Inkjet Printed Superparamagnetic Polymer Composite Hemispheres with Programmed Magnetic Anisotropy

We present the fabrication and characterization of large arrays of inkjet printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures. SPMPCs are appealing for applications in microsystems and nanorobotics due to the added functionality of polymers and the significant magnetic attributes of embedded nanostructures. SPMPC-based microarchitectures can be used to perform different functions wirelessly in various media (e.g. water, solvents) using external magnetic fields: handling and assembling small objects, delivering drugs or biomass, or sensing specific physical or chemical changes. Superparamagnetic magnetite nanoparticles are dispersed in SU-8 to form magnetic hemispheres in this work. Magnetically anisotropic hemispheres are fabricated as well as standard SPMPC hemispheres. Magnetic anisotropy is programmed by applying a magnetic field during curing. The distribution of nanoparticles inside the polymer matrix and magnetic characteristics of the SPMPC are investigated. Magnetic manipulation of hemispheres is demonstrated at liquid-liquid interfaces. Different assembly strategies to form lines or geometric shapes from hemispheres is demonstrated as well as their independent dynamic control. Finally, a two-interface assembly strategy is demonstrated to assemble hemispheres into complete spheres for advanced self-assembly tasks.
info:eu-repo/semantics/published