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Wer nichts tun kann, versteht nichts.
Wer nichts versteht, ist nichts wert.
Wer meint, alle früchte würden gleichzeitig
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The piezoelectric materials that inhabit everything from our cell phones to musical greeting cards may be getting an upgrade thanks to work discussed in the journal Nature Materials released online Jan 21. Xiaoyu 'Rayne' Zheng, assistant professor of mechanical engineering in the College of Engineering, and a member of the Macromolecules Innovation Institute, and his team have developed methods to 3-D print piezoelectric materials that can be custom-designed to convert movement, impact and stress from any directions to electrical energy.
"Piezoelectric materials convert strain and stress into electric charges," Zheng explained.
The piezoelectric materials come in only a few defined shapes and are made of brittle crystal and ceramic—the kind that require a clean room to manufacture. Zheng's team has developed a technique to 3-D print these materials so they are not restricted by shape or size. The material can also be activated—providing the next generation of intelligent infrastructures and smart materials for tactile sensing, impact and vibration monitoring, energy harvesting, and other applications.
Unleash the freedom to design piezoelectrics
Piezoelectric materials were originally discovered in the 19th century. Since then the advances in manufacturing technology has led to the requirement of clean-rooms and a complex procedure that produces films and blocks which are connected to electronics after machining. The expensive process and the inherent brittleness of the material, has limited the ability to maximize the material's potential.
The printed flexible sheet of piezoelectric material. Credit: Virginia Tech
Zheng's team developed a model that allows them to manipulate and design arbitrary piezoelectric constants, resulting in the material generating electric charge movement in response to incoming forces and vibrations from any direction, via a set of 3-D printable topologies. Unlike conventional piezoelectrics where electric charge movements are prescribed by the intrinsic crystals, the new method allows users to prescribe and program voltage responses to be magnified, reversed or suppressed in any direction.
"We have developed a design method and printing platform to freely design the sensitivity and operational modes of piezoelectric materials," Zheng said. "By programming the 3-D active topology, you can achieve pretty much any combination of piezoelectric coefficients within a material, and use them as transducers and sensors that are not only flexible and strong, but also respond to pressure, vibrations and impacts via electric signals that tell the location, magnitude and direction of the impacts within any location of these materials."
