PANI Composites Research Articles

Pr2CuO4/MWCNT/MXene/PANI: A novel quaternary composite with tunable properties for potential applications in optoelectronics and energy storage devices

Pr2CuO4/MXene/MWCNT and PANI composites were synthesized for symmetric supercapacitor applications using a simple hydrothermal and in-situ polymerization technique. Pr2CuO4/ MXene/MWCNT and PANI were of ratios 40:60 (PC1), 50:50 (PC2), and 60:40 (PC3). Composites had a tetragonal single phase of Pr2CuO4 with a preferred orientation peak along (103) plane. FTIR confirmed functional bands of all constituents of the composite. Porous morphology was confirmed by scanning electron microscopy (SEM) beneficial for energy storage capacity. The PC2 Composite possessed the widest absorption range and the smallest band gap energy. The dielectric constant of PC2, was the highest than pure Pr2CuO4 and the other composites. Coercivity and saturation magnetization for the composites decreased with decreasing Pr2CuO4 percentage, producing less eddy currents, which reduced energy dissipation and contributed to the increased efficiency of capacitors and inductors. The best ratio of Pr2CuO4/ MXene/MWCNT and PANI was 50:50 for increasing rate capability. This ratio enhanced surface area, charge storage capacity, specific capacity, and impedance behaviour. The optimized PC2 (Pr2CuO4/MXene/MWCNT: PANI 50:50) electrode exhibited exceptional electrochemical performance, achieving volumetric and gravimetric capacitance values of 2611.47 Fg−1 at 2 Ag−1. This enhanced performance can be explained by the combined effects of Pr2CuO4/MWCNT/PANI, which actively promoted pseudocapacitance and impeded MXene restacking. An excellent candidate for advanced energy storage systems, the electrode has an energy density of 58.032 Whkg−1 and remarkable rate capabilities.

Utilization of waste PET-derived metal–organic framework grafted polyaniline composite for heavy metal adsorption from aqueous solution

In this research, we used waste polyethylene terephthalate (PET) bottles as a source to develop an iron-based MOF-supported polyaniline (Fe-MOF@PANI) composite, which was then applied for the adsorptive removal of cadmium (Cd(II)) and lead (Pb(II)) ions from aqueous environment. A comprehensive characterization of the Fe-MOF@PANI composite was conducted using several analytical techniques including FTIR, PXRD, SEM, EDX with mapping, and XPS analysis, which provided significant insights into its functionality, crystalline structure, surface morphology, and elemental composition. The synthesized Fe-MOF exhibited a spindle-shaped morphology that was evenly distributed over the surface of the PANI composite, as confirmed by SEM analysis. Additionally, the porous characteristics of the Fe-MOF@PANI composite were proven through BET analysis. The Fe-MOF@PANI composite exhibited remarkable adsorption efficiencies for selected metal cations, achieving adsorption capacities of 143.36 mg/g and 258.59 mg/g for Cd(II) and Pb(II) ions, respectively. The findings of the isotherm and kinetic studies demonstrated that the adsorption process fitted well with Langmuir and pseudo-second-order kinetics, indicating that adsorption of both metal cations occurs in a monolayer formation and includes chemisorption mechanisms, respectively. This research paves the way for further development and application of post-functionalized PET-derived MOF adsorbents to remove Cd(II) and Pb(II) ions from water efficiently.

Super capacitive electrode performance analysis of facile synthesized α-Fe2O3 aerogel and its nanocomposite with in-situ formed polyaniline (α-Fe2O3/PANI)

This paper presents the synthesis of an α-Fe2O3-assisted polyaniline (α-Fe2O3/PANI) nanocomposite using a straightforward two-step process. Initially, α-Fe2O3 aerogels with cratered nanohexagon structures are synthesized through a solution combustion method assisted by noni (Morinda citrifolia) fruit extract. In the second step, these nanohexagons facilitate the preparation of α-Fe2O3/PANI via in-situ chemical oxidative polymerization of anilinium chloride. The structural, optical, and morphological properties were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDAX). Electrical conductivity, wettability, and electrochemical properties of the prepared materials were assessed. The results indicate that the 2D cratered α-Fe2O3 aerogel is effectively embedded within PANI, forming a modified nano α-Fe2O3/PANI composite. The composite exhibited altered DC conductivity and electrolyte wettability. After 200 cycles of cyclic voltammetry (CV), the specific capacitance of the nano α-Fe2O3/PANI was determined to be 153 Fg⁻¹ at a scan rate of 10 mVs⁻¹, retaining approximately 90 % of its cycle stability. Electrochemical impedance spectroscopy (EIS) revealed significantly lower charge transfer and equivalent series resistance values for the nano α-Fe2O3/PANI electrode compared to the pure α-Fe2O3-based electrode. Galvanostatic charge-discharge (GCD) tests further demonstrated the superior electrochemical performance of the α-Fe2O3/PANI nanocomposite electrode. Therefore, this α-Fe2O3/PANI is an advanced conducting polymeric electrode for electrochemical applications.

