A Highly Stretchable Circuit Based on Metal-Elastomer Composite

We develop a highly stretchable circuit by utilizing serpentine interconnects made of high-elasticity Cu-Be alloy. An elastic equivalent model of serpentine interconnect is used to optimize the geometric parameters, thereby enhancing its mechanical compatibility with the soft substrate. Furthermore, we propose a rapid fabrication method of highly stretchable circuits through the laser cutting and film transfer techniques. The results indicate that the elastic strain limit of the Cu-Be alloy serpentine interconnect is 4 times that of the Cu interconnect. The Cu-Be alloy serpentine circuit with optimized geometric parameters exhibits an excellent resistance stability under 1000 cycles of tensile testing at 90% strain without local delamination or failure. The light emitting diode (LED) array demonstrates an ultrahigh tensile strain limit of up to 200%. The proposed method can provide a novel and promising way for the fabrication of highly stretchable circuits for future wearable electronic devices.