AUTOPHOBIC PINNING OF DROPS OF ALKANETHIOLS ON GOLD

This paper establishes conditions necessary for autophobic pinning of solutions of alkanethiols by their reaction with a gold surface. Interfacial tension and the kinetics of organization of the SAMs are important considerations in the design of systems that limit the spread of drops across a surface that is reactive toward those drops. The two systems investigated in this paper-hexadecanethiol (HDT) spreading on gold in air and hydroxyundecanethiol (HHT) in hexadecane spreading on gold under water-provide a basis for understanding one aspect of the mechanism of microcontact printing (mu CP) based on the reaction of thiols with bare gold. Adsorbates on the gold surface, and the roughness of the surface, ultimately limit the ext-ent to which liquids are pinned on the surface of gold and constrain pinning of these liquids (and determine the resolution of patterning) by mu CP and related methods.