Structural and dielectric characteristics of doped nickle oxide polyaniline composites

ABSTRACT The PANI-NiO composites were synthesized by employing an in situ chemical polymerization technique, with varying weight percentages of NiO dopant (PANI-5%NiO and PANI-10%NiO). Additionally, AC conductivity, dielectric constant and dielectric loss were investigated within a frequency range from 20 Hz to 1 MHz. XRD confirmed the phase purity and high crystallinity. SEM reveals the granular shape with a porous surface. In addition, the incorporation of NiO with different concentrations influences the composite’s dielectric properties. All samples exhibited frequency-dependent dielectric properties in line with the Maxwell–Wagner model. Notably, the AC conductivity of PANI-10% NiO composite increased as the frequency increased, this behaviour was certified with Jonscher’s power law. The I–V characteristics confirm the ohmic nature of all synthesized samples. Therefore, the potential of PANI and PANI-NiO composites, as efficient dielectric materials, has been explored and can be useful for device applications in diverse fields.

Novel ternary Z scheme carbon quantum dots (CQDs) decorated WS2/PANI ((CQDs@WS2/PANI):0D:2D:1D) nanocomposite for the photocatalytic degradation and electrochemical detection of pharmaceutical drugs

The endocrine-disrupting chemicals (EDCs) and antibiotics are causing negative effects on human beings and animals by disrupting the endocrine system and spreading antimicrobial resistance. The current need is to eradicate pharmaceutical waste from water bodies using advanced catalytic systems with high efficiency. Novel ternary carbon quantum dots (CQDs) decorated Z-Scheme WS2-PANI nanocomposite was prepared by a green synthesis assisted in-situ polymerization for the photodegradation and detection of Estradiol (EST) and Nitrofurantoin (NFT). HRTEM micrographs revealed the formation of CQDs with a mean size of 4 nm anchored on the surface of WS2/PANI (width:PANI ∼ 20-30 nm). The ternary nanocomposite showed excellent photocatalytic activity, degraded NFT (95.7% in 60 min), and EST (96.6% in 60 min). The rate kinetics study confirms the reaction followed pseudo first-order model. This heterostructure exhibited enhanced performances by modulating the energy level configuration, enhancing the absorption of visible light (2.4 eV), and significantly improving the charge separation, three times higher than pristine WS2. These are highly favorable for increasing the generation of photoinduced charges and enhancing the overall performance of the catalyst. Further, the electrochemical sensor was prepared using CQDs@WS2/PANI composite on a paper-based electrode. The CQDs@WS2/PANI exhibit a linear response of 0.01 to 100 nM, with a limit of detection of 13 nM. This synergistic interfacial interaction resulted in the significantly improved electrochemical performance of the modified electrode. The proposed Z-scheme was justified by electron paramagnetic resonance (EPR) and scavenger experiment. An intermediate degradation pathway was also proposed. The synthesized materials were characterized using FESEM, HRTEM, XRD, FTIR, XPS, UV-visible, PL, and TRPL. Therefore, this study provides a direct approach to fabricate a heterojunction that combines two-dimensional, one dimensional, and zero-dimensional properties, enabling control over the energy level configuration and subsequent improvements in photocatalytic and electrocatalytic efficiency.

