Inkjet assisted manufacturing of untethered magnetic devices: A comparison between three routes to pattern artificial water striders

Untethered devices controlled by an external magnetic field are becoming more and more widely used in a wealth of applicative fields: medicine, precise micromanipulation, and environment management. Their production strongly relies on the use of complex and time-consuming technologies typically borrowed from the microelectronic field. In an attempt to reduce costs and enhance manufacturing flexibility, additive manufacturing has been investigated as a relevant alternative for untethered microrobots production. Between the large number of additive manufacturing technologies, inkjet printing is relatively poorly investigated for the production of this kind of devices, and the present work aims at exploring its potential. The work establishes a comparison between different approaches for the inkjet manufacturing of magnetically guidable microdevices. In particular, it focuses on the manufacturing of fully inkjet-printed magnetic devices by proposing two methods of production. The first consists in the electroless metallization of non-magnetic devices printed with SU-8 resin, while the second is based on the inkjet printing of a dispersion of magnetic nanoparticles in SU-8 resin. As a result, inkjet-printed devices controllable by an external magnetic field can be obtained. Multi-step and one-step production methods are compared in terms of quality of the obtained elements, easiness of production, and mechanical properties. The morphology of the finished devices, their surface quality, and their magnetic actuability are analyzed and discussed.