PANI NFs Research Articles

Polyaniline nanofibers based gas sensor for detection of volatile organic compounds at room temperature

In the present study, toluene gas sensor was developed by depositing the film of polyaniline nanofibers (PANI NFs) on silicon substrate. PANI NFs were synthesized by in situ chemical oxidative polymerization method using aniline as monomer. PANI NFs were confirmed by the x-ray Diffraction (XRD), Fourier Infrared Transform Spectroscopy (FTIR), Field - Emission Scanning Electron Microscope (FE-SEM) and High Resolution-Transmission Electron Microscope (HR-TEM). The FE-SEM and HR-TEM were showed that interconnected nanofibers structure of the PANI particles. The diameters of the PANI NFs were measured in range 70–80 nm and length in 400–450 nm. These PANI NFs were explored for the volatile organic compounds (VOCs) sensing such as toluene, ethanol, chloroform, acetone and methanol in the concentration ranging from 50 ppm to 1000 ppm. PANI NFs based sensor was observed to be selective for low concentration of toluene than all VOCs tested. Sensitivity of the PANI NFs sensor found to be 24.5% for 50 ppm for toluene gas. The response and recovery time for toluene (400 ppm) were observed to be 92 s and 120 s, respectively. The PANI NFs sensor was observed to be stable for 45 days.

Preparation of PEI nanofiber membrane based on in situ and solution crosslinking technology and their adsorption properties

ABSTRACTTwo kinds of PEI (Polyethyleneimine) nanofibers membrane were successfully prepared by electrospinning and crosslinking technology, which were insoluble in water. One Polyethyleneimine/ Epichlorohydrin/ Polyacrylonitrile nanofibrous films (abbreviated as PEI/ EPI/ PAN NFs) was prepared by in situ crosslinking of PEI/PAN nanofiber containing of EPI, and the other PEI/ PAN/ EPI NFs was prepared by crosslinking PEI/ PAN nanofibers using EPI solution. The composition and morphology of nanofibers before and after crosslinking were investigated by infrared spectroscopy and scanning electron microscopy. PEI/EPI/PAN nanofibers exhibited excellent adsorption properties toward heavy metal ions and methyl orange dyes, which can also be reused multiple times. The adsorption rate of methyl orange remained around 75% after 4 cycles, meanwhile, the adsorption rate of copper and lead still remained around 90% after 5 cycles. In addition, we found that PEI/ PAN/ EPI nanofibers prepared by solution crosslinking technology solved the problem of easy gel formation in in situ crosslinking technology and facilitated the continuous production of PEI/ EPI/ PAN nanofibers, which is better than in situ crosslinking technology. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48279.

Performance of Polyaniline Nanofibers (PANI NFs) as PANI NFs-Silver (Ag) Nanocomposites (NCs) for Energy Storage and Antibacterial Applications

The conductive property of polyaniline nanofibers (PANI NFs) has attracted great attention due to their higher capacitance, high flexibility, low cost, and ease of synthesis. Herewith, it is demonstrated that at room temperature, the template-free synthesized PANI NFs show the properties of PANI NFs–silver nanocomposites (Ag NCs) without a silver precursor with a new physical insight into energy storage devices and antibacterial applications. The diffraction peak at 2θ = 19.1° using X-ray diffraction analysis indicates the silver nature. UV–vis absorption peaks at 408 and 369 nm indicate the silver absorption (HCl-doped). The spectroscopic studies by FTIR, Raman, and NMR indicate that the PANI NFs behave in a similar manner to PANI NFs-Ag NCs with 48.47 S cm–1 conductivity and 570 F g–1 capacitance. Morphological studies by FESEM (size: 50 nm) and HRTEM reveal that the growth of PANI NFs is one-dimensional and more preferable. It also shows higher bacterial inhibition at lower values of minimum inhibitory...

