1. Interfacial Behavior of Solid- and Liquid-like Polyelectrolyte Complexes as a Function of Charge Stoichiometry
- Author
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Martin Fauquignon, Marie Haddou, Jean-Paul Chapel, Hongwei Li, Christophe Schatz, Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), China Scholarship Council (Grant Number 201709370051, ANR-13-BS08-0015,PANORAMA,Assemblage Macromoléculaire Hors-équilibre Compréhension, Contrôle & nouvelles structures(2013), and ANR-18-CE06-0016,SISAL,Auto-Assemblage de bicouches de copolymères amphiphiles induit par une surface(2018)
- Subjects
Phase transition ,Polymers and Plastics ,Sodium ,chemistry.chemical_element ,Organic chemistry ,interfacial tension ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,pendant drop ,Surface tension ,chemistry.chemical_compound ,QD241-441 ,liquid-liquid and liquid-solid transition ,complex coacervates ,Phase (matter) ,surface tension ,liquid–liquid and liquid–solid transition ,ComputingMilieux_MISCELLANEOUS ,polyelectrolyte complexes ,Acrylic acid ,Coacervate ,Chemistry ,General Chemistry ,021001 nanoscience & nanotechnology ,Polyelectrolyte ,0104 chemical sciences ,3. Good health ,[CHIM.POLY]Chemical Sciences/Polymers ,Chemical engineering ,0210 nano-technology ,Stoichiometry - Abstract
We systematically investigate in this work the surface activity of polyelectrolyte complex (PECs) suspensions as a function of the molar charge ratio Z (= [-]/[+]) from two model systems: the weakly and strongly interacting poly (diallyldimethylammonium chloride)/poly (acrylic acid sodium salt) (PDADMAC/PANa) and poly (diallyldimethylammonium chloride)/poly (sodium 4- styrenesulfonate) (PDADMAC/PSSNa) pairs, respectively. For both systems, the PEC surface tension decreases as the system approaches charge stoichiometry (Z = 1) whenever the complexation occurs in the presence of excess PDADMAC (Z <, 1) or excess polyanion (Z >, 1) consistent with an increased level of charge neutralization of PEs forming increasingly hydrophobic and neutral surface-active species. The behavior at stoichiometry (Z = 1) is also particularly informative about the physical nature of the complexes. The PDADMAC/PANa system undergoes a liquid–liquid phase transition through the formation of coacervate microdroplets in equilibrium with macroions remaining in solution. In the PDADMAC/PSSNa system, the surface tension of the supernatant was close to that of pure water, suggesting that the PSSNa-based complexes have completely sedimented, consistent with a complete liquid–solid phase separation of an out-of-equilibrium system. Besides, the high sensitivity of surface tension measurements, which can detect the presence of trace amounts of aggregates and other precursors in the supernatant, allows for very accurate determination of the exact charge stoichiometry of the complexes. Finally, the very low water/water interfacial tension that develops between the dilute phase and the denser coacervate phase in the PDADAMAC/PANa system was measured using the generalized Young–Laplace method to complete the full characterization of both systems. The overall study showed that simple surface tension measurements can be a very sensitive tool to characterize, discriminate, and better understand the formation mechanism of the different structures encountered during the formation of PECs.
- Published
- 2021
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