of any byproducts and leads to the formation of a stable suspension that can be stored for a prolonged time without sedimentation. The observed stability was explained by two factors: (a) the small size of the obtained rod-like particles (50 nm) and (b) the change of the surface of colloidal PANI particles to a positively charged form by protonation with concentrated formic acid. The films cast from the concentrated suspension were composed of amorphous PANI chains assembled into 2D structures with nanofibrillar morphology. Such PANI films demonstrated fast and efficient diffusion of the ions in liquid electrolyte and showed a pair of revisable oxidation and reduction peaks in cyclic voltammetry. Furthermore, owing to the high mass loading, specific morphology, and porosity, the synthesized polyaniline film was impregnated by a single-ion conducting polyelectrolyte-poly(LiMn-r-PEGMm) and characterized as a novel lightweight all-polymeric cathode material for solid-state Li batteries by cyclic voltammetry and electrochemical impedance spectroscopy techniques.

Effect of graphite on the power density of selenium doped polyaniline ink based hybrid screen-printed flexible thermoelectric generator

Enhancement in the thermoelectric performance of inorganic/organic hybrid composites and the need for low-cost, flexible thermoelectric generators have motivated this work. The thermoelectric effect on the addition of amorphous polyaniline, crystalline selenium, and layer-structured graphite, with different concentrations on the thermoelectric properties of selenium-doped polyaniline, is reported. Tuning of microstrain, dislocation density, and carrier concentration has improved the Seebeck coefficient by 39.10% and electrical conductivity by 60.22%. The maximum power output and power factor exhibited by the hybrid device are 1.89 nW and 0.42 nW/m2K2 at a temperature difference of 100 °C. Replacing 90 wt% of Selenium-doped polyaniline with graphite resulted in a power density of 0.65 mW/m2 under external load conditions.

Enhancing the Cyanide Sensing Performance of the CuBi2O4 Nanoflakes by Polyaniline

Background: Cyanide (CN-) belongs to dangerous anion pollutants owing to its toxicity at low level. The development of an efficient method for the cyanide detection in aqueous solution is of tremendous importance for protecting the environment and human health. Polyaniline/CuBi2O4 composite modified electrode possesses good electro-catalytic activity towards cyanide. Objective: The aim is to synthesize polyaniline/CuBi2O4 nanoflakes by a facile hydrothermal route using the CuBi2O4 nanoflakes and polyaniline as the raw materials, and research the electro-catalytic activity towards cyanide of the composite nanoflakes. Methods: Polyaniline/CuBi2O4 nanoflakes were synthesized by a facile hydrothermal route using the CuBi2O4 nanoflakes and polyaniline as the raw materials. The structure, morphology, chemical bonding and electro-catalytic activity towards cyanide of the composite nanoflakes were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and electrochemical measurements. Results: The obtained composite nanoflakes are composed of tetragonal CuBi2O4 phase. Amorphous polyaniline nanoscale particles with the size of about 50 nm attach to the surface of the CuBi2O4 nanoflakes. The nanoflakes modified glassy carbon electrodes (GCEs) were used for the determination of cyanide. A pair of quasi-reversible cyclic voltammetry (CV) peaks are located at +0.25 V and +0.33 V, respectively at the polyaniline/CuBi2O4 nanoflakes modified GCE. The linear range and detection limit are 0.01-2 mM, 3.1 μM and 0.001-2 mM, 0.39 μM for CuBi2O4 nanoflakes modified GCE, and polyaniline/CuBi2O4 nanoflakes modified GCE, respectively. Conclusion: Polyaniline/CuBi2O4 nanoflakes modified GCE shows good reproducibility and stability for cyanide detection. The electro-catalytic activity towards cyanide of the CuBi2O4 nanoflakes modified GCE can be greatly enhanced by the polyaniline.

