Polyaniline Research Papers - Academia.edu (original) (raw)

We report on a simple chemical route for the synthesis of highly crystalline polyaniline nanoparticles. The method of synthesis presented here has an edge over surfactant or template assisted techniques. The nanoparticles are polycrystalline in nature and show well defined crystallographic lattices. The particles exhibit unique supramolecular behavior and tend to arrange in a more stable fibrillar structure. Nanostructured composite coating with a loading of 2 wt.% graphene showed a decline in corrosion current of mild steel up to ~2 orders of magnitude in 0.1 M HCl.

- by
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- Polyaniline

Simultaneous monitoring of soil moisture at different soil levels or near plant roots and relative humidity are crucial for optimizing the crop yield. In the present paper, we demonstrate a novel, compact and inexpensive polymer nano-composite piezoresistive microcantilever sensor platform for the measurement of relative humidity (% RH) and soil moisture. A piezoresistive microcantilever is realized using SU-8 and carbon black based nano-composite. Its surface is further modified by Poly-aniline (PANI) nanofibers as a sensing layer. The surface functionalization is confirmed by FTIR, SEM and contact angle measurements. The sensor exhibited a maximum response of 28 mV toward 93% RH with sensitivity of 64 μV/0.1% RH. Sensitivity values of 43.6, 275 and 78.6 μV/0.1% change in the moisture content for bentonite soil, white clay and sand, respectively, are achieved. Such high sensitivity values coupled with the low cost can be utilized further for the realization of rugged, portable and handheld devices with wireless networking facility.

- by Arindam Adhikari
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- Sensor, Nanomaterials, Conducting Polymers, Polyaniline

The science and engineering of biomaterials have improved the human life expectancy. Tissue engineering is one of the nascent strategies with an aim to fulfill this target. Tissue engineering scaffolds are one of the most significant aspects of the recent tissue repair strategies; hence, it is imperative to design biomimetic substrates with suitable features. Conductive substrates can ameliorate the cellular activity through enhancement of cellular signaling. Biocompatible polymers with conductivity can mimic the cells' niche in an appropriate manner. Bioconductive polymers based on aniline oligomers can potentially actualize this purpose because of their unique and tailoring properties. The aniline oligomers can be positioned within the molecular structure of other polymers, thus painter acting with the side groups of the main polymer or acting as a comonomer in their backbone. The conductivity of oligoaniline-based conductive biomaterials can be tailored to mimic the electrical and mechanical properties of targeted tissues/organs. These bioconductive substrates can be designed with high mechanical strength for hard tissues such as the bone and with high elasticity to be used for the cardiac tissue or can be synthesized in the form of inject-able hydrogels, particles, and nanofibers for noninvasive implantation; these structures can be used for applications such as drug/gene delivery and extracellular biomimetic structures. It is expected that with progress in the fields of biomaterials and tissue engineering, more innovative constructs will be proposed in the near future. This review discusses the recent advancements in the use of oligoaniline-based conductive biomaterials for tissue engineering and regenerative medicine applications. Statement of Significance The tissue engineering applications of aniline oligomers and their derivatives have recently attracted an increasing interest due to their electroactive and biodegradable properties. However, no reports have systematically reviewed the critical role of oligoaniline-based conductive biomaterials in tissue engineering. Research on aniline oligomers is growing today opening new scenarios that expand the potential of these biomaterials from ''traditional " treatments to a new era of tissue engineering. The conductivity of this class of biomaterials can be tailored similar to that of tissues/organs. To the best of our knowledge, this is the first review article in which such issue is systematically reviewed and critically discussed in the light of the existing literature. Undoubtedly, investigations on the use of oligoaniline-based conductive biomaterials in tissue engineering need further advancement and a lot of critical questions are yet to be answered. In this review, we introduce the salient features, the hurdles that must be overcome, the hopes, and practical constraints for further development.

Multifunctional cotton fabric with high electrical conductivity and ultrastrong UV radiation protection
properties was successfully fabricated by coating graphene oxide (GO) nanosheet dispersion on fabric
surface via vacuum
filtration deposition (VFD) method, and then the treated fabric was assembled with
polyaniline (PANI) by in-situ chemical polymerization process. The structure and morphological studies
showed that the deposition of GO nanosheet is benefit to enhance the uniformity of aniline
polymerization on the surface of PANI-GO-cotton fabric. Furthermore, the electrical resistivity of PANI-
GO-cotton decrease approximately 106 times compared with control cotton, reached at 48.35 V cm.
PANI-GO-cotton also performed ultrastrong UV radiation protection ability with a UPF value of 445.21,
which is superhigher than that of control fabric (UPF rating at 6.86). Moreover, even repeated 10 times
water laundering showed nearly no effect on electrical conductivity and UV radiation protection
efficiency.

