New Piezoceramic Manufacturing Method Using the Surface Tension Effect for Energy Harvesting and Sensing

Description

Is there a flexible manufacturing way to create piezoelectric materials with customizable piezoelectric and mechanical properties? This fundamental question originates from the practical applications of piezoelectricity in sensors and energy harvesters and requires innovative solutions from mechanical and materials engineering. Solving this problem will greatly improve the performance of flexible electronics and mechanical energy harvesters, especially those interact with humans, while minimizing adverse effects on the host. One promising solution is offered by piezoelectric ceramic-polymer composite. However, for most existing composites where piezoelectric ceramic nanostructures are evenly infiltrated into polymers, the stiffness mismatch and spatial discontinuity between ceramic fillers and polymer matrix greatly hinder the force transmission, leading to the degradation of their piezoelectric performance. We propose to develop a simple, inexpensive and customizable method for fabricating piezoceramic composites with excellent piezoelectric properties and outstanding flexibility by utilizing the surface tension effect. Surface tension is widely observed in gas-liquid and liquid-liquid interfaces and has been extensively used in a variety of liquid-related industries.This proposal for the first time introduces the surface tension effect into the manufacturing of solid piezoceramic composites. Via this method, one can easily adjust the piezoceramic distribution, pattern shapes, thickness, elastic modulus, and even stretchability of composites, which will provide a large design freedom for sensors and energy harvesters. We further propose to explore structural engineering strategies of modulus grading and patterning to achieve a synergistic improvement in mechanical and piezoelectric properties. To develop the new surface-tension assisted manufacturing method, the following critical engineering challenges and scientific issues must be addressed: 1) forming and tuning surface-tension liquid films and sintering piezoceramic films; 2) theoretically and experimentally developing a design principle for the film formation, thickness and curvature control; 3) exploring modulus grading and geometric patterning strategies for customizing localized and global piezoelectric and mechanical properties; 4) demonstrating the technology at the device level by developing flexible shoe energy harvesters and stretchable fingertip sensor arrays. Details of our methodologies designed to address these issues are discussed in the proposal. We believe that the new technologies developed in this project will provide an entirely new paradigm for piezoelectric material fabrication with high piezoelectricity and flexibility, which could find applications in the advanced fields of smart materials, sensors, actuators, the Internet of Things, and medical and consumer electronics.