Controlling Malleability of Metamaterials through Programmable Memory

Malleability, the ability to adapt materials to specific shapes, is necessary inapplications where a form closure is requested. The material should be easilydeformable between desired stable shapes. Such stability can be obtained throughbistable elements that act as memory in metamaterials. Herein, a material withmemory behavior programmed by the local temperature is presented. The behaviorcan be switched between a permanent shape change and a complete elasticrecovery after removing an applied mechanical load. Additionally, a deformedmaterial can be forced to recover its shape by heating. Through an adaption of themesostructure and the used polymers, the characteristic behavior (switching timeand temperature) can be adjusted. Furthermore, heating can be applied locally thatonly certain parts are able to change. A unit cell design based on analytical andnumerical analyses is demonstrated that considers not only the mesostructure butalso the combination of polymeric materials with specific thermoresponsivemechanical behavior. Unit cells and structures of several cells are additivelymanufactured to validate the programmable behavior. The concept is extended toindirect heating with an alternating magneticfield, using a compound made from apolymeric material and magnetic particles.