Silicone Adhesion Inspired by Beetle Feet
Inspired by the adhesive elements on beetle feet, a group of researchers from Kiel in Germany have significantly improved the adhesion of silicone surfaces through micro structuring and plasma treatment.
Elastic synthetic materials such as silicone elastomers are very popular in industry. They are flexible, reusable, cheap, and easy to produce. They are therefore used, for example, as seals, for insulation or as corrosion protection. Due to their low surface energy, however, they are barely adhesive, making it difficult to paint silicone surfaces, for example. A research team from Kiel University has now succeeded in boosting the adhesive effect of silicone material significantly by imitating the mushroom-like surface structure of certain male leaf beetles (chrysomelidae), and then treating the silicone elastomers specifically with plasma. They have also discovered that the adhesive property of the micro-structured silicone material is influenced by the degree of curvature.
Highly adhesive in the smallest of spaces
The researchers have demonstrated that silicones with mushroom-like, concavely curved structures exhibit double the range of adhesive strength. They have also observed that plasma treatment can increase the adhesion of unstructured surfaces on glass substrates by about 30 percent. The adhesion on the mushroom-like surface structure improves by up to 91 percent with optimal parameters. "These findings particularly surprised us because the structured surface is only half as large as the unstructured, but adhesion enhancement was even three times better after the plasma treatment," explains doctoral student Emre Kizilkan, lead author of the study, which has been published in the journals "Advanced Materials and ACS Applied Materials & Interfaces".
"We therefore have, on a very small area, an extremely strong adhesion with a wide range," says material scientist Kizilkan, summarising the results. This makes the results especially interesting for small-scale applications such as micro-robots. The Kiel working group's findings have already resulted in the development of highly adhesive tape that works on the "gecko principle" and can be removed without leaving any residue.