Theoretical correlation between localized effective bulk modulus elastography and piezoelectric coefficient in PVDF-based systems

Effective Bulk Modulus Elastography (EBME) has emerged as a powerful tool for resolving localized stiffness variations in poly(vinylidene fluoride) (PVDF)-based materials, yet its connection to piezoelectric behavior remains insufficiently defined. Here, a unified theoretical correlation is established for thermally treated PVDF and PVDF–V2O3 composites by linking effective bulk modulus K, piezoelectric coefficient d33, remnant polarization Pr, refractive index n, and Lorentz local-field factor L. Analysis of previously reported EBME, piezoelectric, and optical datasets shows that these independently measured quantities follow a correlation of the form Pr≈(d33K)/L. In both thermally treated PVDF series and the PVDF–V2O3 concentration series, the highest piezoelectric response coincides with the highest remnant polarization rather than with the minimum bulk modulus. Although the Lorentz local-field factor contributes to the overall framework, it does not independently determine the electromechanical optimum. The study, therefore, establishes a new cross-property relationship that broadens the significance of EBME from stiffness mapping to a central role in the unified interpretation and design of PVDF-based functional materials.