- by Xiaoning Tang
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- Functionalism, Graphene, Polymer Nanocomposites, Polyaniline

tNovel anticorrosive emulsion-type paints were prepared by utilizing organic/inorganic nanohybrid par-ticles (nHPs) of composition (1:1) based on polyaniline (PANI) and nanosilica. Polyaniline (PANI) andnanosilica were synthesized via chemical oxidative and sol–gel polymerization techniques respectively.The prepared materials were characterized via (gel permeation chromatography (GPC), infra red (FT-IR), transmission electron microscope (TEM) and differential scanning calorimetry (DSC)). The binderused in this context is polyvinyl acetate (PVAc). Nanohybrid particles/PVAc emulsion composites (nHPsECs) were simply formed by individual mixing of the prepared neat PANI and nHPs of composition (1:1)with PVAc to produce the corresponding nanohybrid particles/PVAc emulsion composites EC1and EC2respectively. The chemical and basic properties including (acid and alkali resistance, adhesion, washabil-ity, gloss, opacity, whiteness, hardness, impact, and weathering) as well as the anticorrosion propertiesof the blank paint films and the paint films containing neat PANI and nHPs of different concentrations(5%, 10%, and 15%) were investigated and evaluated. The obtained experimental results revealed that thepresence of nHPs in the blank paint are highly enhanced both basic and anticorrosion properties of thecoated films.

- by Magdy K . Zahran
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- Adhesion, Organic/Inorganic Nanohybrid Materials, Weathering, Polyaniline

Several types of polyaniline (PANI) and polypyrrole (Ppy) nanocomposites with embedded glucose oxidase (GOx) and gold nanoparticles (AuNPs) were formed by enzymatic polymerization of corresponding monomers (aniline and pyrrole) in the presence of 6 and 13 nm diameter colloidal gold nanoparticles (AuNPs (6nm) or AuNPs (13nm) , respectively) or chloroaurate ions (AuCl 4 −). Glucose oxidase in the presence of glucose generated H 2 O 2 , which acted as initiator of polymerization reaction. The influence of polymerization bulk composition and pH on the formation of PANI-and Ppy-based nanocomposites was investigated spectrophotometrically. The highest formation rate of PANI-and Ppy-based nanocomposites with embedded glucose oxidase and gold nanoparticles (PANI/AuNPs-GOx and Ppy/AuNPs-GOx, respectively) was observed in the solution of sodium acetate buffer, pH 6.0. It was determined that the presence of AuNPs or AuCl 4 − ions facilitate enzymatic polymerization of aniline and pyrrole.

- by Arunas Ramanavicius
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- Conducting Polymers, Cyclic Voltammetry, Polyaniline, Gold Nanoparticles

Anilin adalah salah satu senyawa yang termasuk dalam kelompok amina.
Rumus molekul anilin adalah C6H5NH2 , anilin merupakan senyawa turunan
benzena yang salah satu atom H diganti dengan gugus –NH2. Anilin tidak
berwarna, berminyak, dan mengeluarkan bau menyengat dan bersifat basa.
Anilin sangat sukar larut dalam air karena anilin merupakan hidrokarbon
hidropobik dengan gugus amina, namun ion anilinium larut dalam air. Anilin
tidak berwarna, namun perlahan-lahan bisa teroksidasi karena interaksi dengan
udara dan berubah warna menjadi kuning atau merah-coklat. Menurut Ryusei
Konaka dkk (1968), anilin bereaksi dengan oksigen menghasilkan nitro benzena
(kuning muda) dan azobenzena

The understanding of the acid–base properties of conducting polymers (CPs) is essential for a rational design of devices based on this type of materials. Much of the work about polyaniline protonation equilibrium is focused on the emeraldine form. However, for the complete description of the pH effect on the electrochemical behaviour, it is required the knowledge of proton binding equilibrium to both the reduced (leucoemeraldine) and the oxidized (emeraldine) forms. In this work, the acid–base titration of polyaniline films was performed by spectroelectrochemistry at constant applied potentials so to keep the polymer in its reduced form. The values of the apparent dissociation constant, pKa,app, result to be about 1. The analysis of the proton binding degree as a function of pH allows determining the distribution of dissociation constants. This distribution is interpreted in terms of a simple thermodynamic statistical model, that allows determining the internal dissociation constant, pKa,int ≈ 1.3. Comparison with the pKa values of related monomers reinforces the results obtained in this work.

