Programmed anisotropic transformations of cellular structures

The physical properties of metamaterials are controlled by the underlying material properties (molecular scale) as well as the design of the periodic structures, including shape, geometry, size, orientation, and arrangement (unit cell scale). Harnessing instabilities in soft materials based periodic structures offers an effective strategy to achieve multifunctionalities. Here, we report the programmable anisotropic transformations of cellular structures made of liquid crystalline elastomers (LCEs) on rigid substrates. By programming the mesogen alignment of liquid crystals (LC) using magnetic fields at the molecular scale, the desired anisotropies are introduced to periodic structures with different geometric designs at the unit cell scale. We demonstrate that the coupling of the two scales of controls leads to various novel deformation modes benefiting from both the mechanical guiding and the chemical guiding, which greatly broadens the design space of metamaterials. The design principle for programmed reconfigurations with prescribed anisotropies in periodic lattices is validated by both mechanics model and finite element simulation.