Polyaniline Nanoparticles Research Articles

PSS-doped PANI nanoparticle/Ti3C2Tx composites for conductometric flexible ammonia gas sensors operated at room temperature

The detection of ammonia (NH3) is significant because it can seriously damage human health and atmospheric environment. However, the development of high-performance flexible NH3 gas sensors operated at room temperature is still challenging. Thus, a flexible NH3 film sensor based on poly(4-stryenesulfonate)-doped polyaniline nanoparticle (PANI:PSS)/Ti3C2Tx composite was developed by in-situ polymerization. This optimized PANI:PSS/Ti3C2Tx film displayed the high response of 0.57–1 ppm NH3, which was improved by 1.78-fold in comparison with PANI:PSS film. Besides, the response value of this film to NH3 was 1.46 times higher than to NO2, and this value was much higher than to other interfering gases (NO, toluene, ethanol, and acetone). Additionally, this film sensor possessed excellent mechanical stability and low detection limit (20 ppb) at room temperature. The abundant Schottky heterojunctions formed in PANI:PSS/Ti3C2Tx composite, the numerous -SO3H groups introduced by PSS anion chains, and the improved protonation degree of PANI component are responsible for the enhanced sensing properties. The monitoring experiment of shrimp spoilage has demonstrated the application feasibility of this film sensor. This research provides a novel and practical method for constructing high-performance polymer/MXene based gas sensors.

Investigation of structural and optical properties of ternary polyaniline–polypyrrole–nickel oxide (PANI‐PPy‐NiO) nanocomposite for optoelectronic devices

AbstractA new ternary nanocomposite comprising nickel oxide (NiO) embedded into a binary polymeric network of polyaniline (PANI) and polypyrrole (PPy), i.e. PANI‐PPy‐NiO, is synthesized using an in situ chemical oxidative method. The infrared spectrum of PANI‐PPy‐NiO exhibits most of the characteristic peaks of unary nanoparticles with slight shift in the frequencies. The shift is due to the synergistic interaction of binary PANI‐PPy with the inorganic NiO nanoparticles. X‐ray diffraction pattern reveals the semicrystalline structure of the PANI‐PPy‐NiO nanocomposite with an average crystallite size of 22 nm. From Williamson–Hall plot, the micro‐strain value of as‐prepared PANI‐PPy‐NiO is found to be −0.16727. Surface morphology of PANI‐PPy‐NiO shows fine grains of NiO‐encapsulated PANI‐PPy that tend to coalesce and form an agglomeration assembly. The elements detected from energy‐dispersive X‐ray analysis indicate the purity of synthesis of the ternary material. Further, the optical constants obtained from UV–visible spectra (absorption coefficient, extinction coefficient, refractive index, optical conductivity and real and imaginary dielectric constants) are found to be higher for PANI‐PPy‐NiO than for the unary PANI, PPy and NiO nanoparticles. Tauc plot and Urbach energy studies indicate the low bandgap energy of PANI‐PPy‐NiO (2.67 eV) compared to unary nanoparticles. Further, the emission intensity peak (492 nm) observed in the photoluminescence spectrum of PANI‐PPy‐NiO corresponds to the blue region of the visible spectrum. Thus, the optical studies clearly indicate the high suitability of the synthesized PANI‐PPy‐NiO in visible‐light‐based device applications. © 2022 Society of Industrial Chemistry.

Protein-sized nanozymes «artificial peroxidase» based on template catalytic synthesis of Prussian Blue

We report on Prussian Blue based nanozymes, comparable in size with a natural enzyme peroxidase. Protein-sized nanoparticles have been synthesized in the course of reduction of ferric ion (Fe3+) and ferricyanide ([Fe(CN)6]3-) one-to-one mixture in reversed micelles (isooctane|AOT|water) used as templates. Aniline chosen as the best reductant for this aim has led to formation of composite (according to Raman spectroscopy) Prussian Blue – polyaniline nanoparticles. The protein-like size of the nanoparticles (∅ = 4 – 6 nm) has been confirmed by DLS and TEM imaging. Kinetic investigations of peroxidase-like activity in reversed micelles resulted in the catalytic rate constant belonging to the same size-dependence as regular bulk catalytically synthesized nanozymes (slope ≈ 2.6), allowing to denote the reported Prussian Blue nanoparticles synthesized in reversed micelles as nanozymes «artificial peroxidase». Hydrogen peroxide sensors made by dipping the suspension of the latter onto the electrode support, displayed two-fold higher sensitivity as compared to the Prussian Blue film-based ones. Protein-sized nanozymes «artificial peroxidase» would obviously provide an advantage over regular nanozymes in (bio)sensors and analytical kits.

