Author ORCID Identifier


Date of Award

Spring 5-15-2023

Document Type

Thesis (Ph.D.)

Department or Program

Engineering Sciences

First Advisor

John X.J. Zhang


Piezoelectric materials show great promise for low-power wearable and implantable sensing, but their rigidity makes it challenging to integrate them with biological tissue. To address this, researchers have started exploring polymer-based functional materials that offer flexibility and are suitable for interfacing with the human body. However, these materials are still in their early stages, and a framework is necessary to illustrate how these materials, in conjunction with novel fabrication techniques and device designs, can enable the development of multi-functional sensing and energy harvesting devices.

This thesis utilizes highly scalable fabrication methods for functional polymers to build and test a flexible piezoelectric transducer that can be used in wearable sensing and implantable energy harvesting applications. The transducer relies on the direct piezoelectric effect and its ability to detect strain, which can be harnessed by interfacing the device with the human body where motion occurs, such as superficial to a near surface artery or directly in the heart itself. The signals generated by these motions are harnessed for energy harvesting or read and processed to monitor cardiovascular health.

The thesis explores a testbed for developing a flexible piezoelectric transducer for cardiovascular health monitoring and energy harvesting. Electrospinning will be used to develop highly sensitive, micro-structured, piezoelectric, and conductive nanofibers, and highly scalable electrode patterning methods such as inkjet printing will be used for device fabrication. Benchtop testing will be conducted to simulate biological systems for device characterization, and algorithms will be developed to predict the parameters of interest. Animal and human subject studies were conducted to evaluate the device design and validate sensor characteristics. Together, this work provides a framework for the development of multi-functional material enabled sensing and energy harvesting devices.