Papers by Keyword: Polyaniline (PANI)

Abstract: A novel solid state and surfactant-free method has been developed for synthesis of polyaniline superstructure composed of dendritic nanofibers. The good crystallinity of the product is confirmed by XRD, while FT-IR analyses indicate the formation of highly doped emeraldine salt of polyaniline product. Microscopic observations show that the product is in the form of polyaniline dendrites with a less-than-40 nm fiber diameter. The unique growth mechanism of the superstructure in solid-state reaction has been discussed.

Abstract: In this work a novel approach for the preparation of Fe3O4/PANI (polyaniline) thin film composite containing magnetic nanoparticles is presented. Magnetite (Fe3O4) nanoparticles have been coated by PANI and the PANI chains have been doped by 10-camphorsulfonic acid (CSA). The doped composite is soluble in common organic solvents. Thin films of composites of polyaniline (PANI) were casted from m-cresol. Several characterization techniques were employed in order to determine composition, structure and magnetic properties of the nanocomposite film (Xray diffraction, transmission electron microscopy, TEM, Scanning electron microscopy, SEM, and optical microscopy). The magnetization data were obtained from M(H) hysteresis loops and zero field cooling – field cooling, ZFC-FC. Magnetic measurements evidence a ferromagnetic behaviour of the obtained composite, at room temperature with saturation magnetization of about 3.4 emu/g and coercivity of 42 Oe. The temperature dependences of the conductivity of the films follows the         = − 1 / 2 ( ) exp T T To o σ σ law, which has been explained within the framework of the onedimensional variable-range-hoping (1D-VRH) model. Application of 1T magnetic field increases the resistivity of the film and the temperature slope dependence.

Abstract: The polyaniline (PANI) coated titania (TiO2) has been prepared with ammonium persulfate (APS) as an oxidant in sodium dodecylsulfate(SDS) micellar aqueous solution. These nanosized powders could transfer into the organic phase. With increase in the amount of SDS, the dispersibility into the organic solvent was increased. Consequently, the electrical conductivity of the product was also decreased. The obtained composites showed 14.16 S/cm of conductivity at maximum while the value was almost independent on the polyaniline coating ratio in range of 100~20wt%. The conductivity value of composite with 20wt% polyaniline was 70000 times higher than that of raw titania. Modified titania had properties of polyaniline and titania together. In addition these composite showed the photoconductive response against the UV irradiation, which might show the existence of P-N junction between titania and polyaniline. The detailed structure and property analyses with X-ray, UV-spectroscopy, electron microscopy and so on will be discussed in relation to the synthetic conditions

Abstract: In order to prepare the enzyme electrode for sensing of chemical molecules, the Au was coated on the surface of PP film by sputter coater. Polyaniline (PANI) was polymerized on the surface of the coated Au film by electrochemical polymerization of aniline in order to use working electrode. Subsequently, horseradish peroxide (HRP) was immobilized on PANI electrode as follows: Method I. The HRP was immobilized on the surface of PANI electrode by using Au nanoparticle as linker (physical adsorption). Method II. The HRP was immobilized on the surface of PANI electrode by using 2-aminothiophenol and Au nanoparticle as linker (Self-assembling immobilization). Method III. HRP was directly immobilized with PANI electrode by using glutaric dialdehyde as linker (covalent bonding). The sensing efficiency of the prepared HRP-PANI electrode was also examined. The sensing efficiency of the HRP-PANI electrode for H2O2 was as following order; Method I > Method III > Method II..

Abstract: Polyaniline doped with camphorsulfonic acid (PANI.HCSA) nanofibers have been successfully prepared using “nanofibers template” via electrospinning. The PVA nanofibers were used as a template to get the PANI/PVA composite fibers. After removing the template by heat treatment, the PANI fibers were obtained. Scanning electron microscope (SEM) with the Energy Dispersive X-Ray Spectrometer software (EDX) and FT-IR spectra were used to characterize the composite fibers and the PANI.HCSA nanofibers. The average diameters of the composite fibers obtained and PANI fibers were 920 nm and 530 nm, respectively.

Abstract: Multi morphology of polyaniline (PANI), nanotubes, micrograins, solid and hollow spheres, were synthesized by aqueous oxidative polymerization of aniline in the presence of sodium hydroxide (NaOH), which was proposed as an alkali-guided method by the authors. By changing the molar ratio of aniline monomer to alkali, with a constant pH, the morphology can be controlled from nanotubes to micrograins, to solid spheres and to hollow spheres which were proved by SEM and TEM. The backbone structure was characterized by UV-VIS, FTIR and XRD.

Abstract: With an average diameter of 300-500 nm, conducting microspheres of polyaniline (PANI) were synthesized successfully by a self-assembly method in the presence of ferrocene sulfonic acid (FcSO3H) as the dopant, and ammonium persulfate ((NH4)2S2O8) as the oxidant. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) proved that the microspheres of PANI- FcSO3H synthesized by a self-assembly process were hollow ones. And the backbone structure of obtained PANI- FcSO3H was characterized by FTIR spectrum. The effect of synthetic conditions, such as the molar ratio of FcSO3H to aniline (An) and the reaction temperature, on the morphology and size was also investigated.

Abstract: Nano-TiO2 particles or TiO2 whiskers encapsulated by polyaniline/cyanate ester composites were fabricated by solution-mixing method. Then the dispersion of particles in cyanate ester was observed with the aid of TEM. The effect of the content of particles or whiskers on the dielectric properties of cyanate ester composites was investigated. As the content of the particles up to 3% or the whiskers up to 7%, the dielectric loss of the composites achieved its maximum.

Abstract: High levels of surface shear experienced during rolling, grinding or machining can cause 6000 series aluminium to develop an ultra-fine grained surface layers which dramatically increase susceptibility to filiform corrosion (FFC) under paint films. In-situ Scanning Kelvin Probe (SKP) measurements in humid air are used to compare the kinetics and mechanism of FFC on abraded and lacquer-coated samples of high copper containing AA6111 and low level copper AA6016. FFC is initiated by applying a small volume of aqueous HCl to a penetrative defect on polyvinylbutyral (PVB) coated alloy samples prior to placement in a chamber maintained at constant humidity and temperature. The SKP is then repeatedly scanned over a fixed surface area to produce a time-lapse animation showing the dynamic evolution of localized free corrosion potential patterns. The spatial distribution of potential variation provides insight into the FFC mechanism and the numerical integration of areas of dissimilar potential provides a measure of the time-dependent area of coating delamination. Various possible FFC inhibition strategies are investigated for use under circumstances where removal of the surface layer prior to application of an organic (paint) coating is not feasible. The two strategies shown in this paper are the use of an anti-corrosion pigments based on an intrinsically conducting polymer called polyaniline. An anion-exchange pigment called hydrotalcite is also used.