CeO2/PANI/MoS2 composite electrode for symmetric supercapacitor application

This work presents, the synthesized CeO2/PANI/MoS2 tri-composite performance as a symmetric electrode material for supercapacitor application. Analysis of XRD and FTIR was performed on the synthesized materials to investigate their crystalline structure and functional groups. The tri-composite SEM morphology shows a sheet-like structure covered with aggregated cerium and polyaniline nanoparticles. The electrochemical performances of the composite were done using the two-electrode symmetric system in 0.5 M of H2SO4. The resultant specific capacitance from the cyclic voltammetry was 177 F/g at 5 mV/s and from galvanostatic charge-discharge was 62 F/g at 0.5 current density. At 5 A/g, the composite demonstrated 98% capacitance retention after 2000 cycles. The impedance of the electrode materials was studied using electrochemical impedance spectroscopy. The tri-composite's solution resistance and transfer resistance values were 3.09 Ω and 0.51 Ω respectively.

Stretchable strain sensor with high sensitivity, large workable range and excellent breathability for wearable electronic skins

Stretchable strain sensors with integrated attributes of flexibility and robustness are urgently required owing to their promising applications in healthcare monitoring and environment detection. Herein, we achieved a highly stretchable thermoplastic polyurethane (TPU) mat (PUM) through electrospinning, then decorated with polyaniline (PANI) nanoparticles bridged by reduced graphene oxide (rGO) nanosheets by in-situ polymerization and ultrasonication. The rGO/PANI/TPU mat (GPTM) was then assembled as the strain sensor (GPTSS), showing a wide sensing range of 0.1%–300% strain, high gauge factor (GF) of 3000.2, favorable sensing stability, short response time (90 ms) and excellent long-term durability after 10000 stretching/releasing cycles, which endows the strain sensor with high discernibility for detecting intricate human motions. The GPTSS shows the capacity to precisely monitor ammonia gas (as low as 5 ppm), which can be used to detect harmful gases. The integrated capabilities of strain sensing and environmental monitoring promote the progress of high-performance electronics.

Red-emitting polyaniline-based nanoparticle probe for pH-sensitive fluorescence imaging.

Fluorescent probes based on semiconducting polymer nanoparticles (NPs) such as polyaniline (PANI) usually require external fluorophore doping to provide fluorescence function. Direct use of PANI-based NPs for bioimaging applications has been limited by PANI's weak blue fluorescence and aggregation-induced quenching in physiological medium. In this report, we developed a facile solid-state synthesis method to produce fluorescent polyaniline nanoparticles (FPNs) that are not only water-soluble but also exhibit high intensity and pH-sensitive red fluorescence. The FPNs showed high photoluminescence quantum yield (PLQY) of 19.3% at physiological pH, which makes FPNs ideal for application as fluorescent nanoprobes in bioimaging. Moreover, we performed an in-depth study of photoluminescence dependence on pH and the phenomena of exciton-polaron quenching at low pH was highlighted. We also found that the ratio of emission intensity at 600nm and 650nm increased from 0.04 to 1.65 as pH was raised from 2.6 to 11.8, which could find its application in ratiometric pH sensing. FPNs exhibited excellent biocompatibility with >85% cell viability for fibroblasts NIH/3T3 and prostate cancer 22RV1 cells even at concentrations as high as 1000μg/mL. In addition, fluorescence microscopy demonstrated concentration-dependent red fluorescence in the cytoplasm owing to the cellular uptake of FPNs in prostate cancer cells.