Zno/Carbon nanofibers for efficient adsorption of lead from aqueous solutions

ABSTRACT Hybrid nanofibers based on ZnO loaded activated carbon nanofibers (ZnO-ACNFs) are proposed here for the elimination of hazardous lead from aqueous solutions. The prepared ZnO nanoscale material was loaded into the polyacrylonitrile nanofibers (PAN NFs) which were later carbonized by using a novel method named as a plate-sandwich method. The Synthesized nanofibrous composite was characterized by SEM, TEM, EDX, FTIR and XRD techniques to analyze its chemical and morphological properties. Moreover, the nanocomposite was efficaciously applied for the lead (Pb2+) ions removal from wastewater and simulated water through continuous filtration and batch filtration. The ZnO-ACNFs membrane showed outstanding results in adsorptive removal, giving adsorption capacity of 92.59 mg/g within the contact time of 45 min. Compared to their counterparts (ZnO and CNFs), the hybrid ZnO-ACNFs showed excellent performance in removing toxic lead.

Degradation of methyl orange on Fe/Ag nanoparticles immobilized on polyacrylonitrile nanofibers using EDTA chelating agents

Bimetallic nanoparticles are effective for the removal of organic pollutants from environmental water samples through catalytic degradation reactions. Hence, this work reports on the preparation of Fe/Ag bimetallic nanoparticles immobilized on electrospun polyacrylonitrile nanofibers (PAN NFs) pre-functionalized with EDTA and ethylenediamine (EDA) chelating agents. Characterization techniques included attenuated total reflectance coupled to Fourier transform infrared spectrometer (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The liquid chromatography coupled to a mass spectrometer (HPLC-MS) was used to investigate the degradation by-products. The impregnation of EDTA-EDA chelating agents imparted changes on the pristine PAN NFs as evidenced by increased nanofiber's average diameter and surface chemistry. The zero valent Fe and Ag NPs were successfully immobilized on PAN NFs and their catalytic activity was tested for the degradation of azo dyes. Results showed efficient decolourization of methyl orange dye molecules from synthetic water samples after four (4) cycles of reuse (e.g. >96% removal efficiency). The hydrogenation of methyl orange was found to be the removal mechanism due to the presence of hydrogenated methyl orange by-products in the treated water samples. Therefore, the fabricated nanocomposites exhibit potential application for the remediation of textile wastewater.

Fe(III)-Tannic Acid Complex Derived Fe3C Decorated Carbon Nanofibers for Triple-Enzyme Mimetic Activity and Their Biosensing Application.

In the past decade, nanomaterials-based artificial enzymes have emerged as a hot spot in the field of catalysis. However, it is a significant challenge to fabricate functional nanomaterials for multiple-enzyme mimetic activity. In this work, we have presented an efficient catalytic platform to mimic peroxidase, oxidase, and catalase-like activity by Fe3C decorated carbon nanofibers (Fe3C/C NFs). First, polyacrylonitrile nanofibers (PAN NFs) are prepared via an electrospinning technique. Next, an Fe(III)-tannic acid (TA) complex is formed on the surface of PAN NFs through a wet chemical reaction. Finally, Fe3C/C NFs are obtained from the carbonization of the PAN/Fe(III)-TA complex nanofibers. The prepared Fe3C/C NFs show an excellent triple-enzyme mimetic property including peroxidase-like, oxidase-like, and catalase-like activity, which is investigated thoroughly by the colorimetric experiment of the 3,3',5,5'-tetramethyl benzidine oxidation and the degradation of H2O2. Thanks to the superior catalytic performance of Fe3C/C NFs for oxidase mimicking, a facile and colorimetric way to determine glutathione with a high sensitivity and favorable selectivity has been achieved. This work provides an efficient platform for multiple-enzyme mimicking, which may expand their promising applications in biosensing, biomedicine, and environmental technology.

