Abstract

Artificial intelligence and flexible wearable electronics have motivated the development of novel high stretchable strain and pressure sensors. PDMS is one of the most studied materials for these sensors although in devices with complex electrodes made of different materials. To fully take advantage of PDMS, we developed high stretchable all-PDMS capacitive sensors using its composites with carbon grease (CG) as the dielectric film and its ternary composites with 10.0 wt% of CG and 2.5 wt% of carbon nanotube (CNT) as the compliant electrode (PDMS/CG/CNT). These all-PDMS capacitors were first tested as capacitive strain-sensors presenting stretchability above 300 % and a linear sensibility appropriated for developing a wearable sensor for biomechanical monitoring. An all-PDMS pressure-capacitive porous sensor was further developed presenting high sensitivities. Noteworthy, the same all-PDMS porous capacitive device further acted as a triboelectric nanogenerator under compression without any change in its configuration adding a second mechanism for sensing based on the voltage generated. By taking advantage of this dual mechanism, a wearable and wireless smart multifunctional sensor was developed able to recognize not only the weight of an object by the capacitive mechanism, but also the type of material by the triboelectric mechanism through the relationship between the triboelectric charge density of each material and the voltage generated from the sensor. Our findings allow the development of novel sensors for remote acquisition of quantitative and qualitative information about objects through a commercial smartphone.