Microcontact deprinting: a technique to pattern gold nanoparticles.

A simple and general patterning technique for inorganic nanoparticles (NPs, e.g., gold NPs) is demonstrated, consisting of the selective lift-off of metal precursor loaded block copolymer micelles. The procedure works as follows: first, a topographically micropatterned polystyrene (PS) stamp is placed in contact with a substrate covered with hexagonally arranged micelles. Then the assembly is heated above the glass transition temperature (T(g)) of PS, and finally, the PS stamp is peeled off, removing from the substrate the micelles that were in contact with the protrusions of the stamp. As a result, patterns of micelles either exactly identical to the original or with much smaller features down to submicrometer were obtained. In a subsequent step, the organic material can be removed and the metal precursor reduced by plasma treatment, resulting in patterns of NPs. This technique, denoted as "micro-contact deprinting", provides a fast and inexpensive way to obtain hierarchical patterns of NPs on a wide range of substrates. It is demonstrated that it can even be applied on curved surfaces because of the softness of the PS stamp above its T(g).