PANI Matrix Research Articles

Localize current burst in modified carbon nanotube/polyaniline composite fibers mat electrode miniaturized resistance and improved rate capability for solid-state supercapacitor

Polyaniline-modified carbon nanotube composite nanofibers are deposited on carbon paper substrate using two steps template-free chemical oxidative deposition process. Regular nanofibers mat was observed through microscopy, and suggested better dispersion and interfacial adhesion ability of modified CNT with PANI matrix, which provided distinct architectural pores. Surface roughness was estimated using AFM surface topography image and decrease in roughness was observed in MPCNT nanofibers mat than PCNT nanofibers mat. Also, decrease in surface roughness due to reduction in agglomeration increased current burst and conducting pathway, which is confirmed in localized current profile plot. In addition, XPS results confirmed the improvement of intrinsic oxidation state, doping degree and conductivity in MPCNT than PC0. Fabricated MPCNT electrode miniaturized resistance and demonstrated highest specific capacitance ~ 1302 F g−1 at current density 0.5 mA cm−2 with good cyclic stability (82% retention even after 6000 cycles). Also, MPCNT electrode exhibited high energy density (250 Wh kg−1) and power density (148 W kg−1). Moreover, develop electrode materials are used to fabricate an asymmetric supercapacitor device for demonstrating the applicability.

Fabrication of polyaniline–few-layer MoS2 nanocomposite for high energy density supercapacitors

Polyaniline–few-layer molybdenum disulfide nanocomposite (PANI–MoS2) has been synthesized by in situ polymerization of aniline over MoS2 using HCl as the dopant. X-ray crystallographic studies show the characteristic peaks of few-layered MoS2 in the PANI matrix. The changes in Raman and UV–Vis spectra have proved that there are definite interactions between PANI and few-layer MoS2.PANI–MoS2 nanocomposite as an electrode material for supercapacitor exhibits a maximum specific capacitance of 687 Fg−1 at a scan rate of 5 mVs−1 using cyclic voltammetry (CV) and a Csp of 612 Fg−1 at a current density of 0.2 Ag−1 using chronopotentiometry (CP). Further, the material also exhibits a high energy density of 128 Wh kg−1with a maximum power density of 9.8 kW kg−1 and a tremendous cyclic stability with 93% capacitance retention after 2000 cycles. These superior electrochemical results over bare PANI and MoS2 showed the PANI–MoS2 nanocomposites to be a capable electrode material for energy storage systems.

Fe-polyaniline composite nanofiber catalyst for chemoselective hydrolysis of oxime

A facile chemoselective one-pot strategy for the deprotection of oxime has been developed using Fe0-polyaniline composite nanofiber (Fe0-PANI), as a catalyst. Nano material based Fe0-PANI catalyst has been synthesized via in-situ polymerization of ANI monomer and followed by reductive deposition of Fe0 onto PANI matrix. The catalyst was characterized by FE-SEM, HR-TEM, BET, XRD, ATR-FTIR, XPS and VSM techniques. The scope of the transformation was studied for aryl, alkyl and heteroarylketoxime with excellent chemoselectivity (>99%). Mechanistic investigations suggested the involvement of a cationic intermediate with Fe3+ active catalytic species. Substituent effect showed a linear free energy relationship. The activation energy (Ea) was calculated to be 17.46 kJ mol−1 for acetophenone oxime to acetophenone conversion. The recyclability of the catalyst demonstrated up to 10 cycles without any significant loss of efficiency. Based on the preliminary experiments a plausible mechanism has been proposed involving a carbocationic intermediate.

