Electrically Programmable Micro-Scale Shape Memory Devices*

We demonstrate microscale shape memory devices capable of achieving micrometer bending radius with a holding time of several tens of hours. The core of these devices consists of a nanometer-thin platinum layer capped on one side by titanium. Under application of potentials in the range of 1 volt, ions oxidize the platinum, create a differential in stress between the two sides, and cause the structure to bend. Using thick panels we can localize the bending and readily create 3D shapes and patterns that can be reversibly erased and rewritten by short electrical pulses. This electrical programmability can be harnessed to make sequential and bidirectional folding. We demonstrate several reconfigurable 3D patterns, kirigami, and origami motifs. As such these micro-scaled shape memory devices enable a variety of applications in fields ranging from mechanical memory storage to microscopic robots.