Plasticized P(VDF-TrFE): A new flexible piezoelectric material with an easier polarization process,promising for biomedical applications

In this work, flexible ferroelectric films of P(VDF-TrFE) softened by a plasticizer are elaborated. Morphology, piezoelectric, mechanical, thermal, and crystalline properties of the films are studied. We show that the elastic constant is reduced up to 30% while increasing the remanent polarization and the piezoelectric coefficient thanks to the lubricant property of the plasticizer, helping the orientation of the crystallites. Plus, the decrease of the coercive field from 46 to 32 V/μm after an annealing at 138°C for a plasticizer content ranging between 20 and 50 wt% is observed and an explanation by based on a polymer/plasticizer demixing is provided. It leads to an easier polarization process with a significant saving in time and applied electric field reducing the breakdown voltage. Both effects could be interesting for an industrial production. Finally, a first sensor is elaborated and characterized electrically with homemade test bench. We show that the softening of the P(VDF-TrFE) offers to the device a larger amplitude range of deformations. The combination of the flexibility with high ferroelectric properties of the plasticized P(VDF-TrFE) make it a very promising material for biomedical sensor applications.