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Accueil du site > Séminaires > Séminaires 2009 > Painleve condensation, counter-ion condensation and coulombic elasticity of biopolymers

Mardi 24 février 2009 — 14:00

Painleve condensation, counter-ion condensation and coulombic elasticity of biopolymers

Emmanuel Trizac (LPTMS, Orsay)

par Pierre Pujol - 24 février 2009

Onsager-Manning condensation is a manifestation of the long range character of the Coulombic potential in cylindrical geometry. This phenomenon is the cornerstone of our understanding of bio-polymers. Beyond a charge density threshold, counterions "condensate" onto the charged polymer. With salt (added electrolyte), which is the experimentally relevant situation, the phenomenon is more complex and has received little attention. We will show that recent mathematical advances allow to obtain analytical results in a large range of salt content. We will in particular discuss the implications of this work for the Coulombic elasticity of bio-polymers through their persistence length. If time permits, the connections with the long standing controversy of colloidal like-charge attraction will be discussed.