Oxidative Polymerization Technique Research Articles

Synthesis and characterization of enhanced azo-azomethine doped PANI/HCl conducting polymers for electrochemical applications

In this study, conducting polymers composed of polyaniline hydrochloric acid (PANI/HCl) with varying concentrations of a newly synthesized azo-azomethine dye (4-(((Z)-2-hydroxy-5-((Z)-(4-hydroxyphenyl)diazenyl)-3-methoxybenzylidene)amino)benzoic acid) were synthesized using a chemical oxidative polymerization technique. The synthesized azo-azomethine was characterized by FTIR, 1H-NMR, 13C-NMR, and HRMS. The effects of varying the concentration of the dopant azo-azomethine in PANI/HCl on its optical, structural, thermal, and electrical properties were examined using FTIR, UV–Vis, XRD, FESEM, TEM, cyclic voltammetry, and electrical impedance spectra. The results indicate that the optical, direct, and indirect band gaps of the doped polymers decreased from 4.48 and 3.96 eV to 3.91 and 2.49 eV, respectively. The crystalline structure and phase transitions in the doped polymers were examined using X-ray diffraction. Cyclic voltammetry demonstrated that the doped polymers exhibited higher electrochemical conductivity compared to the pure polymer, with the specific capacitance increasing from 161.17 to 816.9 F/g. The electrical impedance spectra revealed the bulk resistance and conductivity of the material. Among all the doped polymers, PANI/HCl with an azo-azomethine concentration of 5 × 10−5 M exhibited lower bulk resistance (10 Ω) and higher electrical conductivity (σ = 50.09 × 10−3 S cm−1).

Nanofibrous electroconductive scaffolds composed of poly(vinyl alcohol) and modified polyaniline for skin tissue engineering application

AbstractNanofibrous electroconductive scaffolds were designed and fabricated using electrospinning approach based on a poly(vinyl alcohol)‐grafted polyaniline (PVA‐g‐PANI) and neat PVA with various PVA‐g‐PANI content for skin tissue engineering (STE) application. At first, phenylamine‐functionalized PVA macromonomer was synthesized, and then aniline was grafted onto macromonomer by an oxidation polymerization technique. The resultant PVA‐g‐PANI with different ratios was co‐electrospun with PVA to afford PVA‐g‐PANI/PVA electrically conductive nanofibrous scaffolds. Physicochemical features of the scaffolds, including water uptake properties, surface wettabilities, and morphologies as well as biological properties such as biodegradabilities, cytocompatibilities, cells adhesion and proliferation potentials, hemolysis rates, and protein adsorption capacities were investigated. Surface wettabilities of the scaffolds were altered from 55.7° for pure PVA up to 105.1° for the scaffold with the highest PVA‐g‐PANI content (30 wt%). It was found that the biodegradation rates of the scaffolds were decreased by increasing PVA‐g‐PANI content owing to very low biodegradation nature of PANI. Hemolysis assay revealed that all scaffolds were nonhemolytic (hemolysis rate <2%), except the scaffold that fabricated with 30 wt% of PVA‐g‐PANI. As results, the constructed scaffolds with 15 and 20 wt% of PVA‐g‐PANI (S3 and S4, respectively) exhibited higher potentials in both physicochemical and biological properties for STE application.

Investigation of TiO2/PPy nanocomposite for photocatalytic applications; synthesis, characterization, and combination with various substrates: a review.

The use of photocatalysis technology, specifically visible light photocatalysis that relies on sustainable solar energy, is the most promising for the degradation of contaminants. The interaction of conducting polymer and titanium dioxide (TiO2) leads to the exchange that enhances the alteration of the semiconductor's surface and subsequently decreases the bandgap energy. Polypyrrole (PPy) and TiO2 nanocomposites have promising potential for photocatalytic degradation. Chemically and electrochemical polymerization are two predominant methods for adding inorganic nanoparticles to a conducting polymer host matrix. The most commonly utilized method for producing PPy/TiO2 nanocomposites is the in-situ chemical oxidative polymerization technique. Immobilizing PPy/TiO2 on substrates causes more charge carriers (electron/hole pairs) to be produced on the surface of TiO2 and enhances the rate of photocatalytic degradation compared to pure TiO2. The increased surface charge affects how electron/hole pairs are formed when visible light is used. This study provides a comprehensive investigation into the synthesis, characterization, application, efficiency, and mechanism of PPy/TiO2 nanocomposites in the photocatalytic degradation process of various pollutants. Furthermore, the effect of stabilizing the TiO2/PPy nanocomposite on various substrates will be investigated. In conclusion, the review outlines the ongoing challenges in utilizing these photocatalysts and highlights the essential concerns that require attention in future research. Its objective is to help researchers better understand photocatalysts and encourage their use in wastewater treatment.