- by Waldemar Marmisollé
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- Electrochemistry, Conducting Polymers, Polyaniline, PKa Shift
- by Dr. Bernhard Wessling
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- Polyaniline, Corrosion Protection

We report that the microstructure, electrical and magnetic properties of the
fillers play a very crucial role in synergistically enhancing absorption dominated
electromagnetic interference (EMI) shielding in nanocomposites. We
prepared nanocomposites by dispersing of varying microstructure and magnetic
properties Barium-Lead hexaferrite (BaxPb1xFe12O19; x = 0.0, 0.4, 0.8
and 1.0) particles and polyaniline (PANI) (light weight conducting species) a in
microwave transparent paraffin wax matrix. The EMI shielding behavior of
the nanocomposites was studied in the 8–18 GHz frequency band. The hexaferrite
powder samples used in the nanocomposites were synthesized by the
sol–gel method followed by calcination at 1000C. The electron micrographs
confirm that the pure Pb-hexaferrite sample (x = 0) contains well defined
hexagonal plate-like particles. With increase in Ba-content in the samples, the
hexagonal particles transform to smaller spherical particles, and the magnetic
properties such as coercivity and saturation magnetization change. These
modifications in the morphology and magnetic properties of the samples
facilitate high attenuation of microwave radiation in our developed
nanocomposites. The conducting species (PANI) reflects the microwave from
its surface but absorbs it through conduction-loss (Ohmic absorption), whereas
the (non-conducting) magnetic Ba-Pb hexaferrite particles absorb the microwave
through ferromagnetic resonance but scatter it from their surface due to
impedance mismatch. The scattered waves normally increase the electromagnetic
smog outside the specimen. To reduce this EM-smog, the Ba-Pb
hexaferrite-PANI-Wax nanocomposites provide a synergy among all the
electrical and magnetic properties, which leads to very high attenuation
through absorption of the scattered electromagnetic wave. Our work demonstrates
that the nanocomposites containing Ba-Pb hexaferrite particles are not
only efficient in shielding microwave radiation but also help in controlling the
electromagnetic-smog.

In this report, the polyaniline (PANI)/ZnO nanocomposite system exhibits superior degradation of methyl orange and methylene blue under visible light condition, due to the intermolecular interaction between conducting PANI sponsoring more number of electrons to the conduction band of ZnO nanoparticles. The pure ZnO and the different mole ratios of PANI into ZnO catalysts were prepared by precipitation followed by sonication process. The bandgap of the nanocomposite system revealed in the red region was estimated by Tauc plot. The X-ray diffrac-tion results indicate that the high quantity of PANI into ZnO system reduces the crystallite size and also the crystallinity of the materials. On comparing with the other prepared materials, PZ1.5 illustrated higher degradation of methyl orange and methylene blue. The reason for high catalytic activity and their mechanism of visible light activities were discussed in this paper.

Almost all metals and their alloys are vulnerable to corrosion. To avoid structural damage and to avoid loss of its functionality, the most common protection method used is the application of a coating. In the present work, hydrophobic coatings using modified conducting polyaniline (PAni) were prepared and their corrosion-resistant properties were investigated. Modified PAni was prepared via two different techniques, conventional and rapid mixing method, in the presence of phenyl phosphonic acid (PPA) as dopant. The different PAni-PPA powders thus prepared were dispersed in an epoxy resin and coated on mild steel samples by drawing method. Tremendous improvement in hydrophobicity of the PAni-PPA (rapid)/epoxy was observed as compared to epoxy resin containing PAni-PPA (conventional method). The anticorrosion properties of these coatings on mild steel in 3 wt% NaCl were investigated using different electrochemical methods. Initial redox reactions and changes in conductivity of coating were reflected in the variations of open circuit potential (OCP). Both the coatings displayed stable high OCP, maintained their oxidative state, and provided corrosion protection for mild steel for more than 30 days. PAni-PPA (rapid)/epoxy gave better corrosion protection and showed higher ennoblement which may be due to the small particle size of PAni-PPA (rapid) leading to homogeneous mixing and better dispersion in the epoxy resin. Moreover, this coating is more hydrophobic in nature which is added advantage in case of corrosion-resistant coatings. The present investigation deals with preparation of highly (near super) hydrophobic coating containing conducting polymers for anticorrosion applications.