Rational design of double perovskite La2Ni0.5Co0.5MnO6 decorated polyaniline array on MoO3 nanobelts with strong heterointerface boosting oxygen evolution reaction and urea oxidation

The design and implementation of affordable high-performance electrocatalysts for the oxygen evolution reaction (OER) and urea electrooxidation reaction (UOR) are critical for clean and environmentally friendly energy conversion. Herein, we constructed a novel heterostructure interface engineering of double perovskite La2Ni0.5Co0.5MnO6 (LNCM) nanoparticles and MoO3 nanobelt array-supported amorphous polyaniline (PANI; MoO3/P) for high-performance OER and UOR. Structural and morphological analyses confirmed the formation of a heterostructure interface. The optimized La2Ni0.5Co0.5MnO6@MoO3/P (LMP-30) demonstrated electrocatalytic performance with low overpotentials of 300 mV at 10 mA cm−2 (vs RHE) for OER and 0.48 V at 50 mA cm−2 (vs Hg/HgO) for UOR, as well as better stability after testing for 12 h. The improved electrocatalytic performance was attributed to its distinctive hierarchical nanostructure, which had a synergistic effect on modulating the electrical characteristics and an electrochemically active surface area. More importantly, the LNCM nanoparticles on the surface of MoO3/P nanobelts can potentially provide more electrocatalytic active sites, excellent charge transport capacity, enhanced electrical properties, and strong electronic contacts between MoO3/P and LNCM.

NIR Photothermal-Enhanced Electrocatalytic and Photoelectrocatalytic Hydrogen Evolution by Polyaniline/SnS2 Nanocomposites

A series of polyaniline (PANI)-decorated SnS2 nanoplates (PANI/SnS2) were produced via a hydrothermal method followed by a liquid–solid mixing. The PANI/SnS2 nanocomposites were composed of amorphous PANI and hexagonal-phase SnS2 nanoplates. Infrared thermal images revealed that PANI had an excellent near-infrared (NIR)-induced photothermal effect. Overall, the PANI/SnS2 nanocomposites showed better NIR-enhanced electrocatalytic and photoelectrocatalytic hydrogen evolution activity than bare SnS2 nanoplates. The optimized 4% PANI/SnS2 (which contained 4 wt % PANI) displayed the largest electrochemical double-layer capacitance (Cdl) value (0.85 mF cm–2) and the lowest Tafel slope of 66 mV dec–1 in 0.5 M H2SO4 under NIR irradiation. It was investigated and confirmed that the photothermal effect and the synergistic effects between SnS2 and PANI heterostructure played important roles in promoting electrocatalytic and photoelectrocatalytic hydrogen evolution processes.

Synthesis and characterization of crystalline polyaniline

The present paper deals with the synthesis and characterization of crystalline polyaniline (PANI). In the present work the crystalline PANI was synthesized in two steps. Firstly, the amorphous polyaniline was prepared by co-precipitation method using aniline as precursor and ammonium peroxodisulfate as reagent. In second stage the crystalline PANI was prepared by the melting and slow cooling. Pellets of PANI were prepared at pressure of 3000-4000 kg/cm 2 . The resulting crystalline PANI was characterized by powder X-ray diffraction (PXRD), atomic force microscopy (AFM) and transmission electron microscopy (TEM). The PXRD pattern confirms the crystalline behaviour of PANI. The AFM results also support PXRD result due to presence of tiny crystals on the surface of PANI. TEM analysis reveals various nanorings connecting the characteristics diffraction spots of PANI nanoparticles.

Synthesis of Polyaniline/Co(OH)2/Ni(OH)2 Nanocomposite Electrode Material for Supercapacitor Applications

We attempt to demonstrate the experimentally supercapacitive performance of polyaniline (PANI) - cobalt hydroxide (Co(OH)2)-nickel hydroxide (Ni(OH)2) nanocomposites (NCs), prepared potentiostically via electrochemical deposition, compared to phase pure individual nanostructures. Amorphous PANI, Co(OH)2 – Ni(OH)2 and NCs are entirely different from one another from the surface appearance point of view, PANI exhibits nanofiber morphology, NCs exhibits nanofiber partially covered with Co(OH)2 - Ni(OH)2 materials and Co(OH)2 - Ni(OH)2 shows platelet morphology. The electrochemical properties of the PANI, Co(OH)2 - Ni(OH)2 and HNs electrodes have been investigated by cyclic voltammograms and galvanostatic charge-discharge. The specific capacitances of PANI, NCs and Co(OH)2 – Ni(OH)2 are found to be 0.59, 50, 46.4, 85.7, 74.1 and 312.5 F/g, respectively, at a sweep rate of 10 mV/s in 1.0 M NaOH electrolyte. The same nature of retention values in area of CV curves and power densities of PANI, NCs and Co(OH)2 – Ni(OH)2 with increased in scan rates are 25.8, 70.5, 75.5, 76.6, 57 and 42.4%, respectively and the same nature of retention in charge density, specific capacitance, and energy density values are 38.7, 33.8, 40.7, 42.6, 23.1 and 17.3% respectively for PANI, NCs and Co(OH)2 - Ni(OH)2 electrodes with increase in scan rate.

