PANI NPs Research Articles

MWCNT decorated Magnetic/Ceramic/Polymer (Fe2O3/Fe3O4/SiO2/PANI) nanocomposite with enhanced microwave absorption at an entire X and Ku frequency bands

Two new magnetic/ceramic/carbon and magnetic/ceramic/polymer/carbon nanocomposites were created by decorating the surface of MWCNT with magnetic/ceramic (Fe2O3/Fe3O4/SiO2 NPs) and magnetic/ceramic/polymer (Fe2O3/Fe3O4/SiO2/PANI). First, in order to have a narrow size distribution and high saturation magnetization, Fe2O3/Fe3O4 NPs were produced successively under ideal conditions. Subsequently, Fe2O3/Fe3O4 NPs were produced by coating them with a thin layer of SiO2. Fe2O3/Fe3O4/SiO2/MWCNT nanocomposite was created by applying Fe2O3/Fe3O4/SiO2/NPs at a specified weight ratio (1/2) to the MWCNT surface. Subsequently, Fe2O3/Fe3O4/SiO2 NPs were utilized as an initiator to polymerize the aniline; as a result, Fe2O3/Fe3O4/SiO2/PANI NPs were created and the polyaniline grew at their surface. Ultimately, Fe2O3/Fe3O4/SiO2/PANI NPs were added to MWCNT at a weight ratio of 1/2, resulting in the synthesis of a Fe2O3/Fe3O4/SiO2/PANI/MWCNT nanocomposite. XRD, SEM, and TEM pictures verified the effective synthesis of Fe2O3/Fe3O4/SiO2/MWCNT and Fe2O3/Fe3O4/SiO2/PANI/MWCNT nanocomposites. By evaluating their EM characteristics, the microwave absorption properties of these composites were characterized. The findings shown that for the Fe2O3/Fe3O4/SiO2/MWCNT nanocomposite with an effective bandwidth of 5.7 GHz, the minimum reflection loss reached −18.5 dB. For the Fe2O3/Fe3O4/SiO2/PANI/MWCNT nanocomposite, there was a considerable improvement in both minimum reflection loss and bandwidth in comparison with similar composites. The Fe2O3/Fe3O4/SiO2/PANI/MWCNT demonstrated a minimum reflection loss of −87dB over whole frequency range (8–18 GHz) with an effective bandwidth.

Point-of-care diagnostics for rapid determination of prostate cancer biomarker sarcosine: application of disposable potentiometric sensor based on oxide-conductive polymer nanocomposite

One of the most important reasons for an increased mortality rate of cancer is late diagnosis. Point-of-care (POC) diagnostic sensors can provide rapid and cost-effective diagnosis and monitoring of cancer biomarkers. Portable, disposable, and sensitive sarcosine solid-contact ion-selective potentiometric sensors (SC-ISEs) were fabricated as POC analyzers for the rapid determination of the prostate cancer biomarker sarcosine. Tungsten trioxide nanoparticles (WO3 NPs), polyaniline nanoparticles (PANI NPs), and PANI-WO3 nanocomposite were used as ion-to-electron transducers on screen-printed sensors. WO3 NPs and PANI-WO3 nanocomposite have not been investigated before as ion-to-electron transducer layers in potentiometric SC sensors. The designated sensors were characterized using SEM, XRD, FTIR, UV-VIS spectroscopy, and EIS. The inclusion of WO3 and PANI in SC sensors enhanced the transduction at the interface between the screen-printed SC and the ion-selective membrane, offering lower potential drift, a longer lifetime, shorter response time, and better sensitivity. The proposed sarcosine sensors exhibited Nernstian slopes over linear response ranges 10−3–10−7 M, 10−3–10−8 M, 10−5–10−9 M, and 10−7–10−12 M for control, WO3 NPs, PANI NPs, and PANI-WO3 nanocomposite-based sensors, respectively. From a comparative point of view between the four sensors, PANI-WO3 nanocomposite inclusion offered the lowest potential drift (0.5 mV h−1), the longest lifetime (4 months), and the best LOD (9.95 × 10−13 M). The proposed sensors were successfully applied to determine sarcosine as a potential prostate cancer biomarker in urine without prior sample treatment steps. The WHO ASSURED criteria for point-of-care diagnostics are met by the proposed sensors.Graphical abstract

