Multistability in Nanoscale Origami: Interplay of Geometry, Thermal Fluctuations, and Molecular Forces

The multistable energy landscapes of origami have proven useful for deployable structures, mechanical information, and energy storage. There has been recent interest in applying origami principles to 2D materials in order to design a wide array of nanoscale devices. However, to properly understand the behavior of these origami-based nanodevices, one must consider the interplay of the geometric mechanics of origami with thermal fluctuations, steric repulsion, van der Waals attraction, and other molecular-scale phenomena. Here we develop a model for the statistical mechanics of a single fold in a nanosheet by drawing inspiration from past work on entropic pressure between biological membranes. The statistical mechanics model is then used to inform fold and interfacial free energies of a broader nanoscale origami structure. The free energy landscape and multistability of nanoscale origamis are explored with a particular emphasis on the influences of crease pattern, size, and temperature.