title: Early stage kinetics of polyelectrolyte complex coacervation monitored through stopped-flow light scattering.
abstract: Polyelectrolyte complexes (PECs) between poly(acrylic acid) (PAA) and poly(diallyldimethylammonium chloride) (PDADMAC), a model system forming coacervate particles via electrostatic interaction at pH 10, were prepared by a stopped-flow (SF) fast mixing technique at different mixing charge ratios (z) and ionic strengths. Both PEC final morphologies prepared by either SF or manual one-shot mixing are similar at bench time. In situ light scattering combined with the SF technique pointed-out, however, the presence of three distinct early stage kinetic behaviors in the formation of PECs. The first stage observed at low z is ascribed to the relaxation/reorganization of soluble PECs. At higher z or in the presence of salt, a second stage is found corresponding to the aggregation and/or rearrangement of small soluble PECs into larger structures. Redistribution of excess charges among those PECs produces some neutral condensed coacervate droplets as well, coexisting with PECs in a wide range of mixing ratios. Finally, a last process featured with bell-shaped curves indicates the full coacervation that quickens while approaching charge neutrality and/or at higher ionic strength.
authors.affiliation: CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France. chapel@crpp-bordeaux.cnrs.fr and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France and Université de Bordeaux, Laboratoire de Chimie des Polymères Organiques, UMR 5629, IPB/ENSCBP, 16 avenue Pey-Berland, F-33607 Pessac, France and CNRS, Laboratoire de Chimie des Polymères Organiques, UMR 5629, F-33607 Pessac, France.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Liu
authors.affiliation: CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France. chapel@crpp-bordeaux.cnrs.fr and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France and Université de Bordeaux, Laboratoire de Chimie des Polymères Organiques, UMR 5629, IPB/ENSCBP, 16 avenue Pey-Berland, F-33607 Pessac, France and CNRS, Laboratoire de Chimie des Polymères Organiques, UMR 5629, F-33607 Pessac, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Haddou
authors.affiliation: Institut Laue Langevin, 71 avenue des martyrs, B.P. 156, 38042 Grenoble Cedex 9, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Grillo
authors.affiliation: Bio-logic SAS, 4 rue Vaucanson, 38170 Seyssinet Pariset, France.
authors.forename: Zohra
authors.initials: Z
authors.lastname: Mana
authors.affiliation: CNRS, Centre de Recherche Paul Pascal (CRPP), UPR 8641, F-33600 Pessac, France. chapel@crpp-bordeaux.cnrs.fr and Université de Bordeaux, Centre de Recherche Paul Pascal, F-33600 Pessac, France.
authors.forename: Jean-Paul
authors.identifier: http://orcid.org/0000-0002-1988-1288
authors.initials: JP
authors.lastname: Chapel
authors.affiliation: Université de Bordeaux, Laboratoire de Chimie des Polymères Organiques, UMR 5629, IPB/ENSCBP, 16 avenue Pey-Berland, F-33607 Pessac, France and CNRS, Laboratoire de Chimie des Polymères Organiques, UMR 5629, F-33607 Pessac, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Schatz