Kinetics of formation of a macroscale binary Coulombic material

This paper describes the formation kinetics of a two-dimensional, binary Coulombic material. The material is formed by mechanically agitating millimeter-sized nylon and polytetrafluoroethylene (PTFE) beads that tribocharge positively and negatively, respectively. The authors alter the relative number of nylon and PTFE beads, without changing their combined total. They discover a common transient structure that does not depend on the relative ratio of nylon and PTFE beads, reveal a structure transition driven by the minimization of Coulombic energy, and provide insights for the rational design of materials.