Materials Processing Using Complex Coacervates

The formulation of polymeric materials, such as underwater adhesives and coatings, is particularly challenging due to the interplay between performance (e.g., toughness and flexibility), and processability requirements, such as the use of organic solvents, which can be detrimental to the environment. Marine creatures such as sandcastle worms and mussels show strong underwater adhesion using materials based on complex coacervation. However, it is not clear whether many of the design rules associated with traditional polymers will still hold for materials based on coacervation. As such, we are interested in studying the parameters that affect this phenomenon and how these can be applied to various applications.

Complex coacervation is an entropically driven, associative liquid-liquid phase separation that results in a polymer-rich coacervate and a polymer-poor supernatant. We propose to use complex coacervation as an alternative, environmentally friendly, polymer processing strategy. It has been previously demonstrated that liquid complex coacervates can be processed into solid films and fibers using a fully aqueous approach. However, the materials reported to date were produced with high charge-density polymers, creating a solid complex resembling a highly crosslinked yet brittle network when dried but demonstrating exceptional stability against temperature or solvent challenge. Our work uses polymers with different charge density and composition to study how these parameters affect both the coacervate phase behavior and the properties of the resulting materials. We hypothesize that these materials will be useful for a range of applications, such as, coatings or medical materials via simple production and without the need for harmful organic solvents or chemicals.