Engineering auxetic geometry design for flexible and stretchable devices

In this talk, we present how the auxetic design can be used to flexible and stretchable electronic devices. An auxetic structure called ‘fractal cut’, which means that the basic rotating units can be subdivided into a self-similar hierarchy, enables us to develop extremely and omni-directionally deformable batteries. During stretching or crumpling, deformation occurs only at hinges between two adjacent units while the units did not undergo distortion. In addition, a re-entrant auxetic elastomer used for capacitive-type stretchable strain sensor can overcome the theoretical limit of the conventional capacitive-type strain sensor. We believe that our auxetic geometry design can provide a strategy to apply mechanical metamaterials for fabricating flexible and stretchable electronic devices.