Abstract
Charged closed-cell polymer foams have been found to be
highly sensitive piezoelectric materials. Charging is
shown to arise from dielectric barrier microdischarges
within the voids of the cellular polymer. Above the
threshold voltage for breakdown in the voids, the
microdischarges are evidenced by light emission from the
polymer, as well as by displacement-voltage hysteresis
loops. Monitoring light emission during breakdown is
shown to provide a quick check for the suitability of
foams for piezoelectric applications. Additionally it
allows for the visualization of micropores in foams in a
nondestructive way. The piezoelectric response of the
foam can be switched by applying dc-voltage pulses of
alternating polarity above the breakdown threshold,
thereby showing the feasibility of patterning the
piezoelectric properties within the film plane. Although
piezoelectric foams are nonferroelectric, the experiments
prove similarities to ferroelectric materials with
respect to hysteresis behavior, as well as a threshold
(coercive) field for switching of the polarization and
piezoelectricity.
| Original language | English |
|---|---|
| Pages (from-to) | 5283-5287 |
| Journal | Journal of Applied Physics |
| Volume | 91 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 2002 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- piezoelectric materials
- polymers
- foams
- discharges (electric)
- electric breakdown
- hysteresis
- porous materials
- dielectric polarisation