Advances in porous icephobic surfaces: Toward next-generation aircraft ice protection strategy

The accretion of ice on aircraft wings, sensors, and engines presents a serious hazard to flight safety, underscoring the need for durable and energy-efficient ice protection strategies. Among emerging strategies, porous icephobic surfaces (PISs) have attracted considerable research interest due to the favorable durability, excellent icephobic performance, and low energy requirements. Nevertheless, critical aspects such as design objectives, theoretical foundations, fabrication techniques, and durability test standards for PISs have not yet been systematically examined, resulting in unclear research directions and motivating this review. This article first provides a comprehensive overview of existing aircraft ice protection strategies, establishing a broader context for the development of PIS. Through extensive literature analysis, the review then identifies contact angle hysteresis and icephobic durability as two key design parameters for PISs. Foundational principles related to lubricant transport, heat transfer, and wetting behavior in porous media are also introduced to furnish a solid theoretical basis for PIS design. Subsequently, slippery liquid-infused porous surfaces (SLIPS) are discussed as a prominent and successful example of PIS in ice protection applications, covering their fabrication methods, failure modes, and icing characteristics. However, SLIPS are prone to lubricant depletion under shear flow and rain erosion, which can substantially compromise their icephobic performance. Recent advances in PIS design have therefore incorporated strategies such as antifreeze agent release, lubricant replenishment, and covalent anchoring to reduce lubricant loss and enhance durability. To bridge the gap between simplified laboratory durability tests and the multifaceted testing required for aeronautical applications, this review outlines essential durability evaluation protocols for aeronautical implementation. Furthermore, the potential of artificial intelligence (AI) in accelerating the development and optimization of PIS is explored. Beyond offering a thorough synthesis of recent progress in PIS technology for anti-icing, this work also highlights PIS as a promising next-generation, durable, and energy-efficient candidate for aircraft ice protection.