Synthesis and electrochemical properties of polyaniline/Co(OH)2–Ni(OH)2 nanocomposite electrode materials

Electrochemical supercapacitive properties of polyaniline (PANI)/cobalt hydroxide (Co(OH)2)–nickel hydroxide (Ni(OH)2) nanocomposite (NC) electrode materials, synthesized potentiostatically via a electrochemical deposition method, are explored and compared with PANI and Co(OH)2–Ni(OH)2 electrode materials. From the surface analysis, an amorphous PANI, NCs and Co(OH)2–Ni(OH)2 are entirely different from one another. The PANI surface demonstrates nanofibrous morphology, NCs exhibits nanofiber-platelet morphology and Co(OH)2–Ni(OH)2 endows platelet-type surface morphology. The electrochemical properties of the PANI, NCs and Co(OH)2–Ni(OH)2 electrode materials are obtained from the cyclic-voltammetry and galvanostatic charge-discharge measurements. The specific capacitances of PANI, NCs and Co(OH)2–Ni(OH)2 measured at a sweep rate of 10 mV/s in a 1.0 M NaOH electrolyte are found to be 0.59, 50.0–74.1 and 312.5 F/g, respectively. The retention values of PANI, NCs and Co(OH)2–Ni(OH)2 obtained at the same scan rate for 1000 cycles are 25.8, 70.5–57 and 42.4%, respectively. This work clearly illustrates the reasons for a weak electrochemical performance of PANI and its composites with Co(OH)2–Ni(OH)2 in alkaline electrolyte over Co(OH)2–Ni(OH)2 electrode material.

Room-temperature multiferroicity in magnetic field-poled polyaniline and its enhancement via Cu2+-complexation

We report on the discovery of room-temperature multiferroicity in camphorsulfonic acid-doped polyaniline synthesized under an applied magnetic field of 0.5 T, increasingly enhanced via Cu2+-doping up to 8 wt%, probably as a nitrogen-coordinated square planar-like complex revealed by electron paramagnetic resonance spectra. Room-temperature switchable magnetization and polarization hysteresis cycles are presented, reaching saturated magnetization (polarization) of 0.019 emu/g (4.369 μC/cm2) and coercivity (remanence) of 0.051 kOe (2.089 μC/cm2) and revealing strong electric exchange bias. Both real and imaginary parts of permeability and permittivity exhibit resonance feature enhanced by Cu2+-doping, peaking at about the same position in the microwave range of 2–18 GHz and strongly suggesting magnetoelectricity. The proposed model picture, which accounts for both ferroelectricity and exchange bias, assumes ferromagnetic and ferroelectric orders within the same domain represented by crystalline polyaniline islands immersed within the amorphous polyaniline template. Modified Landau-Lifshitz-Gilbert equations account for the matching of permeability and permittivity resonance features.

Hybrid composite polyaniline-nickel hydroxide electrode materials for supercapacitor applications

