Piezoelectrets: A Brief Introduction
Melkzedekue de Moraes Alcântara Calabrese Moreira, Igor Nazareno Soares, Yuri Andrey Olivato Assagra, Felipe Schiavon Inocêncio de Sousa, Tiago Matheus Nordi, Diego M. Dourado, Rodrigo Henrique Gounella, João Carmo, Ruy Alberto Pisani Altafim, Ruy Alberto Pisani Altafim
Abstract
In its main definition, piezoelectrets are polymeric structures with electric charged internal cavities. The bipolar-trapped charges form macro-dipoles that can be mechanically deformed, thus presenting a high piezoelectric coefficient in the order of hundreds of pC/N. Such results outperform most of the traditional piezoelectric polymers. As piezoelectrets can be manufactured by different methods, some of the techniques allow the inner cavities to be geometrically controlled, therefore providing some degree of freedom in the piezoelectric behavior. This report provides a description of the most relevant methods, starting with a brief introduction of piezoelectret origin and reaching recent achievements in piezoelectret production, such as additive manufacturing (3D printing). Materials that are frequently employed in piezoelectret fabrication and methods for improving their characteristics are also presented.