Printed Capacitive Pressure Sensor with Enhanced Sensitivity through a Layered PDMS/BaTiO3 Structure

Printable electronics have demonstrated significant promise in enabling soft tactile sensing systems. This paper presents a fully printed and soft capacitive pressure sensor realized through a two-dimensional interdigitated capacitor. The sensor transduces applied pressures through a fringing electric field interacting with a deformable elastomer. The deformable elastomer consists of either pure polydimethylsiloxane (PDMS) or a layered PDMS/BaTiO3 structure. A 10 mm overlaid layered structure is created by depositing six alternating layers of a Barium Titanate-PDMS mixture and pure PDMS, followed by a 4 mm PDMS layer on the printed electrode. Multiple tests using standardized pressure and capacitance measurements have been performed to measure and compare the sensitivity between pure PDMS and PDMS/BaTiO3 layered configuration. The capacitive response shows that the layered PDMS/BaTiO3 device enhances the sensitivity for pressures less than 1 kPa by approximately 10x. This work demonstrates the potential of a printed electronic sensor in measuring small-scale pressure variation using inexpensive and simple fabrication methods.