Structural Properties of Prepared PANI/TiO2 Nanocomposite by Chemical Polymerization

A progression of Polyaniline (PANI) and Titanium dioxide (TiO2) nanoparticles (NPs) were prepared by an in-situ polymerization strategy within the sight of TiO2 NPs. The subsequent nanocomposites were analyzed using Fourier-transform infrared spectra (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Analysis (EDX) taken for the prepared samples. PANI/TiO2 nanocomposites were prepared by various compound materials (with H2SO4 0.3 M and without it, to compare the outcome of it) by the compound oxidation technique using ammonium persulfate (APS) as oxidant within the sight of ultrafine grade powder of TiO2 cooled in an ice bath. Nanocomposites were prepared by the addition of TiO2 with two weight ratios (0.3 and 0.5 wt. %) during the polymerization of PANI. The outcomes showed good collaboration between PANI and TiO2. FTIR spectral shows a shift to higher wave numbers in the peaks of PANI/TiO2 nanocomposites, due to the Coulomb force that resulted from the interaction between the TiO2 nanoparticles with PANI. SEM results show that the TiO2 nanoparticles enwrap the polyaniline and agglomeration of uneven distribution of TiO2 particles can be seen in the PANI matrix. The intensity of the peak in the EDX analyses was found to appear by adding the nanoparticles. XRD pattern of PANI polymerization and PANITNCs shows that the TiO2 NPs and PANI affected the crystallization performance of nanocomposites, it was identified that the TiO2 NPs form a relatively irregular distribution in the PANI chain.

Hydrogen production by the layer-by-layer assembled films of PAni-TiO2-AuNPs

The production of high-performance and low-cost nanomaterials enables scale-up within the production sector for green hydrogen. In this regard, polymer films, such as composite films that consist of polyaniline (PAni), titanium dioxide (TiO2), and gold (AuNP) nanoparticles assembled by a layer-by-layer (LbL) technique, have been applied for hydrogen production as efficient photocatalysts. These composite films have been shown to be suitable materials for photochemical and photoelectrochemical hydrogen production, wherein the film morphology and thickness control photocatalytic performance. In addition, reflectance diffuse spectroscopy (UV–vis) was used to establish the synthesis conditions by verifying the plasmon resonance surface of PAni (emeraldine salt - ES) and AuNPs. The presence of PAni-ES increases film crystallinity (XRD) and avoids electron-hole recombination, providing a high recombination time of 9.38 s (3.93 s and 4.2 s for lesser crystalline sample). Thus, the hydrogen photochemical production also increases up to 2 times due to fewer trap states. Furthermore, the composite films can be used as photoanodes in photoelectrochemical hydrogen production due to their current stability. The bands position were calculated through Mott-Schottky and showed increased overpotential for the hydrogen evolution reaction from −0.46 V for bare TiO2 to ∼1.9 V for the best thin film. These results have interesting implications for the synthesis of photocatalytic materials because they identify the crucial parameters necessary for obtaining high-performance and low-cost materials for hydrogen production.

Natural high-porous diatomaceous-earth based self-floating aerogel for efficient solar steam power generation

The application of solar steam generation in seawater desalination is an effective way to solve the shortage of fresh water resources. At present, many kinds of photothermal conversion materials have been developed and used as evaporators in seawater desalination. However, some evaporators need additional thermal insulation or water supply devices to achieve efficient photothermal conversion. In addition, their complex, time consuming and no scalable preparation process, high cost of raw materials and poor salt resistance hinder the practical application of these evaporator. Owing to its distinctive nanoporous structure, diatomite as fossilized single-cells algae diatoms is a promising natural silica-based material for seawater desalination. They are taken from sea and that makes true sense to use them in the sea. Herein, we report the first example of synthesis robust three-dimensional (3D) natural-diatomite composite by assembling polyaniline nanoparticles covered diatomite into the polyvinyl alcohol pre-treated melamine foam frameworks and demonstrate its application as new evaporator for seawater desalination. The porous framework does not only improve the sunlight scattering efficiency, but also offer large network of channels for water transportation. The inherent mechanism behind salt desalination process involves the absorption of water molecules on the surface of the internal silica micro-nano pores, and evaporation under the heat induced by the polyaniline absorbed sunlight. Meanwhile, the metal ions are segregated by many available pores and channels to achieve the self-desalting effect. The developed evaporator possesses the superiority of multi-stage pore structure, strong hydrophilicity, low thermal conductivity, excellent light absorption, fast water transportation and salt-resistant crystallization as well as good durability. The evaporation rate without an additional device is found to be 1.689 kg m−2 h−1 under 1-Sun irradiation, and the energy conversion efficiency is as high as 95%. This work creates a platform and develops the prospect of employing green and sustainable natural-diatomite composite evaporator for practical applications of seawater desalination.

