Near field guided chemical nanopatterning.

This article demonstrates the possibility of creating well-defined and functional surface chemical nanopatterns using the optical near field of metal nanostructures and a photosensitive organic layer. The intensity distribution of the near field controlled the site and the extent of the photochemical reaction at the surface. The resulting pattern was used to guide the controlled assembly of colloids with a complementary surface functionality onto the substrate. Gold colloids of 20 nm diameter were covalently bound to the activated nanosites and proved the functionality of the suboptical wavelength structures and enabled direct visualization by means of electron microscopy. Our results prove, for the first time, the possibility of using optical near field to perform chemical reactions and assembly at the nanoscale.