A thin-film piezoelectric PVDF-TrFE based implantable pressure sensor using lithographic patterning

We report a thin PVDF-TrFE (polyvinyledenedifluoride-tetrafluoroethylene) copolymer film pressure sensor, fabricated using the standard lithography process for cost-effective batch process, film uniformity, and high resolution of polymer patterning. PVDF-TrFE copolymer, a semi-crystalline material, was spin-coated into thin films (1 μm thick or less) to tap the near β-phase formation. Such thin films, curing in the vacuum oven, offer significant piezoelectricity owing to the residual stress between the thin film and the substrate. Pressure measurements demonstrated that the dual film can achieve 0.6 - 1 V output voltages for 0 - 5 psi pressures, as normal physiological pressure range, with fast recovery time of around 0.2 second, and 9% low output variation.