From fish scales to dynamic ice removal mechanisms

The effects of static surface properties, such as free energy, toughness, elasticity, etc., on icephobicity have been extensively studied and documented. However, the role of dynamic surface characteristics in ice detachment remains unclear. This study examines the ice adhesion strength of authentic Arctic salmon (Salmon salar) skin by shear test. The results indicate a 60% reduction in ice adhesion strength when sheared against the growth orientation of fish scales compared to shearing along this orientation, revealing an intriguing anisotropic ice adhesion behavior of the fish scales. With the aid of molecular dynamic simulation, a distinctive structural evolution of fish scales, opening and peeling during ice shearing against the growth orientation, is revealed, resulting in a sequential rupture process and thereby significantly lowering the adhesion compared with concurrent rupture. The opening and peeling capacity of fish scales can be defined as the ability of individual scales to separate from their underlying structures and adhesives under applied force. Enhancing this capacity can further reduce ice adhesion strength, facilitating effortless ice detachment on fish scales. The mechanical robustness of fish scales offers new possibilities for designing hard and durable anti-icing surfaces. This opens a new avenue for understanding and designing surfaces with tailored adhesion mechanics.