Abstract
The richness of liquid-liquid phase separation behavior in mixtures of oppositely-charged polyelectrolyte has been greatly illuminated recently in the polymer physics literature. Precise determinations of phase diagrams, measurements of interfacial tension, scattering measurements of chain configurations, and increasingly insightful theory are all producing a clearer understanding of these phenomena. In parallel, physics is also being brought to bear on manifestations of these behaviors in biology. Diverse biological examples related to liquid0liquid phase separation of polyelectrolyte complexes include membraneless organelles, biological condensates that enhance transcription or protect from stress shock, and other biological functions. This talk will spell out current understanding of the various contributions to the phase behavior, including the role of various entropic contributions, as well as the effects of charge density of the macromolecules. New
results on asymmetric mixtures will be presented, which are more the norm in nature than the perfectly symmetrical mixtures in polymer physics studies.