Three-dimensional crumpled d-Ti3C2Tx/PANI structure enabled by PANI interlayer spacing control for enhanced electrochemical performance

The self-stacking and collapsing of few-layered Ti3C2Tx(d-Ti3C2Tx) results in its poor rate capability and cycle performance during charge/discharge processes. Constructing a three-dementional (3D) structure, introducing interlayer spacers and using alkaline electrolytes are effective and powerful strategies to resolve the problems. Herein, a 3D crumpled d-Ti3C2Tx/PANI composite was successfully prepared by HCl/LiF in-situ etching Ti3AlC2 to obtain d-Ti3C2Tx and polymerizing PANI onto its surface with ice-bath stirring. Benefiting from the synergistic effect of kinetically favorable structure, component and alkaline electrolytes, The PM-1 (d-Ti3C2Tx/PANI-1) as an electrode remarkably improves the electrochemical performances compared with the original d-Ti3C2Tx in 2 M KOH electrolyte. It exhibits a specific capacitance of 230 mF cm−2（115 F g−1）at 2 mA cm−2, high rate capability of 81.2% at 20 mA cm−2 and outstanding stability of 96.7% retention after 5000 cycles at 10 mA cm−2. Furthermore, an assembled symmetric supercapacitor (SSC) also presents an excellent stability performance with 82.4% retention after 5000 cycles at 8 mA cm−2 and a promising energy storage performance. The related work provides a good reference for the MXene-based electrode materials in the conditions of alkaline electrolytes.

Custom and definitive screening designs for evaluating multiple adsorbents: bisphenol-A adsorption onto villi-structured polyaniline/carboxymethyl cellulose composites

ABSTRACT Polyaniline composites consisting of carboxymethyl cellulose (CMC) have enhanced adsorption properties, but recent studies indicate that the oxidised species – dialdehyde carboxymethyl cellulose (DCMC) – outperforms CMC-based composites. However, these studies fail to study the effect of DCMC's aldehyde content and compare the composites with CMC-based composites; numerous experiments required to investigate each adsorbent for each factor limit such studies. We explored a way to study whether villi-structured polyaniline (VSPANI), its CMC composite (CMC/PANI), and its DCMC composites with 35% (DCMC(A)/PANI) and 77% (DCMC(B)/PANI) aldehyde content would be great adsorbents for removing bisphenol-A (BPA). We first customised a D-optimal screening design to alleviate the pitfalls of definitive screening design (DSD), hence estimating all the main effects: initial concentration, pH, flow rate, adsorbent amount, sample volume and type of adsorbent. We excluded CMC/PANI and DCMC(A)/PANI composites, both with low adsorption capacities of 56.57 and 57.27 mg/g from further investigation. The DSD followed to estimate all second-order effects through which we projected a response surface method (RSM) to optimise and model the active factors. Increasing the aldehyde content on the composites favoured adsorption, but there lacked evidence to suggest VSPANI and DCMC(B)/PANI differed significantly in performance. The models were numerically and graphically proven adequate, explaining 80% and 99% of the variation when predicting removal efficiency and adsorption capacity. VSPANI showed potential as an adsorbent for BPA removal with 85% removal efficiency and 129 mg/g adsorption capacity. This comprehensive approach, combining both designs, allows for sustainable investigation of multiple adsorbents and factors, minimising experimental waste.

Synthesis, characterization, and biosensing performance of cobalt sulphide reinforced polyaniline composites

In this work, the CoS was synthesized by the solvothermal method. The PANI and PANI-CoS composites (1, 5, and 15 wt % CoS in the PANI matrix) were synthesized by the oxidative polymerization method. The PXRD pattern confirmed CoS and PANI peaks matched with JCPDS cards. CoS was successfully embedded in the PANI matrix. The surface morphology of the CoS microspheres are flower-like and shows crossed nanoflakes with a thickness of around 40 nm. These CoS microspheres are transformed into nanoparticles by the presence of PANI. The Nickel Foam/Polymer Composites/GOx were prepared by drop-coating the PEG water-dispersed PCs-modified nickel foam electrode and immobilized with the enzyme glucose oxidase. The CV studies were carried out for three-electrode systems. The sensitivity of PCs toward different concentrations of glucose ranging from 1 mM to 1000 mM was evaluated. Also the enzymatic reaction evaluated by Michaelis-Menten kinetic exhibits a high affinity of GOx to glucose.

