Fabrication of Ordered Two-Dimensional Arrays of Micro- and Nanoparticles Using Patterned Self-Assembled Monolayers as Templates

lar substrate is tricky, since the spin-coating solution does not wet the substrate and flies off the rotating surface. Since the OTS pattern after the lift-off technique is the inverse of the originally stamped ODT pattern, the sample in Figure 1d features macroscopically an oxide surface with printed OTS stripes on a micrometer lateral scale. Beyond the specific advantages of our technique, structured SAMs from OTS enjoy several advantages over their ODT analogs. The surface energy difference between OTS and silicon oxide is much larger than between ODT and Au, making patterned OTS substrates more suitable for structured wetting and demixing experiments. Potential applications for chemical and biological sensors also benefit from this increase in polarity. Furthermore, the silane bond is stronger than the chemisorbed thiols allowing experiments at higher temperatures. In conclusion, we have combined the well-established mCP technique of alkane-thiols on Au with a lift-off technique to transfer the stamped pattern onto a silicon-oxide surface. The main benefit of this approach compared to a direct printing technique is the improved control over environmental parameters during the deposition of the alkane-silanes, making the lift-off technique more reliable and reproducible. In addition, the lift-off technique does not depend on specific substrate materials. Therefore, extension to a wide range of surfaces and functionalized alkane chains is possible.