Yulan Chen, Cornell University
Magnetic soft actuators are an interesting material with potential applications in untethered soft robotics, minimally invasive interventions, and light control. These materials are typically soft with low remnant magnetizations. These materials are conventionally synthesized in the presence of a magnetic field which directs assembly but limits the yield because the synthesis can only be done in an area over which the field is applied. Therefore, a self-assembly where the alignment is achieved in the absence of an applied field is desirable. Yulan Chen presented her work on iron cobalt nanocubes that self-aligned into chains. She reported that both the saturation magnetization and overall volume of the particles determined the strength of the particles with each other. Stronger interactions were observed with larger particles and increased concentrations of particles improved the alignment. The direction of the self-assembly also depended on the size of the building blocks where smaller particles aligned face to face, increased sizes moved to edge-to-edge alignment, and increasing the size even further caused a more relaxed corner-to-corner alignment mode. Chen also considered factors such as rotation speed during the nanoparticle synthesis to determine its influence on the chain lengths and alignment. Overall, this talk highlighted an interesting strategy to produce nanochains without the need of an applied external magnetic field and demonstrated their potential for magnetic soft actuator applications.