Soft capacitive tactile sensing arrays fabricated via direct filament casting

Advances in soft electronics are enabling the development of mechanical sensors that can conform to curved surfaces or soft objects, allowing them to interface seamlessly with the human body. In this paper, we report on intrinsically deformable tactile sensing arrays that achieve a unique combination of high spatial resolution, sensitivity, and mechanical stretchability. The devices are fabricated via a casting process that yields arrays of microfluidic channels in low modulus polymer membranes with thickness as small as one millimeter. Using liquid metal alloy as a conductor, we apply matrix-addressed capacitive sensing in order to resolve spatially distributed strain with millimeter precision over areas of several square centimeters. Due to the use of low-modulus polymers, the devices readily achieve stretchability greater than 500%, making them well suited for novel applications in wearable tactile sensing for biomedical applications.