Flexible ferroelectret for zero power wearable application

Abstract

The advancement in Internet of Things (IoT) and 5G technologies are pushing the interest in zero power sensor networks in different sectors including wearables, wellbeing, smart packaging, and agriculture. In this manuscript, we report the adhesive-bonded piezoroelectret for the application in zero-power sensors. Laser-patterned polyvinyl chloride (PVC) adhesive tape is used to bond two 25 µm-thick FEP sheets with chargetrapping voids. The bonded fluorinated ethylene propylene (FEP) sheets were charged using a 1) pyroelectric and 2) corona discharging approach to produce piezoroelectrets. Produced piezoroelectrets were characterized for the force response and piezoelectric coefficient (d33 = 20-30 pC/N) using an in-house built setup. Further, the repeatability between different piezoroelectret samples fabricated using a similar approach is validated. Produced flexible piezoelectret was used to measure the human cardiac pulse pressure in the wrist.