Polyaniline Nanowires Research Articles

Ternary MXene/PANI/ZnO-based composite with a built-in p–n heterojunction for high-performance supercapacitor applications

Abstract Two-dimensional (2D) Ti3C2T x MXene-based materials have attracted widespread attraction in the field of energy storage owing to their high conductivity and accordion-like structure. However, challenges such as restacking and oxidative degradation of the Ti3C2T x MXene structure lead to poor stability, low conductivity, low specific capacitance and, consequently, a low specific energy, hindering their extensive adoption at an industrial scale. In this study, a ternary MXene/polyaniline (PANI)/ZnO (MPZ) composite has been synthesized via surface engineering of two-dimensional (2D) MXene using one-dimensional (1D) PANI nanowires and ZnO nanoparticles to enhance its specific energy and stability while sustaining its specific power. 1D PANI nanowires and ZnO nanoparticles act as spacers to prevent restacking, while also exposing the suppressed redox active sites of 2D MXene and preventing it from being oxidized by forming a porous conductive network all over the surface of the MXene. PANI and ZnO also provide additional electroactive redox sites by forming p–n heterojunctions, thus enhancing faradaic redox reactions and the specific capacitance of the MPZ composite. As a result, the overall electrochemical performance and stability of the ternary MPZ composite are enhanced due to the synergistic interactions among the individual components within the ternary MPZ composite. At a low current density of 0.1 A g−1, the ternary MPZ composite exhibited a maximum specific capacitance of 651.96 F g−1 and a highest specific energy of 32.59 Wh Kg−1 while maintaining a specific power of 60 W Kg−1 as compared to MXene and binary MP composite. Furthermore, it showcased exceptional cyclic stability over 10 000 cycles with 94.75% and 92.95% capacitive retention at 0.6 A g−1 current density and 40 mV s−1 scan rate, respectively. Thus, this current study highlights an effective strategy to enhance the specific energy of MXene-based supercapacitors through surface engineering and the construction of p–n heterojunctions within the composite.

First report for the voltammetric determination of Lamivudine anti-HIV drug in tablet dosage forms by glassy carbon electrode modified with polyaniline nanowires

First report for the voltammetric determination of Lamivudine anti-HIV drug in tablet dosage forms by glassy carbon electrode modified with polyaniline nanowires

A stable and low-fouling lead ion-selective electrode employing polyaniline-MXene composite for solid contact and polypeptide for antifouling

A biofouling-resistant solid-contact lead ion-selective electrode (Pb2+-ISE) with enhanced stability was developed based on dendritic peptides and polyaniline-MXene composites. The biofouling-resistant dendritic peptides, characterized by their high level of hydration and relative conformational entropy, effectively inhibit nonspecific adsorption. Simultaneously, the synergy between polyaniline nanowires and MXene nanosheets is harnessed to enhance the ion-electron transfer rate, thereby improving the stability of the ISE. The fabricated Pb2+-ISEs exhibit commendable electrochemical short-term stability and can rapidly respond to potential changes within 1 second. Under bacterial solution storage conditions, the peptide-modified ISEs maintain their Nernstian response without significant alteration for up to six days. Additionally, the Pb2+-ISEs are insensitive to O2, CO2, N2, and light, making them suitable for the analysis of Pb2+ in real complex samples. The strategic design incorporating dendritic peptides as a biofouling-resistant layer and the PANI-MXene composite as a conductive layer offers an effective approach to construct low-fouling ISEs capable of operating robustly in complex systems.

Growth of polyaniline nanowire arrays on boron nitride microrods enables high‐efficient thermal transport

