Polypyrrole spheres

A. D. W. Carswell, E. A. O Rear, and B. P. Grady, Adsorbed surfactants as templates for the synthesis of morphologically controlled polyaniUne and polypyrrole nanostructures on flat surfaces from spheres to wires to flat films, J. Aon. Chem. Soc., 125, 14793-14800 (2003). 

Polypyrrole-coated SnO hollow spheres In-situ chemical polymerization Pellet Ammonia [53]... 

Other templates have also been used. Polypyrrole nanowires have been produced by growing the polymer in porous alumina. Highly porous conducting polymers have also been produced using the inverse opal method [38], in which the polymer is deposited around a matrix of tightly packed spheres, which form the synthetic opal. When the spheres are removed, a highly porous film is left with... 

Liu HS, Shi Z, Zhang JL, Zhang L, Zhang JJ (2009) Ultrasonic spray pyrolyzed iron-polypyrrole mesoporous spheres for fuel cell oxygen reduction electrocatalysts. J Mat Chem 19(4) 468-470... 

Oxidation at the anode results in the formation of blue to black oxidized materials (thickness 1 mm — 0.61 pm) of high conductivity. The films show a yellow colour in the uncharged low conductivity state upon undoping. The mechanical properties of 1 mm thick polypyrrole films (obtained on platinized electrodes in propylene carbonate partly in the presence of water) were reported Polypyrrole (PP) was obtained in two different morphologies Electrochemical polymerization in an aqueous solution of results in a compact structure of aggregated spheres... 

Relatively high iron contents are found for self-supported iron-polypyrrole catalysts which were prepared by spray pyrolysis. The authors proposed high site densities however, comparatively low current densities with respect to other Fe-N-C catalysts make it most probable that only a small fraction of the overall irrai is bonded in active sites. Nevertheless, the shape of these catalysts is interesting because porous carbon spheres with diameters of 100 up to 1,000 nm are formed [194],... 

In addition, Shen et al. [75] prepared a novel fliree-dimensional electrode using polypyrrole (Ppy) and polystyrene spheres (PS) covered by a platinum catalyst instead of the conventional gas diffusion electrode, in order to reduce the sealing effect in liquid fuel cells. This new type of porous structured electrode allows liquid alcohol to penetrate the catalyst layer quite easily. The approach results in an increased active surface area for electrochemical reactions. The electrochemical active areas of platinum in Pt/Ppy/PS electrodes and E-TEK Pt/C electrodes, calculated by cyclic voltammograms [76, 77], are 4.5 and 23.6 cm g respectively, indicating a larger EAS for the three-dimensional electrode. Preliminary studies show an improved performance for methanol oxidation on a three-dimensional electrode as compared with a conventionally prepared electrode with the same platinum loading. 

The polypyrrole synthesized under the present high SCS concentration is regularly shaped spheres with a constant diameter of about 40 nm, which was determined from conventional TEM observation for the dried sample as shown in Fig. 1. 

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