Anti-ice-pinning superhydrophobic surfaces for extremely low ice adhesion.

• Ice-pinning mechanism on superhydrophobic surfaces was revealed. • Anti-ice-pinning strategies were proposed for obtaining robust icephobicity considering structural design. • Anti-ice-pinning superhydrophobic surfaces were developed by ultrafast laser. • The surface showed excellent static anti-icing performances (<0.1 kPa after 1st deicing cycle). • The developed materials can be used for passive anti-icing under static freezing conditions. Micro-nanostructured superhydrophobic surfaces (SHSs) are considered a promising industrial solution to catastrophic ice accretion, e.g., in aviation and powerlines. However, high ice-adhesion strength causes poor icephobicity on SHSs once ice embeds into the valleys among micro-nanostructures, particularly under low-temperature and high-humidity circumstances. Retarding ice-pinning is the key to realizing robust icephobicity, which needs to be made by customizable structures on SHSs. In this study, ice-pinning was identified to occur through liquid penetration, condensation, icing, and frost-filling processes. The ultimate state ice enlarged the grabbing-structure area, directly leading to a high ice adhesion. Specifically, we designed anti-ice-pinning structures comprising micro-scale features, concave sidewalls and heterogenous depths, and nano-scale particles, which were manufactured by an ultrafast laser. The developed anti-ice-pinning SHSs elevate static anti-icing function by the extremely low ice-adhesion strengths (<0.1 kPa after 1st deicing cycle and ∼ 10 kPa after the 30th deicing cycle at an ambient temperature of −20 ℃ and relative humidity of 18 %) and ice-structure interfacial morphologies captured by cryo-SEM. This previously unknown use of anti-ice-pinning strategies and engineering materials to enhance the robust icephobicity contributes to excellent control over ice adhesion. [ABSTRACT FROM AUTHOR]