AbstractThe rapid development of flexible conductive materials has promoted the research on conductive polymer (CP)‐based materials. However, CPs have relatively low thermal conductivity (TC), which can result in severe heat dissipation problems for device applications. In this work, core–sheath structured polyaniline@boron nitride (BN@PANI) composites were prepared by in‐situ growth strategy, in which PANI nanowire arrays were uniformly anchored to the surface of BN microrods. Thanks to the particular structure, the as‐prepared BN@PANI composite shows excellent thermal management capabilities. Specifically, the TC of the BN@PANI composite is 4.32 W/m·K at low BN loading of 10 wt%, which is almost 17.8 times that of pure PANI. Moreover, the excellent heat dissipation performance is intuitively presented through infrared imaging technology. Impressively, the PANI nanowire arrays are vertically arranged on the BN surface to form a conductive pathway, which results in conductivity comparable to pure PANI. This work broadens the ideas for preparing high‐performance CP‐based composites by using insulating fillers.Highlights Core–sheath structured BN@PANI composites were prepared by an in‐situ growth strategy. The thermal conductivity of composite was 4.32 W/m·K at 10 wt% BN loading. The introduction of BN had little effect on the conductivity of PANI. The BN@PANI composites possessed excellent thermal management capability. This work contributes to understanding heat transport in conductive polymers.

Polyaniline nanowires decorated nickel phosphides hollow spheres hydrogen evolution catalyst for proton exchange membrane electrolysis

Cost-competitive proton exchange membrane water electrolyzer (PEMWE) requires efficient and earth-abundant electrocatalyst to replace Platinum for hydrogen evolution reaction (HER). We report here a polyaniline (PANI) nanowires decorated Ni2P hollow spheres catalyst and its exceptional activity toward HER in 0.5 M H2SO4 aqueous and PEMWE. The excellent catalytic activity of HER originates from unique hybrid structure of PANI/Ni2P with good conductivity, decent surface activity and optimal porous property. As a cheaper alternative to Pt/C, we used PANI/Ni2P as the cathode to set a PEMWE cell (Nafion® 117 membrane), the cell showed a current density of 1.0 A cm−2 at 1.822 V and 2.0 A cm−2 at 2.026 V, which is comparable with Pt/C (1.778 V at 1.0 A cm−2, and 2.086 V at 2.0 A cm−2). Our catalyst maintained a stable performance in a PEM electrolysis at a current density of 1.0 A cm−2 with the temperature of 80 °C, and preserved surface morphology and electron state well after 320 h continuous electrolysis. This study offers PANI/Ni2P HER catalyst as a cheaper replacement for Pt/C in PEMWE and provides a new insight to design earth-abundant catalysts for HER.

Electrochromic Electrode Based on Polyaniline and Silver Nanowires Based Localized Surface Plasmon Resonance

Electrochromic Electrode Based on Polyaniline and Silver Nanowires Based Localized Surface Plasmon Resonance

Mechanical and electrochemical properties of carbon nanotubule-polyaniline nanowire/polyaniline nanoparticle high-strength ultra-flexible aerogel buckypaper

The carbon nanotube-polyaniline nanowire/polyaniline nanoparticle (CNT-PANInw/PANInp) aerogel buckypaper (BP) was constructed, where PANI nanoparticles were uniformly embedded into the CNT network, and a series of downhanging PANI nanowires were grown in situ on the CNT monofilaments. The aerogel BP with 80 µm thickness had a PANI load of 3.5 mg/cm2 and a porosity of 69%. The cross-junctions between CNT monofilaments were anchored by polyvinyl alcohol gel. It had a tensile strength of 25 MPa, with a strain of 11.4%, being folded along sharp creases or violently rubbed without damage. The specific capacitance of the aerogel BP electrode decreased from 3.070 to 2.064 F/cm2, as the current density increased from 2 to 8 mA/cm2, with a capacitance retention of 67.2%. Its specific capacitance was 1.720 and 1.560 F/cm2 after 2000 folding in halfunfolding and 200 zigzag foldingunfolding cycles, respectively, with the capacitance retention of 84.0% and 76.2%, at 8 mA/cm2. Its specific capacitance was 1.832 and 1.224 F/cm2 after 2000 and 10,000 charge-discharge cycles, respectively, with the capacitance retention of 88.8% and 59.3%, at 8 mA/cm2. Its residual specific capacitance after 10,000 cycles was higher than most of the reported initial value of the materials with similar compositions.

