J. Aizenberg et al., CONTROLLING LOCAL DISORDER IN SELF-ASSEMBLED MONOLAYERS BY PATTERNINGTHE TOPOGRAPHY OF THEIR METALLIC SUPPORTS, Nature, 394(6696), 1998, pp. 868-871
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
.