Broadband mechanoresponsive liquid metal sensors

Stretchable electronics have the fundamental advantage of matching the complex geometries of the human body,providing opportunities for real-time biomechanical sensing.We report a method for high-frequency AC-enhanced resistive sensing that leverages deformable liquid metals to improve low-power detection of mechanical stimuli in wearable electronics.The fundamental mechanism of this enhancement is geometrical modulation of the skin effect,which induces current crowding at the surface of a liquid metal trace.In combination with DC sensing,this method quantitatively pinpoints mechanical modes of deformation such as stretching in-plane and compression out-of-plane that are traditionally impossible to distinguish.Here we explore this method by finite element simulations then employ it in a glove to detect hand gestures and tactile forces as well as a respiratory sensor to measure breathing.Moreover,this AC sensor uses lower power(100X)than DC sensors,enabling a new generation of energy-efficient wearables for haptics and biomedical sensing.