TY - JOUR A1 - Altafim, Ruy Alberto Pisani A1 - Altafim, Ruy Alberto Pisani A1 - Qiu, Xunlin A1 - Raabe, Sebastian A1 - Wirges, Werner A1 - Basso, Heitor Cury A1 - Gerhard, Reimund T1 - Fluoropolymer piezoelectrets with tubular channels resonance behavior controlled by channel geometry T2 - Applied physics : A, Materials science & processing N2 - Ferro- or piezoelectrets are dielectric materials with two elastically very different macroscopic phases and electrically charged interfaces between them. One of the newer piezoelectret variants is a system of two fluoroethylenepropylene (FEP) films that are first laminated around a polytetrafluoroethylene (PTFE) template. Then, by removing the PTFE template, a two-layer FEP structure with open tubular channels is obtained. After electrical charging, the channels form easily deformable macroscopic electric dipoles whose changes under mechanical or electrical stress lead to significant direct or inverse piezoelectricity, respectively. Here, different PTFE templates are employed to generate channel geometries that vary in height or width. It is shown that the control of the channel geometry allows a direct adjustment of the resonance frequencies in the tubular-channel piezoelectrets. By combining several different channel widths in a single ferroelectret, it is possible to obtain multiple resonance peaks that may lead to a rather flat frequency-response region of the transducer material. A phenomenological relation between the resonance frequency and the geometrical parameters of a tubular channel is also presented. This relation may help to design piezoelectrets with a specific frequency response. Y1 - 2012 UR - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/35857 SN - 0947-8396 VL - 107 IS - 4 SP - 965 EP - 970 PB - Springer CY - New York ER -