Super-hydrophobic/super-hydrophilic patterning of gold surfaces by photocatalytic lithography

Abstract

Super-hydrophobic and super-hydrophilic gold surfaces were prepared by modifying microstructured gold surfaces with thiols. The perfluorodecanethiol (PFDT)-modified rough gold surface was converted from super-hydrophobic (water contact angle = 150–160°) to super-hydrophilic (0–10°) by photocatalytic remote oxidation using a TiO2 film. During the remote oxidation, oxygen-containing groups were introduced to the thiol, and finally, even sulfur atoms were removed. Super-hydrophobic/super-hydrophilic patterns were also obtained by photocatalytic lithography, by using a TiO2-coated photomask. On the basis of this technique, enzymes and algal cells were patterned on the gold surfaces to fabricate biochips.