Flexible and efficient MXene/PANI/aramid fabrics with high interface durability for wearable electromagnetic wave shielding

The electromagnetic pollution of electronic equipment has a negative impact on the health of aircrews working in special environments. Yet wearable electromagnetic interference (EMI) shielding materials capable of versatility still a challenge. Herein, an effective strategy is developed to construct MXene/PANI/aramid fabric by growing vertically aligned polyaniline (PANI) nanowire arrays on the aramid fabric through impregnating with highly conductive MXene nanosheets to avoid the new accumulation/aggregation of MXene followed by simple polyetherimide (PEI) dipping packaging. In-situ polymerization of PANI solved the problem of weak interaction between inert aramid fiber and MXene to some extent, while PEI packaging solves the existing problem of easy-to-fall MXene nanosheets. The final prepared single-layer composite fabric has suitable highest EMI shielding efficiency value of 31.87 dB, good washing resistance and excellent bending stability (only 4% of the conductivity decreases after 1000 bends). This study provides a simple and easy large-scale method to fabricate multifunctional wearable fabrics to meet the practical application in EMI shielding area.

Polyaniline nanowire arrays on biomass-derived carbon nanotubes with typha longbracteata for high-performance symmetric supercapacitors

Biomass-derived carbons have great competitive advantages in supercapacitor because of their structure diversity, excellent electrochemical performance and environmental protection. In this paper, the biomass-derived carbons nanotubes (BCNs) are fabricated by carbonization of typha longibracteata (TL). Then, the polyaniline nanowire arrays (PANI NWAs) are vertically grown on the TLBCNs to obtain the PANI NWA/TLBCNs electrode by in-situ polymerization. The prepared TLBCNs have a length of ~200 μm and a diameter of ~5 μm, and PANI NWAs have a length of 400 nm. The electrode appears a specific capacitance of 565.9 F·g−1 (at 1 A·g−1). The symmetric supercapacitor has an energy density of 25.4 Wh·kg−1 (at the power density of 1.58 kW·kg−1). Its specific capacitance is retained 87.9 % (after 5000 cycles at 1 A·g−1). Therefore, the PANI NWA/TLBCNs is a hopeful electrode material for the energy storage devices.

Nucleation and growth mechanisms in the electrochemical synthesis of Ag/polyaniline nanocomposites

Nucleation and growth mechanisms in the synthesis of polyaniline nanowires (PANI NWs) and of silver nanoparticles (AgNPs) which are assembly to PANI NWs, are proposed. Aniline polymerization proceeds over a graphite electrode at potentials that go from 0.9 V to 1.15 V (vs Ag/AgCl), using: 0.25, 0.15, or 0.05 M of aniline in HNO3 solution. In the polyaniline nucleation and growth is postulated a diffusional 3D model that involves the dendrites formation and the unidirectional growing step. At lowest aniline concentration, the transients displayed the typical peaked shape, characteristic of a 3D nucleation and diffusion-controlled growth. Silver nanoparticles are synthesized on the polyaniline/graphite substrate. Current-time transients at −0.1 V and −0.2 V (vs Ag/AgCl), displayed a decreasing in the current which is fit to Cotrell modified diffusion-limited aggregation model. Nanowires and nanoparticles morphology observed by SEM corroborated the proposed mechanisms.

A novel sustainable cornstalk-derived porous carbon composited with in-situ polymerized polyaniline nanowires for high-performance asymmetric supercapacitors

In this work, a novel renewable cornstalk-derived porous carbon/polyaniline (PC/PANI) composite used as the electrode material for high-performance asymmetric supercapacitors is synthesized by a facile in-situ polymerization of aniline in the presence of cornstalk-derived PC. The three-dimensional hierarchical PC is successfully prepared by a KOH activation route combined with sodium chloride (NaCl) and potassium chloride (KCl) as the salt templates and cornstalk as carbon source, which the specific surface area reaches 1181.6 m2·g−1. As an electrode material, the PC/PANI possess a high specific capacitance of 1041.2 F·g−1 at 0.5 A g−1 in 1 M H2SO4 electrolyte, compared with the bare PC (234.1 F·g−1) or single PANI (335.6 F·g−1). Moreover, what is noteworthy is that the asymmetric supercapacitor based on PC/PANI electrode exhibits high energy density (31.2 Wh·kg−1) and power density (8135.2 W·kg−1) in a voltage window of 0–1.8 V, as well as an excellent cycling stability (91.2 % capacitance retention over more than 10,000 cycles), revealing that the superior properties of PC/PANI electrode have a substantial promotion for the development of high-performance supercapacitors.

