Self-Assembly by deionization, coacervation, and epitaxy

Surface charging and ionic conductance are ubiquitous properties of colloidal suspensions that also profoundly affect their stability and phase behavior. Rigorous deionization induces long-range electrostatic forces that can drive colloidal crystallization, and small changes in salinity can drive large changes in the assembly of oppositely charged polyelectrolytes. Here we demonstrate a new technique to control the salinity of colloids in-situ, and show how it may be combined with the physics of polyelectrolyte coacervation and epitaxial templating to produce self-assembled crystals of oppositely charged colloidal particles.