Laser-induced hierarchical micro/nanostructures on flexible CNT-silicone film for synergistic passive/active anti/de-icing in extremely low-temperature environments

To address the challenges of efficient anti/de-icing under extremely low temperatures and weak illumination, we propose a synergistic passive-active anti/de-icing film (PAADIF) based on carbon nanotubes (CNTs) and AB-silicone. By systematically optimizing the nanosecond laser parameters (scanning speed, repetition rate, and rescanning cycles), hierarchical micro/nanostructures (MHSs) were directly constructed on the flexible substrate in a single step. MHSs physically suppress ice nucleation by reducing the solid-liquid contact area and trapping air pockets (passive effect) while simultaneously enhancing localized light trapping and multiple reflections to intensify photothermal conversion by CNTs (active effect). This cooperative mechanism, defined as a heat-transfer gating process, allows MHSs to act as a thermal barrier and air reservoir, whereas CNTs provide efficient localized heating that triggers interfacial melting, re-formation of air cushions, and lubricant layer generation, leading to rapid ice detachment with low adhesion. The optimized PAADIF exhibits an ultrahigh optical absorbance of 98.86% and a photothermal conversion efficiency of 89.3%, achieving a surface temperature of 143.2 °C within 360 s under 1 sun irradiation. Under -50 °C and 0.7 sun irradiation, the deposited droplets remain unfrozen throughout the illumination period, and the initially formed frost layer fully melts within 840 s, highlighting efficient photothermal-assisted active de-icing. Even under much weaker illumination of 0.2 sun at -50 °C, the hierarchical micro/nanostructures effectively delay ice nucleation, achieving an ultra-long icing-delay time of approximately 720 s, demonstrating excellent passive anti-icing capability. Furthermore, the film retains superhydrophobicity and anti/de-icing performance after repeated bending, abrasion, peeling, and acid/alkali corrosion, indicating outstanding mechanical and chemical robustness. This work provides a clear mechanistic understanding and quantitative validation of a flexible surface integrating passive ice resistance and photothermal-assisted active de-icing, offering a practical and scalable strategy for extreme-environment applications such as aerospace, transportation, and polar facilities.