Novel exposition on reinforcement mechanism of nanoparticles doped gels for early diagnosis of Parkinson's disease

The early diagnosis of parkinson's disease (EDPD) is of vital importance in preventing dysfunctions of patients and improving their healthcare level. However, the smart devices currently used for EDPD are seriously restricted by the inflexibility, unwieldiness and insensitivity. Herein, polyaniline nanoparticles@ (chitosan-polyacrylic acid) (PANI NPs@(CS-PAA)) hydrogel is prepared with in-situ generated PANI NPs to regulate the performances of CS-PAA dual network (DN) hydrogel. Both the mechanical performances (the elongation at break at 1144% and the toughness at ∼318.36 kJ m−3) and the conductivity (at 9.30 S m−1) are significantly improved. However, both properties do not increase linearly with ANI concentration, but show an inverted-V trend with an inflection point. To investigate the inherent mechanism between PANI NPs and the hydrogels, the measurement with dynamic light scattering, X-ray photoelectron spectroscopy and X-ray diffraction are employed. A superimposed effect of hydrogen bonding between the amide groups of CS-PAA and the imine groups of PANI and hydrophobic association of benzene rings is revealed to play an important role in the propeties of PANI NPs@(CS-PAA) hydrogel. The resultant hydrogel provides high reliable data when serving as flexible electrode in electrocardiogram detection, and regular mornitoring results with fast response time of 0.4 s for EDPD.

Piezoelectric conductive electrospun nanocomposite PCL/Polyaniline/Barium Titanate scaffold for tissue engineering applications

Recent trends in tissue engineering technology have switched to electrical potentials generated through bioactive scaffolds regarding their appropriate effects on cell behaviors. Preparing a piezo-electrical stimuli scaffold with high electrical conductivity for bone and cartilage tissue regeneration is the ultimate goal of the present study. Here, Barium Titanate nanoparticles (BaTiO3 NPs) were used as piezoelectric material and highly conductive binary doped Polyaniline nanoparticles (PANI NPs) were synthesized by oxidative polymerization. Polycaprolactone (PCL) was applied as carrier substrate polymer and conductive spun nanofibrous scaffolds of PCL/PANI composites were prepared in two different amounts of PANI (3 and 5 wt.%). The conductivity of PCL/PANI nanofibers has been analyzed by standard four probes test. Based on the obtained results, the PCL/PANI5 (with 5 wt.% PANI) was selected due to the superior electrical conductivity of 8.06 × 10–4 s cm - 1. Moreover, the piezoelectric nanofibrous scaffolds of PCL/BT composite were electrospun in three different amounts of BT (20, 30, and 40 wt.%). To investigate the synergic effect of conductive PANI and piezoelectric BT, ternary nanocomposite scaffolds of PCL/PANI/BT were prepared using the dual jet electrospinning technique. The piezoelectric properties have been analyzed by determining the produced voltage. The morphological assessment, contact angle, mechanical test, and MTT assay have been conducted to evaluate other properties including biocompatibility of nanofibrous scaffolds. The PCL/PANI5/BT40 composite resulted in an unprecedented voltage of 1.9 Volt. SEM results confirm that BT NPs have been distributed and embedded inside PCL fibers quite appropriately. Also, the chosen scaffolds were homogeneously intertwined and possessed an average fiber diameter of 288 ± 180 nm, and a contact angle of 92 ± 7°, making it a desirable surface for cell attachment and protein interactions. Moreover, Young’s modulus, ultimate tensile stress, and elongation were obtained as 11 ± 1 MPa, 5 ± 0.6 MPa, and 109 ± 15% respectively. Obtained results assert the novel potential of piezo-electrical stimuli conductive nanocomposite scaffold for tissue engineering applications.

