DNA self-organization controls valence in programmable colloid design

Controlling valence is a prerequisite for making materials of arbitrary complexity by design. Previously, solid patchy particles were explicitly engineered to define the valence and geometry of a given assembly. By contrast, this work demonstrates how mobile DNA linkers self-organize at the interface between colloidal droplets into a well-defined number of adhesive patches, that is, valence, to create order on much longer length scales. Our experiments and analytical theory are in excellent agreement, demonstrating that this valence is a thermodynamic equilibrium state, which is tuned by experimental control parameters, such as the number of DNAs, the mechanical properties of DNA, and the patch geometry.