Caractère polyélectrolytique des interactions "ions diffusibles - polymères pariétaux" chez l'algue géante d'eau douce Nitella flexilis (L.) Ag.

Abstract

Polyelectrolyte aspect of the « diffusible ions - ionic polymers » interactions in the wall of the giant freshwater alga Nitella flexilis (L.) Ag. The measurements of the concentration potentials carried out in various ionic environments across the isolated cell wall of Nitella flexilis bring evidence that the fraction of pectic monomers electrostatically active is strongly reduced with respect to the cationic exchange capacity of the wall. A theoretical model - the surface complex model (SCM) - based on the Poisson-Boltzmann theory and on the mass action laws is set up to describe the ion exchange properties of the wall. This model is used to bring evidence of different interaction modes for the counterions at the level of the exchange sites. The predictions of this model are compared with the experimental results of the equilibrium of complexation-dissociation and with the predictions of classical ion exchange change models. Finally, the SCM has been used to establish a repartition of the co-and counterions in the wall phase. This approach generalizes the concept of the Donnan free space in theoretical context of the SCM.

Date of Award	1995
Original language	French
Supervisor	Claude Gillet (Supervisor)