Insights into the structural, optical, thermal, dielectric, and electrical properties of PMMA/PANI loaded with graphene oxide nanoparticles

Polyaniline nanofibers (PANI NFs) was prepared by Interfacial and rapid-mixing polymerization Fourier transform infrared (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) were used to examine of pure nanofibers. The structural, optical, thermal, and conductivity properties of pure blend and PNCs were studied by using FTIR, XRD, SEM, UV–Vis., DTA-TGA, and Ac conductivity measurement techniques and have been prepared using the casting method. The analysis of FT-IR reflects forming hydrogen bond between the PANI and PMMA. Also it's confirmed the presence interaction between GO NPs with the functional groups of PMMA/PANI matrix. The XRD data revealed the increase of amorphous domains of nanocomposites comparing to that of the pure polymer blend. The SEM indicates the uniform distribution of GO NPs on the surface of the prepared samples. From UV. Vis showed the values of optical energy gap (direct and indirect) for pure blend and nanocomposites decreases with increasing content of GO NPs. Based on DTA and TGA data, the thermal stability of all the investigated samples were improved and the activation energies were calculated. Electrical conductivity analysis indicates that the 0.9 wt % sample have a larger conductivity compared to that of prepared samples. The increase in conductivity was mainly due to the increase in mobility of charge carrier according to free-volume model.

Fabrication of Conducting Polyacrylate Resin Solution with Polyaniline Nanofiber and Graphene for Conductive 3D Printing Application.

Three-dimensional printing based on the digital light processing (DLP) method offers solution processability, fast printing time, and high-quality printing through selective light curing of photopolymers. This research relates to a method of dispersing polyaniline nanofibers (PANI NFs) and graphene sheets in a polyacrylate resin solution for optimizing the conductive solution suitable for DLP-type 3D printing. Dispersion and morphology of the samples with different filler contents were investigated by field emission scanning electron microscope (FE-SEM) and optical microscope (OM) analyses. The polyacrylate composite solution employing the PANI NFs and graphene was printed well with various shapes and sizes through the 3D printing of DLP technology. In addition, the electrical properties of the printed sculptures have been investigated using a 4-point probe measurement system. The printed sculpture containing the PANI NFs and graphene sheets exhibited electrical conductivity (4.00 × 10−9 S/cm) up to 107 times higher than the pure polyacrylate (1.1 × 10−16 S/cm). This work suggests potential application of the PANI NF/graphene cofiller system for DLP-type 3D printing.

Hydrous CeO2-Fe3O4 decorated polyaniline fibers nanocomposite for effective defluoridation of drinking water

Hydrous CeO2-Fe3O4 (HCeFe) decorated polyaniline nanofibers (HCeFe NFs) were obtained through a simple co-precipitation deposition approach on pre-synthesized polyaniline nano-fibers (PANI NFs), and evaluated as adsorbents for fluoride removal from synthetic and real water samples. Field emission scanning electron microscopy/energy dispersive X-ray spectroscopy (FE-SEM/EDS), high resolution-transmission electron microscopy (HR-TEM), Braunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric-differential thermal analysis (TGA-DTA), X-ray photoelectron spectroscopy (XPS) and dynamic mechanical analysis (DMA) techniques were used to characterize the hybrid nanomaterials. The optimised HCeFe NFs adsorbent with specific surface area 66 m2/g, exhibited excellent adsorption efficiency towards fluoride ions (F−) via both electrostatic interactions and ion exchange mechanisms. F− adsorption followed the pseudo-second-order rate model and best fitted the Langmuir isotherm, with the maximum capacities within 93.46–117.64 mg/g over a broad pH range 3–10, respectively. The determined thermodynamic parameters, including enthalpy (ΔH° − 15.1 kJ/mol) and Gibbs free energies change (ΔG° < 0) indicated to the exothermic and a spontaneous nature of the sorption process. The regeneration of HCeFe NFs showed a considerable adsorption-desorption efficiency over three consecutive cycles. Ultimately, the adsorbent was tested on spiked F− containing groundwater and the obtained results demonstrated its potential utility for defluoridation of natural water.

