Combining de-icing and self-healing for wind blades through an innovative multilayer coating approach

Abstract

ce accretion is a huge concern for many wind blades installed in colder regions. The approach of active de-icing systems based on coatings has been recently quite explored. Nevertheless, the concern about an external electrically conductive layer leads to the need to develop multilayer insulating/conductive coatings. For this purpose, a novel multilayer coating consisting of a 3D printed carbon nanotube (CNT) and graphene nanoplatelet (GNP) reinforced nanocomposite is proposed, covered by a top coating consisting of a PCL-based epoxy blend. Here, the CNT/GNP layer presents outstanding Joule heating capabilities due to the enhanced electrical conductivity, which increases significantly when increasing the filler content without drastically affecting the quality of the printed ribbons. More specifically, the temperature reached was about 140°C when applying 30 V for the 4 wt.%CNT and 6 wt.%GNP reinforced specimens. In this regard, this resistive heating can promote the thermal stimulus needed to activate de-icing and self-healing mechanisms on the epoxy/PCL top layer. Healing efficiencies obtained by the Joule effect reached up to 90% efficiency in comparison to convective heating, which showed a 68%, explained by the improved heating transfer from the CNT/GNP layer when applying the resistive heating. Finally, a proof-of-concept test as a de-icing system showed a complete ice removal within 2.9 min when applying the resistive heating in the intermediate CNT/GNP layer, proving the multifunctionality of the proposed multilayer coating for self-heating and self-healing applications.

Highlights A multilayer coating with self-healing and de-icing capabilities was successfully developed. Great combination of 3 min de-icing time and 90% self-healing efficiency. Novel inner 3D printed layer allows higher CNT/GNP contents than traditional ones. A multilayer approach with optimized nanoreinforced area required.