Dependence of Ferroelectric Response of P(VDF-TrFE) Films on Preparation Process and Post-Stretching

Poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) can readily form a ferroelectric phase and display distinctive polarization switching in electric fields. It is thus promising for advanced flexible electronics, e.g., bio-inspired actuators and wearable sensors, highlighting its substantial research value. The impact of processing conditions on the multi-level structures and polarization switching performance of them remains yet inadequately elucidated. In this paper, P(VDF-TrFE) films were fabricated via blade-coating and hot-pressing methods, respectively. Their structures and ferroelectric properties before and after post-stretching were systematically investigated. The hot-pressed films exhibit superior ferroelectric properties of advantageous polarization response over 10.0 µC/cm², lower coercive field (E_c), and notably rapid switching dynamics characterized by almost halved activation field (δ) owing to higher crystallinity (X_c) and less gauche defects in polar domains. On the other hand, stretching improves molecular orientation, therefore enhancing the Curie temperature (T_Curie) and switching dynamics in both films, but affects polarization response oppositely. The polarization response increases by 25 % in the blade-coated films due to a reduction of gauche defects, while it weakens in the hot-pressed films due to a critical 10 % decline in X_c. This work delineates the pathway for controlling the switching characteristics and provides fundamental theoretical guidance for developing high performance P(VDF-TrFE) films.