Polarization from dielectric-barrier discharges in ferroelectrets: Mapping of the electric-field profiles by means of thermal-pulse tomography

A polymer-ferroelectret system is fabricated by attaching two uniform polycarbonate films to a grid produced from double-sided adhesive tape by means of computer-controlled laser cutting. The openings of the grid structure result in well-defined voids inside the three-layer system, which can be internally charged through dielectric barrier discharges. The negatively charged internal void surfaces can be made visible by means of xerographical toner, and the electric-field distribution inside such ferroelectrets can be studied with thermal-pulse tomography. Both techniques exhibit polarization patterns that are consistent with the grid structure. Possible reasons for the observed non-uniform charge distributions are discussed. (C) 2010 American Institute of Physics. [doi:10.1063/1.3481802]