Programmable 3D Self-Folding Structures with Strain Engineering

Self-assembly of three-dimensional (3D) structures, through bending, twisting, folding, and buckling, has garnered broad interest among physicists, mathematicians, chemists, and biologists. Herein strain engineering and geometric frustration as an on-demand strategy for fabricating spontaneous rolling “origami” structures with programmable multistability across multiple length scales are exploited. Through experiments, theory, and finite element simulations, it is demonstrated that a strain-engineered bilayer structure can make a transition from a monostable, doubly curved shape to a neutrally stable, developable configuration, depending on a dimensionless parameter that is determined through the plate's geometry and misfit strain. In addition, the doubly curved region near the edge can play a significant role in deciding the final bending direction of the strained bilayer due to edge effects. A strain-engineering approach is further proposed to generate various 3D structures by programming the geometry, misfit strain, and mechanical properties of the bilayer units, for instance, a self-folding buckyball structure. These design principles have promising broad applications in constructing self-deploying, stimuli-responsible, and multifunctional devices across multiple length scales.

Check out our paper at Advanced Intelligent Systems: https://onlinelibrary.wiley.com/doi/full/10.1002/aisy.202000101

Featured on the cover: https://onlinelibrary.wiley.com/doi/abs/10.1002/aisy.202070121