Characterization of Porous Polyvinylidene Fluoride for Use as a Biosensor (2021-03-05)

Abstract

The Transcatheter Aortic Valve Replacement (TAVR) is a minimally invasiveprocedure that has grown in popularity in recent years. However, there has beendocumentation of many complications after this procedure, such as a mortality rate of8.4% for TAVR procedures compared to 4.8% for tissue surgery procedures after 90days for Medicare beneficiaries. The underlying mechanisms of the TAVR procedureand how the replacement valve changes the biomechanical and flow environmentafter implantation has not been well studied. Therefore, it is necessary to design amodel heart and create sensors to understand the underlying mechanisms of theTAVR procedure. The goal of this project is to design a sensor that can detectchanges in blood pressure and blood flow rates in a silicon model heart. Onepromising type of material is piezoelectric sensors. Piezoelectric materials takemechanical stress and create detectable changes in voltage that can be calibrated todetermine changes in pressure. One material that has been used for other sensors isPolyvinylidene fluoride (PVDF). This study will investigate how porosity of PVDFchanges the structural and mechanical properties of the polymer. Pores will beintroduced into the PVDF membrane by adding Zinc Oxide (ZnO) nanoparticlesduring the synthesis process and removing the ZnO particles once the membranehas dried. To study the changes in the structure of the membrane, Scanning ElectronMicroscopy is used to confirm a porous structure. To study how the chainconformation of the polymer changes with porosity, Fourier Infrared Spectroscopy isutilized. A Tensile Tester is used to apply compressive stress onto the PVDFmembranes to study the piezoelectric output. To allow for comparison betweenvarious porous membranes, the d33 coefficient is calculated. This will help determinewhich porosity is optimal for the creation of the biosensor with desired sensitivity.