Piezoelectric polymeric nanofibers, such as P(VDF-TrFE), are promising nanostructures for sensing/actuation applications where flexibility of the component is required, for example soft robotics, conformal sensors, and energy harvesting devices. A challenge in polymeric piezoelectric materials is that their electromechanical coupling efficiency must be improved to approach that of bulk piezo ceramics. The electromechanical coupling factor is proportional to $Y{d}^2$ (where Y is the elastic modulus, and d is the piezoelectric constant); therefore, the investigation of inter-dependence of these properties as function of thermal annealing is important. Although effect of thermal annealing on thin film of PVDF has been studied, however, detailed investigations of correlation of annealing temperature, morphology, and electro-mechanical properties of electrospun piezoelectric nanofibers have not been reported, in particular at single nanofiber level. We report on the effect of various annealing temperatures on mechanical and piezoelectric properties at the single nanofiber level using nanoindentation and piezoresponse force microscopy (PFM). FTIR, XRD, and WAXD spectroscopies were also employed to quantitatively and qualitatively explain the enhancement of these properties.

压电聚合物纳米纤维，例如P（VDF-TrFE），是有前途的纳米结构，可用于需要柔性组件的传感/驱动应用，例如，软机器人，保形传感器和能量收集设备。聚合物压电材料的一个挑战是必须提高其机电耦合效率，以接近压电陶瓷的效率。机电耦合系数与$ÿd^{\mathrm{2个}}$（其中Y是弹性模量，而d是是压电常数）; 因此，研究这些性质之间的相互依赖性作为热退火的函数是重要的。尽管已经研究了热退火对PVDF薄膜的影响，但是，尚未报道有关电纺压电纳米纤维的退火温度，形态和电-机械性能的相关性的详细研究，特别是在单纳米纤维水平上。我们使用纳米压痕和压电响应力显微镜（PFM）报告了在单个纳米纤维水平上各种退火温度对机械和压电性能的影响。FTIR，XRD和WAXD光谱仪还用于定量和定性地解释这些特性的增强。