“Polyaniline nanoparticles: A study on its structural, optical, electrochemical properties along with some possible device applications”

In this report, the Polyaniline (PANi) nanoparticles (NPs) were synthesized by in-situ polymersation method. These PANi NPs were characterized by various standard techniques. The crystal structure study were done by Powder X-Ray diffraction (XRD) technique and confirms its amorphous structure. Scanning Electron Microscopy (SEM) images showed that this material shows micron size microfibers made up of NPs with less porosity. The Fourier Transform Infrared (FT-IR) spectroscopy confirms PANi NPs formation and dominant vibrations corresponding to its Quinone and benzene rings were very much visible in the data. From the UV-Visible spectroscopy data, the absorption data confirms the transitions related to its Quinone ring and pyran rings. The optical band gap was estimated to be around 2.47 eV and this material follows indirect allowed transition. From the Photoluminescence (PL) data, it showed various emission line in visible region after exciting it by various UV photons. PL data also confirms defects and bipolaron formation in it. The Cyclic Voltammetry (CV) of PANi was also studied and the parameters like specific capacitance (CP), energy density (ED),and power density (PD) were estimated. For the current material, the value of CP, ED, PD were calculated to be around 72F/g, 144 J/cm3, and 0.9 W/m3 respectively. Further the energy bands like highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of this material was determined by employing CV and the value obtained goes well as calculated by optical absorption techniques. The Electrochemical Impedance Spectroscopy (EIS) carried on PANi NPs (under different studied conditions) also reveals the formation of defects or the play of existing defects with the incident light photons. From practical application point of view, a diode like structure of this material was also fabricated. To this diode, current-voltage (I-V) and dielectrics spectroscopy measurements was carried out in dark and with photons of various wavelengths. Under different measured conditions, the I-V characteristics showed non-linear behavior. Under above experimental situations, the various parameters related with I-V characteristics were also calculated. Also this material show self-powered phenomenon, one of the essential conditions for photo detector/sensor applications. Further this device was also subjected to transient measurements. The reverse recovery time for this diode was calculated to be around 3.04 μs. The capacitance and loss studied on this device shows well dispersion with applied frequency. The observed capacitance and loss also show some changes in presence of different color of photons. The experimental data and overall properties shown by this material correlate with each other. The various properties shown by this material projects it a good candidate for future flexible optoelectronics applications.

Room Temperature Operating, Fast and Reusable Polyaniline Sensor Synthesized Ultrasonically Using Organic and Inorganic Acid Dopants

In this paper we report a simple, green method for synthesis of polyaniline (PANI) nanoparticles by chemical oxidative polymerization with the assistance of ultrasonic irradiation. The polyaniline nanomaterials were synthesized with several organic acid dopants (tartaric acid (C4H6O6) and oxalic acid (C2H2O4)) and inorganic acid dopants (hydrochloric acid (HCl) and perchloric acid (HClO4)). A comparative study of the effect of the organic and inorganic acid dopants on the sensing properties of PANI for ammonia (NH3) vapors at room temperature was performed. It was observed that the electrical properties of the doped PANI depended on the type of the acid dopant. A remarkable change in resistance was observed upon doping with the different acid dopants. Structural and morphological studies and composition analysis were performed by UV-visible, FTIR, XRD and SEM techniques. The highest conductivity was obtained for PANI with HClO4 acid dopant while the lowest conductivity was obtained for PANI with tartaric acid dopant. The results showed that PANI doped with tartaric acid was an excellent sensor with fast response time and an enhanced sensitivity (26.1% for 5 ppm and 56% for 100 ppm) for NH3 gas at room temperature. PANI doped with organic acids showed faster recovery following NH3 treatment as compared to PANI doped with inorganic acid dopants. The PANI doped with tartaric acid sensor showed excellent stability for 350 days. In summary ultrasonic irradiation and the nature of the dopants showed significant effects on enhancing the sensing performance.