Prostate specific antigen quantification in human serum supported by the designed four-in-one octabranched peptides and AgNPs-based signal amplifier

BackgrounIt remains challenging for biosensors to directly detect clinical targets in complex biological media with high selectivity and low fouling. MethodsHerein, an antifouling and ultrasensitive biosensor supported by the designed four-in-one octabranched peptides and signaling amplification strategy of silver nanoparticles (AgNPs) was constructed for prostate specific antigen (PSA) quantification in human serum. Chondroitin sulfate functionalized polyaniline (PANI) nanowires and gold nanoparticles (AuNPs) were electrodeposited onto the electrode in sequence to promote electrons transport, and followed by the attachment of the designed octabranched peptides. Significant findingsThe peptides were specially designed to contain four structural domains, namely anchoring domain (CC), linking domain (PPPP), antifouling domain (EKEKEKE), and recognition domain (HSSKLQK). AgNPs loaded on graphene oxide were assembled onto peptides as a signal amplification strategy. The peptides were specifically sheared off by PSA, resulting in a significantly reduced electrochemical response that can be used to sensitively indicate PSA concentration. The antifouling biosensor exhibited a linear response range from 1 × 10−14 to 1 × 10−6 M, with a low detection limit of 1.33 × 10−15 M. Furthermore, the biosensor was employed to detect PSA in clinical samples based on the four-in-one octabranched peptides, indicating feasibility of the biosensor for early clinical diagnosis.

Highly sensitive Non-enzymatic, Non-Invasive Disposable Electrochemical Polyaniline Nanocaps based Sweat Sensor for Glucose Monitoring

Diabetes has surged dramatically, leading to a significant healthcare burden worldwide. Consequently, there is a growing need for reliable non-invasive alternatives for glucose monitoring, replacing traditional blood-based analysis. Despite this, enzyme degradation and stability have posed challenges for sweat sensors. To address these obstacles, the present study emphasizes the development of a novel, non-enzymatic electrochemical sweat sensor for glucose monitoring that is painless, reliable, and based on polyaniline nanocaps. Polyaniline (PANI) nanostructures, including nanocaps, nanowires, and nanocollides, were successfully synthesized using sodium dodecyl sulphate (SDS) as a template at varying ratios. The obtained nanostructures were characterized using XRD, FTIR, FESEM, and TEM. For electrochemical analysis, a screen-printed carbon electrode (SPCE) was employed. The presence of subsistent polyaniline nanocaps structure resulted in better catalytic performance, exhibiting superior sensitivity of 94.3859 µA mM−1 cm−2 and a limit of detection (LOD) of 0.04 µM in the linear range of 10–500 µM for glucose monitoring. Furthermore, the stability of the modified PANI nanocaps@SPCE sensor was tested using a mimic sweat sample. These results suggest that the fabricated PANI nanocaps@SPCE sensor holds promise as a non-invasive sweat sensor for glucose monitoring.

Copper decorated polyaniline nanowires: A tow-step electrochemical synthesis and a development of a non-enzymatic electrochemical glucose sensor

In this work, a nanostructured electrode material based on copper metal decorated polyaniline nanowires (PANi NWs@Cu) was directly fabricated on a Pt (Pt/PANi NWs@Cu) microelectrode using a novel and effective two-step electrochemical procedure. Herein, the polyaniline nanowires were firstly electropolymerized on the Pt microelectrode using a cyclic voltammetry method, and the copper metal coated onto the polyaniline nanowires were fabricated via a chronoamperometry deposition to form the PANi NWs@Cu with an average diameter of 85 nm. The electrocatalytic activity showed that the as-synthesized PANi NWs@Cu can directly oxidize glucose in alkaline medium, which suggested that the PANi NWs@Cu can be applied as an artificial enzyme for development of a non-enzymatic electrochemical glucose sensor. Obtained results exhibits that the Pt/PANi NWs@Cu has the ability to directly detect glucose with a rapid response, high selectivity, good repeatability, excellent stability with a wide linear range of glucose concentration from 0.5 mM to 50.0 mM and a low detection limit of 94 μM. The developed Pt/PANi NWs@Cu-based electrochemical sensor also shows the ability to directly detect glucose in a 5% glucose intravenous infusion sample with an error of 1.21% from a labelled value.

