Eintrag in der Universitätsbibliographie der TU Chemnitz
Volltext zugänglich unter
URN: urn:nbn:de:bsz:ch1-qucosa2-824513
Akbar, Farzin
Schmidt, Oliver. G. (Prof. Dr.) ; Richter, Andreas (Prof. Dr.) (Gutachter)
Self-sufficient oscillating microsystem at low Reynolds numbers
Kurzfassung in englisch
This work is inspired by the peculiar behavior of the natural systems, namely the ability to produce self-sustained oscillations in the level of tens of Hertz in constant ambient conditions. This feature is one of the key signatures prescribed to living organisms. The firing rate of neuronal cells, a pulsating heart, or the beating of cilia and flagella are among many biological examples that possess amazing functionalities and unprecedented intelligence solely relying on bio-electro-chemical processes. Exploring shapeable polymeric technologies, new self-oscillating artificial microsystems were developed within this thesis. These microsystems rely on the novel nonlinear architecture that exhibits a negative differential resistance (NDR) within the parametric response that enables periodic oscillations. These systems are made of polymers and metals and were microfabricated in a planar fashion. The electrochemically deposited ionic electroactive polymers act as actuators of the system. Upon the self-assembly process, due to the interlayer strains, the planar device transforms into a three-dimensional soft nonlinear system that is able to perform self-sustained relaxation oscillations when subjected to a constant electric field while consuming extremely low powers (as low as several microwatts). The parameters of these systems were tuned for a high oscillation amplitude and frequency. This electro-mechanical parametric relaxation oscillator (EMPRO) can generate a rhythmic motion at stroke frequencies that are biologically relevant reaching up to ~95 Hz. The EMPRO oscillations at high frequencies generate a flow in the surrounding liquid, which was observed in the form of vortices around the micro actuators. This flow was further studied in ex-vivo conditions by measuring Doppler shifts of ultrasound waves. The EMPRO was made autonomous by integrating an electrochemical voltaic cell. Four different electrochemical batteries were tested to match the power consumption of the EMPRO system and electrochemical compatibility of the surrounding media. An Ag-Mg primary cell was then integrated with the EMPRO for autonomous operation without the need for external power sources, cables or controllers. This biomimicking self-powered self-sustaining oscillating microsystem is envisioned to be useful in novel application scenarios operating at low Reynolds numbers in biologically relevant conditions. Furthermore, as the system is electromechanical in nature, it could be integrated with electronic components such as sensors and communication devices in the next generation of autonomous microsystems.
| Universität: | Technische Universität Chemnitz | |
| Institut: | Professur Materialsysteme der Nanoelektronik | |
| Fakultät: | Fakultät für Elektrotechnik und Informationstechnik | |
| Dokumentart: | Dissertation | |
| Betreuer: | Schmidt, Oliver. G. (Prof. Dr.) | |
| URL/URN: | https://nbn-resolving.org/urn:nbn:de:bsz:ch1-qucosa2-824513 | |
| SWD-Schlagwörter: | Polypyrrole , Aktor , Reynolds-Zahl , Autonomes System | |
| Freie Schlagwörter (Englisch): | relaxation oscillation , self-sufficient , self-sustained , autonomous , self-assembly , negative differential resistance , Polypyrrole , ionic electroactive polymers , actuators , low Reynolds number , biomimetic | |
| DDC-Sachgruppe: | 621.3 | |
| Sprache: | englisch | |
| Tag der mündlichen Prüfung | 14.11.2022 |
