Flexible and wearable capacitive pressure sensor for blood pressure monitoring

• Published in: Sensing and Bio-Sensing Research Vol. 33; p. 100434
• Main Authors: Bijender, Kumar, Ashok
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2021; Elsevier
• Subjects: Blood pressure; Oscillometric waveform; PDMS; Pressure sensor; Blood pressure; Oscillometric waveform; Pressure sensor; PDMS
• ISSN: 2214-1804; 2214-1804
• DOI: 10.1016/j.sbsr.2021.100434

A flexible pressure sensor based on a capacitive transduction mechanism having a polydimethylsiloxane (PDMS) layer incorporated between indium‐‑tin-oxide (ITO) coated flexible polyethylene terephthalate (PET) electrodes has been developed. The sensor's key parameters have been improved by increasing the dielectric layer's porosity by introducing deionized water (DIW) into it. The sensing device with a porous dielectric layer (PDMS-DIW) exhibits a 0.07%–15% relative difference in capacitance for the applied pressure range from 1 Pa to 100 kPa. The device also demonstrates improved sensitivity compared to a PDMS layer (unstructured) throughout the complete external pressure range. The device with porous PDMS layer shows an extensive operating pressure range (1 Pa to 100 kPa), high working stability, quick response (≈110 ms) and ultra-low detection limit of pressure, i.e., 1 Pa. In addition, the blood pressure monitoring was also studied, and the devices gave a signature of the oscillometric waveform for different blood pressure (BP) values. The fabricated flexible pressure sensor can be used for wearable BP devices and biological applications due to its excellent functional properties. •Low cost PDMS-DI water dielectric as flexible and wearable pressure sensor.•It shows a relative difference of 0.07% - 15% in capacitance for the applied pressure range from 1 Pa to 100 kPa.•The sensor has high working stability, response time of 110 ms and ultra-low detection limit of pressure i.e., 1 Pa.•It shows remarkably improved sensitivity as compared to the unstructured PDMS layer.•The sensor gave a signature of the oscillometric waveform for different blood pressure (BP) values.