Conducting polymer blends whose undiluted components have different properties are promising materials for specific applications and have attracted interest in recent years. The aim of this study was to obtain and evaluate the electrical conductivity of polyaniline doped with dodecylbenzenesulfonic acid (PAni.DBSA)/polyurethane thermoplastic (TPU) blends. The PAni.DBSA was synthesized from DBSA-aniline (DBSAn) salt through an emulsion polymerization in tetrahydrofurane (THF) or in the presence of polyurethane thermoplastic solution, resulting in pure PAni.DBSA or PAni.DBSA/TPU blends. Blends of PAni.DBSA/TPU were also prepared through casting, at room temperature, after dissolving both components in THF as a common solvent. The insulator-conductor transition was very sharp and the percolation threshold was lower than 2.7 wt% of PAni.DBSA. The electrical conductivity of PAni.DBSA/TPU blends, prepared by both methods, reached maximum values at a PAni.DBSA concentration of 40 wt%, close to the value observed for the undiluted conducting polymer. However, for a PAni.DBSA content lower than 30 wt%, the electrical conductivity was dependent on the blend preparation method. Blends were characterized by infrared spectroscopy, thermogravimetric analysis (TG) and optical microscopy. The electrical conducting characteristics of the PAni.DBSA/TPU blends prepared using different procedures indicate a high potential for their successful application in electrical processes. 相似文献
Superhydrophobic conducting polyaniline (PAni) films were electrochemically deposited in acetonitrile‐H2O electrolyte containing aniline monomer and perfluorooctanesulfonic (PFOS) acid. The films exhibited an extended network structure composed of helical PAni sub‐micron fibers. The helical fibrous structure is thought to form through a supermolecular templating process. The surface of the PFOS‐doped PAni films showed a water contact angle of 153°. Reducing the PFOS‐doped PAni (in emeraldine salt form) by negative potential led to de‐doped PAni films (in leucoemeraldine base form) which were superhydrophilic (water contact angle close to 0°). By controlling the electrical potential, PAni films were changed between the doped state and de‐doped state, resulting in reversibly switchable superhydrophobic and superhydrophilic surfaces.
The electrochemical oxidation of methanol was investigated on a Pt–Ru–Mo catalyst with an in situ infrared reflectance spectroscopy. The electrocatalysts were prepared by an electrochemical deposition and dispersed in a conducting three-dimensional matrix of polyaniline (PAni). We observed that CO2 is produced from methanol oxidation at 350 mV vs. RHE on PAni/Pt–Ru–Mo, which is 100 mV less negative than on PAni/Pt–Ru and 200 mV less than on PAni/Pt. The results suggest that Pt–Ru–Mo is less sensitive to COADS poisoning than Pt–Ru and much more sensitive than Pt. Large differences are observed concerning the average wavenumber of ADS between Pt–Ru–Mo, Pt–Ru, and Pt. 相似文献
Nanostructures of polyaniline (PAni) and polypyrrole (PPy) with controlled morphologies have been synthesized on atomically flat surfaces using adsorbed surfactant molecules as templates. Atomic force microscopy (AFM) has been used to investigate polymer film formation on highly oriented pyrolytic graphite (HOPG) and chemically modified HOPG. Morphological control over the resulting polymer film is possible by the addition of coadsorbing molecules, manipulation of the length of the surfactant hydrophobe, or by changing the surface chemistry of the adsorbing substrate. Phase transitions between spheres, cylinders/wires, and featureless films have been observed which exactly parallel transitions between spheres, cylinders, and flat layers in the adsorbed surfactant. Parallel arrays of PAni nanowires can be synthesized with alignment evident over large areas in a simple self-assembly technique in which fabrication and arrangement take place simultaneously. Such a technique in which one can engineer sub-100-nm-ordered nanoscale pi-conjugated polymer structures of a desired shape by a simple self-assembly process presents potential as templates, sensors, and microelectronic devices. 相似文献
Hex nut : An emerging synthetic approach based on metal–organic coordination‐polymer templates has been used to fabricate micro‐ and nanoscale crystals. By using a diverse range of molecular building blocks coupled with conventional synthetic techniques, it is possible to synthesize ZnO crystals with tailored sizes, shapes (such as hexagonal rings; see figure), and surface properties.
The surface morphology of polyaniline (PAni) composite films was studied by using the fractal dimension concept. This work presents the utilization of the cyclic voltammetry and electrochemical impedance spectroscopy to determine the fractal dimension. The small angle X-ray scattering (SAXS) technique has been extensively used to investigate the structure of several materials and it was used here to verify the confidence of electrochemical methods by comparison. All techniques employed revealed that PAni/Silica and PAni/PVDF composites present surface fractals. 相似文献
In this study, we report on the electrosyntheses of polyaniline (PAni) and PAni/magnetite nanoparticle (PAni/Fe3O4-NP) composite films by a potentiodynamic method from water and ethanol solutions. The aim of the study is to evaluate the effect of the solvent on the electrochemical growth of these films. The growth cyclic voltammograms and the mass change variation (Δm), determined by the electrochemical quartz crystal microbalance technique, show that the polymer growth rate is lower in ethanol than in water (Δm in water is ca. 50% higher than in ethanol after 30 voltammetric cycles). As a consequence, the films grown from ethanol show a more compact and uniform morphology, as we observed with scanning electron microscopy. Furthermore, the formation of oxidation products is inhibited in ethanol. The PAni/Fe3O4-NP composite films electrosynthesized in ethanol showed enhanced electrochemical response than the composite films grown from water. This is attributed to the better dispersion of the nanoparticles in this solvent and consequently in the polymer matrix, as confirmed by the Δm value and the spectroscopic characterization. We conclude that electropolymerization from ethanol solution provides high-quality PAni and PAni/Fe3O4-NP composite films; the electrochemical and morphological properties of these films suggest that their use for corrosion protection is promising. 相似文献