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

Opening MXene Ion Transport Channels by Intercalating PANI Nanoparticles from the Self-Assembly Approach for High Volumetric and Areal Energy Density Supercapacitors.

Two-dimensional (2D) MXene materials have attracted great attention as advanced energy storage devices. A Ti3C2 MXene film can be used as a high-performance electrode material for flexible supercapacitors owing to its high specific capacitance, excellent conductivity, and remarkable flexibility. Unfortunately, self-stacking of MXene nanosheets makes them hard to balance the volumetric and areal capacitance performance. Herein, high conductive polyaniline nanoparticles (PANI NPs, ∼10 nm) are proposed as intercalators to regulate the MXene nanosheet interlayer by the self-assembly method. Interlayered PANI NPs not only restrain MXene self-stacking but also enable more ion transport routes, and conductive PANI NPs filled in MXene interlayer are in the form of nanoparticles that can build interconnected conductive channels. Meanwhile, PANI NPs slightly changes the thickness of the MX/PANI NPs hybrid film, thus bringing a high volumetric capacitance. As a result, the freestanding MX/PANI NPs-10% electrode displays an excellent areal capacitance of 1885 mF cm-2 (377 F g-1), meanwhile maintains a high volumetric capacitance of 873 F cm-3 even when the load of MXene reaches 5 mg cm-2. Moreover, the symmetric supercapacitor assembled by MX/PANI NPs hybrid film demonstrates high areal energy density (90.3 μWh cm-2) and volumetric energy density (20.9 Wh L-1) compared to MXene-based symmetric supercapacitors reported in the literature. This rational design balancing areal and volumetric energy densities provides another approach for solving the inherent problems of MXene and further exploiting MXene materials toward application in advanced energy storage devices.

Effects of a Dielectric Barrier Discharge (DBD) on Characteristics of Polyaniline Nanoparticles Synthesized by a Solution Plasma Process with an Ar Gas Bubble Channel

The quality of polyaniline nanoparticles (PANI NPs) synthesized in plasma polymerization depends on the discharge characteristics of a solution plasma process (SPP). In this paper, the low temperature dielectric barrier discharge (DBD) is introduced to minimize the destruction of aniline molecules induced by the direct current (DC) spark discharge. By adopting the new electrode structure coupled with a gas channel, a low temperature DBD is successfully implemented in a SPP, for the first time, thus inducing an effective interaction between the Ar plasma and aniline monomer. We examine the effects of a low temperature DBD on characteristics of polyaniline nanoparticles synthesized by a SPP with an Ar gas bubble channel. As a result, both carbonization of aniline monomer and erosion of the electrode are significantly reduced, which is confirmed by analyses of the synthesized PANI NPs.

Gamma irradiated electro-conductive polylactic acid/polyaniline nanofibers

In this study, polyaniline nanoparticles (PANI NPs) in emeraldine base (EB) form were prepared by a modified method and characterized by FTIR and UV–vis spectroscopies. The average size of the nanoparticles was 140 nm measured by DLS method. The nanoparticles were embedded into polylactic acid (PLA) nanofibers prepared by electrospinning method. It was found that inclusion of PANI NPs in PLA resulted in reduced diameter of the fibers during the electrospinning process. Also, the surface of nanofibers appeared smooth in FE-SEM images without formation of beads. Improvement in mechanical and electrical properties of PLA/PANI nanofibers over the neat PLA nanofibers implied a good dispersion of PANI NPs in PLA matrix and existence of fairly strong interactions between two polymers. Also, wettability tests revealed that PLA/PNAI nanofibers were less hydrophobic than neat PLA. To explore the effect of irradiation on physical properties of the nanofibers, the nanofibers were exposed to gamma ray at 25 kGy which is a typical dose for sterilization of bio-implants. Then, the physical properties of irradiated nanofibers were compared with the non-irradiated counterparts in terms of electrical, mechanical and thermal properties. Also, morphology and hydrophilicity of the surface of the nanofibers after irradiation were compared with non-irradiated ones. It was concluded that gamma irradiation contributed to stronger interfacial interactions between PLA and PANI NPs that resulted in further improvements on the desired properties of the nanofibers such as wettability, electrical conductivity and tensile strength.

