Mushroom-Shaped Adhesive Structures with Smooth Contour via Electrical Growth

Bioinspired
dry adhesives based on van der Waals forces have a
wide range of impact in space operations, robot manipulation, and
other fields. Previous studies have confirmed the significant advantages
of a mushroom-shaped structure in uniformly distributing the separation
stress. However, most of them are based on the structure with an abrupt
geometric contour and have neglected the effect of a smooth contour
on the contact process. Here, we analyze the effect mechanism of geometric
contours on the contact-separation behavior of mushroom-shaped adhesive
structures by finite element analysis and investigate the enhancement
of smooth contours on the adhesive properties of mushroom-shaped structures.
On this basis, we propose a one-step forming strategy inspired by
the growth mechanism of biological adhesive structures to obtain mushroom-shaped
structures with smooth contours by flow forming. The mushroom-shaped
structures with smooth contours exhibit more excellent adhesive performance
than those with mutant contours in the adhesion test, which verifies
the correctness of our proposed law of geometric contours’
influence on adhesive behavior, providing a new idea for the design
of dry adhesives and dry adhesive-based systems.