FORMATION AND IN-SITU MODIFICATION OF MONOLAYERS CHEMISORBED ON ULTRAFLAT TEMPLATE-STRIPPED GOLD SURFACES

We have previously described the preparation of ultraflat Au(111) surfaces as substrates for scanning probe microscopy. We report here alternative ways to produce polycrystalline Au(111) thin films of similar, high quality (i.e., with mean roughness smaller than 5 Angstrom over 25 mu m(2)). All of them are based on the same principle, i.e., that of exposing the very first layer of gold atoms which had deposited onto mica. One alternative route leads to substrates which are transparent enough for optical microscopy. Two other routes make use of ceramic glues, providing substrates which can be handled with most organic solvents without disruption of the Au(111) layer. The substrates prepared by the latter procedures can thus be used to produce gold-directed self-assembled monolayers (SAMs) from nearly all omega-functionalized alkanethiols or dialkyl disulfides; they can also be used for the in. situ chemical modification of SAMs on gold. For this purpose, appropriate reaction chambers have been developed. As an example of the use of the new techniques described here, we report the preparation of a SAM of N-palmitoylcysteamine, either from ex situ synthesis of the precursor or from in. situ acylation of the amino head groups of a cysteamine SAM.