Silver nanoparticles decorated a hybrid of PANI/MoS2 and PANI/WO3 as potential catalysts for direct photoelectrochemical oxidation of glucose

AbstractThis paper presents an effective electrodeposition method for generating hybrid material based on polyaniline (PANI), n‐type semiconductor (MoS2/WO3), and silver nanoparticle (AgNPs) which can trigger direct oxidation glucose in solution without an enzyme catalyst. To do so, the working electrode surface is firstly electrochemically modified by the PANI layers decorated with MoS2 and/or WO3, then electrodeposition of AgNPs on the as‐prepared electrode is carried out subsequently. The addition of WO3 and/or MoS2 and AgNPs to PANI matrix improves interfacial charge transfer efficiency. Especially, under light irradiation, the synergistic effect of n‐type semiconductor and AgNPs into the PANI matrix prompted its higher electrocatalytic activity which is exploited for direct oxidation of glucose in solution without the presence of any enzyme. This strategical approach reveals a promising manner for generating non‐enzymatic glucose electrochemical sensors upon laser excitation.

Electrochemical study of modified glassy carbon electrode with polyaniline nanoparticles using cyclic voltammetry

ABSTRACT. The mechanical attachment method was used to modify the glass carbon electrode (GCE) with polyaniline nanoparticles (PANI NPs) to produce a new nanosensor (PAN NPs/GCE). Electrochemical properties was studied by a new nano working electrode using cyclic voltammetric (CV) technique to develop the oxidation – reduction reaction. K4[Fe(CN)6] solution is one of the standard solutions for CV titration by redox peak current of FeII/FeIII in KCl solution as electrolyte, which can be used to study different concentrations, scan rates, pH, diffusion coefficient (Df) and reliability and stability PAN NPs/GCE modified electrode. The CV results of the new PANI NPs/GCE nanosensor have two peaks at 400 and 200 mV for oxidation-reduction FeII/FeIII, respectively. The current ratio value of the new PAN NPs/GCE was found to be Ipa/Ipc ≈ 1 with a separation peak of ∆Epa-pc = 200 mV. From these results, the nanosensor acts as an irreversible and heterogeneous reaction. Other electrochemical properties of the new sensor have a low detection limit of K4[Fe(CN)6]. In addition to the highly enhancement of the redox peak current in acidic pH, it was obtained good stability of nanomaterial on the electrode.
 
 KEY WORDS: Polyaniline nanoparticles, GCE, K4[Fe(CN)6], Redox process, Cyclic voltammetry
 Bull. Chem. Soc. Ethiop. 2022, 36(3), 687-696. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i3.17

Solvent-assisted self-assembly to fabricate a ternary flexible free-standing polyaniline@MXene-CNTs electrode for high-performance supercapacitors

MXene, a kind of booming two-dimensional (2D) nanomaterials, has exhibited a promising application on free-standing high-performance supercapacitors. However, researches on MXene-based cathodes are still under development because its susceptibility to oxidation. Herein, a flexible free-standing polyaniline@MXene-carbon nanotubes (CNTs) film was prepared by a delicately-designed solvent-assisted self-assembly method followed with a vacuum filtration process. The zero-dimensional (0D) polyaniline (PANI) nanoparticle, which is often used as a cathode nanomaterial, was coated on the surface of 2D MXene nanosheets by solvent-assisted self-assembly to prevent MXene from oxidation and provide high specific capacitance simultaneously. The one-dimensional (1D) CNTs were introduced to endow the composite with well mechanical strength and flexibility. The ternary composite film delivers an excellent mechanical performance with a tensile strength of 99.4 MPa, a high specific capacitance of 463 F g−1 at 5 mV s−1, and good cyclic stability with 92 % capacitance retention after 10,000 cycles. The asymmetric supercapacitor device assembled with the ternary composite film as cathode and the prepared free-standing MXene-CNTs as anode achieves a high energy density of 10 Wh kg−1 and an exceptional power density of 2808 W kg−1.

