Tuning the Ferroelectric Phase Transition of P(VDF-TrFE) through a Simple Approach of Modification by Introducing Double Bonds

Electroactive polymer (EAP) is a kind of intelligent material that, driven by external electric field, could produce changes in shape or volume. As an important class of EAP materials, poly(vinylidene fluoride) (PVDF) based relaxor ferroelectric polymers show remarkable potential for applications in sensors, actuator, and artificial muscles because of their excellent electro-strictive properties. However, the strain of PVDF-based relaxor ferroelectrics relies strongly on a high electric field, which seriously damages their reliability and limits their practical applications as wearable devices. To explore more suitable materials for actuator applications, in this present work, we report the influences of a double bond (DB) on the electroactive properties of P(VDF-TrFE) (TrFE: trifluoroethylene). The crystalline phase of P(VDF-TrFE) is partially destroyed after the DB is introduced, and the molecular chain flexibility of the product P(VDF-TrFE-DB) can be greatly improved. Therefore, P(VDF-TrFE-DB) has a larger electric displacement while having a lower dipole orientation electric field compared with that of P(VDF-TrFE). The result confirms that the DB could tune the ferroelectric properties and effectively reduce the driving electric field of the PVDF-based relaxor ferroelectric polymers. This work offers a strategy for the preparation of novel EAPs with low driving electric fields.