Elastomeric Foam-Based Soft Capacitive Pressure Sensors Using Direct Ink Writing

Abstract

Conformable and flexible tactile/pressure sensors are of interest in applications such as robotics, wearable and interactive systems to measure the contact forces. These applications require a large number of robust sensors, for which simple manufacturing routes such as additive manufacturing can be useful. Herein, we present the fully 3D printed capacitive touch sensors comprising of elastomeric foam-based soft dielectric layers (blends of PDMS and BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) and PEDOT: PSS and AgNWs composite-based electrodes. The devices were encapsulated with 3D printed PDMS and tested under dynamic and static stimuli. The sensor with 1% wt. of BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> exhibited the best performance with a sensitivity of 0.571 %kPa <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> and excellent linearity (99.32%). The observed capacitive behavior of the sensor is significantly higher than a similar sensor with bulk PDMS as the dielectric. The fabrication approach employed in this work has the untapped potential to develop soft and flexible electronic skin (e-skin) for wearables, health monitoring, and rehabilitation.