Morphable Metamaterials: Metamaterials obtain their effective properties mainly by structure rather than composition. Mechanical metamaterials, in particular, have been designed to show superior mechanical properties, such as ultrahigh strength-to-weight ratio, or unusual properties, such as a negative coefficient of thermal expansion (CTE). However, once fabricated, structural modifications are generally difficult, making it rare to find metamaterials that can be reconfigured beyond their original design. Recent efforts have produced metamaterials with morphing functionalities by mimicking the snap-through mechanism of Venus Flytrap in nature (Fig. a). For example, multi-stable metamaterials have two or more different stable stages that can be switched reversibly among each other via snap-through buckling caused by mechanical loading (Fig. b). Morphing metamaterials can provide unprecedented performance for multiple sectors, such as aerospace, medical devices, and soft robotics.

Metamaterials with tunable thermal expansion: In extreme thermal environments, sensitive applications that require very fine precision call for materials with zero thermal expansion. They can thus avoid undesired thermal deformation. For example, thermal expansion of the supporting struts can change the distance between the sub-reflector and the antenna. Thus the signal cannot be received accurately. To suppress such failures, materials with a zero Coefficient of thermal expansion (CTE) over a wide range of temperatures are desired. The developed structural efficient metamaterials with near-zero thermal expansion have been engineered for a satellite antenna of the MDA Corp. to avoid undesired thermal distortion in extreme environments.