Tuning the surface potential of Ag surfaces by chemisorption of oppositely-oriented thiolated carborane dipoles

0429454 - ÚACH 2015 RIV US eng J - Journal Article
Lübben, J.F. - Baše, Tomáš - Rupper, P. - Künniger, T. - Macháček, Jan - Guimond, S.
Tuning the surface potential of Ag surfaces by chemisorption of oppositely-oriented thiolated carborane dipoles.
Journal of Colloid and Interface Science. Roč. 354, č. 1 (2011), s. 168-174. ISSN 0021-9797. E-ISSN 1095-7103
R&D Projects: GA AV ČR(CZ) IAA400320901
Keywords : Adsorption * Thiolated carboranes * Silver surface * Surface potential * X-ray photoelectron spectroscopy
Subject RIV: CA - Inorganic Chemistry
Impact factor: 3.070, year: 2011

Two selected carboranethiol isomers were used to modify flat silver surfaces. Both isomers, 1,2-(HS)(2)-1, 2-C(2)B(10)H(10) (a) and 9,12-(HS)(2)-1,2-C(2)B(10)H(10) (b), are relatively strong dipoles with two SH groups per molecule. They are both anchored to the surface via two SH groups per molecule. Topography and surface potential changes of the modified silver surfaces were studied using Scanning Kelvin Probe Force Microscopy (SKPFM). These measurements proved that both isomers are oppositely oriented on the surface. The former isomer increases, and the latter one decreases the surface potential of a modified silver film. The relative changes of the surface potential correlate well with the dipole moments of the isomers. Competitive chemisorption from a 1:1 mixture of both isomers shows that the isomer (a) is found in a significantly higher concentration on the surface than the isomer (b). This has been proved by both SKPFM and X-ray photoelectron spectroscopy (XPS) techniques. Additionally, contact angle measurements were carried out to characterise the modified surfaces, and these and XPS results show the presence of hydrophobic hydrocarbon contaminants.
Permanent Link: http://hdl.handle.net/11104/0234572