(193n) Flash Nanocomplexation: A Continuous and Scalable Platform for Functional Polyelectrolyte Complex Colloids

Upon mixing solutions of oppositely-charged polyelectrolytes, charge associations between chains result in the formation of nanoscale complex colloids (PECs). The controllable size and characteristics of PECs enable their use in diverse applications including the encapsulation of active ingredients as well as the design of advanced materials. While PEC properties are well-correlated to the attributes of constituent polyelectrolytes and complexation conditions, an understanding of the impact of mixing, specifically at time scales commensurate with chains associations (~10^-4 s), is limited. In this work, we present a new technique for PEC formation termed Flash NanoComplexation (FNC) in which confined impingement jet (CIJ) mixing, a scalable and continuous process, enables fast mixing of polyelectrolyte solutions on the order of milliseconds. The effects of stream concentrations, charge ratios, and ionic strength on PEC size, dispersity, surface charge, and stability are evaluated in this new experimental context. From insights gained in foundational studies, the utility of FNC is demonstrated through applications including the green nano-encapsulation of sensitive active ingredients as well as the fabrication of structured colloids for advanced materials.