Polyaniline-metal organic framework nanocomposite as an efficient electrocatalyst for hydrogen evolution reaction

Abstract Polyaniline-metal organic framework (PANI/MOF) composite was prepared by chemical oxidation of aniline monomer in the presence of 3.6 wt% MOF content for hydrogen evolution reaction (HER). The structure, morphology and properties of the fabricated composite were investigated. There was a clear interaction of MOF on the backbone of the PANI matrix through electrostatic interaction as investigated by both Raman and Fourier transform infrared analyses. The MOF exhibited irregular crystals with further wrapping of MOF by PANI matrix as evidenced by both scanning electron microscopy and transmission electron microscopy studies. The PANI composite showed some nanorods and microporous structure. The energy band gap values of PANI and its composite were found to be 1.50 and 1.35 eV, respectively. The thermal stability of the neat PANI increased upon composite formation, which was due to a stabilizing effect of MOF and a change in morphology of the composite. The catalytic effect of MOF, PANI and PANI/MOF composite on HER was studied using exchange current density (i0) and charge transfer coefficient determined by the Tafel slope method. A drastic increase in catalytic H2 evolution was observed in the composite. In addition, the Tafel slope values of PANI and the composite decreased with increasing the concentration of the acid, suggesting the Volmer reaction coupled with either Heyrovsky or Tafel reaction. The i0 increased with increasing the acid concentration and in an order of PANI/MOF > MOF > PANI at various concentrations.

Polyaniline/zinc oxide nanocomposite as room‐temperature sensing layer for methane

Methane detection in ambient condition has become essential as it is being increasingly used as compressed natural gas in many industrial processes and for domestic and transportation purposes. Hence, in this work, we report a room‐temperature methane sensor based on polyaniline/zinc oxide (PANI/ZnO) nanocomposite. The PANI/ZnO nanocomposite was prepared by chemical polymerization of aniline in the presence of ZnO nanoparticles. Electron microscopy results revealed the successful formation of nanocomposites with rod‐like ZnO nanoparticles embedded into the network of nanofibrillar PANI matrix. The PANI/ZnO nanocomposites exhibited a high response to methane at room temperature within a short response time of 20 s for a methane concentration (500 ppm) much lower than its flammability limit. Moreover, the humidity dependence of the sensor response was found to be very low. POLYM. ENG. SCI., 58:1438–1445, 2018. © 2017 Society of Plastics Engineers

Microwave Absorption Properties of Polyaniline/Carbonyl Iron Composites

In this work, carbonyl iron (CI) containing polya- niline composites (PANI+CI) were prepared via in-situ polymerization of aniline in an aqueous solution containing different amounts of CI as the magnetic filler for the micro- wave absorbers. The incorporation of the magnetic powder to the PANI matrix was confirmed by X-ray diffraction (XRD), IR and SEM. Synthesized PANI+CI composite particles were subsequently added to an epoxy resin matrix to produce related R-PANI+CI composites. Study of thermal properties by thermogravimetric analysis revealed enhanced thermal stability of the composites. The electromagnetic-absorbing properties were studied by measuring the reflection loss in the frequency range of 8.0 to 12.0 GHz. The experimental results indicated that the electromagnetic wave absorbing properties of PANI+CI composites are dependent on the PANI/CI weight ratio. The good reflection loss of the composite at the optimum PANI/CI weight ratio of 1:6 suggests its potential applicability as a good radar absorber.

Preparation, characterization and thermoelectric properties of a polyaniline matrix Ge0.94Pb0.01Bi0.05Te composite

In times of industrialization, much low temperature waste heat is released and no viable technology exists which can produce electricity from this low energy density heat. So the long sought-after class thermoelectric (TE) material which directly achieves conversion between thermal and electrical energy obtains much attention. However, the traditional TE materials are alloys of inorganic materials and expensive, and most of them have some level of toxicity, so the research on organic TE materials is very important. The polyaniline (PANI, i. e., a conducting polymer) and PANI matrix Ge0.94Pb0.01Bi0.05Te composite material were prepared. The chemical structure, microstructure and thermoelectric properties were investigated by FTIR, XRD, SEM and ZEM. Results showed that the molecule chains in the PANI were not ranged very neatly, and Ge0.94Pb0.01Bi0.05Te in the composite material formed interconnected network as 20 wt.-% Ge0.94Pb0.01Bi0.05Te was added. Power factor of the composite material increased greatly while its ZT was almost two times of PANI. The addition of Ge0.94Pb0.01Bi0.05Te was an effective method to increase the thermoelectric properties of PANI.

