Robust Flexible Superhydrophobic Film with Skin-Inspired Gradient Design

Flexible superhydrophobic materials are attractive in separation technology, thermal management, anti-icing, and wearable electronics since their adaptability to curved surfaces and deformation. However, their fragility and high susceptibility to abrasion, caused by the destruction of micro/nano structures, remain significant challenges. A skin-inspired gradient design is proposed to combine flexibility and superhydrophobicity by facilitating the nanoparticle engulfment in polymer through pressure, electrostatic forces, and enhanced capillary forces. The resulting freestanding superhydrophobic film demonstrates remarkable flexibility and robust superhydrophobicity against strain (70%), stretching or bending (>5000 cycles), Taber abrasion (400 cycles), UV aging (>1500 h), and salt spray corrosion (>40 days). Combined with the low thermal conductivity, it exhibits high-performance anti-icing (icing delay time of ≈320 s) and durable de-icing (ice adhesion strength of ≈45 kPa, with no significant alterations over 20 icing/de-icing cycles). Additionally, its skin-like breathability and sensing support underwater electronics. This skin-inspired gradient strategy offers a promising paradigm for engineering freestanding, flexible, robust superhydrophobic materials design.