Self-powered ammonia nanosensor based on the integration of the gas sensor and triboelectric nanogenerator

A new self-powered ammonia (NH3) nanosensor with flexibility, portability, good selectivity and sensitivity has been developed from conducting polyaniline nanofibers (PANI NFs) based triboelectric nanogenerator (TENG). The power supply and gas sensor have been successfully integrated into one device. The PANI NFs with NH3 sensing property work both as a frictional layer and an electrode in the TENG. The TENG shows high output performance with the maximum short current circuit of 45.70 μA and output voltage of 1186 V in air, while its output voltage is obviously reduced in varying degrees after being exposed to NH3 with different concentrations, resulting from the change of electroconductivity of PANI, which is the design principle of the NH3 sensor. Meanwhile, this NH3 nanosensor exhibits good selectivity and sensitivity with the limit detection of 500 ppm at room temperature. This work proposes a new thought to design the self-powered NH3 nanosensor, which has the widespread application prospect to harvest ambient energy for detecting toxic NH3 without any external power sources.

Triboelectrification based on double-layered polyaniline nanofibers for self-powered cathodic protection driven by wind

Polyaniline nanofibers (PANI NFs) are introduced to construct a wind-driven triboelectric nanogenerator (TENG) as a new power source for self-powered cathodic protection. PANI NFs serve as a friction layer to generate charges by harvesting wind energy as well as a conducting layer to transfer charges in TENG. A PANI NFs-based TENG exhibits a high output performance with a maximum output voltage of 375 V, short current circuit of 248 μA, and corresponding power of 14.5 mW under a wind speed of 15 m/s. Additionally, a self-powered anticorrosion system is constructed by using a PANI-based TENG as the power source. The immersion experiment and electrochemical measurements demonstrate that carbon steel coupled with the wind-driven TENG is effectively protected with an evident open circuit potential drop and negative shift in the corrosion potential. The smart self-powered device is promising in terms of applications to protect metals from corrosion by utilizing wind energy in ambient conditions.

Fabrication of Shape‐Controlled Palladium Nanoparticle‐Decorated Electrospun Polypyrrole/Polyacrylonitrile Nanofibers for Hydrogen Peroxide Coalescing Detection

AbstractShape‐controlled palladium nanoparticle‐decorated electrospun polypyrrole/polyacrylonitrile nanofibers (Pd_PPy/PAN NFs) are fabricated by electrospinning, vapor deposition polymerization (VDP), and electrodeposition. The electrospun PAN NFs are used as the framework for a composite nanomaterial. To make the material electrically conductive, the framework is coated with PPy by VDP. As‐prepared PPy/PAN NFs are used as the working electrode during electrodeposition of Pd. During Pd introduction, the presence of sulfuric acid in the electrolyte influences the shape of the Pd nanoparticles. Sulfate ions prevent the growth of the Pd, resulting in nanoparticles with sharp features. The fabricated Pd_PPy/PAN NFs are then incorporated as the active element in an electrochemical hydrogen peroxide (H2O2) biosensor. Tailoring the morphology of the Pd nanoparticles enables a minimum detectable limit of 1 × 10−9m H2O2, which is sufficiently low for monitoring diseases related to H2O2 concentration, such as Parkinson's disease and Alzheimer's disease. The low detection limit is achieved by coalescing detection of Pd and PPy.

Phytic Acid Doped Polyaniline Nanofibers for Enhanced Aqueous Copper(II) Adsorption Capability

This study demonstrates the enhanced Cu2+ adsorption capability of polyaniline nanofibers (PAni NFs) by doping of phytic acid. The PAni NFs were synthesized by radical polymerization process using acidic solutions of hydrochloric and phytic acid, yielding chlorinated (Cl-) and phytic acid-doped (Ph-) PAni NFs. The Ph-PAni NFs showed remarkably higher Cu2+-adsorption efficiency than Cl-PAni NFs, presumably owing to high capacity and/or high ionic affinity of the doped phytic acid in Ph-PAni NFs. The pH-dependent adsorption capability exhibited increasing Cu2+ adsorption trend as increasing aqueous pH because of spontaneous deprotonation of the doped phytic acid in a basic environment. Furthermore, Ph-PAni NFs showed stable, high Cu2+ adsorption capability, irrespective of Co2+ concentration in the bimetallic Cu and Co aqueous solution. Surface morphologies of PAni NFs were investigated using electron microscopy, and molecular structures were identified using X-ray photoemission and Fourier transform infrar...

