P(VDF/TrFE) Thin‐Film Piezoelectric Actuators Sealed Parylene C for Medical Micropumps

Abstract

Wearable piezoelectric micropumps may contribute to improving drug delivery in the field of medicine. Poly(vinylidene fluoride/trifluoroethylene) (P(VDF/TrFE)), an organic ferroelectric polymer, is a desirable material for fabricating the piezoelectric layer of medical micropumps owing to its biocompatibility and flexibility. However, a large voltage is required to drive the micropumps because the piezoelectric response of P(VDF/TrFE) is small compared with that of inorganic materials, such as lead zirconate titanate. In this study, thin films (P(VDF/TrFE)) are focused that can reduce applied voltage and improve the flexibility of entire actuators. In addition, actuators sealed with poly(monochloro‐paraxylene) (Parylene C) are considered, which has excellent chemical resistance, flexibility, and biocompatibility. The calculated piezoelectric constant |e31| of the fabricated P(VDF/TrFE) thin films is 42 mC m−2. A large deformation of 1 mm is observed in the fabricated cantilever‐type actuators sealed with Parylene C when a voltage of 160 V is applied. Furthermore, the vibration of the actuators by the reverse piezoelectric effect on the water surface is observed. It is indicated in these results that a low voltage can safely drive P(VDF/TrFE) thin‐film piezoelectric actuators sealed with Parylene C in medical micropumps.