Patterning Polyelectrolyte Complexes with Alternating Monomer Sequence Distributions

Abstract

Charge-driven complexation of polyelectrolytes in water is a fundamental phase separation phenomenon that is prevalent in nature and across the high-value technology landscape.Condensed ionic biopolymers often rely on multiple non-covalent driving forces in patterned sequences to carefully preserve hierarchical structure and direct emerging function, and while synthetic polyelectrolyte complex (PEC) assemblies have sought to emulate and recapitulate such associative capabilities into applications, molecular engineering design strategies to precisely modulate monomeric building blocks remain vastly limited. Here we describe an experimentally convenient and versatile approach to construct patterned PECs, comprising well-defined charged macromolecules with both ionic styrene and neutral maleimide units alternating in the chain sequence. The controlled chemical structure of the alternating polyelectrolytes directly impacted the physical properties of bulk complex assemblies, demonstrated by elevated salt resistance and differences in viscoelastic relaxation and stiffness. Analogously, by engineering alternating diblock polyelectrolyte architectures for micelle self-assembly, the kinetic formation and stability pathways of PEC micelles were tailored without modifying nanoparticle size, attributed to the reduction in charge density and increased core hydrophobicity. We conclude by showing how multiple segments of donor/acceptor styrene-maleimide blocks can be incorporated into model polyelectrolyte chains in semi-batch reactions, enabling avenues to further explore sequencecontrolled polymers that regulate placement of N-substituted maleimides in polymer encryption endeavors. This unique copolymerization approach integrates appealing aspects of precision polymer synthesis with programmable self-assembly for advancing new directions in chemistry, physics, and engineering related to the complexation of oppositely-charged designer polymers.

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