Influence of annealing conditions on elastic and dielectric properties of P(VDF-TrFE) copolymer and its composites

In this article, we report on investigation of wave attenuation and longitudinal velocity at ultrasonic frequency in P(VDF‐TrFE) composites with fillers of conductive carbon nanotubes (CNT). Large thermal hysteresis was observed in temperature dependences of both the ultrasonic velocity and attenuation. Moreover, the temperature dependences of the ultrasonic velocity and attenuation were shown to be sensitive to thermal cycling over the ferroelectric phase transition. In our knowledge, this is the first time when the effect of annealing on the ferroelectric phase in P(VDF‐TrFE) composites is investigated by means of ultrasonic spectroscopy. Obtained results are compared with data of dielectric spectroscopy, differential scanning calorimetry, as well as thermally stimulated discharge current measurements. An analysis of the impact of CNT fillers on the dipolar charge distribution in P(VDF‐TrFE)/CNT composites was performed by means of thermally stimulated discharge current measurements.