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Equilibrium Overcompensation in Polyelectrolyte Complexes

Title: Equilibrium Overcompensation in Polyelectrolyte Complexes.
Name(s): Fares, Hadi M., author
Schlenoff, Joseph, author
Type of Resource: text
Genre: Text
Journal Article
Date Issued: 2017-05-09
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Association between positive, Pol+, and negative, Pol-, units on polyelectrolytes drive spontaneous formation of a range of morphologies, some with “fuzzy” structure but most essentially amorphous. An excess of one type of charge over the other, known as overcompensation or overcharging, is essential for certain types of processing, such as the formation of polyelectrolyte “multilayers” on substrates or “polyplex” nanoparticles in solution. In this work, uniform, stoichiometric, smooth thin films of polyelectrolyte complex, PEC, from poly(diallyldimethylammonium), PDADMA, and poly(styrene sulfonate), PSS, were prepared starting from rough, nonstoichiometric multilayers of these materials. A narrow concentration range of added salt was found which promoted steady-state bulk overcompensation of PEC films in the presence of a large excess of polycation or polyanion without loss of PEC to solution. The extent of overcompensation, about 35% for PDADMA in 1.0 M NaCl and about 40% for PSS in 1.4 M NaCl, was independent of solution polymer concentration and only weakly dependent on salt concentration. A weak dependence of overcompensation on molecular weight was also determined. Erosion/instability of films for [NaCl] > 1.4 M was observed, with more prominent or faster erosion for higher molecular weight PSS. The mechanism for overcompensation in this entropically driven system was attributed to the formation of a Donnan ion equilibrium between the PEC and solution phases.
Identifier: FSU_libsubv1_scholarship_submission_1540238171_d94189a0 (IID), 10.1021/acs.macromol.7b00665 (DOI)
Keywords: polyplex, overcharging, Donnan equilibrium, PSS, PDADMAC, multilayers, layerby-layer
Publication Note: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Macromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see
Grant Number: DMR 1506824 (NSF)
Persistent Link to This Record:
Owner Institution: FSU
Is Part Of: Macromolecules.

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Fares, H. M., & Schlenoff, J. (2017). Equilibrium Overcompensation in Polyelectrolyte Complexes. Macromolecules. Retrieved from