Polyaniline: a polymer with many interesting intrinsic redox states

Symmetric redox supercapacitor with conducting polyaniline electrodes

Redox-Active Polymers for Energy Storage Nanoarchitectonics

Thermal properties of chemically synthesized polyaniline (EB) powder

Complexes of some transition-metal salts and emeraldine base of polyaniline were synthesized and characterized by UV−vis−IR spectroscopy, morphology studies, and conductivity measurements. Depending on the inorganic salt used, two extreme cases of doping were distinguished. The first regime of doping resulted in films of grained morphology, with a relatively high conductivity of up to 10-1 S/cm and electronic absorption spectra showing features of both pseudo-protonic doping and oxidation of the polymer backbone. IR absorption spectra were consistent with interaction of the benzenoid groups of the polymer with metal cations. The second regime of doping resulted in a smoother film morphology without grains, but with poor conductivity, normally not more than 10-3 S/cm, and higher solvent concentration in the film. Electronic and IR absorption spectra were consistent with pseudo-protonation of the polymer backbone. On the basis of the obtained data, a model of the macromolecular polyaniline−transition-metal ...

Doping of Polyaniline by Transition-Metal Salts

Polyaniline (PAn) can be doped through a protonation by protonic acids, in addition to an oxidation doping by Lewis acid as for the other conjugated conducting polymers. This work reports the new class of dopant, ionic salt, such as LiClO 4 , LiBF 4 , LiPF 6 , and Zn(ClO 4 ) 2 , for PAn. The ionic salt can be used to dope PAn by mixing an ionic salt with PAn in the common solvent 1-methyl-2-pyrrolidone and then casting the solution into a film. The structure and properties of ionic salt doped-PAn are investigated by UV-visible, IR and XPS spectroscopies, dynamic mechanical analysis, scanning electron microscopy, and conductivity measurement. It is found that the PAn therein is doped via pseudoprotonation of the imine nitrogen by the metal cation. As in the case of HCl-doped PAn, polarons/bipolarons are generated as reflected in the presence of UV-visible absorption peaks at 420 and 865 nm. The LiBF 4 -doped PAn film retains a conductivity at the level of 10 -2 S/cm in the temperature range 25-140 °C. The conductivity then decays to 10 -3 S/cm as temperature increases to 175 °C, resulting from the increased ring distorsion in the PAn subchains due to the glass transition.

Polyaniline Doped by the New Class of Dopant, Ionic Salt: Structure and Properties

An electroconductive polymer composite for use in secondary batteries as positive electrode active materials is disclosed. It includes 10-99 weight percent of a conjugated electroconductive polymer, such as polyaniline, and 90-1 weight percent of polymeric electrolyte. The latter is composed of 10-90 weight percent of an ionic salt, such as LiClO 4 , and 90-10 weight percent of a polymer which can form an electrolyte material with the ionic salt. The polymer, for example, can be polyvinyl alcohol or polyalkylene oxide. A method of using the electroconductive polymer composite to prepare the positive electrode of secondary batteries is also disclosed. It includes the steps of dissolving the above three components in an appropriate solvent (such as 1-methyl-2-pyrrolidinone), casting the resulting solution on an appropriate metallic grid or plate (such as nickel, aluminum or platinum) and removing the solvent therein to form a film which adheres to the metal grid or plate, in which the film is a positive electrode active material and the metallic grid or plate is a current collector. This invention also discloses a non-aqueous secondary battery which uses such positive electrode.

Electroconductive polymer composites as positive electrode active materials in secondary batteries

Method for preparing and using electroconductive polymer composites as positive electrode active materials to prepare secondary batteries

The preparation of carbon-supported platinum nanoparticles (Pt/C NPs) with excellent catalytic activities can greatly benefit both the fundamental research and industrial applications. However, the ability for rapid Pt/C NPs synthesis and engineering, especially in a simple, green, and controllable manner, remains essentially limited. Herein, Pt/C NPs were prepared via a microplasma-liquid interaction method from chloroplatinic acid solution and carbon black. Systematic experiments have been performed to investigate the synthesis process. Their catalytic performance was further evaluated via electrochemical reactions and measurements. Results revealed the successful synthesis of Pt/C nanoparticles, where small sized Pt nanoparticles (2∼3.6 nm) were well-dispersed over the carbon black. The formed Pt/C NPs have active electrocatalytic performance, and the electrochemically active surface area (ESA) can be tuned from 28.65 to 78.80 m2/g by adjusting the Pt content (3∼10%) through process control. A maximum catalytic activity of 24.23 mA/cm2 was achieved for methanol oxidation using the Pt/C-10%, better than commercial samples (ESA: 65.13 m2/g, MOR: 20.07 mA/cm2). Additionally, the Pt/C NPs for hydrogen evolution reaction (HER) exhibited small Tafel values in both the acid and alkaline solution. The demonstrated microplasma process is envisaged to be applicable for multiple functional nanomaterials synthesis. 

Plasma-liquid synthesized carbon-supported platinum nanoparticles as active electrocatalysts

Surface modification of nitrile membranes to achieve antibacterial activities is of great importance. In the present study, an atmospheric pressure DBD plasma setup is used for the surface modification of nitrile membranes, where silver nanoparticles and copper oxides particles prove to be generated from silver acetylacetonate (Ag(acac)) and copper acetylacetonate (Cu(acac)2). Complementary characterization has been performed to study the plasma-derived products as well as the modified membranes, such as XRD, TEM, FT-IR, SEM, AFM, EDX, XPS, OES, etc. It is shown crystalline Ag nanoparticles and CuOx particles are directly prepared by the DBD plasma setup, which can be strongly absorbed on the surface of the nitrile membranes. Based on the experiment results and previous studies, the plasma surface modification process is discussed. Antibacterial tests against Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis) show the AgNPs-deposited nitrile membranes possess apparent antibacterial activities, in contrast to the CuOx particles-deposited membranes. This simple, rapid, and flexible plasma process together with the antibacterial activities of membranes is expected to provide guidance for the surface modification of polymers with desired properties. 

Liang-Chang Lin

Papers

Polyaniline Doped by the New Class of Dopant, Ionic Salt: Structure and Properties

Electroconductive polymer composites as positive electrode active materials in secondary batteries

Method for preparing and using electroconductive polymer composites as positive electrode active materials to prepare secondary batteries

Plasma-liquid synthesized carbon-supported platinum nanoparticles as active electrocatalysts

Surface modification of nitrile membranes by DBD plasma and their antibacterial properties