Boosting the hydrophobicity of eco‐friendly polyaniline coating using TiO2 and ZnO nanoparticles

This article clarifies the thin layer deposition of superhydrophobic coating using eco‐friendly polymer (polyaniline [PANI]) incorporated with TiO2 and ZnO nanoparticles on indium tin oxide substrate. Using the cyclic voltammetry method, in situ polymerization of PANI incorporated with hybrid (TiO2–ZnO) was accomplished. The morphology and hydrophobicity of electro‐deposited films were examined; the impact of deposition cycles was also investigated. The morphological structure was studied using field‐emission scanning electron microscopy and high‐resolution transmission electron microscopy. X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analysis proved the incorporation of nanoparticles into the composite matrix. Additionally, the water contact angle of the PANI composite was found to be 150.4°, and the findings reflected that (TiO2–ZnO) nanoparticles were significantly implicated in enhancing this superhydrophobicity. The surface roughness of the PANI matrix was increased when TiO2 and ZnO are added, as was shown by atomic force microscope investigation.

Tailoring frequency/temperature independent colossal dielectric constant in Zn-doped Fe3O4/Fe2O3@C/PANI using phase co-existence approach

Introducing doped binary oxides to polymers offers a promising way towards advancement of charge density/energy storage materials with colossal dielectric constant. However, the origin of colossal dielectric constant explored in terms of conduction mechanism with a deeper understanding of the coexistence of phases/interfaces in these materials still requires much attention. In this context, we synthesised Zn-doped Fe3O4/Fe2O3@C/PANI composite that exhibits frequency and temperature independent colossal dielectric constant over a broad range, 1 Hz to 10 MHz and 93 K to 333 K, respectively. We analyzed the impedance data using an equivalent circuit model and Cole-Cole fitting to gain insight into the colossal dielectric response and low dielectric loss. The relaxation phenomenon corresponding to a highly stable electroactive region is validated by the distribution of relaxation time (DRT). Furthermore, the composite exhibited a non-relaxor-like behavior due to diffuse phase transition near semiconductor-to-metallic transition (SMT), observed at 303 K. The charge carriers follow the variable range hopping (VRH) and Arrhenius models yielding localization length of 3 Å and activation energy of 35 meV, which supports the charge transport mechanism between like cation interfaces. This detailed analysis covering the frequency and temperature independent dielectric constant along with the understanding of relaxation and conduction phenomena could provide a viable approach towards producing charge density/energy storage devices for practical applications.

Construction of liquid metal nanoparticles-decorated on nitrogen-doped Ti3C2Tx MXene with flower-like structure for efficient lithium-ion batteries

Two-dimensional (2D) transition metal carbides, nitride compounds, or carbon-nitride compounds (MXenes), has attracted great attention as very popular energy storage materials, since their obvious characteristics compared with other energy storage materials, such as outstanding electrical conductivity, 2D lamellar structure, and abundant surface functional groups. These merits are further boosted by the construction of three-dimensional (3D) structures. Herein, we present a facile strategy of spontaneous converting 2D titanium carbide (Ti3C2Tx) MXene nanoflakes into 3D conductive frameworks of Ti3C2Tx /PANI (TP) composites, which is achieved by conducting oxidation-free polymerization of aniline on the surface of Ti3C2Tx MXene nanosheet, and then introducing liquid metal nanoparticles (LMNPs) with high theoretical capacity into the TP framework to build a 3D hydrangea macrophylla like Ti3C2Tx/PANI/LMNPs (TPL) composite. The TPL composites integrated the unique high-capacity speciality of LMNPs and the conductivity of the MXene framework. Lithium-ion batteries (LIBs) based on TPL electrodes exhibit higher specific capacity of 906.9 mAh g−1 at 0.1 A g−1, capacity retaining ratio of 96.44 % as well as a long cyclic stability (467.0 mAh g−1 after 1500 cycles at 5 A g−1).

Effect of Crystal Morphology on Electrochemical Performances of IRH-2 and IRH-2/PANI Composite for Supercapacitor Electrodes.