- by Pallavi Patil
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- Chemical Engineering, Materials Science, Chemistry, Physical Chemistry
- by Syed Muhammad Imran and +2
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- Nanotechnology, Polyaniline, Silver Nanoparticles, Conductive Polymers
- by Rinat Iskakov
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- Doping, Polyaniline, Polyimide composites

In recent years, much effort have been dedicated to achieve thin, lightweight and even flexible energy-storage devices for wearable electronics. Here we demonstrate a novel kind of ultrathin all-solid-state supercapacitor configuration with an extremely simple process using two slightly separated polyaniline-based electrodes well solidified in the H2SO4-polyvinyl alcohol gel electrolyte. The thickness of the entire device is much comparable to that of a piece of commercial standard A4 print paper. Under its highly flexible (twisting) state, the integrate device shows a high specific capacitance of 350 F/g for the electrode materials, well cycle stability after 1000 cycles and a leakage current of as small as 17.2 μA. Furthermore, due to its polymer-based component structure, it has a specific capacitance of as high as 31.4 F/g for the entire device, which is more than 6 times that of current high-level commercial supercapacitor products. These highly flexible and all-solid-state paperlike polymer supercapacitors may bring new design opportunities of device configuration for energy-storage devices in the future wearable electronic area.

- by Chuizhou Meng
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- Flexible Manufacturing, Carbon Nanotubes, Graphene, Nanomaterials

Please cite this article as: Semwal V, Gupta BD, Highly sensitive surface plasmon resonance based fiber optic pH sensor utilizing rGO-Pani nanocomposite prepared by in situ method, Sensors and amp; Actuators: B. Chemical (2018),... more

- by vivek semwal
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- Fiber Optic Sensors, Polyaniline, Surface plasmon resonance, Graphene Oxide

Conducting polymers have generated a great deal of interest because of their physical and chemical properties
as well as their potential application in industry particularly in packaging applications. However
one of short comings of most conducting polymer is that they are often formed as intractable films that
are difficult to process. To overcome this problem we have incorporated conducting polymer, namely
polyaniline into sheets of paper in order to create new composite material which combine the universal
properties of paper product with the chemical and electrically conducting properties of the conducting
polymer. Paper conducting polymer composite have been prepared by polymerizing aniline directly onto
the paper sheet using ammonium peroxydisulfate (APS) as an oxidant at different temperatures. The prepared
composite was characterized by FT-IR and SEM. The thermo-oxidative degradation was studied
by thermo gravimetric analysis (TGA); electrical conductivities measurements of the composites were
significantly increased over those of the precursor paper.

- by Mohamed El-Sakhawy
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- Composites, Polyaniline, Papers, Sugarcane Bagasse

We present a high-energy local power supply based on a flexible and solid-state supercapacitor for miniature wireless implantable medical devices. Wireless radio-frequency (RF) powering recharges the supercapacitor through an antenna with an RF rectifier. A power management circuit for the super-capacitive system includes a boost converter to increase the breakdown voltage required for powering device circuits, and a parallel conventional capacitor as an intermediate power source to deliver current spikes during high current transients (e.g., wireless data transmission). The supercapacitor has an extremely high area capacitance of ~1.3 mF/mm2, and is in the novel form of a 100 μm-thick thin film with the merit of mechanical flexibility and a tailorable size down to 1 mm2 to meet various clinical dimension requirements. We experimentally demonstrate that after fully recharging the capacitor with an external RF powering source, the supercapacitor-based local power supply runs a full system for electromyogram (EMG) recording that consumes ~670 μW with wireless-data-transmission functionality for a period of ~1 s in the absence of additional RF powering. Since the quality of wireless powering for implantable devices is sensitive to the position of those devices within the RF electromagnetic field, this high-energy local power supply plays a crucial role in providing continuous and reliable power for medical device operations.

