PVDF Based Static Charge Induced Flexoelectric Microphone

Abstract

Abstract Polyvinylidenedifluoride (PVDF)‐based microphones are either categorized as piezoelectric (PE) microphones or flexoelectric (FE)‐induced PE microphones. Based on the production of electrostatic charge and higher sensitivity, here, a static charge induced flexoelectric microphone (SCIFEM) is introduced. In this research, two SCIFEM transducers are fabricated, one by sandwiching P(VDF‐TrFE) laminate between pair of two aluminum electrodes wrapped in stretched paper sheets (called Device 1) and the other by sandwiching P(VDF‐TrFE) laminate between a pair of two Al electrodes wrapped in stretched rubber sheets (called Device 2). Devices 1 and 2 are compared with a simple PVDF‐based FE microphone (called Device 0). In this study, Devices 0, 1, and 2 are characterized for flexoelectric (FE) and charge induction (CI) properties. It is observed that despite its poor FE behavior, higher sensitivity of Device 1 is due to its electrostatic charge induced beta phase present at 1170 cm−1 of Fourier transform infrared spectra. The X‐Ray diffraction spectroscopy is also performed in accordance to the polar beta phase. It is reported that due to the enhancement in beta phase and the unique charge induction property represented at 1170 cm−1 of the FTIR spectra, the performance of SCIFEM microphone is much improved at a lower frequency range.

Keywords

• flexoelectric coefficient
• flexoelectric effect
• microphones
• piezoelectric effect
• static charge