| AVS 61st International Symposium & Exhibition | |
| Thin Film | Monday Sessions |
| Session TF-MoA |
| Session: | Self-Assembled Monolayers, Layer-by-Layer Assemblies, and Hydrophobic/Amphiphobic Thin Films |
| Presenter: | Piotr Cyganik, Jagiellonian University, Poland |
| Authors: | T. Zaba, Jagiellonian University, Poland A. Noworolska, Jagiellonian University, Poland C.M. Bowers, Harvard University B. Breiten, Harvard University G.M. Whitesides, Harvard University P. Cyganik, Jagiellonian University, Poland |
| Correspondent: | Click to Email |
Self-assembled monolayers (SAMs) based on C-Au bonding and prepared by reaction of terminal n-alkynes (HCΞC(CH2)nCH3, n = 5, 7, 9, and 11) with Au(111) at elevated temperatures (60 oC), were characterized using scanning tunneling microscopy (STM), infra-red reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS) and contact angle of water.1 In contrast to previous spectroscopic studies2-4 of this type of SAM, these combined microscopic and spectroscopic experiments confirm the formation of highly-ordered SAMs having packing densities and molecular chain orientations very similar to those of alkanethiols on Au(111). Physical properties—hydrophobicity, high surface order, and packing density—also suggest that SAMs of alkynes are similar to SAMs of alkanethiols. The preparation of high-quality SAMs from alkynes requires careful preparation and manipulation of the reactants in a rigorously oxygen-free environment: trace quantities of oxygen lead to oxidized contaminants and disordered surface films. The influence of oxygen on the quality of the SAM is apparently not related to reaction of the Au−C bonds in a SAM with oxygen as suggested earlier,3 but instead, suggests gold-catalyzed oxidation of the terminal acetylene in solution before incorporation into the SAM. Importantly, once clean alkyne based SAM is formed it becomes resistant to further oxidation in ambient conditions. This stability, together with high structural order, provides the basis for potential applications of this new type of SAM.
References
(1) Zaba, T.; Noworolska, A.; Bowers, C. M.; Breiten, B.; Whitesides, G. M.; Cyganik, P. submitted, 2014
(2) Zhang, S.; Chandra, K. L.; Gorman, C. B. J. Am. Chem. Soc. 2007, 129, 4876.
(3) McDonagh, A. M.; Zareie, H. M.; Ford, M. J.; Barton, C. S.; Ginic-Markovic, M.; Matisons, J. G. J. Am. Chem. Soc. 2007, 129, 3533.
(4) Scholz, F.; Kaletova, E.; Stensrud, E. S.; Ford, W. E.; Kohutova, A.; Mucha, M.; Stibor, I.; Michl, J.; Wrochem, F. , J. Phys. Chem. Lett. 2013, 4, 2624.