Flexible thin-film PVDF-TrFE based pressure sensor for smart catheter applications.

We demonstrate the design of thin flexible pressure sensors based on piezoelectric PVDF-TrFE (polyvinyledenedifluoride-tetrafluoroethylene) co-polymer film, which can be integrated onto a catheter, where the compact inner lumen space limit the dimensions of the pressure sensors. Previously, we demonstrated that the thin-film sensors of one micrometer thickness were shown to have better performance compared to the thicker film with no additional electrical poling or mechanical stretching due to higher crystallinity. The pressure sensors can be mass producible using standard lithography process, with excellent control of film uniformity and thickness down to one micrometer. The fabricated pressure sensors were easily mountable on external surface of commercial catheters. Elaborate experiments were performed to demonstrate the applicability of PVDF sensors towards catheter based biomedical application. The resonant frequency of the PVDF sensor was found to be 6.34 MHz. The PVDF sensors can operate over a broad pressure range of 0-300 mmHg. The average sensitivity of the PVDF sensor was found to be four times higher (99 μV/mmHg) than commercial pressure sensor while the PVDF sensor (0.26 s) had fivefold shorter response time than commercial pressure sensor (1.30 s), making the PVDF sensors highly suitable for real-time pressure measurements using catheters.