Who

Piezoelectric materials are used in everything from cellphones and wearables, to robotics, energy harvesting, and tactile sensors.

What

A printed flexible sheet of piezoelectric smart material. (Photo by H. Cui of the Zheng Lab)

Piezoelectric materials come in only a few defined shapes and are made of brittle crystal and ceramic, requiring manufacture in a cleanroom. This new design method and platform 3D-prints these materials so they are not restricted by shape or size and can be custom-designed to convert movement, impact, and stress from any direction to electrical energy. By programming 3D active topology, any combination of piezoelectric coefficients can be achieved within a material, which can be used as transducers and sensors that are not only flexible and strong but also respond to pressure, vibration, and impact via electric signals that tell the location, magnitude, and direction of the impacts. Highly sensitive piezoelectric inks can be sculpted into complex 3D features with ultraviolet light. The inks contain highly concentrated piezoelectric nanocrystals bonded with UV-sensitive gels that form a solution that is printed with a high-resolution digital light 3D printer. The stiffness and shape of the material can be tuned and produced as a thin sheet resembling a strip of gauze or as a stiff block.

An assembled, smart, piezo-active structural sensor.

Where

Virginia Tech College of Engineering, Blacksburg

When

Internal topology of 3D-printed piezoelectrics spanning the width of a human hair.

The team has printed and demonstrated smart materials wrapped around curved surfaces, worn on hands and fingers to convert motion, and harvest the mechanical energy. A team is making wearable devices — such as rings and shoe insoles — and is fitting them into a boxing glove to record impact forces and monitor the health of the boxer.

Why

The technology has applications beyond consumer electronics. It can also be applied as a smart transducer that converts underwater vibration signals to electric voltages. The structure of the material is the sensor — it can monitor itself.

Watch a video about the technology on Tech Briefs TV here. For more information, contact Dr. Xiaoyu Zheng at This email address is being protected from spambots. You need JavaScript enabled to view it.; 540-231-2476.

Tech Briefs Magazine

This article first appeared in the March, 2019 issue of Tech Briefs Magazine.

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