In the context of recent progress in designing metal-organic framework (MOF)-based supercapacitor electrodes, we report herein the successful growth of two different crystal morphologies of a cerium-based MOF, octahedral crystals named IRH-2-O and elongated square-bipyramidal crystals named IRH-2-ESBP (IRH = Institute de Recherche sur l'Hydrogène). The identical crystal structure of both materials was confirmed by powder X-ray diffraction (PXRD). Furthermore, scanning electron microscopy and energy-dispersive X-ray mapping analysis corroborated this fact and showed the crystal shape variation versus the surface composition of synthesized materials. Fourier transform infrared spectroscopy, UV-vis spectroscopy, and PXRD were used to confirm the purity of pristine MOFs as well as desired MOF//PANI composites. Cyclic voltammetry and electrochemical impedance spectroscopy highlighted the effect of crystal shape on the electrochemical performance of IRH-2 MOFs; the specific capacitance tripled from 43.1 F·g-1 for IRH-2-O to 125.57 F·g-1 for IRH-2-ESBP at 5 mV·s-1. The cycling stability was notably ameliorated from 7 K for IRH-2-O to 20 K for IRH-2-ESBP. Regarding the composites, the cell voltage was notably ameliorated from 1.8 to 1.95 V. However, the electrochemical performance of IRH-2/PANI composites was drastically decreased due to instability in the acidic media. To the best of our knowledge, our work is the first work that related the MOF crystal shape and the electrochemical performance.

Assessing thermoelectric performance of quasi 0D carbon and polyaniline nanocomposites using machine learning

Thermoelectric materials have been widely recognized as a simple approach to harness green energy by converting thermal gradients into electrical energy. However, the intricate interplay between electrical conductivity, Seebeck coefficient, and thermal conductivity in thermoelectric materials presents a challenge to improving their efficiency. Traditional experimental methods and calculation methods have troublesome steps and long cycles for predicting new thermoelectric materials. In this work we present materials informatics-based approach, where statistical and machine learning models like correlation matrix, multiple linear regression, principal component analysis and artificial neural network were employed to find the relationship between features and thermoelectric performance. Furthermore, artificial neural network was used to analyze the roles of several compositional and microstructural features along with temperature on electrical conductivity, thermal conductivity, Seebeck coefficient and thermoelectric figure of merit (ZT) for PANI and quasi 0D carbon-based composites.

Detailed investigation of structural, elastic, and thermal properties of PANI doped silver ferrites AgFe2O3/ZnO

We report the infrared absorption properties of polyaniline nanocomposites (AgFe2O3/ZnO) with different amounts of PANI (5 and 10 wt%) powder samples by in situ chemical oxidation polymerization synthesis. In contrast, silver ferrite nanomaterial has been synthesized using a hydrothermal approach. X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize the prepared samples. Rhombohedral structures were seen in the pure (AgFe2O3/ZnO) and its PANI composites. The size of the crystallites was found between 30 to 40 nm. The SEM images of the composites confirmed the morphology of prepared samples. The FTIR spectrum for each of the samples consists of two wide absorption bands that correspond to the tetrahedral V1 and octahedral V2 sites bending vibrations. Force constants were found higher for tetrahedral sites as compared to octahedral sites. FTIR parameters have been used to calculate the Bulk modulus (B), Rigidity modulus (R), Young’s modulus (Y), and Poisson ratio (σ). Elastic parameters for PANI doped ferrites have improved significantly compared to pure AgFe2O3/ZnO ferrite due to strong inter atomic bonding. This can be beneficial in overcoming physical stresses that may arise during material fabrication and commercialization. Debye temperature increased with increasing PANI concentration.

Revealing the causes of degradation of an asymmetric ionic liquid supercapacitor with a composite polyaniline/carbon electrode

The extended window of electrochemical stability of ionic liquids and the high specific capacitance values of activated carbon (AC)/conductive polymer (polyaniline, Pani) composite materials are promising approaches to improve the performance of supercapacitors (SC).In this work, we studied the stability of an asymmetric AC//Pani-C cell with 1 M solution of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) in acetonitrile as an electrolyte. Pani-C (56 wt% of Pani) composite was prepared by oxidative polymerization of aniline in the presence of high surface area AC (SBET = 2300 m2‧g−1). Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission and scanning electron microscopies data confirmed the formation of Pani-C composite. Combination of cyclic voltammetry, galvanostatic charge/discharge method, and electrochemical impedance spectroscopy in 2- and 3-electrode cell configurations gave information about anodic (1 V vs. Ti) and cathodic (−1.8 V vs. Ti) potential limits of electrochemical stability, and potential of zero charge of Pani-C and AC.From these data, optimal mass ratio of Pani-C and AC electrodes was obtained for asymmetric SC assembly. It was found that after 500 charge/discharge cycles, the capacitance of the asymmetric AC//Pani-C SC decreased by 15% from 46.8 to 39.9 F·g−1 as a result of Pani-C degradation. The specific capacitance of AC remained virtually unchanged (decreased from 144 to 141 F·g−1), while that of Pani-C decreased by 8.7% from 230 to 210 F·g−1. Electrochemical measurements showed that degradation is accompanied by an increase in the working potential window of Pani-C (from 0.85 V to 0.97 V) and a shift in Emin…Emax working potentials from 0.15 … 1 to 0.52 … 1.49 V vs. Ti in the beginning and in the end of stability test, respectively. The last region is related to the potential for non-conductive pernigraniline formation (1.3 V vs. Ti). It was shown that the main reason of AC//Pani-C SC capacitance decay is a gradual increase in the operating potential window with a constantly shifts towards anodic values of positive Pani-C electrode, which resulted in accumulation of nonconductive polymer form that does not participate in charge accumulation.

