Minji Kim1 Yuen-shing Wu1 Jintu Fan1

1, Cornell University, Ithaca, New York, United States

A novel breathable piezoelectric membrane has been developed by adding zinc oxide (ZnO) to electrospun polyvinylidene fluoride (PVDF) nanofibers. Notable improvements in the piezoelectric response of PVDF membrane was achieved without compromising breathability, conformability, or safety of the material. Three ZnO nanorod addition method was investigated: hydrothermal growth on the fiber surface, fillers in electrospinning solution, and electrospraying on the PVDF membrane surface. PVDF is one of the most frequently used piezoelectric polymers due to its high piezoelectric coefficient values. However, its piezoelectric response requires further improvements for the use of high-performance sensors or energy harvesters. Previous studies have demonstrated piezoelectric ceramic and polymer composites with a remarkably improved piezoelectric constant. However, such composites often lack breathability, and some contain piezoelectric ceramics with heavy metal which limits its use in wearable applications. The said limitations can be alleviated by electrospinning piezoelectric polymers into porous membranes, and by selecting non-toxic piezoelectric ceramics. Unlike many piezoelectric ceramics containing heavy metal, ZnO is a non-toxic material which has been widely used in many fields of applications including cosmetics. The fabrication process is simple and economical due to no additional poling process needed for PVDF membranes after electrospinning in high electric field.