CONTROLLING LOCAL DISORDER IN SELF-ASSEMBLED MONOLAYERS BY PATTERNINGTHE TOPOGRAPHY OF THEIR METALLIC SUPPORTS

Micropatterning is a powerful method for controlling surface propertie s, with applications hom cell biology to electronics(1-8). Self assemb led monolayers (SAMs) of alkanethiolates on gold and silver(9-11) the structures most widely used for preparing organic films with specific surface properties-are usually patterned by partitioning the surface i nto regions formed from different thiols(12-15). Here we describe a wa y to pattern SAMs using a single alkanethiol on substrates consisting of regions of different topography: planar islands of one metal on the surface og a second (which may be different from or the same as the f irst). These topographically patterned SAMs consist of three regions: two planar surfaces and a transition region between the two. The chara cters of the SAMs on these three regions were inferred from images of three structures that form on them: condensation figures, pasterns of crystals of CaCO3 and regions of selective etching. The transition reg ion is more active in tbe processes generating these structures than e ither of the two planar regions, and we propose that this activity is clue to the relatively high disorder in the organic film there. We bel ieve that this ability to control the local disorder in a SAM with hig h resolution will be important in controlling processes such as nuclea tion, wetting, adhesion and etching on scales of below 50 nm to 5 mu m .