Adsorption Studies of Organophosphonic Acids on Differently Activated Gold Surfaces

Publication year: 2016
Authors: Katrin Niegelhell †, Simon Leimgruber †‡, Thomas Grießer §, Christian Brandl ∥, Boril Chernev ∥, Robert Schennach ⊥, Gregor Trimmel †, and Stefan Spirk †
 - Institute for Chemistry and Technology of Materials, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria
 - Polymer Competence Center Leoben GmbH, Roseggerstraße 12, 8700 Leoben, Austria
§ - Institute for Polymer Chemistry, University of Leoben, Otto Glöckel-Straße 2/IV, 8700 Leoben, Austria
 - Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
 - Institute of Solid State Physics, Graz University of Technology, Petersgasse 16/II, 8010 Graz, Austria
Published in: Langmuir, 2016, Vol. 32 (6), p. 1550–1559
doi: 10.1021/acs.langmuir.5b04467

In this study, the formation of self-assembled monolayers consisting of three organophosphonic acids (vinyl-, octyl-, and tetradecylphosphonic acid) from isopropanol solutions onto differently activated gold surfaces is studied in situ and in real time using multiparameter surface plasmon resonance (MP-SPR). Data retrieved from MP-SPR measurements revealed similar adsorption kinetics for all investigated organophosphonic acids (PA). The layer thickness of the immobilized PA is in the range of 0.6–1.8 nm corresponding to monolayer-like coverage and correlates with the length of the hydrocarbon chain of the PA molecules. After sintering the surfaces, the PA are irreversibly attached onto the surfaces as proven by X-ray photoelectron spectroscopy and attenuated total reflection infrared and grazing incidence infrared spectroscopy. Potential adsorption modes and interaction mechanisms are proposed.

MP-SPR keywords: adsorption, organophosphonic acids, refractive index, SAM, surface cleaning methods, thickness