When exposed to sufficiently high electric fields, polymer-foam electret materials with closed cells exhibit ferroelectric-like behavior and may therefore be called ferroelectrets. In cellular ferroelectrets, the influence of the cell size and shape distributions on the application-relevant properties is not yet understood. Therefore, controlled inflation experiments were carried out on cellular polypropylene films, and the resulting elastical and electromechanical parameters were determined. The elastic modulus in the thickness direction shows a minimum with a corresponding maximum in the electromechanical transducer coefficient. The resonance frequency shifts as a function of the elastic modulus and the relative density of the inflated cellular films. Therefore, the transducer properties of cellular ferroelectrets can be optimized by means of controlled inflation.

1.
L. J. Gibson and M. F. Ashby, Cellular Solids: Structure and Properties, 2nd ed. (Cambridge University Press, Cambridge, UK, 1997), in particular, Chaps. 5 and 6.
2.
M. Paajanen, Ph.D. thesis, VTT Publications Vol. 436, (Technical Research Centre of Finland, Espoo, 2001);
M.
Paajanen
,
M.
Wegener
, and
R.
Gerhard-Multhaupt
,
J. Phys. D
34
,
2482
(
2001
).
Google Scholar
Crossref
Search ADS
 
3.
M.
Lindner
,
S.
Bauer-Gogonea
,
S.
Bauer
,
M.
Paajanen
, and
J.
Raukola
,
J. Appl. Phys.
91
,
5283
(
2002
).
Google Scholar
Crossref
Search ADS
 
4.
J. Hillenbrand and G. M. Sessler, in 2000 Annu. Rep., Conf. Electr. Insul. Diel. Phenom., 15–18 October 2000, Victoria, Canada (IEEE, New York, 2000), pp. 161–164.
5.
R.
Gerhard-Multhaupt
,
IEEE Trans. Dielectr. Electr. Insul.
9
,
850
(
2002
), and references therein.
Google Scholar
Crossref
Search ADS
 
6.
M. Lindner, H. Hoislbauer, R. Schwödiauer, S. Bauer-Gogonea, and S. Bauer, IEEE Trans. Dielectr. Electr. Insul. (to be published).
7.
A.
Savolainen
and
K.
Kirjavainen
,
J. Macromol. Sci., Chem.
A26
,
583
(
1989
).
Google Scholar
 
8.
J. Raukola, H. Minkkinen, and K. Kirjavainen, Patent No. PCT/FI95/00433–FI 943957 (24 April 2001, Canada).
9.
H.
Ohigashi
,
J. Appl. Phys.
47
,
949
(
1976
).
Google Scholar
Crossref
Search ADS
 
10.
G. S.
Neugschwandtner
,
R.
Schwödiauer
,
M.
Vieytes
,
S.
Bauer-Gogonea
,
S.
Bauer
,
J.
Hillenbrand
,
R.
Kressmann
,
G. M.
Sessler
,
M.
Paajanen
, and
J.
Lekkala
,
Appl. Phys. Lett.
77
,
3827
(
2000
).
Google Scholar
Crossref
Search ADS
 
11.
A.
Mellinger
,
IEEE Trans. Dielectr. Electr. Insul.
10
,
842
(
2003
).
Google Scholar
Crossref
Search ADS
 
12.
G. M.
Sessler
and
J.
Hillenbrand
,
Appl. Phys. Lett.
75
,
3405
(
1999
).
Google Scholar
Crossref
Search ADS
 
13.
M.
Paajanen
,
H.
Välimäki
, and
J.
Lekkala
,
J. Electrost.
48
,
193
(
2000
).
Google Scholar
Crossref
Search ADS
 
14.
M. Paajanen, H. Minkkinen, and J. Raukola, Proceedings of the 11th International Symposium on Electrets, 1–3 October 2002, Melbourne, Australia (IEEE, New York, 2002), pp. 191–194.
15.
D. Royer and E. Dieulesaint, Elastic Waves in Solids (Springer, Berlin 2000), Vols. I and II.
This content is only available via PDF.
© 2004 American Institute of Physics.
2004
American Institute of Physics
You do not currently have access to this content.