Synthesis of polyaniline/α-Fe2O3 nanocomposite electrode material for supercapacitor applications

Polyaniline/Ferric oxide (PANI/α-Fe2O3) nanocomposites were synthesized via a simple precipitation of FeCl3 using NH4OH as the precipitating agent, followed by in situ polymerization of aniline. PXRD pattern of as-synthesized nanocomposites showed characteristic peaks of α-Fe2O3 in the PANI matrix. Structural and morphological characterization confirmed the encapsulation of α-Fe2O3 nanoparticles in PANI matrix to form PANI/α-Fe2O3 nanostructures. PANI/α-Fe2O3 as an electrode material for supercapacitor exhibited a maximum specific capacitance of 974 Fg−1 at a scan rate of 2 mVs−1 using CV and Csp of 857 Fg−1 at a current density of 0.2 Ag−1 using CP. Further, the material also exhibited a high energy density of 118 Wh kg−1 with a maximum power density of 9.8kWkg−1 and an excellent cyclic stability with capacitance retention of about 94% after 2000 cycles. These superior electrochemical results over bare PANI and α-Fe2O3 shows the PANI/α-Fe2O3 nanocomposites to be promising electrode material for high performance energy storage systems.

Structural, optical and dielectric properties of polyaniline-Nio.5 Zno.5Fe2O4 nano-composites

Nio.5Zno.5Fe2O4 spinel ferrite was prepared by sol gel method. In situ polymerization method was used to synthesize polyaniline-Nio.5Zno.5Fe2O4 nano-composites having general formula (1-x)ferrite+(x)PANI where x = 0,0.3,0.5,1 (CP,CP1,CP2 and PANI). The effect of structural, optical and dielectric properties of the PANI- Nio.5Zno.5F2O4 nano-composites were investigated. XRD analysis confirmed that the Nio.5Zno.5Fe2O4 particles were successfully dispersed in the PANI matrix with single phase structure. The crystallite size of nano-composites increased with increasing spinel ferrite contents in the PANI matrix due to amorphous structure of PANI. Optical band gaps was calculated by using Tauc relation which found that optical band gradually decreases with the increasing amount of Nio.5Zno.5Fe2O4 in PANI. The dielectric constants (ε′,ε′′), dielectric loss (tanδ) and AC conductivity (Ϭac) were explained as a function of frequency (1kHz to 1MHz) which is described by Maxwell Wagner Model. The spinel ferrite-PANI composite are valuable as microwave absorbers because of their low cost, light weight and flexibility.

Robust electron transport properties of PANI/PPY/ZnO polymeric nanocomposites for OLED applications

Nanostructured pristine PANI, pristine PPY and PANI/PPY/ZnO polymeric nanocomposites were synthesized via chemical oxidative polymerization process. The formation of PANI and PPY matrix and the respective change in the nano strain with the embodiment of ZnO nano-particles were examined by X-ray diffraction technique (XRD) technique. The FESEM images showed topological structure with agglomerated nano-flakes of the PANI/PPY/ZnO ternary nanocomposites. The optical transmittance spectra showed optimized transmittance characteristic peak observed at ∼495nm associated to blue-green region. The PL spectra revealed high electron-hole non-radiative recombination corresponding to blue, green and yellow bands respectively. Enhanced current density (∼263%) and optimized reduced band gap (∼2.53eV) were estimated that led to the improved conductivity of PANI/PPY/ZnO nanocomposites. The reduced energy band gap, improved conductivity and increased rate of electron-hole non-radiative recombination with fairly improvement of transmittance inferred that it can be used as electron transport layer in OLED device fabrication.

Fabrication of a novel PANI/[Co(NH3)4(C3H4N2)2]Cl3 nanocomposite with enhanced dielectric constant and ac-conductivity