Dual S-scheme CuSe-Cu3Se2/Ag-PANI heterostructures for the impressive degradation of dye pollutants

A dual S-scheme structure for the photocatalytic activity of copper selenide (CuxSey)/Ag-polyaniline (CuxSey/Ag-PANI) nanocomposites to degrade dye pollutants under visible light illumination conditions has been proposed. In the first step, PANI composites have been decorated by Ag nanoparticles (NPs) with different concentrations of Ag NPs. Then, a cost-effective and straightforward co-precipitation method has synthesized the CuxSey/Ag-PANI nanocomposites with different Ag NPs concentrations. Additions of the CuxSey/Ag-PANI nanocomposites, pristine CuxSey nanostructures, and CuxSey/PANI nanocomposites have also been synthesized with the same conditions. X-ray diffraction patterns (XRD) and high-resolution transmission electron microscopy (HRTEM) images indicated the CuxSey nanostructures in the nanocomposites included two phases that were CuSe nanodisks with a few nanometers in thickness and Cu3Se2 NPs with average diameters of 10±2 nm. In contrast, the pristine CuxSey nanostructures have included several extra phases. These microscopy images showed the Cu3Se2 NPs have decorated the CuSe nanodisks. According to the UV–vis results, the Ag NPs in the CuSe-Cu3Se2/Ag-PANI nanocomposites showed surface plasmon resonance (SPR) effects, and this factor became one of the most critical factors for the better photocatalytic performance of the CuSe-Cu3Se2/Ag-PANI nanocomposites. By comparing the Fermi level (Ef) of the structures that make up the CuSe-Cu3Se2/Ag-PANI heterostructures, these structures had the conditions for forming the dual S-scheme structure. Based on this structure and also the synergistic effect of the plasmonic properties of the Ag NPs, the reason for the better photocatalytic performance of the CuxSey/Ag-PANI nanocomposites compared to the pristine CuxSey nanostructures and CuxSey/PANI nanocomposites has been explained.

Controllable synthesis of composite electrode material to enhance the electrochemical performance of supercapacitors

Cobalt oxide (Co3O4), cobalt oxide/reduced graphene oxide (Co3O4/rGO), and cobalt oxide/reduced graphene oxide/polyaniline (Co3O4/rGO/PANI) ternary composites with varying PANI concentrations are created using the hydrothermal route and in-situ polymerization of aniline monomer. X-ray diffractometer XRD results reveal the presence of cubic Co3O4, hexagonal rGO, and emeraldine salt structure of PANI. SEM images reveal dense interconnected PANI fibers and rGO clusters across the quasi-cube-like Co3O4 structure. (Co3O4/rGO)/PANI (80%:20%) composites offer excellent optoelectronic properties with 2.32 eV bandgap. As the concentration of PANI increases, the (Co3O4/rGO)/PANI (40%:60%) exhibits 1673 dielectric constant, making it suitable for various electronics and electrical engineering applications. The electrochemical findings show that the (Co3O4/rGO)/PANI (60%:40%) based electrode has an exceptional capacitance of 3103.27 F/g at 2 A/g, maintaining a capacitance of nearly 92% after 10,000 continuous cycles. The composite also exhibits an extraordinary specific capacitance of 2101.3 F/g at 5 mV/s and the lowest ohmic resistance. These findings support the use of the (Co3O4/rGO)/PANI (60%:40%) ternary composite as a valuable and innovative electrode for supercapacitors.

