Meeting Abstract
While artificial suction cups usually only attach to very smooth surfaces, Northern clingfish can attach to a huge variety of surfaces ranging from very smooth to very rough. Larger specimens can attach to surfaces as rough as 0.5-1 mm grain size, which is about as rough as sandstone. Moreover, the little intertidal fish can even hold onto slimy biofilm covered surfaces. All these are abilities which are highly desirable for technical applications. In our former work we could show that the elasticity of the suction cup in combination with the hierarchical structures on the disc margin are some of the key features enabling the fish to attach to this challenging surfaces. The hierarchical structures on the disc margin consist of papillae (~150µm) covered with rods (~5µm), which are divided into tiny filaments at their tips (~0.2µm). These specialized structures enable not only a perfect adaptation to the surface irregularities of a substrate, but also increase the friction properties of the disc margin. The increased friction forces act against the forces pulling the disc margin in central direction during detachment. Therefore, the increased friction properties of the disc margin avoid or delay failure of the suction cup and result also in increased attachment forces. Transferring the principle of increased friction properties and the high adaptability of the disc margin to an artificial suction device we were able to develop a bio inspired suction cup. Our bio inspired suction cups develop tenacities of up to 70KPa on surfaces as rough as 270 m grain size (roughest surface in the experiment). On substrates of the same roughness the bio inspired suction cups attached several weeks under water in an experimental setting. Our suctions cups could be technical applied in fields such as whale tagging or surgery.
