Self-assembled monolayers (SAMs) on gold are attractive for the development of sensors,1,2 interfaces,3 and nanofabrication.4-6 Here we report the use of reactive contact lithography to create patterns on a preformed ω-functionalized self-assembled monolayer on gold.
5-Mercapto-2-benzimidazole sulfonic acid sodium salt (MBS-Na+) was used as a ligand for gold nanoparticles. These monolayer-protected gold colloids (MPCs) were transformed into the catalytically active H+-form by ion exchange. This colloid-bound catalyst hydrolyzed the TMS adsorbate (TMS-OC11H22S)2 both in solution and when self-assembled on gold surfaces. The colloidal particles were deposited on the same SAM surfaces by microcontact printing. Thus, local hydrolysis of the TMS adsorbate created patterns on the SAM surfaces.
Furthermore, MBS-Na+ was used to form a self-assembled monolayer on a metallized PDMS stamp. After transformation from Na+ to H+ form, this stamp was brought into contact with the TMS adsorbate monolayer. The surface was imaged by contact mode AFM (Figure 1) showing a patterned surface has been created, which confirmed the reactivity of reactive stamp.
Figure 1. Contact mode AFM images (acquired in air) of TMS adsorbate SAM after contact with a functionalized PDMS stamp for 15 min. (left, height profile; middle and right, friction)
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