Capillary-Induced Self-Organization of Soft Pillar Arrays into Moir\'{e} Patterns by Dynamic Feedback Process

We report a self-organized pattern formation of polymer nanopillar arrays by dynamic feedback: two nanopillar arrays collectively structure a sandwiched liquid and pattern the menisci, which bend the pillars into Moir\'{e} patterns as it evaporates. Like the conventional Moir\'{e} phenomenon, the patterns are deterministic and tunable by mismatch angle, yet additional behaviors---chirality from achiral starting motifs and preservation of the patterns after the surfaces are separated---appear from the feedback process. Patterning menisci based on this mechanism provides a simple, scalable approach for making a series of complex, long-range-ordered structures. Reference: Sung H. Kang, Ning Wu, Alison Grinthal, and Joanna Aizenberg, Phys. Rev. Lett., \textbf{107}, 177802 (2011).~