Vanadium nitride /poly(0-methoxy aniline)- poly(3,4-ethylene dioxythiophene) interpenetrated into nanocomposite for efficient photocatalytic degradation of methylene blue and enhanced electrochemical sensing of mebendazole

Vanadium nitride-poly (0-methoxy aniline)- poly(3,4-ethylene dioxythiophene) (VN-POMA-PEDOT) hybrid was synthesized via ammonolysis and chemical oxidative polymerization technique using VN-POMA-PEDOT/GCE with electrocatalytic activity has two dimensional VN hierarchical porosity with POMA-PEDOT structure created VN-POMA-PEDOT modified GCE working electrode. Donor-acceptor behavior and double-layer growth enable enhanced electrochemical performance and catalytic activity of mebendazole (MBZ). This work investigated the electrochemical sensing conduct of a VN-POMA-PEDOT hybrid composite towards MBZ. The detection limit (DL) and quantification limit (QL) were determined to be 2.192 × 10−9 μM μA−1 and 5.245 × 10−9 M μA−1. Estimation of anti-interference ability, long-term stability, and reproducibility revealed that the prepared VN-POMA-PEDOT electrode is appropriate for the electrochemical sensing finding of MBZ in real analysis, such by way of anti-helminthic drug milk. The VN-POMA-PEDOT achieved 98.9% efficiency in the photocatalytic degradation of methylene blue (MB) within 50 min with degradation rate 8.3 × 10−3 min−1. The suppleness of this method was confirmed by the hybrid morphology VN-POMA-PEDOT, which shows an enormously superior and enhanced photocatalytic presentation of MB.

Polyaniline layered N-doped carbon-coated iron oxide nanocapsules for extremely active Li-ion battery anode and oxygen evolution reaction

We report the effective synthesis of polyaniline (PANi)-layered nitrogen-doped carbon-coated Fe3O4 (FNC@PANi) nanocapsules (NCs) for electrocatalysis of oxygen evolution reaction (OER) as well as anode material for lithium (Li)-ion batteries (LIBs) via a simple hydrothermal method and oxidative polymerization technique. The prepared FNC@PANi NCs revealed a dual core-shell structure, in which an intermediate carbon layer allowed excellent electrical conduction between the Fe3O4 NCs and PANi. The dual core-shell structure also allowed the Fe3O4 NCs to expand freely during the Li-ion insertion/extraction and OER processes without breaking the outer layer, thus providing a high surface area (147.85 m2 g−1) and enhanced electrical conductivity. These properties facilitate the application of the dual core-shell FNC@PANi NCs as an advanced electrode material for LIBs, delivering a high reversible specific capacity of 1556.48 mAh g−1 at 0.1 A g−1, excellent rate performance (896.96 mAh g−1 at 1 A g−1), and durable cycling life (680.12 mAh g−1 at 5 A g−1 for 3000 cycles). The dual core-shell FNC@PANi NCs exhibited high electrocatalytic activity in the OER, with a small Tafel slope of 108.7 mV dec−1 owing to synergistic effects between the copious active sites of the Fe3O4 NCs and the carbon core-shell structure and a modest overpotential of 219 mV at 10 mA cm−2. The electrodes showed excellent stability over 10 h, as determined by chronopotentiometry at 10 mA cm−1. The resultant dual-core-shell FNC@PANi NCs are efficient iron-oxide-based electrode materials for LIBs and OER electrocatalysts.

Influence of FRET, charge separation, and density of defect states on the improvement of UV light-driven photocatalytic activity of PMMA capped ZnO nanomaterials

