Experimental evidence for deterministic chaos in electrochemical deposition

We report an experimental study of the statics and dynamics of electrodeposition of zinc in an aqueous medium, in the intermediate regime between dendritic and DLA-like metallic clusters. During the growth process, periodic and nonperiodic oscillations of the voltage are recorded under constant applied current intensity. Period-doubling bifurcations are identified. Analysis of the data in terms of phase portraits, Poincare maps and 1-D maps shows that the fractal geometry of these electrochemical deposits is the signature of a low-dimensional deterministic chaotic dynamics which displays sensitivity to initial conditions. The study of the apparently more complex dynamics recorded in the DLA limit is a very promising experimental challenge Nous presentons ici les resultats d'une etude experimentale du processus d'electrodeposition de zinc en milieu aqueux bidimensionnel. Les regimes etudies sont intermediaires entre des croissances metalliques de nature dendritique et des croissances plus desordonnees similaires aux agregats fractals engendres par simulation numerique de modele d'agregation limitee par la diffusion de Witten et Sander (DLA model). L'etude de ces dynamiques complexes apporte une premiere evidence experimentale du caractere chaotique deterministe de ces phenomenes de structuration d'interface et la signature d'une dynamique a faible nombre de degres de liberte. L'etude dynamique de regimes encore plus complexes observes dans la limite DLA s'avere etre un challenge experimental des plus prometteurs