Dynamical phase transition in the growth of programmable polymorphic materials

The hallmark feature of polymorphic systems is their ability to assemble into many possible structures at the same thermodynamic state. Designer polymorphic materials can in principle be engineered via programmable self-assembly, but the robustness of the assembly process depends on dynamical factors that are poorly understood. Here we predict a failure mode for the growth of multicomponent polymorphic materials in which dynamical coexistence occurs between ordered and disordered assembly trajectories. We show that this transition is preceded by the formation of a steady-state disordered wetting layer, suggesting a nonequilibrium analogy to premelting phenomena at equilibrium. This dynamical phase transition is likely to occur in a variety of systems and may fundamentally limit the complexity of polymorphic materials that can be designed through programmable self-assembly.