Fremdschichtverhalten nanostrukturierter superhydrophober Isolierstoffoberflächen unter simultanen elektrischen und klimatischen Beanspruchungen
Wu, Junliang; Schnettler, Armin (Thesis advisor)
Aachen / Mainz (2009) [Dissertation / PhD Thesis]
Page(s): II, 110 S. : Ill., graph. Darst.
Polymeric insulating materials can exhibit a significant self-cleaning effect (superhydrophobicity) after their surfaces are treated by a naonstructured hydrophobic layer. These housing materials are of great interest for an application in electrical insulation systems, because water droplets, along with the possible contaminations, can be removed from the surface in the presence of such extreme unwettability. As a result, an enhancement of pollution behaviour under electrical fields is expected. This thesis describes the short- and long-term performance of superhydrophobic insulating surfaces, which are usually exposed to simultaneous electrical and climatic stresses. According to their application in different equipment, it is of fundamental importance to examine the mechanisms of degradation under outdoor and indoor conditions, depending on the influencing factors, which need to be taken into account either separately or simultaneously. The implementation of relevant test procedures plays also a key role in this work. In order to investigate the aging behaviour of the superhydrophobic polymeric surfaces under critical operating conditions, the specimens are subject to a number of accelerated aging tests like clean fog test, modified rotating wheel dipping test and condensation test. The multiple stresses, consisting of humidity and electrical field, are simulated during these tests, allowing for real aging mechanisms. Thereafter, the results are evaluated and discussed for achieving an insight into the characteristics of the superhydrophobic insulating surfaces. Based on previous findings, the superhydrophobicity and its durability have a considerable effect on the life span of the polymeric materials concerned. The specimens are characterized according to their surface conditions. Furthermore, the surface analysis demonstrates the change of the surface structures. Finally, the models of the surface degradation are extended in the event of superhydrophobicity.
- URN: urn:nbn:de:hbz:82-opus-26872
- REPORT NUMBER: RWTH-CONV-120975