Pristine and nanocomposite (NC) hybrid electrodes of polyaniline (PANI)-nickel hydroxide [Ni(OH)2] have been prepared by single and two-step electrodeposition processes, respectively, onto stainless-steel (SS) substrates. Enhanced reversibility and stability of amorphous PANI- Ni(OH)2 NC electrodes compared to single electrode materials have been explored. PANI has a nanofibrous morphology, Ni(OH)2 has nanoplatelet-type morphology, and the NC electrodes retain an overall nanofibrous morphology. The maximum specific capacitance (SC), obtained from integrated charge under voltammetric conditions, for PANI (electro-deposited for 5 min), NC (electrodeposition of Ni(OH)2 for 10 min and 20 min onto PANI electrode surface) and Ni(OH)2 (electrodeposited for 10 min) electrodes, are 0.59, 39.06, 32.36, and 113.8 F/g, respectively, suggesting higher electrochemical performance of Ni(OH)2 electrode compared to PANI and NC electrodes. The retention in SC values with faster scan rates from 10 to 100 mV/s for PANI, NC (10 min), NC (20 min) and Ni(OH)2 are 38.7, 61.1, 52.4, and 29.0 %, respectively, explicitly confirming a higher reversibility in NC electrodes. The retention in SC values with increase of cycle number up to 1000 for PANI, NC (10 min), NC (20 min) and Ni(OH)2 electrodes are 34.9, 61.5, 67.5, and 40.7 % respectively, demonstrating higher electrochemical stability of NC electrodes over pure-phase electrodes. Nearly 2.15, 79.36, 66.66 and 406.83 mC/cm2 charges on PANI, NC (10 min), NC (20 min) and Ni(OH)2 electrodes, respectively, are obtained. Inner to total charge and outer to total charge ratios have been used to explain contributing sites to total charge in pristine and NC electrodes.

Polyaniline/zinc bismuthate nanocomposites for the enhanced electrochemical performance of the determination of L-Cysteine

A simple in-situ aniline monomer polymerizing process in aqueous solution has been used for the synthesis of the polyaniline/zinc bismuthate nanocomposites. X-ray diffraction (XRD) pattern shows that the nanocomposites have cubic ZnBi38O58 structure. Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) techniques show that the amorphous polyaniline attaches firmly to the surface of the zinc bismuthate nanorods. The polyaniline/zinc bismuthate nanocomposites modified glassy carbon electrode (GCE) exhibits good electrocatalytic activity toward L-Cysteine. The electrochemical performance for the determination of L-Cysteine is greatly enhanced which may be contributed to the polyaniline and synergistic role between polyaniline and zinc bismuthate nanorods. The influences of scan rate, L-Cysteine concentration and polyaniline content are investigated. The peak current is linearly dependent on the scan rate and L-Cysteine concentration. The limit of detection (LOD) decreases obviously from 0.032 μM to 0.012 μM with increasing the polyaniline content from 10 wt% to 40 wt%. The polyaniline/zinc bismuthate nanocomposites modified GCE shows good reproducibility and stability.

Functionalization-induced changes in the structural and physical properties of amorphous polyaniline: a first-principles and molecular dynamics study.

In this paper, we present a first-principles and molecular dynamics study to delineate the functionalization-induced changes in the local structure and the physical properties of amorphous polyaniline. The results of radial distribution function (RDF) demonstrate that introducing -SO3−Na+ groups at phenyl rings leads to the structural changes in both the intrachain and interchain ordering of polyaniline at shorter distances (≤5 Å). An unique RDF feature in 1.8–2.1 Å regions is usually observed in both the interchain and intrachain RDF profiles of the -SO3−Na+ substituted polymer (i.e. Na-SPANI). Comparative studies of the atom-atom pairs, bond structures, torsion angles and three-dimensional structures show that EB-PANI has much better intrachain ordering than that of Na-SPANI. In addition, investigation of the band gap, density of states (DOS), and absorption spectra indicates that the derivatization at ring do not substantially alter the inherent electronic properties but greatly change the optical properties of polyaniline. Furthermore, the computed diffusion coefficient of water in Na-SPANI is smaller than that of EB-PANI. On the other hand, the Na-SPANI shows a larger density than that of EB-PANI. The computed RDF profiles, band gaps, absorption spectra, and diffusion coefficients are in quantitative agreement with the experimental data.

Role of polyaniline morphology in Pd particles dispersion. Hydrogenation of alkynes in the presence of Pd-polyaniline catalysts

AbstractTwo polyaniline (PANI) samples of various molecular masses were used for the preparation of palladium catalysts (with 2 mass % of Pd). The physicochemical features of starting polyanilines were found to substantially affect the size and extent of palladium nanoparticles aggregation. Strongly aggregated large palladium particles appeared in the PANI sample of more compact morphology (PANI-H), higher crystallinity and lower specific surface area. Pd nanoparticles of a definitively smaller size were formed in the more amorphous PANI sample of looser morphology (PANI-L) and the extent of particles aggregation was markedly lower. The catalytic properties of Pd/PANI samples were studied in a liquid phase hydrogenation of unsaturated triple bond (C≡C) in alkynes reactants, phenylacetylene, and cyclohexylacetylene. The 2 mass % Pd/PANI-L catalyst prepared using polymer of less compact texture exhibited much higher activity in both reactions. In the presence of the 2 mass % Pd/PANI-L catalyst, alkene products were formed with a high selectivity (approximately 90 %) attained at the almost complete conversion of alkynes. This highly selective hydrogenation of the C≡C to the C=C bond was related to the presence of an electroactive polymer, PANI, in close proximity with Pd active sites. Polyaniline could have a role in a steric effect as well as in a modification of adsorptive properties of Pd centres.

