Contact-Inking Stamps for Microcontact Printing of Alkanethiols on Gold

Microcontact printing uses an inked patterned stamp to direct chemical reactions during contact between molecules from the ink and the surface of a substrate. Here, we use this technique with solutions of alkanethiols on the stamp surface as ink and gold as the substrate to form a self-assembled monolayer in the regions of contact to protect the gold from a subsequent wet etch. We describe an alternative method for inking stamps based on their contact with
an elastomer impregnated with ink. One of the principal findings is that control over the amount of ink transferred during inking from the inker pad to the stamp is possible by changing the concentration of the thiol solution used for impregnation. Contact inking partially localizes the ink where it is needed to form a protective self-assembled monolayer. As a consequence, the degree of completion of the printed monolayer becomes largely independent from
the geometry of the pattern, and uncontrolled diffusion of the thiols during printing interferes noticeably less than when wet inking is performed.