Abstract:Stretching is one of the most effective methods to improve the piezoelectric properties of PVDF-HFP films. In this study, PVDF-HFP piezoelectric films were prepared using the solution casting method, and the changes in morphology and crystal structure during stretching were studied by varying the stretching rate and temperature. The results indicate that tensile stress can induce a transformation of the matrix’s internal structure from spherical crystals to fibrous crystals, thereby facilitating the transition from the non-polar α-phase to the polar β-phase. Under optimal conditions of a elongation ratio of 5, a stretching temperature of 60 ℃, and a stretching rate of 10 mm/min, the relative β-phase content exceeds 90 %, and the calibrated open circuit voltage reaches 1.50 V under a maximum poling electric field Emax of 60 MV/m. Furthermore, when the maximum poling electric field is increased to 100 MV/m, the calibrated open circuit voltage rises to 2.24 V. The higher poling field improves the orientation of dipole moments within the matrix, leading to enhanced piezoelectric performance.
