A PVDF-based flexible and shapeable acoustic power source for implantable biomedical devices

Abstract

Piezoelectric materials have been increasingly investigated over the past decade for energy harvesting and remote acoustic/ultrasonic/mechanical powering. In particular, wireless powering of implantable devices with sound and/or mechanical waves provides certain advantages compared to the traditional inductive method, mainly increased range, omni-directionality, and increased efficiency at mm and sub-mm scales. In this paper, we present a low-cost method for fabricating polyvinylidene fluoride (PVDF) power sources in form factors that are easily insertable with a biopsy needle and can form a desired shape once inside the body via a shape-memory alloy (SMA) wire. In-vitro experiments using receivers with 1 × 2 cm2 in dimensions driven by an acoustic transmitter with an output intensity of 92 dB at 250 Hz results in an electrical output power of 9.5 nW.