Self-Powered Flexible Piezoelectret Array for Wearable Applications

In this manuscript, a flexible piezoelectret array is demonstrated for wearable applications. Piezoelectrets/ferroelectrets are voided polymers that exhibit piezoelectric effect after being subjected to a charging process that generates and orients charges in the voids. The developed piezoelectret array is composed of two fluorinated ethylene propylene (FEP) sheets bonded with a patterned adhesive layer. A piezoelectret array with optimized void geometry and a piezoelectric coefficient d
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= 74 ± 5 pC/N is tested as a flexible pressure sensor, allowing the measurement of the wrist flexors during contraction. The developed sensor is tested for the frequency and force response to understand the broad-band nature of the developed sensor. The sensor can be further miniaturized or fabricated in different shapes for particular applications.