Conformable pressure sensor array based on silver nanowires and PDMS for electronic skin application

Electronic skin (e-skin) is one of the important sensing and protection components for future generations of robots and medical devices to interact with their surroundings. The measurement of contact pressure is recognized as a relatively challenging task. Recently, silver nanowires (AgNWs) based stretchable conductors on polydimethylsiloxane (PDMS) thin film have been used in many skin-like devices. Here we report a partially transparent, highly flexible and stretchable pressure sensor array (8 x 8 sensor cells) based on piezoresistive principle. The AgNWs/PDMS conductors are used as stretchable interconnects and electrodes, and the pressure-sensitive rubber (PSR) serves as the sensing material. Our e-skin operating at 5 V, is responsive to the pressure with a high repeating frequency (3 Hz) or irregular profile, and can be stretched up to 30%. Not only can it cover a PDMS cylinder (20 mm in diameter), it can also conform to the varied three-dimensional surface of a cylinder during the bending process. The e-skin can detect the contact pressure even under the stretched state.