- by Chuizhou Meng
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- Wireless Communications, Power Electronics, Carbon Nanotubes, Polyaniline

In this work, a solid-state high performance supercapacitor is fabricated based on a ternary polyaniline@Fe3O4@carbon fibers nanocomposite. To prepare the polyaniline@Fe3O4@carbon fibers electrodes, a two-step method including electrophoretic deposition of Fe3O4 nanoparticles on carbon fibres followed by an in situ polymerization process of polyaniline is utilized. The results show that the polyaniline@Fe3O4@carbon fibers nanocomposite with a layer by layer microstructure is successfully formed. The fabricated nanocomposite represents a specific surface area of 3.12 m2 g−1. The electrochemical measurements in a three-electrode configuration reveals a high specific capacitance of 245.5 F g−1 at 0.5 A g−1 and an excellent cycle stability (82.44% after 1000 cycle) of the polyaniline@Fe3O4@carbon fibers electrode. The as-fabricated solid-state supercapacitor based on the polyaniline@Fe3O4@carbon fiber nanocomposite cloth with a surface area of 25 cm2 powers up a blue light-emitting diode for 4 min and delivers a high energy density of 78.6 Wh.kg−1 at a power density of 1047.5 W kg−1.

- by Aydin Bordbar-Khiabani
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- Polymer Engineering, Polymer Chemistry, Energy, Carbon Nanotubes

A flexible fabric strain sensor was prepared by in situ chemical polymerization of aniline on knit polyester fabric surface in aqueous acid solutions using ammonium persulfate as an oxidant. Furthermore, the optimum addition
ratio of titanium dioxide (TiO2) in polyaniline (PANI)
in the granular conductive network membrane was investigated. The morphological, structural, thermal, electrical,
strain-sensing, and water-repellent properties of the polyester
knit fabrics modified with PANI and PANI/TiO2 hybrid
were analyzed. The surface electrical resistance of PANI/
TiO2 conductive films on the knit fabric was higher than
that of pristine PANI, which was due to the particle blocking
the conduction path effect caused by TiO2 embedded
in the PANI matrix. However, it was further found that the
addition of TiO2 could improve the durability properties of
flexible fabric strain sensor against cycles of elongation,
though with a little loss in electrical conductivity and sensitivity. Moreover, the water-repellent property was evaluated by measuring water contact angles. The results showed that for PANI/TiO2 nanocomposites-coated flexible fabric strain sensor, a desirable level of contact angle (127.5° ± 1.7°) was even preserved at 121.8° ± 2.6° after 100 cycles of
elongation. This indicated that the flexible fabric strain sensor had rather high water-repellent efficiency and excellent durability during the elongation cycles.

- by Xiaoning Tang
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- Composite Materials and Structures, Textiles Design, Polyaniline, Smart Textiles
- by tamil arasan
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- Materials Science, Nanocomposites, Nanotechnology, Polyaniline
- by Sudha J DEVAKI
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- Materials Science, Physical Chemistry, Conducting, Polyaniline

- by Arunas Ramanavicius
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- Polymerization, Polyaniline, Gold Nanoparticles, Polypyrrole

Polyaniline (PANI) nanofibers with diameters ranging from 60nm to 190 nm were successfully synthesized by rapid mixing polymerization method at room temperature. The effects of synthesis conditions such as concentration of hydrochloric acid (HCl), ammonium persulfate (APS), and aniline monomer (Ani) on the morphology of PANI nanofibers were investigated using scanning electron microscopy (SEM). FTIR and UV-Vis analysis were performed to characterize the PANI nanofibers.The effect of polymerization time and electrical properties of PANI nanofibers was also discussed. A rapid mixing polymerization method is found to be advantageous in producing bulk quantities of nanofibers.

- by A.K.M. Shafiqul Islam
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- Nanofibers, Nanomaterials, Nanotechnology, Polyaniline
- by Editor IJRET
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- Materials Science, Physical Chemistry, Polyaniline, Ammonia
- by Luiz L Faria
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- Chemistry, Organic Chemistry, Physical Chemistry, Electrochemistry
- by Dr. Bernhard Wessling
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- Polyaniline, Corrosion Protection

