A Novel Slippery Liquid-like Icephobic Surface Coating for Unmanned-Aerial-Vehicle Propeller Icing Protection

Freezing rain poses a substantial hazard to the operation and safety of unmanned aerial vehicles (UAVs) in cold-weather environments. In the present study, a comprehensive experimental campaign was conducted to investigate the effect of surface icephobicity on ice accretion and shedding from rotating UAV propellers under freezing-rain conditions. A novel, durable, slippery liquid-like surface (SLLS) coating, characterized by low contact-angle hysteresis and low ice adhesion, is utilized as a passive strategy for UAV icing mitigation. The coating was assessed through wettability and ice-adhesion measurements, phase-locked high-speed imaging of supercooled large-droplet impingements, rotating-propeller ice accretion experiments, accelerated rain erosion testing, and surface-topography characterization. The measurement results revealed distinct normal and oblique droplet impingement regimes and demonstrated that the evolving leading-edge ice geometry substantially altered droplet deformation, liquid redistribution, and subsequent ice growth. Compared with the uncoated, baseline propeller, the SLLS-coated propeller was found to promote earlier ice shedding and reduce the ice-induced power consumption by approximately 36%. These findings highlight the potential of SLLS coatings as a promising strategy for UAV propeller icing protection to ensure safer and more efficient UAV operations under adverse weather conditions.