Ice-phobic polyurethane composite coating characterized by surface micro silicone loops with crumpling edges

Abstract

This study developed a tactic to attain an ice-phobic polyurethane (PU) composite coating, which was fabricated by incorporating minor dosages of hybrid silica particles and silicone oil (SO) into the formulation of a commercial aerospace PU topcoat. The hybrid silica particles were synthesized by anchoring polydimethylsiloxane (PDMS) oligomers to silica microspheres. Both hybrid particles and SO amalgamate in the surface matrix of PU to induce a spread of wrinkling micro-loops over the coating. This coating surface morphology is structurally different from the well-known slippery liquid-infused porous surface since no liquid bulk is embedded in the surface matrix of PU coating. The icephobic property was characterized on a thermoelectric Peltier cooling plate, over which the frosting extents with cooling in ambient humidity conditions (~75 % RH) were compared. We have identified three coating fabrication factors responding to the delay of frosting inside the condensed water droplets overlying the PU coating. At the same time, they are cooled: the fuzzy PDMS layer on silica microspheres, i.e., hybrid particles, the fusion of SO with the hybrid particles, and the dosages of the hybrid particles and SO applied. Typically, when the PU composite topcoat comprises 0.4 wt% (based on PU matrix) hybrid particles and 0.4 wt% SO of the hybrid particle, it adjourns the onset of frosting to ~ −10 of from - 5.6 °C on the aerospace PU topcoat. This outcome is attributed to the micro round loops with folding edges and peripheric wrinkles that possess low-temperature softness and play a pivotal role in deferring icing inside the overlying water droplets.