Dual-Material Aerosol Jet Printing of Magneto-Responsive Polymers with In-Process Tailorable Composition for Small-Scale Soft Robotics

The opportunity to create magneto-responsive soft materials (MSMs) with in-process tailorable and locally controllable magnetic properties is highly desirable across many technological and biomedical applications. In this paper, this capability is demonstrated for the first time using computer-controlled dual-material aerosol jet printing (DMAJP) technology. This approach allows controlled variation of composition between the aerosols of a magnetic nanoparticles (MNPs) ink and a photocurable polymer during the printing process. The mixing ratio of the two aerosols determines the MNPs loading in the nanocomposite, which can be used to locally control the magnetic properties of the printed structures. The printing process is structured in a layer-by-layer fashion in combination with a sacrificial layer approach for building fully freestanding MSM structures that combine magnetoactive and non-magnetoactive elements in a single process multi-material printing method with no further assembly requirements. Using this method, the direct manufacturing of small-scale multi-material soft objects with complex shapes and programmable functions whose movements can be controlled by the application of an external magnetic field is demonstrated.