Complexation and coacervation of like charged polyelectrolytes inspired by mussels
Significance Conventional coacervates can form on mixing oppositely charged polyelectrolytes in aqueous solutions, due to electrostatic attraction between the oppositely charged polymers. This report describes the first instance (to the best of our knowledge) of complexation and coacervation of two positively charged polyelectrolytes by overcoming longer range electrostatic repulsion. The molecular force measurements and theoretical simulations demonstrate that the complexation of the like charged coacervate is most likely driven by strong cation p interactions inspired by marine mussel adhesives. This like charged coacervation mechanism provides new insights into biological self assembly processes and a new paradigm for engineering strong, reversible interactions between polymers underwater, which has various potential applications like encapsulation and dispersion of particles and cells. It is well known that polyelectrolyte complexes and coacervates can form on mixing oppositely charged polyelectrolytes in aqueous solutions, due to mainly electrostatic attraction between the oppositely charged polymers. Here, we report the first (to the best of our knowledge) complexation and coacervation of two positively charged polyelectrolytes, which provides a new paradigm for engineering strong, self healing interactions between polyelectrolytes underwater and a new marine mussel inspired underwater adhesion mechanism. Unlike the conventional complex coacervate, the like charged coacervate is aggregated by strong short range cation p interactions by overcoming repulsive electrostatic interactions. The resultant phase of the like charged coacervate comprises a thin and fragile polyelectrolyte framework and round and regular pores, implying a strong electrostatic correlation among the polyelectrolyte frameworks. The like charged coacervate possesses a very low interfacial tension, which enables this highly positively charged coacervate to be applied to capture, carry, or encapsulate anionic biomolecules and particles with a broad range of applications.
Proceedings of the National Academy of Sciences