Oppositely-charged polyelectrolytes can undergo an associative phase separation known as complex coacervation, forming dense polymer phases that maximize favorable electrostatic interactions. This interaction motif can be harnessed to drive polymer assembly, via the incorporation of opposite charges on pairs of block copolymers. Coacervation is thus widely used in the self-assembly of structures such as gels and micelles, motivated by creating compartments capable of carrying hydrophilic cargo, or structures that are responsive to a variety of environmental stimuli. Despite the utility of this method of self-assembly, there remain fundamental questions about how molecular and environmental parameters govern phase behavior.<br/><br/>We will present a recent theory developed to describe the equilibrium phase behavior of complex coacervation, which is capable of predicting both the correlated molecular structure of the bulk coacervate phase as well as matching experimental phase diagrams. We incorporate this model into a self-consistent field theory (SCFT) of polyelectrolyte self-assembly, to predict phase behaviors over a wide range of molecular parameters (chain lengths, block fractions) and environmental parameters (salt, polymer concentrations). We predict a correspondence between salt concentration in charge-driven assembly and temperature in solvophobicity-driven assembly, due to the analogous role of salt in weakening the governing interactions. We also show the limits of blockiness, mapping out the transition between micro-phase separated and macro-phase separated polymers as the sequence of monomers on a polyelectrolyte changes from alternating to blocky. This demonstrates the existence of a critical blockiness, that demarcates the micro-phase and macro-phase separation as a function of block number, size, and salt concentration. Ultimately, this highlights the promise of monomer sequence as a tunable parameter in coacervation, due to the subtle interplay of the local electrostatic environment around a polyelectrolyte and its location within a self-assembled structure.

From monomer sequence to self-assembly in polyelectrolyte coacervation

Macromolecular Chemistry: The Second Century

[Author Benefits](https://scimeetings.acs.org/?utm_source=pubs_content_marketing&utm_medium=website&utm_campaign=0320_MCF_NPI_Launch_Spring_Homepage&ref=pubs_content_marketing)

[How to use SciMeetings](https://storage.googleapis.com/dl.morressier.com/acs/SciMeetings-ACSSpring2020-HowToGuide_M3020-Final.pdf)

[Frequently Asked Questions](https://storage.googleapis.com/dl.morressier.com/acs/SciMtng_ACSNMSp2020_FAQ_M3120_Final.pdf)

ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.