拉伸速率与拉伸温度对PVDF-HFP薄膜压电性能的影响

Effects of stretching rate and temperature on the piezoelectric properties of PVDF-HFP thin films

拉伸是提高PVDF-HFP薄膜压电性能最有效的方法之一。采用溶液浇铸法制备PVDFHFP压电薄膜,以拉伸速率和拉伸温度为变量,研究了薄膜拉伸前后形貌变化及晶体结构变化。结果表明,沿拉伸方向的应力可以迫使基体内部结构由球晶转变为纤维状晶体,从而促使非极性α相转变成极性β相,在拉伸伸长率为5、拉伸温度为60℃和拉伸速率为10mm/min时,薄膜的β相相对含量超过90%。在最大极化电场E_(max)=60 MV/m作用下,其标准开环电压达到1.50 V;在此拉伸工艺下,将最大极化电场提升到100 MV/m,薄膜的标准开环电压达到2.24 V,提高最大极化电场使基体内部固有偶极矩取向更充分,压电性能更优异。

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-polarα-phase to the polarβ-phase.Under optimal conditions of a elongation ratio of 5,a stretching temperature of 60℃,and a stretching rate of 10 mm/min,the relativeβ-phase content exceeds 90%,and the calibrated open circuit voltage reaches 1.50 V under a maximum poling electric field E_(max) 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.