A new polyaniline/[Co(NH3)4(C3H4N2)2]Cl3 nanocomposite was synthesised by in-situ oxidative polymerisation of aniline monomer in non-aqueous DMSO medium. The nanocomposite was investigated as a suitable material for energy storage and high frequency device applications due to its high value of dielectric constant (≈104) and ac-conductivity (≈108) with a rapid decrease in loss tangent in the high frequency region. The nanocomposite was characterised by techniques like UV–Vis spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and field emission scanning electron microscopy (FESEM). The results revealed presence of photoadduct (PA) in PANI@PA nanocomposite with significant interaction between PANI matrix and PA nanoparticles. The PANI@PA nanocomposite exhibit enhanced thermal stability broadening its scope of usability. The better dispersion of PA nanoparticles in the PANI matrix as observed in FESEM, facilitates better charge transport. Dielectric study showed capacitive effect of the nanocomposite at low frequency and a conductivity effect at high frequency. The high value of dielectric constant and ac-conductivity of PANI@PA nanocomposite is attributed to the heterogeneous structure of nanocomposite with enhanced interface, which has a positive effect on the dielectric properties of the material.

Influence of polyaniline/multiwalled carbon nanotube composites on alkyd coatings against the corrosion of carbon steel alloy

AbstractPolyaniline (PANI) and its composites with multiwalled carbon nanotubes (MWCNTs) were synthesized by chemical oxidative polymerization. High-resolution transmission electron microscopy (HR-TEM), thermogravimetric analysis (TGA), and Raman spectroscopy were used to characterize the investigated compounds. The synthesized composite is formulated as pigments in alkyd resin with different pigment-binder (P/B) ratios and investigated as anticorrosive coatings on carbon steel in 1mHCl using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The protection mechanism of PANI occurred through the barrier and passivation effect on the carbon steel surface. The encapsulation and dispersion of MWCNTs into the PANI matrix promoted the anticorrosive efficiency of the alkyd coating.

Synthesis, characterization and electrical property of MWCNT-ZnS nanocomposite embedded in polyaniline

PANI/MWCNT-ZnS nanocomposites with different contents of ZnS wt.% have been synthesized by the chemical oxidative in situ polymerization reaction of aniline in the presence of multi-walled carbon nanotube (MWCNT). TEM, XRD, RAMAN and TGA studies have been done for the structural and thermal characterizations of the samples. The particle sizes of ZnS nanoparticles have the values in the range from 3.21 to 5.08 nm. XRD spectrum reveals the co-existence of MWCNT, ZnS in PANI matrix, where ZnS forms a hexagonal structure. TGA result shows that nanocomposite becomes more thermally stable with increase in ZnS content. The dc electrical transport property of PANI/MWCNT-ZnS nanocomposites has been investigated within a temperature range 77 K ⩽ T ⩽ 300 K. The dc conductivity follows a 3D variable range hopping (VRH) model. A large magnetoconductivity change (23.1%) is observed for 2 wt.% ZnS content in PANI/MWCNT-ZnS, which is explained by the wave function shrinkage model.

Design and synthesis of graphene-SnO2 particles architecture with polyaniline and their better photodegradation performance

The photodegradation in two different types of dyes like a cationic and anionic dye, namely, methylene blue and reactive yellow 15 under the direct sunlight irradiation respectively, have been carried out using graphene-SnO2/PANI matrix as photo catalyst. The graphene-SnO2 particle architecture PANI matrix was successfully synthesized via two step methods Firstly, graphene-SnO2 colloidal suspension was prepared by hydrothermal precipitation method and secondly, the resulting graphene-SnO2 colloidal suspension was effectively attached on the PANI matrix by in situ chemical oxidative polymerization method. The resulting respective nanocomposite materials of graphene, SnO2 and PANI were characterized and confirmed by FTIR, X-ray diffraction, UV–vis DRS, HR-SEM with EDAX, TEM, BET and TG-DTA analysis. Thus results demonstrate that graphene-SnO2 nanoparticle-architecture PANI matrix was synergistic effect among the three component of graphene, SnO2 and PANI. Therefore, graphene-SnO2 particles architecture PANI acts as an efficient photo catalyst for the degradation of methylene blue and reactive yellow 15 dyes under the direct sunlight irradiation.

