title: Fabricating chemical gradients on oxide surfaces by means of fluorinated, catechol-based, self-assembled monolayers.
abstract: Catechols bind strongly to several metal oxides and can thus be used as a binding group for generating self-assembled monolayers. Furthermore, their derivatives can be used to produce well-defined, centimeter-scale surface-chemical gradients on technologically relevant surfaces, such as titanium dioxide (TiO(2)). A simple dip-and-rinse gradient-preparation technique was utilized to produce surface-hydrophobicity gradients from perfluoro-alkyl catechols and nitrodopamine (ND). Chemical composition, quality, and properties of the functionalized surfaces were determined by means of X-ray photoelectron spectroscopy (XPS), variable-angle spectroscopic ellipsometry (VASE), and static water contact angle (sCA) measurements. Contact angles were found to be in the range of 30°-95°, correlating well with the determined surface chemical composition and adlayer thickness.
authors.affiliation: Laboratory for Surface Science and Technology, Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland.
authors.forename: Mathias
authors.initials: M
authors.lastname: Rodenstein
authors.forename: Stefan
authors.initials: S
authors.lastname: Zürcher
authors.forename: Samuele G P
authors.initials: SG
authors.lastname: Tosatti
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Spencer
mesh_terms: D002396:Catechols / Q000737:chemistry*; D004298:Dopamine / Q000031:analogs & derivatives / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008567:Membranes, Artificial; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*
chemical_list: D002396:Catechols; D008567:Membranes, Artificial; C009495:titanium dioxide; D014025:Titanium; D004298:Dopamine