Versatile water-floated nanostructures for three-dimensional nanotransfer printing.

Integrating functional nanostructures onto diverse three-dimensional surfaces is important for a wide range of applications, including holography, sensors, and extended reality. Nanotransfer printing (nTP) has emerged as a leading approach owing to its high throughput and resolution. However, conventional nTP techniques often require toxic solvents, adhesives, or thermal treatments, which limit the range of compatible substrates. Here, we introduce a water-floating-based nanotransfer printing (WF-nTP) technique inspired by hydrographic printing. In WF-nTP, nanostructures are floated on water and transferred onto target substrates via a scooping process. WF-nTP enables conformal transfer of Au, Pt, Pd, and Ni nanomeshes onto diverse substrates, including curved optical lenses, fibers, and plant leaves with micro-/nanoscale roughness. The technique also supports transfer onto hydrophobic surfaces by modulating the surface tension of the water bath. To highlight process versatility, two representative applications are demonstrated: the fabrication of multilayer SERS nanomesh fabrication for pesticide detection and the integration of Pd nanomeshes onto electrospun fibers for sensitive hydrogen sensing. Overall, WF-nTP provides a straightforward, substrate-independent route for nanostructure transfer with broad potential in advanced sensing and display technologies.