Optical, structural and conductivity properties of ferrous sulfate doped polyaniline

Conducting polyaniline -ferrous sulfate composite was prepared by the chemical oxidative polymerizing method by adding different weight % of finely powdered ferrous sulfate salt during polymerization of polyaniline. The oxidative polymerization of aniline is carried out by using ammonium persulfate as an oxidant. The synthesized PANI/FeSO4 composites were characterized with FTIR, XRD, SEM, DSC, UV–Vis., and discussed conducting properties. FTIR characterization is done in KBr medium, the results reveal the formation of polyaniline composite with ferrous sulfate. XRD characterization shows a decrease in the crystallinity of the PANI composite with an increase in dopant concentration and morphology also observed to change with dopant as revealed by the SEM images. Based on Differential Scanning Calorimetry (DSC) profiles one can see clear evidence for the insertion of the salt in the polymer matrix. The variation of band gaps with dopant concentration is studied using UV– Visible spectroscopy, which shows that both direct and indirect band gaps of the doped PANI decrease with increase in dopant concentration. The conductivity of PANI composite is found to increase with an increase in the concentration of the salt. These results show that doping with FeSO4 is a very effective technique for altering the electrical and optical properties of PANI.

Preparation of Symmetrical Capacitors from Lignin-Derived Phenol and PANI Composites with Good Electrical Conductivity.

As a natural polymer, lignin is only less abundant in nature than cellulose. It has the form of an aromatic macromolecule, with benzene propane monomers connected by molecular bonds such as C-C and C-O-C. One method to accomplish high-value lignin conversion is degradation. The use of deep eutectic solvents (DESs) to degrade lignin is a simple, efficient and environmentally friendly degradation method. After degradation, the lignin is broken due to β-O-4 to produce phenolic aromatic monomers. In this work, lignin degradation products were evaluated as additives for the preparation of polyaniline conductive polymers, which not only avoids solvent waste but also achieves a high-value use of lignin. The morphological and structural characteristics of the LDP/PANI composites were investigated using 1H NMR, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and elemental analysis. The LDP/PANI nanocomposite provides a specific capacitance of 416.6 F/g at 1 A/g and can be used as a lignin-based supercapacitor with good conductivity. Assembled as a symmetrical supercapacitor device, it provides an energy density of 57.86 Wh/kg, an excellent power density of 952.43 W/kg and, better still, a sustained cycling stability. Thus, the combination of polyaniline and lignin degradate, which is environmentally friendly, amplifies the capacitive function on the basis of polyaniline.

Role of polyaniline/molybdenum trioxide nanocomposites in tuning the characteristics of humidity sensors

AbstractReal time humidity monitoring is crucial in several fields such as pharmaceuticals, electronic device manufacturing, in agricultural irrigation system due to drastic changing climates and so forth. In this work, we studied humidity sensing behavior of molybdenum trioxide (MoO3) in composition with conductive polyaniline (PAni). The conductive PAni used in the present study was in the emeraldine salt (ES) form and was doped with amino tris‐methylene phosphonic acid (PAni‐ATMPA) as a potential candidate for humidity sensors. PAni‐ATMPA is synthesized by oxidative polymerization of aniline monomers and ATMPA in the ratio of 1:1. Thus synthesized PAni and hydrothermally synthesized MoO3 were mixed together to form nanocomposites. The synthesized composites were then used to fabricate planar sensors on alumina substrate with pre‐deposited silver electrodes. XRD analysis of synthesized MoO3 shows an orthorhombic crystal structure whereas synthesized PAni shows amorphous nature. FESEM analysis of synthesized MoO3 shows sheet‐type morphology. Different compositions of MoO3:PAni were prepared by varying MoO3 and PAni wt%. The fabricated sensors were then tested over the range of 20%–90% RH and concluded that the sensitivity of the composite is seen to be higher for the composite with 20% PANi and 80% MoO3 with response time, recovery time and the linearity 7 s, 4 s, 13–62 RH% respectively. The above mentioned parameters are found to be improved in the composites as a result of PAni addition to MoO3 than the pristine MoO3. The experimental knowledge demonstrates that the films showed good repeatability (with and reproducibility (with uncertainty). Altogether, these results indicate that it is possible to tune the humidity sensing characteristics by optimizing the amount of MoO3 and PAni in MoO3:PAni composite.