J. Phys. II France
Volume 7, Number 8, August 1997
Page(s) 1099 - 1109
DOI: 10.1051/jp2:1997174
J. Phys. II France 7 (1997) 1099-1109

Collective Diffusion of "Living Polymers"

A. Ott1, 2, J.P. Bouchaud1, 3, W. Urbach1 and D. Langevin1

1  École Normale Supérieure, Laboratoire de Physique Statistique Associé au CNRS et aux universités Paris 6 et 7, 75005 Paris, France
2  Institut Curie, Laboratoire de Physico Chimie Curie UMR 168 du CNRS, associé à l'université Paris 6, 75231 Paris, France
3  Service de Physique de l'État Condensé, Centre d'Études de Saclay, Orme des Merisiers, 91191 Gif-sur-Yvette Cedex, France

(Received 5 November 1996, revised 24 March 1997, accepted 5 May 1997)

We have studied the "collective" diffusion of a concentrated solution of "living polymers" in brine, which in certain concentration conditions exhibit superdiffusive (Lévy flight) behaviour when tracer diffusion is considered. The concentration profile of the diffusion front is monitored over time using a Michelson interferometer. We show how a concentration dependent diffusion constant can be extracted from the fringe pattern. We find that the diffusion constant decreases linearly with increasing concentration, at variance with a power-law dependence, expected when the interaction between chains is neglected.

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