Degradation assessment of nanostructured superhydrophobic insulating surfaces using multi-stress methods

This paper describes the electrical insulation property of modified superhydrophobic surfaces, which are prepared on epoxy based composites by using special nano-particles. After surface modification the samples exhibit an extreme unwettability with a static contact angle thetasges130deg. In order to investigate the long term stability under multiple stress, the specimens are subjected to electric fields and moisture in accelerated aging tests like modified-rotating-wheel-dipping-test (MRWDT), clean fog test and condensation test, according to the critical outdoor and indoor service conditions, respectively. It is shown that leakage current and effective power dissipation of contamination layers are significantly suppressed in the presence of superhydrophobic insulating surfaces. Thus, the pollution performance of the insulation systems can be enhanced to a great extent in clean fog test and MRWDT, whereas the insulating surfaces covered with nanoparticles seem to have no beneficial effect during the condensation experiments because of the different wetting mode. In addition, the impact of release agents and fillers on the surface superhydrophobicity is also examined in this study. Moreover, the surface analyses are employed to characterize the topographical change of the nanostructure in connection with the material degradation.