Nanoparticle intercalation-induced interlayer-gap-opened graphene–polyaniline nanocomposite for enhanced supercapacitive performances

This study demonstrates a method for improving supercapacitive performance of two-dimensional nanosheet-based composite electrode. As a hybridized electrostatic double layer capacitor–electrochemical pseudocapacitor (EDLC–PC) electrode, we synthesized reduced graphene oxide–polyaniline nanofibers (rGO–PANi NFs) composite electrode. For the enhanced supercapacitive performances, insulator silver chloride nanoparticles (AgCl NPs) were intercalated into the interlayer gap of rGO. The AgCl NP intercalation (i) exfoliated rGO layers and (ii) prevented rGO-self-agglomeration that makes it difficult to utilize the high surface-to-volume ratio of ideal mono- (or few-) atomic-thick rGO layers. As a result, (iii) the specific capacitance was improved in accordance with the enlarged specific surface area of rGO. Furthermore, (iv) the well-developed rGO edges, which were opened by the AgCl intercalation, enabled formation of more bonds between PANi and rGO by selective grafting of PANi to the rGO edges. Hence, the bonds of PANi–rGO, as conducting paths, substantially reduced the total electrical resistance. Enhanced specific capacitance, ion diffusion efficiency, and reduced electrical resistance indicated the bi-functional roles of AgCl NP insertion for high performance hybridized EDLC–PC electrodes.

Metal-Support Interactions of Platinum Nanoparticles Decorated N-Doped Carbon Nanofibers for the Oxygen Reduction Reaction.

N-doped carbon materials are discussed as catalyst supports for the electrochemical oxygen reduction reaction (ORR) in fuel cells. This work deals with the preparation of Pt nanoparticles (NPs) supported on N-doped carbon nanofibers (N-CNF) from a polyaniline nanofiber (PANI NF) precursor, and investigates the ORR activity of the produced materials. Initially, Pt NPs are deposited on PANI NFs. The PANI NF precursors are characterized by near-edge X-ray absorption fine structure (NEXAFS) and transmission electron microscopy (TEM) measurements. It is shown, that in the PANI NF precursor materials electrons from the Pt are being transferred toward the π-conjugated systems of the aromatic ring. This strong interaction of Pt atoms with PANI explains the high dispersion of Pt NPs on the PANI NF. Subsequently, the PANI NF precursors are carbonized at different heat-treatment conditions resulting in structurally different N-CNFs which are characterized by NEXAFS, X-ray photoelectron spectroscopy (XPS) ,and TEM measurements. It is shown that an interaction between N-groups and Pt NPs exists in all investigated N-CNFs. However, the N-CNFs differ in the composition of the N-species and the dispersion of the Pt NPs. A small mean Pt NP size with a narrow size distribution is attributed to the presence of pyrdinic N-groups in the N-CNFs, whereas, for the N-CNFs with mainly graphitic and pyrrolic N-groups, an increase in the average Pt NP size with a broad size distribution is found. The ORR activity in alkaline media investigated by Koutecky-Levich analysis of rotating disk electrode measurements showed a largely enhanced ORR activity in comparison to a conventional Pt/C catalyst.

Polyaniline nanofibers as highly effective re-usable adsorbent for removal of reactive black 5 from aqueous solutions

Polyaniline nanofibers (PANI NFs) with 50–80nm in diameter were successfully prepared at room temperature (22°C) using ferric chloride (FeCl3) as an oxidant via a simple rapid mixing polymerization method. The prepared PANI NFs were characterized by FE-SEM, HR-TEM, BET, ATR-FTIR and by Zeta potential measurement method. The adsorption of azo dye Reactive Black 5 (RB5) onto PANI NFs from aqueous solutions was investigated. Adsorption studies were carried out at different initial dye concentrations, initial solution pH and adsorbent doses. The kinetic data fitted well with the pseudo-second-order model while the equilibrium data were satisfactorily described by the Langmuir isotherm model. The Langmuir maximum adsorption capacity of RB5 at pH 6.0 was found to be 312.5, 389.1 and 434.7mg/g at 25°C, 35°C and 45°C, respectively. Thermodynamic parameters including the Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes indicated that the adsorption of RB5 onto PANI NFs was feasible, spontaneous, and endothermic. Moreover, desorption experiments revealed that the PANI NFs can be reused effectively for five consecutive adsorption–desorption cycles without any loss of its original capacity.

