Scanning Tunneling Microscopy Fractal Characterization of Poly (o-toluidine) Films Produced Electrochemically on Polyfaceted Gold Single Crystal Spheres
The topography evolution of a poly(o-toluidine) layer (the object) electrodeposited on a polyfaceted Au single crystal from 0.5 M H<sub>2</sub>SO<sub>4</sub> + 0.65 M o-toluidine aqueous solution at 25 °C has been studied combining nanometer scale ex-situ scanning tunneling m...
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| Autores principales: | , , , , , |
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| Formato: | Articulo |
| Lenguaje: | Español |
| Publicado: |
1994
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| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/127137 https://pubs.acs.org/doi/abs/10.1021/j100060a032 |
| Aporte de: |
| Sumario: | The topography evolution of a poly(o-toluidine) layer (the object) electrodeposited on a polyfaceted Au single crystal from 0.5 M H<sub>2</sub>SO<sub>4</sub> + 0.65 M o-toluidine aqueous solution at 25 °C has been studied combining nanometer scale ex-situ scanning tunneling microscopy and electrochemical techniques. A thin polymer layer structure consists of nodular elements following the substrate topography, whereas a thick polymer structure corresponds to a rather disordered structure made up of agglomerates formed by nodular elements with average diameter size d<sub>s</sub> ≅ 15 nm. In contrast to the former one, this structure is independent of the substrate topography. For thick layers ξ, the root-mean-square roughness of the polymer coating, and L<sub>s</sub>, the scan length, fulfill a ξ ∝ L<sup>α</sup> relationship with a = 0.33 ± 0.05 for L<sub>s</sub> > d<sub>s</sub> and α = 0.85 ± 0.05 for L<sub>s</sub> < d<sub>s</sub>- Accordingly, the polymer layer surface behaves as a self-affine fractal. For L<sub>s</sub> < d<sub>s</sub> the value of a agrees with that predicted for moving interfaces generated by the Eden model, whereas for L<sub>s</sub> < d<sub>s</sub> the value of a approaches that expected from an Euclidean surface. The topographic analysis of these polymer layers can be related to the kinetics of electrochemical reactions at polymer-coated Au electrodes. |
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