Stable glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes, polyaniline nanoparticles and polyaniline microparticles as ion-to-electron transducers: A comparative study

Glycopyrronium bromide solid contact ion selective potentiometric sensors using multi-walled carbon nanotubes (MWCNTs), polyaniline nanoparticles (PANI NPs) and microparticles (PANI MPs) as ion-to-electron transducers were fabricated and compared to transducer free blank sensor. Their inclusion in solid contact (SC) sensors offer shorter response time, lower potential drift and longer life time.From a comparative point of view, inclusion of MWCNTs offer longer lifetime (50days) to the SC sensor compared to PANI based SC sensors. While, the inclusion of PANI showed shorter response times. Hence, PANI-based sensors showed better stability on short term, while MWCNTs offered long term stability.PANI NPs gave faster response than MPs. This may be attributed to the higher surface/volume ratio in NPs which enlarges the contact area with the polymeric membrane, increasing the transduction at the interface. Moreover, PANI NPs showed lower potential drift and relatively longer life time than MPs. Nano-sized particles result in smooth surfaces with a good surface coverage (protection) of the underlying SC.The proposed sensors were successfully applied to content uniformity testing of GLY in a newly approved pharmaceutical dosage form with high accuracy.

Synthesis of hydrophilic and conductive molecularly imprinted polyaniline particles for the sensitive and selective protein detection

In this work, a novel kind of water-dispersible molecular imprinted conductive polyaniline particles was prepared through a facile and efficient macromolecular co-assembly of polyaniline with amphiphilic copolymer, and applied as the molecular recognition element to construct protein electrochemical sensor. In our strategy, an amphiphilic copolymer P(AMPS-co-St) was first synthesized using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and styrene (St) as monomer, which could co-assemble with PANI in aqueous solution to generate PANI particles driven by the electrostatic interaction. During this process, ovalbumin (OVA) as template protein was added and trapped into the PANI NPs particles owing to their interactions, resulting in the formation of molecular imprinted polyaniline (MIP-PANI) particles. When utilizing the MIP-PANI particles as recognition element, the resultant imprinted PANI sensor not only exhibited good selectivity toward template protein (the imprinting factor α is 5.31), but also a wide linear range over OVA concentration from 10–11 to 10−6mgmL−1 with a significantly lower detection limit of 10–12mgmL−1, which outperformed most of reported OVA detecting methods. In addition, an ultrafast response time of less than 3min has also been demonstrated. The superior performance is ascribed to the water compatibility, large specific surface area of PANI particles and the electrical conductivity of PANI which provides a direct path for the conduction of electrons from the imprinting sites to the electrode surface. The outstanding sensing performance combined with its facile, quick, green preparation procedure as well as low production cost makes the MIP-PANI particles attractive in specific protein recognition and sensing.

Application of Polyaniline Nanoparticles Modified Screen Printed Carbon Electrode as a Sensor for Determination of Hg(II) in Environmental Samples