This study employs oxidative polymerization, co-precipitation, and ex-situ surface capping techniques to fabricate pristine PMMA, ZnO, and PMMA-capped ZnO specimens with varying PMMA concentrations. X-ray diffraction reveals reduced directional growth of ZnO, while Fourier transform infrared spectroscopy confirms PMMA chain bonding with ZnO in PMMA-capped specimens. Scanning electron microscopy illustrates decreased average length and thickness of ZnO nanoplates post-surface modification, indicating a robust interaction between PMMA and ZnO. X-ray photoelectron spectroscopy identifies suppressed defects, including zinc interstitials and oxygen vacancies, affirming ZnO surface capping by PMMA. Absorption spectra display a blue shift in band-edge or increased bandgap, attributed to the combined effects of band alignment offset and reduced oxygen vacancy states. Luminescence spectra show gradual quenching linked to PMMA content increase, with defect-related emission suppression attributed to ZnO surface capping. UV emission suppression is ascribed to donor concentration-dependent Förster resonance energy transfer (FRET) from PMMA to ZnO. Photocatalytic tests reveal enhanced efficiency in PMMA-capped ZnO catalysts attributed to synergies involving charge separation, bulk recombination centers, oxygen vacancy states, and FRET. Efficiency improves with higher PMMA content, aligning with changes in emission intensity. The study demonstrates emission intensities' tunability through surface capping and donor concentration-dependent FRET, ultimately influencing degradation efficiency.

Comparative Study on Structural, Dielectric Behavior and AC Conductivity of PPY-PVA Incorporated with TiO2 Fine and Nano Particles

Abstract An in-situ oxidative chemical polymerization technique to prepare thin films of PPY, PVA, and PPY-PVA blend doped with variable concentrations of TiO2 fine- and nano-particles was further investigated by X-ray diffractometer (XRD) and impedance spectrometer to study structural, dielectric, and AC conducting behavior. XRD spectra established that sharp and high intense peaks of PPY-PVA- fine TiO2 films indicated more crystallinity, which might be due to higher compactness and modification in interplanar spacing. Dielectric plots revealed that PPY-PVA-nano TiO2 films exhibited higher dielectric constants and lower dielectric loss compared to films of PPY-PVA- fine TiO2 in shorter frequency region, suggesting that these films are more suitable for charge storage devices. Conductivity plots revealed that AC conductivity of pure PPY was low (4.8 x10-3 S/cm at 313 0K) and was increased to 5.3 x10-3 S/cm by addition of PVA. AC conductivities of PPY-PVA-nano TiO2 thin films are relatively higher (7.43x10-3 S/cm to 1.14x10-2 S/cm) than PPY-PVA-fine TiO2 films (6.35x10-3 to 9.78x10-3 S/cm) with increasing frequency and temperature, which could be due to large surface area to volume ratio of nano-size dopant. This suggests that PPY-PVA-nano TiO2 thin films may be used for sensing various gasses.

FLEXIBLE COMPOSITE AgNPs-PPy/CELLULOSIC PAPER ELECTRODE FOR ELECTROCHEMICAL DETECTION OF NITRATE

In this work, we describe a simple strategy for the preparation of a low-cost electrode material based on polypyrrole (PPy) film grown on an insulating cellulosic paper (CP) substrate via in-situ oxidative polymerization technique and functionalized by silver nanoparticles (AgNPs) uniformly dispersed on its surface. The properties of the obtained AgNPs-PPy composites were characterized using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The electrocatalytic activity of the prepared electrode was investigated for the electroreduction of nitrate using cyclic voltammetry in 0.1 M KOH solution. Results demonstrated that the incorporation of AgNPs into the PPy matrix significantly improves the catalytic behaviour of this film. The effect of the amount of incorporated AgNPs on the electrode response was also investigated.

Feasibility analysis of synthesized polyaniline nanocomposites loaded by Co-doped ZnO nanorods for aqueous pollutants oxidation

Polyaniline (PANI) nanocomposites (NCs) based on cobalt (Co)-doped ZnO nanorods were fabricated (PANI-NCs) using chemical oxidation polymerization technique. Co-doped ZnO nanorods were synthesized using hydrothermal route. Microstructure characterization and UV–Visible absorption measurement confirm the formation of wurtzite ZnO nanostructured crystals. Introducing effect of Co-doped ZnO nanorods into PANI matrix on microstructural, optical, surface morphology and electrical properties of the investigated NCs were studied. The characterization of the fabricated NCs was examined using X-ray diffraction (XRD), Fourier transform infrared (FTIR), high-resolution transmission electron microscopy (HR-TEM) and four-probe DC electrical conductivity. Also, the photocatalytic activity of the fabricated NCs was examined using UV irradiation for Procion Blue dye wastewater oxidation. The photocatalytic experimental parameters were studied and the results revealed high photocatalytic activity reached to complete dye removal within 60 min of irradiation time (at pH 7.0 and room temperature). Finally, the data fitted with first-order kinetic model.