Synthesis and characterization of hybrid PANI/MWCNT nanocomposites for EMI applications

The present study reports on a simple and very efficient solution mixing method for the preparation of functionalized multiwalled carbon nanotube/polyaniline nanocomposites (f‐MWCNT/PANI) for electromagnetic interference (EMI) application. The synthesized composites have been characterized by different physiochemical techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffractometry (XRD), and Fourier transform infrared (FT‐IR) spectroscopy. The electron microscopy analysis of nanocomposites reveals the good dispersion and agglomeration of CNT in PANI matrix at higher concentration. X‐ray study shows the higher crystallinity of PANI with the addition of f‐MWCNT. FTIR spectroscopy has confirmed the interactions of the carbonyl group of f‐MWCNT with the quinoid ring of PANI. The resulting f‐MWCNT/PANI nanocomposites (0 to 21 vol% CNT) shows higher electrical conductivity than that of pure PANI due to the formation of conducting path between CNT and PANI matrix. The increased electrical conductivity of nanocomposites also improved the estimated EMI shielding. The percolation threshold was found to occurs at 0.1 vol% of f‐MWCNT, where the DC electrical conductivity started to increase abruptly. The one‐order increment in electrical conductivity was observed which is 12 times more than that of pure PANI. The DC electrical conductivity of nanocomposite at 3.3 vol% and 13.9 vol% of f‐MWCNT was 1.6 × 10−1 S/cm and 1.8 × 10−1 S/cm, respectively. In addition, the estimated EMI shielding of nanocomposites at 3.3 vol% of f‐MWCNT and beyond it was found to be 12dB. POLYM. COMPOS., 39:3858–3868, 2018. © 2017 Society of Plastics Engineers

Polyaniline–Cadmium Ferrite Nanostructured Composite for Room-Temperature Liquefied Petroleum Gas Sensing

We introduce polyaniline–cadmium ferrite (PANI–CdFe2O4) nanostructured composite as a room-temperature-operable liquefied petroleum gas (LPG) sensor. The structure of PANI and the composite prepared by chemical polymerization was characterized by Fourier-transform infrared (FT-IR) spectroscopy, x-ray diffraction (XRD) analysis, and field-emission scanning electron microscopy. Comparative XRD and FT-IR analysis confirmed CdFe2O4 embedded in PANI matrix with mutual interfacial interaction. The nanostructure of the composite was confirmed by transmission electron microscopy. A simple LPG sensor operable at room temperature, exclusively based on spin-coated PANI–CdFe2O4 nanocomposite, was fabricated with maximum sensing response of 50.83% at 1000 ppm LPG. The response and recovery time of the sensor were 50 s and 110 s, respectively, and it was stable over a period of 1 month with slight degradation of 4%. The sensing mechanism is discussed on the basis of the p-n heterojunction barrier formed at the interface of PANI and CdFe2O4.

Preparation of silver/carbon fiber/polyaniline microwave absorption composite and its application in epoxy resin

Microwave absorbing Ag/CF/polyaniline (PANI) composites with PANI particles evenly wrapped on the surface of the silver-plated carbon fiber, were prepared via in situ polymerization. The obtained composite was analyzed by SEM, XRD, TGA, four probes resistance tester and a vector network analyzer. The results indicated that silver nanoparticles were deposited on the surface of CF uniformly and Ag/CF was completely wrapped by PANI particles. Ag/CF/PANI composite with conductivity of 2.16 S/cm displayed better thermal stability than that of PANI. Meanwhile, Ag/CF/PANI composite with microwave reflection loss up to −13.2 dB at 9.3 GHz at thickness of 2.0 mm outperformed that of PANI matrix and CF/PANI composite. The epoxy matrix composite with Ag/CF/PANI dispersed inside homogenously performed −8 dB at 4.5 wt% loading content.

Excellent Microwave Absorption Behaviors of Polyaniline Composites Containing CeO2 Nanorods in the X-Band

Conductive polyaniline/CeO2 nanocomposite powders (PANI/CeO[Formula: see text] were prepared by an in situ polymerization method. The effects of CeO2 content on the microwave absorption properties of composites were investigated. The phase composition, morphological characteristics, electromagnetic parameters and microwave absorption properties of the composites were characterized through X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and vector network analysis. Results show that CeO2 nanorods are coated with PANI to form a well-defined hierarchical structure. CeO2 is well-incorporated into the PANI matrix. CeO2/PANI exhibits excellent microwave absorption properties at 2–18[Formula: see text]GHz. As the CeO2 content increases to 30[Formula: see text]wt.%, an optimal reflection loss (RL) of [Formula: see text]40[Formula: see text]dB (99.99% of electromagnetic wave absorption) is observed at 8.8[Formula: see text]GHz with a thickness of 3.0[Formula: see text]mm. The frequency bandwidth corresponding to 90% of electromagnetic wave absorption crosses the X-band. Therefore, PANI/CeO2 can be used as an advantageous candidate for a new type of microwave absorptive material.