A New Comparative Potentiometric Method for Analysis of Omarigliptin Using Three Different Sensors

AbstractThis work represents first attempt for potentiometric determination of the most recent antidiabetic; omarigliptin. Three sensors, employing potassium tetrakis (p‐chlorophenyl) borate as a lipophilic cation exchanger, were developed and compared. One liquid contact ion‐selective electrode and two carbon paste‐based solid contact ones, plain one and another one modified with polyaniline nanoparticles, were employed. Performances of fabricated sensors were assessed as per IUPAC recommendations. Incorporation of hydrophobic polyaniline nanoparticles as ion‐to‐electron transducer layer at solid contact/ion‐sensitive membrane interface enhanced sensitivity and stability of the third sensor showing LOD of 2.5×10−7 mol L−1 and slope of 58.57 mV decade−1. The three sensors were applied for omarigliptin determination in presence of its degradation products, in dosage form and spiked human plasma.

Boosting biohydrogen production from dairy wastewater via sludge immobilized beads incorporated with polyaniline nanoparticles

In this study, the immobilization of anaerobic sludge in sodium alginate (SA) with polyaniline (PANI) nanoparticles (NPs) was performed for producing biohydrogen from dairy wastewater (DWW). The effect of PANI on immobilization in SA was investigated at different PANI concentrations (5, 10, 20, 40, and 80 mg L−1). DWW, PANI NPs, and immobilized beads were characterized through physicochemical analysis, surface area, X-ray diffractometry, and scanning electron microscopy (SEM). The results revealed that the immobilization of anaerobic sludge in SA with PANI NPs enhanced the degradation of organic matter in DWW into volatile fatty acids and biohydrogen yield. There is a direct relationship between PANI NPs concentration in SA, degradation in DWW, and bio-hydrogen production. The degradation of organic matter in terms of chemical oxygen demand reached 75.5% at the optimum dose of PANI NPs (40 mg L−1), which confirmed the high reactivity of PANI NPs with SA compared with the control sample. In addition, at 40 mg L−1 PANI NPs concentration, the maximum hydrogen yield were 54.5 mL g−1 VS from anaerobic fermentation was obtained with a 285% increase compared with the fermentation without using any PANI. The SEM image of beads before and after treatment indicated that the addition of PANI NPs up to 40 mg L−1 enhanced the production of bio-hydrogen yield through SA in a regular pattern, whereas increasing the concentration to 80 mg L−1 resulted in shrinking of SA surface and consequently decreased the biohydrogen yield.

Highly Stretchable, Ultra‐Soft, and Fast Self‐Healable Conductive Hydrogels Based on Polyaniline Nanoparticles for Sensitive Flexible Sensors

AbstractHerein, novel conductive composite hydrogels are developed with high stretchability, ultra‐softness, excellent conductivity, and good self‐healing ability. The hydrogels are formed in the water/glycerol binary solvent system, in which the polyaniline nanoparticles (PANI‐NPs) are incorporated into the poly(poly(ethylene glycol) methacrylate‐co‐acrylic acid) (P(PEG‐co‐AA)) scaffolds via the dynamically electrostatic interactions and hydrogen bonds. The PANI‐NPs serve as conductive fillers to assign conductivity to the hydrogel, while the enhanced interfacial interactions between the PANI‐NPs and P(PEG‐co‐AA) matrix endow the hydrogel with high stretchability (>1000%), low modulus (≈6 kPa), excellent elasticity (η = 0.07, energy loss coefficient at 500% strain), and fast self‐healing ability (93.3% after 10 mins). Particularly, the desirable anti‐freezing property is achieved by introducing a binary solvent system. The composite hydrogel‐based sensors are proposed, with the states‐independent properties, low detection limit (0.5% strain and 25 Pa), highly linear dependence, and excellent anti‐fatigue performance (>1000 cycles). In addition, during the practical wearable sensing tests, various external stimulus and human motions can be detected, including speaking, writing, joint movement, or even small water droplets, indicating the potential applications for the next generation of epidermal sensors.

