Patterning of chemical gradients with submicrometer resolution using edge-spreading lithography

A simple and flexible approach for patterning gradient self-assembled monolayers (SAMs) of alkanethiols on gold substrates using the technique of edge-spreading lithography (ESL) was analyzed. An important feature of ESL, a relief structure present on the gold substrate, mediates the transport of alkanethiol molecules from a poly(dimethylsiloxane) stamp to the gold surface and determines the geometry of the emerging SAM. The edges of the emerging monolayer serve as nucleation sites, that the molecules reach by diffusion. Using this effect, multiple alkanethiolate SAMs can be patterned on gold in a side-by-side arrangement by performing successive points on the same substrate. It was found that SAMs are suitable for introducing functionality to substrates in a chemical defined way and are well suited for gradient fabrication.