Role of Charge Patterning and Hydrophobicity in Peptide-Based Complex Coacervates

Complex coacervation has emerged as a powerful model for studying the self-assembly of intrinsically disordered proteins (IDPs) in biological condensates in cells. We characterized the phase behavior and rheology of coacervates formed from peptides with regular repeating sequences to examine the effects of charge patterning and hydrophobicity on coacervate stability and material properties. Our results show that increasing the size of charged blocks enhances salt resistance via electrostatic cooperativity, while incorporating small hydrophobic segments further stabilizes coacervates and increases viscosity through hydrophobic clustering. Interestingly, our results involving alanine as the neutral residue suggest that structural conformations present for peptides with shorter block sizes may contribute to increased viscosity within the coacervate phase. Overall, these findings underscore the potential of sequence-controlled materials as versatile platforms for engineering self-assembling materials with tunable mechanical and phase properties.