The Clingfish-Effect®

The CLINGFISH-EFFECT

Named after the fish’s remarkable abilities, suction cups with clingfish® effect provide strong, but reversible attachment, not only to smooth surfaces, but also to rough, uneven, and structured surfaces®

… above and below water.

Bio-inspired design

The Northern Clingfish is a small fish that lives in the harsh environment of the surf zone. With the suction disk on its belly, it can attach to the rough, structured, and even wet and slimy surfaces of the intertidal rocks. Using its suction cup this fish can hold up to 230 times its own body weight, an ability that comes in handy when intertidal waves crush in. While working with Prof. Adam Summers at the University of Washington, Dr. Petra Ditsche, the founder of Clingtech Bionics researched the biomechanics behind the function of the abdominal sucker of the Northern clingfish.

Key to the suction cup breakthrough was understanding how the clingfish’s natural suction works so effectively — especially on rough surfaces that normally cause a manufactured suction cup to fail. The clingfish’s rim of the disc is covered with layers of micro-sized, hairlike structures, in many different hierarchical sizes. This layered effect allows not only perfect sealing on different roughness orders, but also creates more friction along the rim and helps the fish stick to rough surfaces. The entire disk is flexible and elastic, allowing it to adapt and hold on to coarse, uneven surfaces.

After investigating many years of how the clingfish suction cup works, Ditsche began building a prototype, borrowing from the innovations of nature. The team discovered that combining different materials helped give the artificial suction cups a rigid structure that was strong enough to hold tension, while also soft and flexible enough to conform and stick to rough surfaces. They also found a way to increase the friction on the rim of the cup. https://www.washington.edu/news/2019/10/02/inspired-by-northern-clingfish-researchers-make-a-better-suction-cup/. Back in Germany, Ditsche took the development of the bio-inspired suction cup further. After receiving an EXIST grant she and her team developed the first prototype to a product that can be manufactured in serial production for first applications.

Research articles:
P. Ditsche, & A. Summers. Learning from Northern Clingfish (Gobiesox maeandircus) (2019): Bio-inspired suction cups attach to rough surfaces. Philosophical Transactions of the Royal Society B 374: 20190204. Doi: 10.1098/rstb.2019.0204 (cover story).

P. Ditsche, M. Hicks*, L. Truong*, C. Linkem* & A. Summers (2017) From smooth to rough, from water to air: the intertidal habitat of Northern clingfish (Gobiesox maeandricus) Sci Nat 104: 33. doi:10.1007/s00114-017-1454-8.

P. Ditsche & A. Summers (2014) Aquatic versus terrestrial attachment – water makes a difference. Beilstein Journal of Nanotechnology Special Issue Biological and Bioinspired Adhesion and Friction, 5: 2424-2439.

P. Ditsche, D. Wainwright* & A. Summers (2014) The impact of surface roughness and fouling on suction adhesion in Northern Clingfish. Journal of Experimental Biology 217: 2548-2554 (cover story)