Superior ammonia sensing properties of PET‐supported polyaniline/reduced graphene oxide/zinc ferrite ternary nanocomposite thin film at room temperature

AbstractThis article introduces a ternary nanocomposite‐based flexible thin film ammonia sensor developed on transparent polyethylene terephthalate (PET) substrate in the well‐known in situ chemical oxidative polymerization technique. The nanocomposite consists of three different materials: polyaniline (PANI), reduced graphene oxide (rGO), and zinc ferrite (ZF). Keeping the PANI amount constant, seven PANI/rGO/ZF (PRZ) samples are produced by performing stoichiometric variation between rGO and ZF. Later on, various structural, morphological, and spectroscopic analysis of all the composite materials is accomplished with field emission scanning electron microscopy (FESEM), high‐resolution transmission electron microscopy (HRTEM), X‐ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible spectroscopy (UV–Vis). The sensing performance of the as‐produced sensors toward ammonia (NH3) is examined in the concentration range from 250 ppb to 100 ppm. The study reveals the excellent sensing ability of the PRZ3 sensor (rGO = 30%, ZF = 20%) achieving minimum and maximum responsivity values of ~51% and ~1052%, respectively, at the lowest (250 ppb) and highest (100 ppm) concentration of ammonia. The sensor also exhibits admirable repeatability, good dynamic responsivity, rapid response (tres ~2.9–5 s), moderately faster recovery (trec ~37.9–69.7 s), superb linearity against ppm variation (R2 ~ 0.989), low detection limit (~123 ppb), and exceptional selectivity toward ammonia. The substrate temperature variation divulges that room temperature (30°C) is the ideal temperature for getting outstanding responsivity of the sensor. The study is further accompanied by humidity variation in the incoming air and bending flexibility test of the substrate. A compulsory and legitimate model regarding the sensing mechanism is presented at the end.

Synthesis and evaluation of core–shell nanocomposites for the photodegradation of liner alkyl-benzene sulfonate water contaminations

Linear alkyl-benzene sulfonate surfactants (LAS) are a major pollutant source of sewage and wastewater. They trigger severe impact on the environmental fauna and flora. Current research explores the synthesis of three different core–shell nanocomposites (CSNCs) containing titania through an inexpensive oxidative polymerization technique. The fabricated CSNCs were evaluated for the photocatalytic degradation of LAS water contaminations. The selected CSNCs investigated for this study were the TiO2/poly(aniline-co-pyrrole) and TiO2/ poly(aniline-co-3-Me-thiophene) as well as the TiO2/terpolymer (aniline-pyrrole-m-aminobenzoic acid). The structure of the formed nanocomposites was confirmed by varied characterization spectroscopy. The core–shell structure of the nanocomposites was confirmed by scanning electron micrographs and transmission electron microscopy. The CSNCs exhibited intensive photo catalytic degradation efficacy toward LAS under visible light exposure in comparison with the exposure in their absence. The parameters optimizing their photovoltaic degradation efficiency were assessed. The presented approach implies that an effective, economical, and environmentally friendly synthetic setup was achieved to produce novel CSNCs with high potential as LAS photodegradation agents.

Ultrahigh adsorption capacity of a new metal sieve-like structure nanocomposite-based chitosan-graphene oxide nanosheet coated with poly-o-toluidine for the removal of Acid Red dye from the aquatic environment

This article describes an easy and simple method to remove a toxic Acid Red dye from aqueous solution. Ternary poly(O-toluidine)/graphene oxide/chitosan P(OT)/GO/CS nanocomposites (NCs) were fabricated by an oxidative polymerization technique to remove Acid Red (A.R.) dye from aqueous solutions using solid-phase extraction. The P(OT)/GO/CS NCs exhibit a metal sieve-like structure consisting of GO nanosheets and a core shell-shell porous structure, which provides several adsorption sites and channels for the transport of dye molecules. FTIR, XRD, RAMAN, TEM, SEM, BET, and TGA-DTG investigations were carried out on NCs. To investigate the removal effectiveness of the NCs using adsorbent dose, pH and solution temperature, shaking time, and ionic strength. Experimental adsorption findings, utilizing 15 mg of solid-phase NCs, can remove the majority of the A.R. dye in 75 min at pH 2.0 with an adsorption efficiency and an adsorption capacity of 99.6% and 169.5 mg/g, respectively. The pseudo-second-order kinetic model best captures the adsorption process of A.R. dye on the NC solid phase, according to experimental data. Thermodynamically, the removal process was endothermic, spontaneous, and associated with increasing randomness. Finally, NCs were tested by removing A.R. dye from real samples. NCs removed A.R. dye from aqueous solutions for four cycles.