We have described the development of electrochemical nano sensor for the detection of mercury ions from aqueous solutions based on the formation of polyaniline nanoparticle films. Screen printed carbon electrodes were modified with polyaniline nanoparticles. Electropolymerization of polyaniline nanoparticles was performed by the pulsed potentiostatic method. The sample of polyaniline nanoparticles was prepared by repeating the potential step process three times. Structural and morploigcal characterization of polyaniline nanoparticles modified screen printed carbon electrode was performed using Fourier Transmission infrared (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). PANI nanoparticles were spherical shaped having an apparent dimeter varying from 20 to 45 nm. Square wave anodic stripping voltammetry was used for the detection of Hg(II) on PANI NPs modified screen printed carbon electrode under optimized conditions. Hg(II) was deposited for 60 seconds by the reduction of Hg(II) in buffer solution:(citric acid and sodium chloride pH 2.30), followed by Hg stripping between 0.3 and 0.8 V at the following parameters: Scan rate: 100 mV s-1, frequency: 60 Hz, amplitude: 0.025 V and increment: 4.0 mV. it was found that the PANI NPs modified screen printed carbon electrode had a highest anodic stripping peak current in solution of pH 2.30. The limit of detection value for Hg(II) was found to be 2.50 ± 0.03 ppb. The limits of detections determined are below the corresponding guideline value from the World Health Organization (WHO). In addition, the modified nano electrode exhibited excellent reproducibility and high stability. The developed method was successfully applied to determine Hg(II) in real water samples with satisfactory results.

Biological pH sensing based onthe environmentally friendly Raman technique through a polyaniline probe.

The biological pH plays an important role in various cellular processes. In this work, a novel strategy is reported for biological pH sensing by using Raman spectroscopy and polyaniline nanoparticles (PANI NPs) as the pH-sensitive Raman probe. It is found that the Raman spectrum of PANI NPs is strongly dependent on the pH value. The intensities of Raman spectral bands at 1225 and 1454cm-1 increase obviously with pH value varying from 5.5 to 8.0, which covers the range of regular biological pH variation. The pH-dependent Raman performance of PANI NPs, as well as their robust Raman signals and sensitivities to pH, was well retained after the nanoparticles incorporated into living 4T1 breast adenocarcinoma cells. The data indicate that such PANI NPs can be used as an effective biological pH sensor. Most interestingly, the PANI spherical nanostructures can be acquired by a low-cost, metal-free, and one-pot oxidative polymerization, which gives them excellent biocompatibility for further biological applications.

Targeted lipid–polyaniline hybrid nanoparticles for photoacoustic imaging guided photothermal therapy of cancer

Designing a targeted and versatile photothermal agent for the integration of precise diagnosis and effective photothermal treatment of tumors is desirable but remains a great challenge. In this study, folic acid ligand conjugated lipid-coated polyaniline hybrid nanoparticles (FA–Lipid–PANI NPs) were successfully fabricated by a distinctive technology. The obtained hybrid FA–Lipid–PANI NPs with small size exhibited not only significant photoacoustic (PA) imaging signals, but also a remarkable photothermal effect for tumor treatment. With PA imaging and photothermal therapy (PTT), the tumor could be accurately positioned and thoroughly eradicated in vivo after intravenous injection of FA–Lipid–PANI NPs. These multifunctional nanoparticles could play an important role in simultaneously facilitating imaging and PTT to achieve better therapeutic efficacy.

Nano-functionalized filamentous fungus hyphae with fast reversible macroscopic assembly & disassembly features.

A uniform decoration of hyphae by polyaniline nanoparticles (PANI NPs) was achieved here. This novel hybrid structure can be effectively assembled into a film by filtration and disassembled in water by shaking. This reversible process is very fast, which promises applications in nanomaterials including adsorption.