P-doped PANI/AgMWs nano/micro coating towards high-efficiency flame retardancy and electromagnetic interference shielding

With the rapid development of 5G technology, functional coatings with both high-efficiency flame retardancy and electromagnetic interference shielding (EMI) are urgently needed, while traditional inefficient methods have encountered bottlenecks. Herein, we demonstrate an eco-friendly and multifunctional nano/micro coating constructed by biomass phytic acid (PA) induced polymerization and self-assembly of polyaniline (PANI) nanoparticles and dip-coating of silver microwires (AgMWs). In this design, PA with high flame-retardant efficiency is smartly doped into PANI to achieve P-N synergistic flame retardancy and improve electrical conductivity of PANI simultaneously. Consequently, under the coaction of AgMWs, P-doped PANI nanoparticles, as well as unique continuous micro-nano structures, the nano/micro coating can endow commercial polyurethane (PU) foams with outstanding EMI shielding performance (∼51 dB in X-band). Meanwhile, the coated PU foam exhibits high flame retardancy due to the P-N synergistic effect of PA/PANI, which self-extinguishes immediately after ignition during the UL-94 vertical burning test, shows a high limiting oxygen index (LOI) value of 34.8%, and exhibits a 50.7% lower peak heat release rate compared with pure PU foam. Further, the functional nano/micro coating with three-dimensional and highly porous structure makes the foam thermally insulating and infrared stealthing. The eco-friendliness and simplicity of this method and its successful application in commercial PU foam make it potentially applicable for the preparation of various kinds of multifunctional EMI shielding materials.

The Contribution of Polyaniline and Gold Nanoparticles for Enhancing Current Signals of Streptavidin Based Immunosensors

The presence of streptavidin has been found to serve as an electrically insulating layer. This could reduce the initial current response of an electrochemical immunosensor, reducing its performancefor detecting the analyte of interest. The work aimed to investigate the current response of the streptavidin based electrochemical immunosensor at polyaniline and gold nanoparticle modified screen-printed electrodes and compare to without gold nanoparticle addition. The result of the streptavidin modified gold nanoparticles - polyaniline sensor exhibited a three-times higher current response than that of the streptavidin modified polyaniline sensor (without gold nanoparticle).Additionally, antibody immobilization (EpCAM as a model) on the modified electrode showed high performances for use further in antigen target detection. The high conductivity of the developed immunosensor could become a promising candidate for immunosensor development with high sensitivity in the future.

Characterization and optical properties of polymer nanocomposite films for optoelectronic applications

Polymer nanocomposite films combining polyaniline (PANI) and lead (II) sulfide (PbS) nanoparticles (PbSNPs) were effectively synthesized using a casting solution approach for use in optical energy applications. Transmission electron microscopy, X-ray diffraction and infrared spectroscopy showed that PbSNPs were successfully introduced into the PANI matrix. Scanning electron microscopy images revealed that lead (II) sulfide was homogenously loaded and distributed in the PANI chain. Using ultraviolet–visible optical absorbance, the optical parameters of PANI/PbSNPs were evaluated, including absorption edge (E d), bandgap (E g), carbon cluster number (N) and Urbach energies (E u). PbSNPs were investigated for their impact on PANI polymer linear optical as well as non-linear optical characteristics, including refractive index, non-linear susceptibility and dielectric parameter. When comparing the PANI/PbSNP film to the pure PANI film, the bandgap of the PANI/PbSNP samples was found to be reduced significantly. However, the addition of PbSNPs increased the predicted value of optical conductivity and the carbon cluster number. The addition of PbSNPs to the PANI polymer improved its optical characteristics, resulting in a synthetic composite that can be used in energy applications as well as optoelectronic devices.