Thermal and microwave-absorbing properties of doped polyaniline–epoxy nanocomposites for stealth applications

The thermal properties of polymeric nanocomposites can be examined using TGA and DSC techniques, while dielectric properties can be examined through simulated scattering (S11, S12, S21, and S22) parameters. Polyaniline (PAni) nanopowder was synthesized using chemical oxidative polymerization techniques. Consequently, the crystallite size and morphology of the synthesized powder were examined using the XRD, TEM, and FESEM techniques. Further, a series of polymeric nanocomposites was developed via wet mixing and compressor molding techniques for various volume percentages (54.0, 57.5, 60.1, and 61.7 vol%) of synthesized powder within PAni/epoxy composites. Consequently, dielectric and absorbing properties have been measured using a vector network analyzer and its software module. The computed complex permittivity data were used to evaluate the absorption for different thicknesses of samples. A minimum reflection loss of − 22.3 dB (> 99.9% absorption) was optimized with broadband frequency ranges. The unique heterostructures of nanocomposite are responsible for the enhanced absorption and shielding performance.Graphical abstract

Study of CuO/TiO2/Polyindole (CTPIN) electrocatalyst in membraneless electrolyzer for solar hydrogen generation

Efficient electrocatalysts are indispensable for promoting the hydrogen evolution reaction (HER). Existing electrocatalysts are limited by sluggish HER kinetics, higher over potential leading to greater energy demand, instability over time, and low tolerance to impurities. These challenges lead to a lower solar-to-hydrogen conversion efficiency of 2.46% using MoS2 electrocatalyst in authors’ previous research work. Mixed metal oxide/conducting polymer nanocomposites have shown great potential for use in hydrogen evolution reaction (HER) reactors due to their high surface area, excellent catalytic activity, and stability in acidic and alkaline environments. A major requirement for suitable electrocatalyst is a low overpotential for hydrogen evolution, a high tolerance to impurities and a long-term durability which makes it more efficient than traditional electrocatalysts. With this brief background, the present work focuses on the application of CuO/TiO2/Polyindole (CTPIN) nanocomposite synthesized with the help of two-step process involving microemulsion and oxidative polymerization techniques. The resulting material was characterized using miscellaneous physicochemical techniques. HRTEM analysis clearly demonstrates the formation of CTPIN nanocatalysts with ultrasmall particle sizes of 10–30 nm. The nickel strip was coated with CTPIN nanoparticles was used as cathode for generating solar hydrogen through membraneless electrochemical water splitting. Membraneless electrolyzers offer a promising and cost-effective substitute to traditional electrolyzers, enabling efficient electrochemical hydrogen generation. At a radiation intensity of 320 W/m2 and under normal working conditions, the CTPIN nanocomposite demonstrated a solar-to-hydrogen generation efficiency of 3.43% which is greater than previous results obtained using MoS2. The CTPIN electrocatalyst has a high potential for electrocatalytic solar hydrogen generation. The CTPIN electrocatalyst could make it possible to produce hydrogen from clean and renewable energy source.

Successful preparation of polyaniline‐modified polystyrene novel composite membrane

AbstractThis work describes the polyaniline (PANI) nanoparticles' impregnation into the polystyrene (PS) membrane and its impact on the different membrane properties for the first time. PANI nanoparticles were synthesized separately using the oxidative polymerization technique and then impregnated into the polystyrene‐DMF matrix solution. Membranes were cast via the Non‐Solvent Induced Phase Separation (NIPS) process. The surface and structural properties of the fabricated membranes were thoroughly characterized using contact angle measurement (CA), x‐ray diffraction (XRD), Fourier‐transform infrared spectrometer (FTIR), and scanning electron microscopy (SEM). Thermal gravimetric analysis (TGA) and the mechanical characteristics of the membrane were also investigated. According to the CA results, the addition of PANI in the matrix improved the polystyrene membrane's hydrophilicity from 65° to 54.5°. The FTIR spectra revealed that the PANI nanoparticles were successfully impregnated into the PS matrix. SEM images illustrated that the porosity of the PANI‐modified membrane was enhanced by 50% compared to the pristine PS membrane. Furthermore, adding PANI to the PS membrane significantly reduced the average pore size. The filtration experiment showed that PANI modified membrane had 81% rejection of MO dye as compared to the pristine PS membrane which had 60%. Therefore, The PANI added to the PS membrane greatly enhanced the PS membrane's structural properties.

