An investigation into active piezoelectric nanocomposites for distributed energy harvesting

Abstract

The use of monolithic piezoceramic materials in sensing and actuation applications has become quite common over the past decade. However, these materials have several properties that limit their application in practical systems. These materials are very brittle due to the ceramic nature of the monolithic material, making them vulnerable to accidental breakage during handling and bonding procedures. In addition, they have very poor ability to conform to curved surfaces and result in large add-on mass associated with using a typically lead-based ceramic. These limitations have motivated the development of alternative methods of applying the piezoceramic material, including piezoceramic fiber composites (PFCs), and piezoelectric paints. Piezoelectric paint is desirable because it can be spayed or painted on and can be used with abnormal surfaces. The ease at which the active composite can be applied allows for far larger surfaces to be used for energy harvesting than can be achieved with typical materials. Developments in piezoelectric nanocomposites for energy harvesting will also allow for the development of compliant materials with electromechanical coupling greater than available through existing piezoelectric polymers such as polyvinylidene floride (PVDF). Furthermore, the application of PVDF is limited to thin films due to the straining process required to obtain piezoelectric phase of the material. However, active nanocomposites can be molded into geometries that could not be obtained using currently available materials. The present study will characterize a variety of piezoelectric nanocomposite materials to determine how the properties of the polymer matrix and the piezoelectric inclusion affect the energy harvesting performance. The resulting active nanocomposites will be compared to existing piezo-polymers for power harvesting.