Negatively bias driven enhancement in piezo response for self-powered biomedical and facial expression sensor

Abstract

Negatively poled nylon-11 nanofibers with enhanced piezoresponse were prepared using negative bias polarity in the electrospinning setup, thereby achieving a piezoelectric charge coefficient d33 of ∼27 pm/V; this was three times higher than their positively poled counterpart. Polarized Fourier transform infrared spectroscopy indicated that the use of a negative bias increased the degree of molecular dipole alignment and crystallinity content, compared to using a positive bias. In order to assess the piezoelectric performance of these two types of polarized nanofibers, piezoelectric nanogenerators (PNGs) were fabricated. It was observed that the PNG based on negatively biased nanofibers exhibited mechanosensitivity 11 times higher than the PNG based on positively biased nanofibers. As a result, excellent bio-sensing capabilities of negatively poled nylon-11 nanofibers enable tracking of physiological events such as arterial pulse, carotid pulse, and various facial movements for a next generation health care system.