| Abstract
| - The platinum loading, electronic and ionic conductivity, tuned porosity, and electrode potential oflayer-by-layer (LBL) conducting polymer films for thin film catalytic electrodes are presented. Films ofpolyaniline (PANi)/poly(acrylic acid) (PAA) or PANi/poly(acrylic acid)-co-polyacrylamide (PAA-co-PAAm) of 3.0-μm thickness were pH-tuned to induce porosity as they were assembled. Three differenttechniques were used to dose the LBL PANi films with platinum. The first method used reductiveprecipitation of platinum and ruthenium salts adsorbed within LBL films of PANi/PAA-co-PAAm. Thesecond method, termed polyelectrolyte colloidal platinum stabilization, was applied to load platinumnanoclusters into LBL films of either PANi/PAA or PANi/poly(styrene sulfonate) films. The third methodused a PANi/platinum powder dispersion to load platinum crystals into LBL films of PANi/PAA-co-PAAm or poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (PAA-co-PAMPS). The first methodyielded the best metal loadings with maximum platinum loadings of 0.3 mg cm-2, and the resultingPt-containing PANi/PAA-co-PAAm films were further examined for their electrochemical characteristics.The electrode potential and chronopotentiometric current control in the resulting electrodes were examinedfor the best-performing LBL PANi film assembled in this study. The catalyzed PANi/PAA-co-PAAmelectrodes exhibited an electrode potential similar to that of pure platinum, a relatively high and stableelectrical conductivity of 2.3 S cm-1, and an ionic conductivity of up to 10-5 S cm-1.
- Platinum-catalyzed layer-by-layer conducting polymer films were synthesized, as this optical microscopy image of a layer-by-layer film of polyaniline/poly(acrylic acid) assembled at pH conditions of 2.5/4, respectively, indicates. The 40-bilayer conducting film was dosed with a platinum salt, which was then reduced to platinum clusters.
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