Designing Sequence-Defined Complex Coacervates*

Complex coacervation has been employed as a versatile materials-based platform to investigate how the material microenvironment influences the stability, self-assembly, and functionality of various biomacromolecules in response to a wide range of biophysical and biochemical stimuli. This phenomenon involves liquid-liquid phase separation driven by the electrostatic and entropic complexation of oppositely charged polyelectrolytes. Here, we design and synthesize various patterned peptides as model polymers to study the role of sequence and hydrophobicity in our coacervates. Additionally, we employ microrheology to demonstrate how sequence and hydrophobicity can significantly impact the charge-charge interactions between polypeptides that drive this process and the change in viscosity within coexisting immiscible phases. Overall, our systematic and practical approach integrates sequence effects into our physical understanding of the coacervate system, thereby broadening the spectrum of chemical functionalities accessible in our peptides.