Oak Ridge, TN--The reverse piezoelectric effect—creating a mechanical strain by applying an electrical voltage to a material—is ten times stronger in a new non-polar polymer developed at Oak Ridge National Laboratory than in crystals or ceramics that exhibit this property, making it suitable for hundreds of everyday uses in motion control and positioning, energy storage devices, power sources, and biomedical devices.
"We thought about comparing the effects that we observed to more 'classic' piezoelectric materials and were surprised by how large the effects were by comparison," said Urban, a member of the Department of Energy lab's Neutron Scattering Science Division. Until now, scientists did not believe that non-polar polymers were capable of exhibiting any piezoelectric effect, which occurs only in non-conductive materials. This research, however, shows up to 10 times the measured electro-active response as compared to the strongest known piezoelectric materials, typically crystals and ceramics.
"We observed this effect when two different polymer molecules like polystyrene and rubber are coupled as two blocks in a di-block copolymer," Urban said.
The paper, titled "Piezoelectric Properties of Non-Polar Block Copolymers," was published recently as the cover article in Advanced Materials. In addition to Urban, other authors are Markus Ruppel and Jimmy Mays of ORNL and Kristin Schmidt of the University of California at Santa Barbara. Authors from Aachen University are Christian Pester, Heiko Schoberth, Clemens Liedel, Patrick van Rijn, Kerstin Schindler, Stephanie Hiltl, Thomas Czubak and Alexander Böker.
SOURCE: Oak Ridge National Laboratory; www.ornl.gov/info/press_releases/get_press_release.cfm?ReleaseNumber=mr20110922-00