Empirical Study of Magnetically Induced Modulus and Contact Area Changes in a Switchable Adhesive

Magnetically switchable adhesives offer wireless and rapid control of adhesion, making them attractive for soft robotic grippers and manipulators. However, most existing studies have primarily focused on scale and structural design, with limited investigation of how magnetic properties modulate both modulus and contact area, two key factors for enhancing switchable adhesive performance. Here, we introduce a magnetorheological elastomer-based responsive switchable adhesive (MaRSA) that enables coupled control of modulus and contact area through magnetic actuation. The adhesive is based on carbonyl iron particle (CIP)─elastomer composites, engineered in two geometries: nonpatterned and wall-patterned. By systematically varying CIP content (0-70 wt %) and magnetic field strength (0-230 mT), we characterize the mechanical, magnetic, and adhesive behavior of the MaRSA systems. In the nonpatterned MaRSAs, shear modulus increases by up to ∼275% under magnetic fields. In the wall-patterned MaRSAs, magnetic actuation induces stepwise wall bending, and when the bending angle exceeds ∼5°, the contact area is reduced by half, leading to a sharp drop in adhesion force. These results clarify how dual modulation of modulus and contact area enables dynamic tuning of adhesive performance and demonstrate the applicability of MaRSA-based soft robotic grippers for manipulating electronic devices.