(608d) A Materials Genome Approach for Enabling Designer Block Polyelectrolytes

Polyelectrolyte complexes (PECs) materialize through associative phase separation of oppositely–charged polymers in aqueous settings. Depending on the chemical attributes, electrostatic interactions, and arrangement of the constituent monomers, these ion-containing macromolecules can be tailored toward completely hydrophilic, compartmentalized assemblies in solution. This uniquely positions them to transport challenging biomolecules such as nucleic acids or proteins, coat underwater substrates with ionic surfaces, and repair tissues between skin and bone as biocompatible soft adhesives. However, the functional roles of chemical and ionic interactions need to be reconciled for translation into safe, effective, and reliable end-use technologies. A materials–genome approach, based on expanding experimental/simulation datasets of PEC systems, can build a more-diverse materials information infrastructure for understanding how specific non-covalent intermolecular interactions prevail in governing polyelectrolyte behavior. Herein, we report recent advances in soft matter design based on charge complexation in micelle and hydrogel platforms. New synthesis–screening campaigns using aqueous reversible addition-fragmentation chain transfer (RAFT) polymerization have been pursued in a parallel synthesizer, enabling the rapid preparation of well-defined block polyelectrolyte candidates from polyethylene oxide, with targetable molar masses and functionalizable end–groups. The complex formation, temporal evolution, and disassembly of structured PECs from rationally–paired RAFT di- and triblocks were evaluated using dynamic light scattering, small angle X-ray scattering, cryogenic imaging, and fluorescent spectroscopy techniques. Time-resolved salt responsivity experiments elucidated structure dynamics and characteristic relaxation times of different polyelectrolyte pairings. Collectively, this concerted endeavor reveals how to better predict and strategically design specialized nanocomplexes for emerging nonviral delivery challenges in the biomedical landscape such as genome editing.