Projects
Project description
The triboelectric effect describes the following phenomenon: when two dissimilar contacting materials move in opposite directions, the difference in their electron-affinities causes charges to separate. However, for insulators, it is unclear whether electrons, ions or material fragments transfer during contact. In my research, I utilize Atomic Force Microscopy (AFM) with Kelvin Probe method to analyze the topography and surface potential of triboelectric interfaces before and after contacting. This approach will provide a better understanding of the relation between surface properties and triboelectric behavior.
Project outcomes
In my work, I and colleagues used AFM to study the structures of interfaces used in catalysis and filtration, and investigated the triboelectric effect for energy harvesting using Kelvin Probe Force Microscopy (KPFM) and AFM-based force spectroscopy. In the first project, we studied hydrogenase enzymes that catalyze hydrogen gas oxidation. AFM imaging revealed that the enzymes formed a single layer on a specific surface. The second project focused on the stability of porous membranes made from a block copolymer. AFM showed that UV cross-linking improved their resistance to water and ethanol. We also confirmed that another type of polymer film had nanopores unaffected by ozonolysis. To explore the triboelectric effect, we developed a micro-scale triboelectrification assay (TEAMS) using AFM. KPFM detected surface potentials, while force spectroscopy studied material contacts at the micro-scale. We found that contact separation and humidity significantly influenced charge generation. Redox active molecules enhanced the triboelectric effect, showing promise for triboelectric nanogenerators. The TEAMS methodology offers valuable insights into the triboelectric effect at the molecular level.
Supervisor
Prof. Dr. Thorsten Hugel
Co-Supervisor
Dr. Bizan N. Balzer
Qiwei Hu successfully defended his dissertation in April 2023.
Dissertation: Atomic force microscopy based characterization of functional interfaces