PANI-PAA/PEI multilayers with controllable thickness were fabricated by spin assembly.PAA matrix results in the homogeneous dispersion of PANI in the composite coatings.Spin coating combined with heating assures the linear increase in thickness with n.The corrosion protection property of PANI-PAA/PEI coatings were optimized at n = 20.Enhanced protection owing to multilayer structure that lengthens the diffusion pathway of ions.In the present study, polyaniline-polyacrylic acid/polyethyleneimine (PANI-PAA/PEI) composite coatings with a multilayer structure for corrosion protection of 316 stainless steels (316SS) were prepared by an alternate deposition. Spin coating combined with heating assists removal of residual water that result in a linear increase in thickness with layer number (n). The combination of PANI-PAA composite with PEI and their multilayer structure provides a synergistic enhancement of corrosion resistance properties as determined by electrochemical measurements in 3.5% NaCl solution. Importantly, the PANI-PAA/PEI coating with an optimized layer number of n = 20 shows improved corrosion protection. The superior performance was attributed to the formation of an interfacial oxide layer as well as the multilayer structure that extend the diffusion pathway of corrosive ions.

- by Junaid Ali Syed
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- Nano Composites, Polyaniline, Multilayer coating

Nanostructured materials have opened a new opportunity
for science and technology [1,2]. There has been much interest
in polyaniline (PANI) and based materials for more
than three decades simply due to their low cost and ease
of synthesis [3]. PANI can be synthesized by chemical and
electrochemical ways. In addition, PANI, being an excellent
organic conductor with good environmental stability
and biocompatibility [4], has often been used to fabricate
composites with carbonaceous materials for supercapacitor
applications [5] and sensor applications [6].

A novel green method for the synthesis of conductive nanocomposite -using silver nitrate, methyl cellulose (MC), glycerol, and aniline- was adopted. Here, silver nitrate was used as a precursor, methyl cellulose as both reducing and capping agent, glycerol as a co-reducing and ductility agent and water as solvent. While silver nitrate oxidizes aniline to polyaniline, it is reduced to silver nanoparticles. Doing so, both conductive polyaniline and conductive silver nanoparticle were in-situ synthesized via the formation of methyl cellulose- silver-polyaniline nanocomposite. Reproducibility of the nanocomposite revealed that the synthesis process is consistent. The nanocomposite film was characterized by FTIR, SEM, EDAX, XRD, and conductivity. XRD pattern showed poly crystallinity. TEM of the colloidal solution showed different particle shapes of AgNPs with size from 4-36 nm and d-spacing of 0.22 nm. SAED exhibits ring pattern with bright spots displaying polycrystallinity. Nanocomposite film, coated glass, cotton and polyester fabrics showed promising conductivity.

- by Manal A . El-Sheikh
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- Synthesis of nanoparticles, Polyaniline, Fabrics, Silver Nanoparticles

The synthesis of polyaniline thin films by oxidative polymerization of anilinium ion in the presence of inorganic acid is explored. Electrical conductivity measurements made from poly(aniline) electrolyte showed activation energy of 0.085 eV attributed to the intrinsic conduction of the protonated long chain. The dielectric parameters including real part, imaginary part and loss of tangent have been measured in the wavelength range of 400 – 1100 nm. This was employed to determine the dielectric relaxation time τ which exhibited Arrehnius-like behaviour. The temperature dependent relaxation time which is a function of activation energy of dipole orientation otherwise known as Gibbs free energy G # was also calculated. Finally, some thermodynamic parameters such as enthalpy H # and entropy S # were estimated using the obtained G # .

- by Balogun Bolaji
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- Polyaniline

A sensor has been developed that selectively catalyses the oxidation of l-ascorbic acid at low potentials (+100 mV). The low applied potential minimises the effects of many common electrochemical interferents. The interferents tested are those commonly found in juices and pharmaceutical preparations, including 4-acetamidophenol (paracetamol), uric acid and citric acid. Polyaniline was grown on both glassy carbon and screen-printed electrodes, and the analytical behaviour of both sensor types investigated. The linear ranges of the batch mode sensors were determined to be between 0.4 M and 2 mM, with a limit of detection of 0.4 M, while in flow injection format the linear range extended from 5 M to 0.1 mM with a limit of detection of 2.45 M.

- by Mila Pravda
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- Polyaniline, Chemically Modified Electrode, Ascorbic Acid

This paper presents the process of obtaining thin films of polymer polyaniline that has been doped directly in the production process. Samples of thin films were obtained using a rotating disk method at different speeds. Polyaniline synthesis (PANI) was performed at 0°C and room temperature of 20°C. Doping was made with hydrochloric acid (PANI-HCl). We have shown what were the important factors that had influence on obtaining reproducible patterns of about the same characteristics. As indicators of these properties we measured electrical resistance, on the basis of which was calculated specific electrical conductivity of the obtained samples of thin films of polyaniline from different series of production.

