TY  - JOUR
A1  - Mellinger, Axel
A1  - Wegener, Michael
A1  - Wirges, Werner
A1  - Gerhard, Reimund
T1  - Thermally stable dynamic piezoelectricity in sandwich films of porous and non-porous amorphous fluoropolymer
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Mellinger, Axel
A1  - Singh, Rajeev
A1  - Wegener, Michael
A1  - Wirges, Werner
A1  - Gerhard, Reimund
A1  - Lang, Sidney B.
T1  - Three-dimensional mapping of polarization profiles with thermal pulses
N2  - High-resolution, large-area three-dimensional mapping of polarization profiles in electret polymers was carried out by means of a fast thermal pulse technique with a focused laser beam. A lateral resolution of 38 mu m and a near- surface depth resolution of less than 0.5 mu m was achieved. At larger depths, fast thermal diffusion in the metal electrode rather than the laser spot size becomes the limiting factor for the lateral resolution. (c) 2005 American Institute of Physics
Y1  - 2005
SN  - 0003-6951
ER  - 
TY  - JOUR
A1  - Wegener, Michael
A1  - Wirges, Werner
A1  - Fohlmeister, Jens Bernd
A1  - Tiersch, Brigitte
A1  - Gerhard, Reimund
T1  - Two-step inflation of cellular polypropylene films: Void-thickness increase and enhanced electromechanical properties
N2  - In cellular, electromechanically active polymer films, the so-called ferroelectrets, the cell size and shape distributions can be varied through a controlled inflation process. Up to now, high-pressure treatments were usually performed at elevated temperatures. There are, however, significant experimental limitations and complications if the pressure and temperature treatments are performed at the same time. Here, we demonstrate the controlled inflation of cellular polypropylene films by means of sepal-ate pressure and temperature treatments. Separate procedures are Much easier to implement. Excellent electromechanical properties were achieved with Such a two-step inflation process. The technique has significant potential for inflating large-area transducer films for electromechanical and electroacoustical applications
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Paajanen, Mika
A1  - Wegener, Michael
A1  - Gerhard, Reimund
T1  - Understanding the role of the gas in the voids during corona charging of cellular electret films : a way to enhance their piezoelectricity
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Wegener, Michael
A1  - Bergweiler, Steffen
A1  - Wirges, Werner
A1  - Pucher, Andreas
A1  - Gerhard, Reimund
T1  - Voided space-charge electrets : piezoelectric transducer materials for electro-acoustic applications
Y1  - 2004
ER  - 
TY  - JOUR
A1  - Mellinger, Axel
A1  - Flores Suárez, Rosaura
A1  - Singh, Rajeev
A1  - Wegener, Michael
A1  - Wirges, Werner
A1  - Gerhard, Reimund
T1  - Zerstörungsfreie Tomographie von Raumladungs- und Polarisationsverteilungen mittles Wärmepulsen
N2  - Non-destructive, three-dimensional imaging of space-charge and polarization distributions in electret materials has been implemented by means of laser-induced thermal pulses. In pyroelectric films of poled poly(vinylidene fluoride), images of up to 45 x 45 pixels with a depth resolution of less than 0.5 mu m and a lateral resolution of 40 mu m were recorded, the latter being limited by fast thermal diffusion in the absorbing metallic front electrode. Initial applications include the analysis of polarization distributions in corona-poled piezoelectric sensor cables and the detection of patterned space-charge distributions in polytetrafluoroethylene films.
Y1  - 2007
UR  - http://www.oldenbourg-link.com/loi/teme
U6  - https://doi.org/10.1524/teme.2007.74.9.437
SN  - 0171-8096
ER  -