A Novel Printed Fabric Based Porous Capacitive Pressure Sensor For Flexible Electronic Applications

A novel porous polydimethylsiloxane (PDMS) capacitive pressure sensor was fabricated on a fabric platform using additive screen printing process. The porous PDMS was prepared using a mixture of PDMS, sodium hydrogen bicarbonate (NaHCO3) and nitric acid (HNO3) and implemented as a dielectric layer. The fabric based top and bottom electrodes were developed by screen printing silver (Ag) ink on thermoplastic polyurethane (TPU) and permanently attaching it on to a fabric using heat lamination process. The capacitive response of the pressure sensor was recorded for varying pressures ranging from 0 to 900 kPa. A relative capacitance change of similar to 10%, similar to 180% and similar to 300% was obtained for the applied pressure ranges of 0 to 20 kPa, 50 to 200 kPa and 300 to 900 kPa, respectively. The detailed fabrication process of the pressure sensor as well as its capacitive response is analyzed and reported in this paper.