Fabrication of porous polymer based pressure sensors using sacrificial PVA 3D scaffolds for the refined tuning of sensor performances

PDMS foams have been recently considered to design enhanced flexible capacitive pressure sensors. Indeed, PDMS foams offer a promising tradeoff between bulky and structured PDMS film, allowing enhanced and easily adjustable sensor performances to be obtained. Here we explore the use of 3D printed polyvinyl alcohol (PVA) as a sacrificial mold in a polymer casting process. The PVA mold network defines channels within the PDMS film and is dissolved after curing the polymer casted around it. Sensors fabricated with PDMS scaffolds and bulk PDMS are electromechanically characterized under normal stress and compared. PDMS foam based sensors are shown to exhibits enhanced and adjustable performances compared to bulk PDMS based sensor of same dimensions. This work opens the way to the accurate design of pressure sensors for wearable pressure sensing applications.