| AVS 57th International Symposium & Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS-ThA |
| Session: | Environmental Interfaces |
| Presenter: | N.M. Barrentine, University of California, Irvine |
| Authors: | N.M. Barrentine, University of California, Irvine R.L. Grimm, University of California, Irvine J.C. Hemminger, University of California, Irvine |
| Correspondent: | Click to Email |
Water interactions with organic surfaces are of great importance to chemistry in the environment as well as a variety of device manufacturing and performance issues. We have carried out studies of the interaction of D2O with organic surfaces as a function of the hydrophilic/hydrophobic nature of the surface. Temperature programmed desorption (TPD) experiments are used to follow the strength of the interaction of adsorbed D2O with the surface and to follow the extent of H/D exchange that occurs on the surface. Self-assembled monolayers (SAM) of alkanethiols on Au(111) surfaces are used as a highly characterized organic surface. Hydrophilic SAMs are generated using 6-mercapto-1-hexanoic acid (HSC5H10COOH) on Au(111). Similarly, hydrophobic SAMs are generated using 1-octanethiol (HSC7H14CH3). TPD experiments were carried out following adsorption of D2O on the SAM surface at a temperature of 120 K. H/D exchange was observed by simultaneously monitoring m/z = 20 (D2O+), 19 (HDO+), and 18 (OD+ and H2O+) in the TPD experiments. Our experiments showed an increase in the m/z 19/20 ratio for experiments with the hydrophilic SAM in comparison to the hydrophobic SAM, indicative of H/D exchange with the acidic proton of the 6-mercapto-1-hexanoic acid SAM. Results will also be presented for mixed hydrophilic/hydrophobic monolayers as a function of the hydrophilic/hydrophobic ratio.