Reports

Manipulation of the Wettability of Surfaces on the 0.1- to 1 -Micrometer Scale Through Micromachining and Molecular Self-Assembly

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Science  04 Sep 1992:
Vol. 257, Issue 5075, pp. 1380-1382
DOI: 10.1126/science.257.5075.1380

Abstract

Micromachining allows the formation of micrometer-sized regions of bare gold on the surface of a gold film supporting a self-assembled monolayer (SAM) of alkanethiolate. A second SAM forms on the micromachined surfaces when the entire system—the remaining undisturbed gold-supported SAM and the micromachined features of bare gold—is exposed to a solution of dialkyl disulfide. By preparing an initial hydrophilic SAM from HS(CH2)15COOH, micromachining features into this SAM, and covering these features with a hydrophobic SAM formed from [CH3(CH2)11S]2, it is possible to construct micrometer-scale hydrophobic lines in a hydrophilic surface. These lines provide new structures with which to manipulate the shapes of liquid drops.