Papers by Keyword: Polyaniline (PANI)

Abstract: The modern development of (PEMFCs) is still faced by several obstacles such as membrane cost and performance. Perfluorosulfonic acid membranes (e.g. Nafion of DuPont) are currently the most successful in PEMFCs. PEMFCs usually operate at temperatures around 80°C and at atmospheric pressure. Higher temperature operation (T >100°C) is preferred and has several advantages including enhanced fuel cell kinetics, improved catalysts tolerance for contaminants and recovery of useful heat. However, the high-temperature operation is not permitted using Nafion membranes as they dehydrate and their proton conductivity dramatically decreases, thus, lowering the fuel cell efficiency. Therefore, this work aims at developing a Nafion-free membrane that would successfully operate at higher temperatures and with reasonable proton conductivity (preferably higher than 10-3 S/cm). In this study, novel solid proton conductors based on polyaniline (PANI) and ionic liquids (ILs) are proposed as membranes in PEMFCs. PANI-IL composite membranes are fabricated using porous polytetrafluoroethylene (PTFE) as support. The composite membrane was evaluated for its proton conductivity. The results showed a high proton conductivity range of 0.01 to 0.02 S/cm when a 3.7 wt % of the ionic liquid (IL)[1-Hexyl-3-Methylimidazolium Tricyanomethanide] was used.

Abstract: Pristine, catalyst-free and carboxylated carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) were modified with polyaniline via oxidative polymerization of aniline using ammonium persulfate. The effect of the nanocarbon support nature, degree of CNT functionalization and modification conditions on the specific surface area of the obtained composites was studied. Prospects of the application of the polyaniline-modified CNTs-and GNPs-based materials as sorbents for retention of different substances, including pathogenic organisms, were analyzed.

Abstract: Electrophoretic deposition (EPD) is a technique that uses electric field to deposit particles onto a conductive substrate. In this study, EPD technique has been utilized for fabrication of acid functionalized multi-walled carbon nanotubes (f-MWCNTs) and polyaniline (PANi) or denoted as (f-MWCNTs-PANi) nanocomposite film. The nanocomposite was prepared using ex-situ synthesis. This study revealed that the f-MWCNTs and protonated PANi in dimethyl formamide (DMF) can be well dispersed with addition of magnesium nitrate hexahydrate, Mg (NO₃)₂.6H₂O. The fabricated films were characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) and X-Ray Photoelectron Spectroscopy (XPS). Their surface morphologies were characterized by Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (TEM). FT-IR results indicate the presence of carboxyl groups in f-MWCNTs spectrum. The presence of PANi was detected in the spectrum of f-MWCNTs-PANi nanocomposite. These results were further supported by FESEM and TEM results that show the morphology of f-MWCNTs and PANi coating around their sidewalls. The use of Mg (NO₃)₂.6H₂O as dispersant for f-MWCNTs and protonated PANi allowed efficient EPD of their nanocomposite film fabrication. The fabricated f-MWCNTs-PANi composite thin film has future application in the development of supercapacitor device.

Abstract: In this study, a PANI covalently grafted GO (GO-PANI) was obtained through amide reaction and a PANI covered GO (GO/PANI) was prepared via in-situ polymerization. The better thermoelectric properties were achieved in GO-PANI compared with GO/PANI under the same situation, i.e., the equal mass ratio of GO and PANI as well as the oxidative degree of polymerization reaction. Furthermore, polyaniline grafted from the reduced graphene [R(GO-PANI)] was prepared by reducing the above GO-PANI using hydrazine hydrate and the improved power factor as high as 3.6 × 10^-8 W m^-1 K^-2 was attained at 341 K.

