title: Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect.
abstract: The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains.
authors.affiliation: Normandie Université, France; Université de Rouen, Laboratoire 'Polymères, Biopolymères, Surfaces', F-76821 Mont Saint Aignan, France; CNRS UMR 6270 & FR3038, F-76821 Mont Saint Aignan, France. Electronic address: didier.le_cerf@univ-rouen.fr.
authors.forename: Didier
authors.initials: D
authors.lastname: Le Cerf
authors.affiliation: Normandie Université, France; Université de Rouen, Laboratoire 'Polymères, Biopolymères, Surfaces', F-76821 Mont Saint Aignan, France; CNRS UMR 6270 & FR3038, F-76821 Mont Saint Aignan, France. Electronic address: annesophiepepin@hotmail.fr.
authors.forename: Anne Sophie
authors.initials: AS
authors.lastname: Pepin
authors.affiliation: Normandie Université, France; Université de Rouen, Laboratoire 'Polymères, Biopolymères, Surfaces', F-76821 Mont Saint Aignan, France; CNRS UMR 6270 & FR3038, F-76821 Mont Saint Aignan, France. Electronic address: papemomar.niang@etu.univ-rouen.fr.
authors.forename: Pape Momar
authors.initials: PM
authors.lastname: Niang
authors.affiliation: "Petru Poni" Institute of Macromolecular Chemistry, Al. Gr., Ghica Voda 41A, 700487 Iasi, Romania. Electronic address: mcristea@icmpp.ro.
authors.forename: Mariana
authors.initials: M
authors.lastname: Cristea
authors.affiliation: Normandie Université, France; Université de Rouen, Laboratoire 'Polymères, Biopolymères, Surfaces', F-76821 Mont Saint Aignan, France; CNRS UMR 6270 & FR3038, F-76821 Mont Saint Aignan, France. Electronic address: carole.karakasyan-dia@univ-rouen.fr.
authors.forename: Carole
authors.initials: C
authors.lastname: Karakasyan-Dia
authors.affiliation: Normandie Université, France; Université de Rouen, Laboratoire 'Polymères, Biopolymères, Surfaces', F-76821 Mont Saint Aignan, France; CNRS UMR 6270 & FR3038, F-76821 Mont Saint Aignan, France. Electronic address: luc.picton@univ-rouen.fr.
authors.forename: Luc
authors.initials: L
authors.lastname: Picton
mesh_terms: D002151:Calorimetry / Q000379:methods; D003637:DEAE-Dextran / Q000737:chemistry* / Q000378:metabolism; D004573:Electrolytes / Q000737:chemistry* / Q000378:metabolism; D004586:Electrophoresis / Q000379:methods; D011108:Polymers / Q000737:chemistry* / Q000378:metabolism
chemical_list: D004573:Electrolytes; D011108:Polymers; D003637:DEAE-Dextran
keywords: DEAE Dextran; ITC; Polyelectrolyte complexes; Polysaccharide