Three-dimensional porous AuNPs-decorated polyaniline array for ultrasensitive determination of trace Cd(II) and Pb(II) in drinking water

Herein, a three-dimensional porous nanomaterials AuNPs-decorated polyaniline nanowire arrays/carbon nanotube (Au-PANI-array@CNT) was constructed by modified dilute polymerization and redox reaction. The Au-PANI-array@CNT exhibited a larger specific surface area (50.03 m2 g−1) and abundant mesopores (average pore size: 19.6 nm), due to the vertical growth of PANI nanowire arrays on CNT. The Au-PANI-array@CNT composite with a three-dimensional interconnected porous structure exhibited abundant electroactive sites and high adsorption capacity, significantly enhancing the deposition and electrochemical reaction process of heavy metals. The AuNPs embedded on PANI nanowries can provide high catalytic activity and multidimensional electron transport channels, further improving the detection sensitivity. A sensing platform with ultra-high sensitivity (2091, 3890 μA μM−1 cm−2) and lower limit of detection (0.18, 0.15 nM) for Cd(II) and Pb(II) determination was developed based on the three-dimensional porous PANI composite. Furthermore, the sensing mechanism of Au-PANI-array@CNT with Cd(II) was explored by XPS and FTIR spectroscopy. The current response only decreased by 5% after being stored at room temperature for 2 months, indicating that the sensor has high reproducibility and stability. Finally, the analysis of drinking water samples verified the excellent practicability of the sensor for the simultaneous measurement of trace levels (nM) of Cd(II) and Pb(II).

Carbon Inks-Based Screen-Printed Electrodes for Qualitative Analysis of Amino Acids.

Due to the great significance of amino acids, a substantial number of research studies has been directed toward the development of effective and reliable platforms for their evaluation, detection, and identification. In order to support these studies, a new electrochemical platform based on PANI/ZnO nanowires' modified carbon inks screen-printed electrodes was developed for qualitative analysis of electroactive amino acids, with emphasis on tyrosine (Tyr) and tryptophan (Trp). A comparative investigation of the carbon ink before and after modification with the PANI/ZnO was performed by scanning electron microscopy and by Raman spectroscopy, confirming the presence of PANI and ZnO nanowires. Electrochemical investigations by cyclic voltammetry and electrochemical impedance spectroscopy have shown a higher charge-transfer rate constant, which is reflected into lower charge-transfer resistance and higher capacitance values for the PANI/ZnO modified ink when compared to the simple carbon screen-printed electrode. In order to demonstrate the electrochemical performances of the PANI/ZnO nanowires' modified carbon inks screen-printed electrodes for amino acids analysis, differential pulse voltammograms were obtained in individual and mixed solutions of electroactive amino acids. It has been shown that the PANI/ZnO nanowires' modified carbon inks screen-printed electrodes allowed for tyrosine and tryptophan a peak separation of more than 100 mV, enabling their screening and identification in mixed solutions, which is essential for the electrochemical analysis of proteins within the proteomics research field.

A nanowire-on-microrod polyaniline@FeS2 hybrid as the cathode in high-performance Al-ion batteries.

A nanowire-on-microrod structured polyaniline (PANI)@FeS2 hybrid was developed via a facile metal-organic framework (MOF)-derived chemical method. The in situ grown PANI nanowires on the surface of pyramidal FeS2 microrods displayed better mechanical flexibility and improved Al-storage performance. The PANI nanowires not only enhanced electron transfer during the electrochemical reaction, but also accommodated the volume expansion of FeS2 during discharge. The PANI@FeS2 hybrid as the cathode in AIBs delivered a reliable battery capacity of 152.8 mA h g-1 along with a Coulombic efficiency of >96.5% after 500 cycles at a current density of 1.5 A g-1. In addition, a high capacity retention of 160.2 mA h g-1 after 150 cycles at 0.5 A g-1 at -10 °C was achieved. These findings provide a feasible strategy by constructing a nanowire-on-microrod hybrid that can be applied in high-performance secondary batteries.

