Polypyrrole films (0.2–1.0 μm thick) were electrosynthetized in organic media by potentiodynamic electropolymerization on silicon surfaces. To improve the electronic conductivity of the polypyrrole films, elemental copper was electrodeposited directly on the film surface by simple electrolysis from a copper chloride bath. Copper electrodeposited onto the surface of the polypyrrole film was characterized by X‐ray diffraction and consisted only of Cufcc phase. The presence of copper on the PPy surface did not greatly affect the overall electronic conductivity of the material. However, immersion of polypyrrole films in Cu2+ solution for a period of time caused Cu2+ ions to enter the polypyrrole matrix. The reduction of the Cu2+after insertion into the polypyrrole template formed a polypyrrole/Cu composite with high electrical conductivity; this conductivity was higher for longer steeping (immersion) time. Raman spectroscopy shows much greater peak intensities when copper was present in the polypyrrole matrix. Scanning electron microscopy and cross‐sectional analysis showed clear differences in the appearance of the films with copper deposited onto the polypyrrole surface and copper inserted into the polypyrrole matrix.
Two methods of Pyrrole electropolymerization were investigated to prepare polypyrrole films growing onto n-doped silicon n- Si (111): Polypyrrole films prepared by galvanostatic method exhibits toroidal morphology for thin films, and mixture of toroidal and globular morphologies for thick films. Polypyrrole films obtained from this method were characterized by lower surface roughness. Electropolymerization of pyrrole by potentiodynamic method provided Polypyrrole films with beans-like structures for both thin and thick films with high surface roughness. Due to their lower surface roughness, polypyrrole films produced by galvanostatic method exhibit high intensities in Raman spectroscopy. These polypyrrole films show better capacitive properties according to discharge test.
In this work, a modified electrode of copper-polypyrrole (Cu-PPy) is elaborated by charging the polymer matrix by Cu particles. The response to ascorbic acid (AA) of this material was tested. The results show good performances. The results indicated a sensitive oxidation peak current of AA on the modified electrode. The success of this application led us to study the nucleation mechanism of copper on the PPy surface which permits to obtain this response. Nucleation and growth of electrodeposited copper onto PPy substrate have been studied in an aqueous solution of 0.01[Formula: see text]M CuCl2 and 1[Formula: see text]M KCl by means of electrochemical methods: cyclic voltammetry, chronoamperometry, and using atomic force microscopy (AFM). The model described by Scharifker and Hills was used to analyze current-time transients. According to this model, the nucleation and growth kinetics at the initial stages of deposition process involve an instantaneous nucleation followed by three-dimensional (3D) growth mechanism.
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