A major challenge in planar and 3D printing is the ability to pattern materials over a wide range of physical properties. Commercial printing techniques are limited to narrow range of ink viscosities (e.g., inkjet printing) or materials set (e.g., thermoplastics for fused deposition modeling) as dictated by the specific printing mechanism. Decoupling the physical properties of the ink from the printing process would allow unprecedented freedom in the type of materials that can patterned, ranging from electronic to biological inks. Here, researchers from the Lewis lab, introduce, model, and experimentally verify acoustophoretic printing, in which nonlinear acoustic forces are harnessed to print droplets of disparate classes of materials on demand. Specifically, they show that ink viscosities spanning more than four orders of magnitude (0.5 mPa to 5000 mPa) can be printed by this nascent method. Moreover, the ejected droplet size can be varied continuously by more than two orders of magnitude by controlling the acoustic forces, from the subnanoliter to microliter range. To highlight its flexibility, they have printed a broad palette of materials, including concentrated polymer solutions, colloid suspensions, liquid metals and, even, more complex droplets, such as double emulsions. In summary, acoustophoretic printing represents a new paradigm for patterning functional, structural and biological materials in both planar and 3D form factors.
Intellectual Property Status: Patent(s) Pending