Phosphomolybdic acid-modified polyaniline nanowires with abundant acidic sites for efficient photocatalytic reduction of nitrate to nitrogen in water

Although polymeric conductive polyaniline (PANI) is an effective material for catalytic nitrate reduction in water, its catalytic efficiency is limited. Here, we report that phosphomolybdic (PMoA) acid-modified PANI nanowires exhibit superior activity in the catalytic reduction of nitrate to harmless N2. Excellent catalytic efficiency is attributed to the construction of Z-scheme heterojunctions and the combined contribution of chemical-photocatalytic reduction. Pyridine infrared analysis confirms that the introduction of PMoA adds an abundance of acidic sites to PANI, which explains the extraordinary N2 selectivity. Additionally, DFT calculations are used to determine the band structures and surface electron transfer pathways of the two materials. Impressively, the effectiveness of catalytic nitrate reduction under various conditions is evaluated together with the practicality of PMoA-PANI by simulating saltwater. This work sheds new light on the mechanism of polymer for efficient reduction of nitrate and develops innovative technology for the remediation of practical wastewater.

One-step synthesis of ultrafine silver-decorated polyaniline nanowire arrays for trace analysis of sulfamethoxazole

Sulfamethoxazole (SMX), a broad-spectrum antibiotic, has potential risk of ecological damage and human health, due to its over-dosage utilization and wanton discharge. It is desirable to develop a highly sensitive sensor for the rapid and accurate determination of SMX to evaluate the environmental risk of antibiotics. Herein, an ultrafine Ag nanoparticles-decorated polyaniline nanowire arrays (AgNPs-PANI-NAs) were successfully formed on the carbon nanofibers (AgNPs-PANI-NAs@CNF) by in-situ one-step redox reaction. The PANI wire length around CNFs and the AgNPs amount were conveniently tuned by adjusting Ag+ concentration. The conductivity and electrochemical activity of the AgNPs-PANI-NAs@CNF were significantly improved. With AgNPs-PANI-NAs@CNF as sensing material, the resultant AgNPs-PANI-NAs@CNF modified glassy carbon electrode (AgNPs-PANI-NAs@CNF/GCE) presented a super-high electrochemical response to the oxidation of SMX by strong interaction of SMX with the sensing interface. A wide linear range (1 nM ∼ 10 μM) was achieved with an ultra-low detection limit (80 pM, S/N>3). The chronocoulometry measurement proved that the adsorption capacity of SMX at AgNPs-PANI-NAs@CNF/GCE was significantly enhanced, thus improving the sensitivity of SMX detection. The related reaction mechanism and strong interaction of SMX with AgNPs-PANI-NAs were demonstrated by X-ray photo spectroscopy and ultraviolet-visible spectroscopy characterization. This work provides a novel strategy of constructing high-performance sensing materials for pollutants analysis in environmental waters.

A glassy carbon electrode modified with polyaniline nanowires: An electrochemically effective surface area and an electrocatalytic activity for the oxidation of methanol under alkaline conditions

Polyaniline nanowires are directly synthesized on a glassy carbon electrode (3 mm diameter) by an electrochemical process. The polyaniline nanowires, of uniform size, a diameter of 85–95 nm, and high conductivity, distribute evenly throughout the surface of the working electrode. Electrochemical measurements are conducted in order to determine the electrochemically effective surface area of the obtained glassy carbon electrode modified with polyaniline nanowires, and an investigation of the electrocatalytic activity of polyaniline nanowires for the oxidation of methanol under alkaline conditions is carried out. The electrochemically effective surface area of the glassy carbon electrode modified with polyaniline nanowires is nearly 27 times larger than that of a glassy carbon electrode. In a cyclic voltammetry curve of the glassy carbon electrode modified with polyaniline nanowires measured in a 3.0 M CH3OH and 0.5 M KOH solution, an anodic peak corresponding to the oxidation of methanol under alkaline conditions appears at 0.17 V with a peak current of 34.4 μA.