Smart polyaniline nanoparticles with thermal and photothermal sensitivity

Conductive polyaniline nanoparticles (PANI NPs) are synthesized by oxidation of aniline with persulfate in acid media, in the presence of polymeric stabilizers: polyvinilpyrrolidone (PVP), poly(N-isopropylacrylamide) (PNIPAM), and hydroxylpropylcellulose (HPC). It is observed that the size of the nanoparticles obtained depends on the polymeric stabilizer used, suggesting a mechanism where the aggregation of polyaniline molecules is arrested by adsorption of the polymeric stabilizer. Indeed, polymerization in the presence of a mixture of two polymers having different stabilizing capacity (PVP and PNIPAM) allows tuning of the size of the nanoparticles. Stabilization with biocompatible PVP, HPC and PNIPAM allows use of the nanoparticle dispersions in biological applications. The nanoparticles stabilized by thermosensitive polymers (PNIPAM and HPC) aggregate when the temperature exceeds the phase transition (coil to globule) temperature of each stabilizer (Tpt = 32 °C for PNIPAM or Tpt = 42 °C for HPC). This result suggests that an extended coil form of the polymeric stabilizer is necessary to avoid aggregation. The dispersions are reversibly restored when the temperature is lowered below Tpt. In that way, the effect could be used to separate the nanoparticles from soluble contaminants. On the other hand, the PANI NPs stabilized with PVP are unaffected by the temperature change. UV-visible spectroscopy measurements show that the nanoparticle dispersion changes their spectra with the pH of the external solution, suggesting that small molecules can easily penetrate the stabilizer shell. Near infrared radiation is absorbed by PANI NPs causing an increase of their temperature which induces the collapse of the thermosensitive polymer shell and aggregation of the NPs. The effect reveals that it is possible to locally heat the nanoparticles, a phenomenon that can be used to destroy tumor cells in cancer therapy or to dissolve protein aggregates of neurodegenerative diseases (e.g. Alzheimer). Moreover, the long range control of aggregation can be used to modulate the nanoparticle residence inside biological tissues.

Organic memory device with polyaniline nanoparticles embedded as charging elements

Polyaniline nanoparticles (PANI NPs) were synthesized and fabricated as charging elements for organic memory devices. The PANI NPs charging layer was self-assembled by epoxy-amine bonds between 3-glycidylpropyl trimethoxysilane functionalized dielectrics and PANI NPs. A memory window of 5.8 V (ΔVFB) represented by capacitance-voltage hysteresis was obtained for metal-pentacene-insulator-silicon capacitor. In addition, program/erase operations controlled by gate bias (−/+90 V) were demonstrated in the PANI NPs embedded pentacene thin film transistor device with polyvinylalcohol dielectric on flexible polyimide substrate. These results can be extended to development of fully organic-based electronic device.

Nanocomposite synthesis by absorption of nanoparticles into macroporous hydrogels.Building a chemomechanical actuator driven by electromagnetic radiation

Macroporous hydrogels irreversibly absorb solid nanoparticles from aqueous dispersions. Ananocomposite is made using a macroporous thermosensitive hydrogel (poly(N-isopropylacrylamide-co-(2-acrylamido-2-methyl propane sulfonic acid)) (poly(NIPAm-co-AMPS))and conductive polymer (polyaniline, PANI) nanoparticles (PANI NPs). Macroporous gels of poly(NIPAm-co-AMPS) were made by a cryogelation technique. NPs of PANI were produced byprecipitation polymerization. It is found that PANI NPs are easily absorbed into themacroporous hydrogels while conventional non-porous hydrogels do not incorporate NPs. Itis shown that PANI NPs, dispersed in water, absorb NIR laser light or microwaveradiation, increasing their temperature. Upon irradiation of the nanocomposite withmicrowaves or NIR laser light, the PANI NPs heat up and induce the phase transition ofthe thermosensitive hydrogel matrix and the internal solution is released. Othernano-objects, such as gold nanorods and PANI nanofibers, are also easily incorporated intothe macroporous gel. The resulting nanocomposites also suffer a phase transitionupon irradiation with electromagnetic waves. The results suggest that, usinga thermosensitive matrix and conducting nanoparticles, mechanical/chemicalactuators driven at a distance by electromagnetic radiation can be built. Thesensitivity of the nanocomposite to electromagnetic radiation can be modulated by thepH, depending on the nature of the incorporated nanoparticles. Additionally, itis possible to make systems which absorb either NIR or microwaves or both.