- by Tem Journal
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- Polymers, Doping, Polyaniline, Thin Films
- by Majda Žigon
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- Conducting Polymers, Polyaniline
- by priya malik
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- Physics, Materials Science, Nanotechnology, Polyaniline
- by MUTHUKUMAR N
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- Thermodynamics, Polyaniline, Conductive Fabrics, Surface Resistance

Highly conducting graphene/polyaniline (GN@Pani) nanocomposite was prepared by the in-situ oxidative polymerization of aniline in the presence of GN and the surfactant, cetyltrimethylammonium bromide (CTAB). The micellar structure of CTAB assisted both, the formation of GN@Pani tubules and the dispersion of GN. Sheet-like GN was distributed uniformly in the Pani matrix, leading to high electrical conductivity because of the π-π interactions between Pani and GN. Studies of the thermoelectrical behavior using isothermal and cyclic aging techniques showed that GN@Pani possessed a high combination of electrical conductivity and thermal stability, even beyond 150°C. GN@Pani was used as cathode active material in microbial fuel cells, and showed an enhanced power density and cell voltage, leading to better catalytic performance compared to plain carbon paper.

- by Dr. Bernhard Wessling
- •
- Polyaniline, Conductive Polymers
- by V Sitaram
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- Conducting Polymers, Polyaniline, Conducting Polymers Devices

AbstrAct: Polyanilines have many applications in Aerospace, especially in their doped form. Studies on their synthesis in a pilot scale can contribute to obtain products with desirable characteristics for such applications. The present study reports the chemical oxidative synthesis of polyaniline in pilot scale and different reaction times in order to determine if there are variations in the polyaniline structure, morphology and conductivity due to these synthesis conditions. It is very common to analyze these data for polymers obtained through bench scale. However, several parameters change the properties of final material in major scales, such as thermal, mechanic and diffusive variables. Therefore, the reaction time is the only variable into the 9 syntheses carried out, and polyaniline is obtained in a doped form, being dedoped with ammonium hydroxide and redoped with dodecylbenzenesulphonic acid. The doped and redoped samples were characterized by their molecular structure, thermal behavior, crystallinity and morphology. The electrical conductivity of redoped samples was determined. Some differences in the structure and morphology of doped and dedoped forms, identifying the doping structures, were reported. This paper aims to present the relationship between changes on structure and morphology of doped and undoped polyaniline obtained by the mentioned experiments. Furthermore, some addicts on conductivity are carried out. It was possible to contribute in order to obtain a more conductive polyaniline in pilot scale.

- by Journal of Aerospace Technology and Management and +2
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- Raman Spectroscopy, Morphology, Polyaniline, Crystallinity

We studied the kinetics of the oxidative chemical homopolymerization of 2-methoxyaniline (OMA) in aqueous acid solutions by monitoring OMA depletion with 1H NMR spectroscopy. We used the same semiempirical kinetic model used for aniline (ANI) homopolymerization to evaluate the experimental data. The reaction kinetics of OMA homopolymerization was similar to that of ANI, although we obtained longer induction and propagation times for OMA. This was attributed to steric hindrance of the bulky methoxy substituent during the coupling reaction. Furthermore, it was
suggested that a lower OMA polymerization rate could also be related to a lower concentration of nonprotonated OMA molecules in the reaction solution due to a higher pKa value for OMA than for ANI. This may also explain the lower OMA end conversion (90%) compared with that of ANI (96%). The OMA end conversion was not influenced substantially by reaction conditions; it was lower than 90% only when high acid or low oxidant (oxidant-deficient oxidant/OMA ratio) concentrations were applied. Because the oxidant took an active part in polymerization, it markedly influenced the polymerization
rate, especially the initiation rate. The OMA initiation and propagation rates increased with increasing oxidant and initial monomer concentrations and with the reaction temperature, but there was no uniform trend in the correlation between the
homopolymerization rate and acid concentration. The activation energies of the OMA initiation and propagation were 57 and 10 kJ/mol, respectively.

- by Majda Žigon
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- Conducting Polymers, Polyaniline