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Screen printing for producing ferroelectret systems with polymer-electret films and well-defined cavities

: Sborikas, M.; Qiu, X.; Wirges, W.; Gerhard, R.; Jenninger, W.; Lovera, D.


Applied physics. A 114 (2014), No.2, pp.515-520
ISSN: 0340-3793
ISSN: 0721-7250
ISSN: 0947-8396 (Print)
ISSN: 1432-0630 (Online)
Journal Article
Fraunhofer IAP ()

We report a process for preparing polymer ferroelectrets by means of screen printing - a technology that is widely used for the two-dimensional patterning of printed layers. In order to produce polymer-film systems with cavities that are suitable for bipolar electric charging, a screen-printing paste is deposited through a screen with a pre-designed pattern onto the surface of a polymer electret film. Another such polymer film is placed on top of the printed pattern, and well-defined cavities are formed in-between. During heating and curing, the polymer films are tightly bonded to the patterned paste layer so that a stable three-layer system is obtained. In the present work, polycarbonate (PC) films have been employed as electret layers. Screen printing, curing and charging led to PC ferroelectret systems with a piezoelectric d 33 coefficient of about 28 pC/N that is stable up to 100 âC. Due to the rather soft patterned layer, d 33 strongly decreases already for static pressures of tens of kPa. The results demonstrate the suitability of screen printing for the preparation of ferroelectret systems.