Enhanced ammonia sensing characteristics of tungsten oxide decorated polyaniline hybrid nanocomposites

Polyaniline (PAni)-tungsten oxide (WO3) hybrid nanocomposites sensor have been lucratively synthesized by in-situ chemical oxidative polymerization method by entrapping tungsten oxide nanoparticles (10–50%) in the polyaniline matrix on precleaned glass substrate. The structural, morphological and surface composition elucidation of PAni-WO3 hybrid nanocomposites were explored by X-ray diffraction (XRD) technique, field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS). The existence of WO3 in PAni matrix and interaction between them was confirmed using XRD and Raman spectroscopy. The incorporation of WO3 nanoparticles into the PAni matrix introduces porosity which enhanced gas sensing properties. The TEM image of PAni-WO3 hybrid nanocomposite film exploded the average diameter of WO3 nanoparticles ranging from 40 to 50 nm. Chemical composition of PAni-WO3 hybrid nanocomposites was characterized by using X-ray photoelectron spectroscopy (XPS). In order to investigate the gas sensing parameter of PAni-WO3 hybrid nanocomposite, hybrid nanocomposite film was exposed to different oxidizing gases (Cl2, NO2) and reducing gases (NH3, H2S, CH3OH, C2H5OH) in range 5–100 ppm concentration of gas. It was observed that the sensors of PAni-WO3 hybrid nanocomposites showed better sensitivity, selectivity, stability and reproducibility compared to pure PAni and pure WO3. PAni-WO3 (50%) hybrid nanocomposite sensor operating at room temperature reveals maximum response of 158% towards 100 ppm of NH3 gas and also capable to respond very little concentration of 5 ppm NH3 gas with reasonable response of 24%. The gas sensing mechanism of the nanocomposites in presence of air and with target NH3 gas atmosphere was discussed in detail with the help of energy band diagram. The interaction of NH3 and NO2 gas with PAni-WO3 hybrid nanocomposite sensor was investigated by employing an impedance spectroscopy also.

Enhancing the electrochromic properties of polyaniline via coordinate bond tethering the polyaniline with gold colloids

In this paper, we designed a novel organic-inorganic nanohybrid electrochromic material through tethering polyaniline and gold colloids with an interfacial coordinate bond. The enhanced electrochemical and electrochromic properties were expected owing to the high conductivities of the gold colloids and strong interfacial interaction between the organic phase and inorganic phase. The water-dispersible polyaniline-gold (PANI-Au) nanohybrids were synthesized successfully through grafting copolymerization of aniline with p-aminothiophenol (PATP) functionalized gold colloids in an aqueous system using a macromolecular acid, poly(styrene sulfonate) (PSS) as the dopant agent. The structures, morphologies, and electrochemical and electrochromic properties of PANI-Au nanohybrids were characterized by the UV–vis, FTIR, Raman spectrometers, SEM, and electrochemical working station, respectively. The results show that through incorporating gold nanoparticles into the PANI matrix with the interfacial coordinate bond, PANI-Au nanohybrids possess uniform nanoparticles morphologies with diameter ~180nm. The electrochemical activity and the charge transfer process of PANI were enhanced, which is proved by the CV test and EIS analysis. As the results, the PANI-Au nanohybrids can switch at relatively lower potentials and give a higher optical contrast as comparison with neat PANI: PSS. With ~1.4wt% Au loading amount, the contrast of PANI-Au nanohybrid is 0.97, which is much higher than 0.76 of PANI: PSS. The coloration and bleaching time are also shortened from 13.4s and 8.9s for PANI: PSS to 8.3s and 7.6s for PANI-Au-c, respectively.