Unraveling the Effects of Improved Cooling and Bias Force in the Actuation of a Shape‐Memory Soft Multimaterial Gripper

Abstract This study explores the enhancement of a soft actuator made from a NiTiCu 6 Shape Memory Alloy (SMA) element embedded in a silicone rubber matrix functionalized with high aspect ratio graphene nanoparticles (GNPs). As a proof‐of‐concept we present the design, fabrication by stepwise molding, and testing of an operational soft gripper. Prototypes with the GNPs‐enriched matrix are compared with plain elastomer ones with two different Shore hardness to assess thermal and mechanical effects on the actuation speed and energetics. They are tested in grasp‐and‐release cycles and during prolonged grip maintenance at constant force at 1.5 N and 1 N. Input electric currents are also varied between 5 and 9A. With GNPs‐modified matrix, it is possible to speed up the release phase up to 40%, as the enhanced thermal diffusivity improves cooling rates, but it may also lead to increased energy consumption during low‐current activations and prolonged gripping phases. In particular, for the grasp‐and‐release cycles, a stiffer matrix also requires higher input energies without comparable improvements in cooling times. Our findings underscore the potential for tailoring matrix properties to improve the overall functionality of SMA‐based soft actuators, setting the stage for future work to refine performance through further material optimization and expanded testing scenarios.