Morphology of highly porous conducting polyaniline nanofibres synthesized in a multi-phase system

Polyaniline nanofibres are typically synthesized in a two-phase system with aniline placed in one liquid phase and the initiator in the other. The authors modified this method by introducing the monomer as a salt, thus creating a third, solid phase. This salt is in the organic phase as acetonitrile. Salts of aniline+DBSA and aniline+CSA were examined. As both these salts have limited solubility in acetonitrile, they do not dissolve during polymerization. To further reduce their solubility, acid was also added to both liquid phases. DBSA and CSA were used in the organic phase while in the aqueous phase, hydrochloric acid, sulfuric acid, DBSA and CSA were used along with the initiator (APS). Numerous polymerizations were carried out to examine various phase compositions. SEM, FTIR and UV-Vis observations revealed interesting properties of the polyaniline obtained in this way. Its morphology and spectroscopic properties strongly depend on the combination of the components used in each phase. Amorphous polyaniline was obtained as were well-developed spatial forms such as blades, spheres or nanofibres.

Supercapacitive Characteristics of Electrodeposited Polyaniline Thin Films Grown on Indium-doped Tin-oxide Substrates

Polyaniline (PANI) thin films were successfully synthesized using the electrodeposition (ED) technique from a mixed solution of 0.2M aniline and 0.2M H2SO4. PANI films with thicknesses of 220 and 250 nm were synthesized. The formation of compact and amorphous PANI films was confirmed with scanning electron microscopy (SEM) and X-ray diffraction (XRD) measurements. The electrochemical supercapacitor properties of the PANI films were examined using cyclic voltammetry and galvanostatic charge-discharge measurements. A specific capacitance of ∼473 Fg−1 at 1 mAcm−2 in a 0.5 M H2SO4 electrolyte was obtained for the PANI electrodes. The electrochemical stability of the PANI electrodes was investigated using cyclic voltammetry and charge-discharge measurements. Both the films were quite stable with 16% capacitance loss after a few initial charge-discharge cycles.

Facile and efficient route for preparation of nanostructured polyaniline thin films: Schematic model for simplest oxidative chemical polymerization

More purposely, the current paper is related to “bottom-up” approach chemical method for preparation of polyaniline (PANI) via simplest oxidative chemical polymerization. The paper portrays advantages of facile chemical method successive ionic layer adsorption and reaction (SILAR) for depositing fused nanorods structured PANI in the thin film form onto the large-scale area efficiently. The deposition of PANI thin films have been carried out onto cost-effective glass and stainless steel substrates of large area. The two beaker SILAR system is adopted with aqueous acidic aniline solution in H2SO4 as cationic source and solution of ammonium persulfate in double distilled water as anionic precursor for deposition purpose at room temperature. The physico-chemical characteristics of deposited films were studied via analysis of structural, morphological, surface wettability, optical and electrical properties. The amorphous PANI film with fused nanorods showed hydrophilic nature with water contact angle of 56°. Electrical and optical properties revealed that, p-type conductivity PANI with room temperature resistivity of 0.84Ωcm has band gap of 3.2eV.

Alternative Approach to Computing Transport Coefficients: Application to Conductivity and Hall Coefficient of Hydrogenated Amorphous Silicon

We introduce a theoretical framework for computing transport coefficients for complex materials with extended states, and defect or band-tail states originating from static topological disorder. As a first example, we resolve long-standing inconsistencies between experiment and theory pertaining to the conductivity and Hall mobility for amorphous silicon and show that the Hall sign anomaly is a consequence of localized states. Next, we compute the ac conductivity of amorphous polyaniline. The method may be readily integrated with current abinitio methods.