Nanostructuring surfaces with conjugated silica colloids deposited using silicon-based microcantilevers.

In this paper, the assembly and stability of locally spotted spherical nanoparticles onto various substrates are studied. Arrays of silicon-based microcantilevers, combined with an automated three-stage spotter, are used to deposit picolitre droplets containing 300 nm diameter polyethylene glycol and 150 nm diameter amino conjugated silica nanospheres onto silicon, allylamine and acrylic acid surfaces. Matrices of colloid spots ranging from 10 to 100 µm in diameter have been successfully patterned. SEM characterizations of the nanoparticles’ geometry and spatial distribution within the spots were carried out, showing the colloid aggregation at the droplet’s rim and the selective stability of the printed patterns. The expected substrate functionalization was assessed by XPS characterizations of the nanoparticles’ surfaces. Finally, polyethylene glycol–SiO₂ nanoparticle conjugates were used as masks during a selective reactive ion etching of the silicon substrate, and silicon nanopillars have been obtained. This work opens up possibilities of high spatial resolution nanopatterning with nanoparticle conjugates. [ABSTRACT FROM AUTHOR]