Design of Organic Soft Magnets for Applications in Small-Scale Robotics

Traditional magnetic materials consist of heavy metals and rare-earth elements that typically entail corrosion, toxicity, and sustainability concerns. On the other hand, organic magnetic materials present a metal-free opportunity to develop lightweight non-toxic magnets. Although magnetic molecules based on stable free radicals have been used as monolayers and dopants in spintronics and as imaging contrast agents, shortcomings in stability, limited processing, and loss of properties have hindered their expansion into other fields such as small-scale soft robotics. To address this issues, we have developed intrinsically magnetic polymer gels with stable nitroxide radicals in their backbone structure. Using TEMPO precursors, we can design the polymer network to tailor the bulk mechanical and magnetic properties. Although weaker than purely metallic magnets, these organic magnets exhibit lightweight, non-toxic, compliant, and bulk paramagnetic properties suitable for small-scale robotics applications, such as remote manipulation and navigation through confined spaces.