Flexible sandwich-shaped piezoresistive sensors with microtextured electrodes and porous sensing layers of carbon nanocomposite

Flexible piezoresistive sensors based on carbon nanomaterials have attracted significant attention with regard to their application to wearable electronics. The enhanced performance of these sensors is primarily due to the integration of microstructures and conductive coatings. In this study, a flexible sandwich-shaped piezoresistive pressure sensor is fabricated by adopting microstructured electrodes and a porous sensing layer of carbon nanocomposite. The microtextured electrodes are obtained from a template by three-dimensional printing using digital light processing (DLP), and the porous structure is obtained by scarification of an NaCl crystal template. Multiwalled carbon nanotubes (MWCNTs) and graphene nanoparticles (GNPs), composited with polydimethylsiloxane and silica (ESSIL 296), are used to fabricate the functional structures, including the upper and lower electrode layers and a sandwiched porous sensing layer. The sensor exhibits a rapid response and recovery speed (∼80 ms), a high sensitivity (0.437 kPa−1) within a range of 0–1.08 kPa, and excellent stability. In addition, such sensors demonstrate potential applications for finger motion monitoring and information encryption.