Polyaniline grafted pullulan: Optical, thermal, structural, and electrical characterization studies in combination withdensity functional theorycalculations

AbstractPolyaniline (PANI), a conducting polymer, has great interest for a large number of applications. However, poor processability and mechanical properties limits its usage and many methods like blending, grafting etc. are used to overcome this disadvantage. We have carried out grafting of PANI onto pullulan (PULL) via chemical oxidative polymerization technique. The percentage of grafting is favored by increasing concentration of aniline monomer. The formation of PANI is confirmed through UV–Vis spectroscopic studies. The possible grafting mechanism is studied using Fourier transform infrared spectroscopy and validated by Hartree‐Fock density functional theory (HF‐DFT) calculations. Further, thermal properties of grafted polymers are studied using differential scanning calorimetry and thermo gravimetric analysis. Using FESEM and x‐ray diffraction, structural properties of graft polymer were studied. DC electrical conductivity of grafted polymer is measured from I‐V characteristics, shows a significant conductivity which is the highlight of this work.

Ameliorated optical, luminescent and thermo-chemical features of polymer derived PPy-SnO2 nanocomposite as efficient emissive layer material (EML)

PPy-SnO2 (PS) nanocomposite was synthesized with varying doses of SnO2 through in-situ oxidative polymerization technique. Morphological study was performed through FESEM analysis. Particle size of the 15% PS nanocomposite was estimated in the 13–35 nm range by XRD analysis. Elemental presence and its deconvoluted states in the 15% PS nanocomposite were confirmed by XPS analysis. Optical band gap for optimized 15% PS was calculated ∼1.83 eV. PL intensity increases with increase in the concentration of SnO2. Its value was found highest for 15% PS laid in the light blue region (close to white light). CIE color coordinate study of the nanocomposites elucidated that optimized 15% PS could be used as efficient emissive layer material for WLED application. A comparative TGA study of the PPy and 15% PS illustrated that optimized 15% PS nanocomposite proved to have better thermal stability.

Synthesis and characterization of ferromagnetic polyaniline-cobalt chloride composite through in situ oxidative polymerization technique

Synthesis and characterization of ferromagnetic polyaniline-cobalt chloride composite through in situ oxidative polymerization technique

Synthesis of polystyrene/poly(o-anisidine) core/shell structured microparticle and its electrorheological behavior

We fabricated core/shell typed semiconducting poly(o-anisidine) (POA) coated polystyrene (PS) composite microspheres and used them as an electrorheological (ER) material. Micro-spherical PS seeds were initially fabricated through a dispersion polymerization method, and the semiconducting POA was coated onto the PS seeds through a chemical oxidation polymerization technique. Uniform coating of the POA onto the PS particles was confirmed via morphology analysis. Their chemical structures and thermal behaviors were identified using Fourier transform infrared spectroscopy and thermogravimetric analysis, respectively. Using a rotational rheometer, PS/POA based ER fluid (5 vol%) exhibited a yield stress of about 72 Pa under an electric field strength of 2.5 kV/mm. Over the range of electric field strength, both dynamic and elastic yield stresses grew in proportion to the power of 1.5 of the electric field strength. Dielectric properties of the ER suspension were also found to be correlated with its ER properties.

Enhanced Sensing Performance of an Ammonia Gas Sensor Based on Ag‐Decorated ZnO Nanorods / Polyaniline Nanocomposite

AbstractThe development of low‐cost ammonia sensors with high sensitivity and selectivity has gained considerable interest. Though the response of these sensors at room temperature is low and needs enhancement. In the present study high sensitivity ammonia gas sensors based on nanocomposite films of polyaniline (PANI) and with varying ZnO concentrations were synthesized and investigated. With a loading of 10 at% ZnO, the gas sensing response of 59 % was obtained for 120 ppm NH3 gas. The gas response was further enhanced by decorating the ZnO nanorods with different concentrations of silver (Ag) nanoparticles. The Ag‐decorated ZnO nanorods were embedded in the PANi matrix using the in‐situ oxidative polymerization technique. It was shown that PANi ZnO, p‐n junction, and the introduction of porosity in nanocomposite act synergistically in increasing the resistance caused by the deprotonation of PANi by NH3. Among various compositions studied, 2 % loading of Ag in ZnO embedded in PANi matrix, thin films were found to be highly selective and sensitive towards NH3 gas at room temperature with a chemiresistive response of 70 % at 120 ppm and a recovery time of less than 120 s. The selectivity of the nanocomposite was also studied towards various reducing and oxidizing gasses.