Switchable adhesion of gecko-inspired adhesives on curved substrates by magnetically induced self-peeling

Inspired by the gecko's ability to achieve strong attachment and easy detachment through the rolling-in and rolling-out behavior of its feet, a novel switchable structural adhesive has been designed and fabricated in this study. The adhesive consists of a magnetically sensitive backing layer with an initial curvature and mushroom-shaped fibrillar arrays. Switchable adhesion is achieved through the synergistic effects of an external magnetic field and the adhesive's curvature. When a magnetic field is applied, the adhesive forms conformal contact with the substrate, ensuring strong attachment due to the benefits of the mushroom-shaped fibrillar arrays. Upon removal of the magnetic field, the adhesive reverts to its initial curved state, allowing for easy detachment. Such switchable adhesion is applicable to both flat and curved surfaces. Specially, a theoretical model is further established to elucidate the mechanical mechanism underlying the magnetic-curvature induced switchable adhesion. The experimental and theoretical results indicate that the switchable adhesion is primarily attributed to the competition among the magnetic field force potential energy, the bending elastic energy stored in the deformed adhesive under the magnetic field, and the interfacial adhesion energy. This study provides a new design strategy for developing intelligent functional surfaces with reversible adhesion.