Fe-aminoclay-entrapping electrospun polyacrylonitrile nanofibers (FeAC-PAN NFs) for environmental engineering applications

Electrospun polyacrylonitrile nanofibers (PAN NFs) with entrapped water-soluble Fe-aminoclay (FeAC) [FeAC-PAN NFs] were prepared. Slow dropwise addition of water-soluble FeAC into a PAN solution, less aggregated of FeAC into electrospun PAN NFs was one-pot evolved without FeAC post-decoration onto as-prepared PAN NFs. Taking into consideration both the Fe3+ source in FeAC and the improved surface hydrophilicity, the feasibility of Fentonlike reaction for decolorization of cationic model dye methylene blue (MB) under 6 hrs UV-light irradiation was established. In the case where FeAC-PAN NFs were enhanced by hydrogen peroxide (H2O2) injection, the apparent kinetic reaction rates were increased relative to those for the PAN NFs. Thus, our flexible FeAC-PAN NF mats can be effectively utilized in water/waste treatment and other environmental engineering applications.

Ultrafine formation of optically transparent polyacrylonitrile/polyacrylic acid nanofibre fibrils via electrospinning at high relative humidity

Abstract Optically transparent and cable-like Polyacrylonitrile/polyacrylic acid (PAN/PAA) nanofibres filled with ultrafine fibrils were obtained via eletrospinning at a high relative humidity. PAN fibrils 20.8 nm in diameter were dispersed in the nanofibre core. The optical property of composite NFs membrane can be tailored by atmosphere humidity during electrospinning and the bicomponent proportion. The transmittance and the tensile strength of these composites increased with the content of PAA increasing, their transmittances were from 74.8 to 88.8% and tensile strengths were from 12.0 to 15.6 MPa, much higher than pristine PAN NFs of 46.0% and 5.7 MPa. Optically transparent PAN/PAA composites have potential to be a promising alternative as components of optoelectronic devices.

A unique solar radiation exfoliated reduced graphene oxide/polyaniline nanofibers composite electrode material for supercapacitors

Solar radiation exfoliated reduced graphene oxide (SRGO) and polyaniline nanofibers (PANi NFs) containing composite is synthesized using the typical chemical oxidative polymerization. The composite exhibits an excellent specific mass capacitance of ~655F/g owing to an optimal chemical interaction between SRGO and PANi NFs in the composite. Specific mass capacitance of the composite remains almost constant at different current densities making it expedient as a working electrode material in supercapacitors.

Electrochemically Active Polyaniline (PANi) Coated Carbon Nanopipes and PANi Nanofibers Containing Composite

A composite constituted by carbon nanopipes (CNPs) and polyaniline nanofibers (PANi NFs) is synthesized using in-situ chemical oxidative polymerization. Owing to its electrochemical activity the composite is found to be suitable as a working electrode material in hybrid type supercapacitors. Microstructural and phase analyses of the composite showed that (i) CNP surfaces are coated with PANi and (ii) PANi coated CNPs are distributed among PANi NFs. The composite shows an excellent electrochemical activity and a high specific capacitance of ~224.39 F/g. The electro-chemical activity of the composite is explicated in correlation with crystallinity, intrinsic oxidation state, and doping degree of PANi in the composite. The electro-chemical activity of the composite is also explicated in correlation with BET surface area and ordered meso-porosity pertaining to the composite. Charge/discharge curves indicate that the specific capacitance of the composite is a result of electric double-layer capacitance offered by CNPs and Faradaic pseudo capacitance offered by PANi NFs.