Abstract: A Polymer blends compose of Poly (3,4-ethylenedioxythiophene):Poly (styrene sulphonic acid)(PEDOT:PSS) and Polyaniline (PANi) have been prepared using drop casting technique. Optical parameters such as refractive index (n), extinction coefficient (k), reflectance, and optical dielectric were determined in this study. It is found that reflectance spectra increase as the PANi concentration decreases in the sample of small photon energy. The refractive index of the sample shows significant effect with the PEDOT:PSS concentration. As the concentration of PEDOT:PSS increases, the refractive index shows a normal dispersion behavior. Extinction coefficient decrease as the wavelength increase within the range of 300 nm to 350 nm that may contribute to the loss fraction of light due to scattering and the decreasing of absorbance at this range. However, the extinction coefficient increases from 350 nm to the maximum wavelength of 800 nm since the absorbance is also increasing. Both the real and imaginary part of the dielectric constant decreases when the photon energy increases. This revealed that the compositions of PEDOT:PSS influence the optical properties of hybrid PEDOT-PSS:PANi thin film.

Abstract: In this work, conducting polyaniline (PANI) nanofibers were fabricated by electrospinning technique. PANI (emeraldine-based) and polyvinyl alcohol (PVA) were used as the starting precursors for electrospinning technique and their concentrations were kept at 0.01 and 0.08 g/ml respectively. The effects of electrospinning conditions including volume ratio of polymer solution, operating voltage and injection rate at constant electrospinning distance on the morphologies and size distribution of the fibers were investigated. Scanning electronmicroscopy (SEM) and Fourier transforms infrared (FT-IR) were utilized to characterize morphologies and physical properties of the fibers. The optimized conditions with PVA:PANI (27;3, v/v), 20 kV voltage, 0.8 ml/hr injection rate to fabricate well-defined PVA/PANI nanofibers was acknowledged.

Abstract: CdSe semiconductor nano crystals (NCs) and Polyaniline (PAni) are mixed uniformly to prepare CdSe NCs/PAni complex. PAni can quench the fluorescent signal of CdSe NCs. The fluorescent intensity of CdSe NCs/PAni complex is related to the size of CdSe NCs and concentration of PAni. Ultraviolet visual (UV-Vis) absorption spectra and fluorescence spectra are employed to analysis the quenching phenomenon. The mechanism of fluorescence quench is dependent on two factors: on one hand, the FÖrster resonance energy transfer conducts from CdSe to PAni; on the other hand, PAni can intercept the electron charge of CdSe and lead to the interruption of radiative recombination.

Abstract: Technical development and rapid telecommunication create convenient consumer products, but produce electromagnetic radiation that hurts the human body, which makes the development of antistatic and electromagnetic-wave-resistant textiles important. This study combines polylactic acid (PLA) fibers and low melting point polylactic (LPLA) fibers by needle punching to make PLA nonwoven fabrics. The lamination layer number is then changed to explore its influence on the mechanical properties of the PLA nonwoven fabrics. Next, the nonwoven fabrics are spray-coated with polyaniline (PANI) to form the PANI/PLA nonwoven fabrics. The PANI/PLA nonwoven fabric with a lamination layer number of 5 has the optimum tensile and tear strength. A coating of PANI can reduce the surface resistivity.

Abstract: High energy ion beam induced modifications in polymeric materials is of great interest from the point of view of characterization and development of various structures and filters. Due to potential use of conducting polymers in light weight rechargeable batteries, magnetic storage media, optical computers, molecular electronics, biological and thermal sensors, the impact of swift heavy ions for the changes in electrical, structural and optical properties of polymers is desirable. The high energy ion beam irradiation of polymer is a sensitive technique to enhance its electrical conductivity, structural, mechanical and optical properties. Recent progress in the radiation effects of ion beams on conducting polymers are reviewed briefly. Our recent work on the radiation effects of ion beams on conductive polymers is described. The electrical, structural and optical properties of irradiated films were analyzed using V-I, X-Ray diffraction (XRD), scanning electron microscopy (SEM), UV-Visible spectroscopy and Fourier transform infrared spectroscopy methods.

Abstract: In this paper,antistatic property of PAN/PANI composite fiber was studied through the grafted polymerization of Polyacrylonitrile and Polyaniline (PANI). The preconditioning and the dosage of ANI influenced on the rate of bodyweight gain, breaking strength and tensile rate,mass specific resistance of the composite fiber were discussed. The mass specific resistance of conventional polyacrylonitrile fiber is 1011Ω•cm,the mass specific resistance of PAN/PANI composite fiber could be reduced to 106-108Ω•cm. It could prove that the antistatic property of PAN fiber has been greatly improved by PANI.