Development of Magnetically Actuated Pillars with NiTi–Polydimethylsiloxane Integration for Advanced Mobility in Soft Robotics

Abstract

The use of responsive pillar arrays and cilia-like structures is linked with many groundbreaking applications, including microfluidic devices, biomedical applications, and soft robotics. To be effective, cilia or pillar arrays must exhibit flexible and controllable motion tailored to their specific applications. In this context, in this work, developing a compliant structure, which combines longitudinal stiffness controlled by a shape-memory alloy and magnetically actuated pillars, is aimed at. Polydimethylsiloxane is used as the matrix material, while nickel–titanium (NiTi) alloy provides stiffening to the base, and the pillars are enriched with iron via magnetron sputtering. The structures are generated through cast molding, employing pillar array-forming templates obtained by additive manufacturing. Various physicochemical and mechanical analyses are conducted to assess the composite's properties, including tensile testing, pullout test, and magnetometry. Overall, tailored dexterity and actuation are achieved by controlling temperature and magnetic field application. This advancement not only demonstrates the feasibility of creating responsive pillars at a relatively low cost—in comparison to commercial iron nanoparticles—and environmentally friendly techniques but also opens avenues for their integration into sophisticated devices requiring precise and adaptable movements. Future research should focus on optimizing the actuation efficiency and exploring broader applications in bioengineering and robotics.