Biopolymer based triboelectric nanogenerators

The use of electronic devices including smart phones, iPads, and personal computers has increased significantly owing to ease of use and increased effectiveness and efficiency in collecting information. The traditional methods to power most of these devices rely on the use of batteries. Batteries have a limited lifetime, need to be constantly replaced, and can pose environmental and health concerns. A promising alternative to batteries is triboelectric nanogenerators (TENGs). TENGs can harvest mechanical energy from human body motion providing a reliable and environmental friendly power source for small electronic devices. The triboelectric effect is a process by which, through friction, a charge builds up between the contact surfaces of two materials with different electrostatic properties. Electricity is induced once the charge is allowed to flow leading to triboelectricity. In this regard, TENGs provide an application for nanomaterials to be used in harvesting energy generated by the triboelectric effect. In this research project, our main goal has been to study triboelectric properties of nanomaterials in order to make TENGs that can be used to power small medical devices such as hearing aids or glucose sensors. We have explored the triboelectric properties of poly-lactic acid (PLLA) and ethyl cellulose (EC) biopolymers. These polymers were chosen because they are biodegradable and biocompatible. We have employed facile manufacturing methods (drop casting and spin-coating) to make PLLA and EC films. The surface morphology of these films were characterized using atomic force and scanning electron microscopies. These studies have informed ongoing work to explore the influence of TENG materials and device structures on energy conversion and have merged multiple disciplines including chemistry, nanotechnology, material science, physics, biomedical engineering and electrical engineering.