Roll-to-Roll Compatible Topochemical Wetting Control for Metamaterial Printing

The widespread utilization of metamaterials, despite their immense transformative potential, faces challenges regarding scalability in mass production. To address these limitations, an additive method that leverages liquid inks and selective wetting to produce scalable and cost-effective metamaterials is presented. UV-based imprinting lithography is utilized to fabricate surface energy-modulated patterns, enabling precise solution patterning. This approach, unlike conventional UV-based imprinting lithography, not only accurately produces the negative replica of the stamp topography during UV-induced crosslinking but also transfers a hydrophobic layer onto the raised surfaces of the imprinted hydrophilic layer, resulting in 3D shapes with spatially modulated surface energy. In the second process step, a functional ink is dragged over the patterned substrate where it dewets to fill the hydrophilic recesses. This innovative process enables high-speed metamaterial production, with ink deposition speeds up to 12 m min-1. The method accommodates a wide range of inks, including metals, dielectrics, and semiconductors, providing meticulous control over vertical structures such as pattern thickness and hetero-multilayer formation. Additionally, it offers flexibility in creating metamaterials on free-standing ultra-thin sheets, introducing desirable attributes like foldability and disposability. The effectiveness of this approach is validated through the fabrication and characterization of metallic metamaterials. An innovative printing platform for additive manufacturing of metamaterials using wetting contrast is introduced. By combining imprinting lithography with transfer printing, precise control over local wettability is achieved. This method enables us to pattern various functional materials and finely adjust vertical structures, including pattern thickness and hetero-multilayer formations. Additionally, the platform produces foldable, disposable metamaterials on ultra-thin sheets.image