Non-lithography hydrodynamic printing micro/nanostructures on curved surfaces.

A key issue of micro-nano devices will be how to integrate micro/nanostructures with specified chemical component onto various curved surfaces. Here, we achieve hydrodynamic printing micro/nanostructures on three-dimensional curved surfaces via the combination strategy from the template-induced hydrodynamic printing and self-assembly of nanoparticles. Non-lithography flexible wall-shaped templates are replicated with microscale features from the dicing trench-shaped silicon wafer. Arising from the capillary pumped function between the template and curved substrates, nanoparticles in the colloidal suspension self-assemble into close-packed micro/nanostructures without the gravity effect. The theoretical analysis via lattice Boltzmann model (LBM) reveals the fundamental principle of the hydrodynamic assembly process. Spiral linear structures achieved by two kinds of fluorescent nanoparticles show non-interfering photoluminescence properties, while the waveguide and photoluminescence are confirmed in 3D curved space. The printed multi-constituent micro/nanostructures with single-nanoparticle resolution can serve as a general platform for optoelectronics beyond the flat surface.