Piezoresistive E-Skin Sensors Produced with Laser Engraved Molds

The recent interest of electronic skin (e-skin) has pushed the research toward the development of flexible sensors, namely, for pressure detection. Several mechanisms can be used to transduce pressure into electrical signals, but piezoresistivity presents advantages due to its simplicity. The microstructuration of the films composing these sensors is a common strategy to improve their sensitivity. As an alternative to conventional and expensive photolithography techniques and low customizable techniques based on natural molds, a novel strategy for the microstructuration of polydimethylsiloxane (PDMS) films is proposed, based on molds fabricated by laser engraving. After design optimization of these microstructured films, which relies on microcones, piezoresistive sensors with a limit of detection of 15 Pa and a sensitivity of -2.5 kPa(-1) in the low-pressure regime are obtained. These sensors are used with success on the detection of the blood pressure wave at the wrist, thus exhibiting a great potential for health applications.