Effects of Porosity on Piezoelectric Characteristics of Polyvinylidene Fluoride Films for Biomedical Applications

Objective: The objective of this work is to study the effects of porosity on mechanical and piezoelectric properties of polyvinylidene fluoride (PVDF) films for biomedical applications. Impact Statement: By investigating the piezoelectric properties of PVDF and the porosity effect on its electromechanical performance, there is potential for further development of PVDF as a hemodynamic sensor that can lead to further technological advancements in the biomedical field, benefiting patients and physicians alike. Introduction: PVDF thin films have shown potential in the application of hemodynamic flow sensing and monitoring the effects on blood flow caused by prosthetic valve implantation via the transcatheter aortic valve replacement operation. The piezoelectric performance of PVDF films can be influenced by the porosity of the material. Methods: In this study, strain tracking was performed on thin film PVDF specimens with various levels of porosity and pore sizes to determine the mechanical properties of the specimens. The mechanical properties were used to model the PVDF material in COMSOL multiphysics software, in which compression test simulations were performed to determine the piezoelectric coefficient d(33) of the PVDF. Results: A decline in the elastic modulus was found to be highly inversely correlated with porosity of the specimens and the simulation results show that elastic modulus had a much greater effect on the piezoelectric properties than Poisson's ratio. Conclusion: A combination of experimental and computational techniques was able to characterize and correlate the mechanical properties of PVDF films of varying porosities to their piezoelectric properties.