Polarization Modulation in PVDF During the Electric Field Rising and Falling Runs

Polyvinylidene difluoride (PVDF) is a hot research topic material in the field of energy storage and conversion due to its high polarization response. However, the mechanism of the behavior of VDF dipoles under varying electric field stresses is still not well understood. Here, effect of amplitude variation of sinusoidal electric field on the dipole reorientation behavior is studied by polarization-electric field (P-E) hysteresis loops. Experimental results suggest that when the applied electric field amplitude goes from high to low, the intense reorientation at high field strengths expands the intermolecular spacing, resulting in a reduced hindrance to dipole reorientation at low field strengths, and thus increasing the polarization intensity. At 160 MV/m sinusoidal electric field, the maximum polarization intensity <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathrm{P}_{\max})$</tex> is increased from 4.68 to 5.32 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mu \mathrm{C}/\text{cm}^{2}$</tex> during the fall amplitude process compared to the rise amplitude process, resulting in a 20% increase in energy consumption. These findings not only deepen our understanding of the behavior mechanism of VDF dipoles but also provide useful guidance for regulating the properties of PVDF-based films.