Stabilization of self-assembled monolayers of carboxylic acids on native oxides of metals

Journal of the American Chemical Society

Volumn 119, Issue 2, 1997, Pages 259-262

  Aronoff, Yael G ^a   Chen, Bo ^a   Lu, Gang ^a   Seto, Carwai ^a   Schwartz, Jeffrey ^a   Bernasek, Steven L ^a  

^a PRINCETON UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALKANOIC ACID; ALUMINUM;

ADSORPTION; ARTICLE; INFRARED SPECTROPHOTOMETRY;

EID: 0031049564     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja953848+     Document Type: Article

References (22)

1. For example, see: Porter, D.; Bright, T. B.; Allara, D. L.; Chidsey, E. D. J. Am. Chem. Soc. 1987, 109, 3559.
2. Laibinis, P. E.; Hickman, J. J.; Wrighton, M. S.; Whitesides, G. M. Science 1989, 245, 845.
3. For example, see: (a) Kumar, A.; Biebuyck, H.; Whitesides, G. M. Langmuir 1994, 10, 1498. (b) Allara, D. L.; Nuzzo, R. G. Langmuir 1985, 1, 45.
4. For example, see: (a) Kumar, A.; Biebuyck, H.; Whitesides, G. M. Langmuir 1994, 10, 1498. (b) Allara, D. L.; Nuzzo, R. G. Langmuir 1985, 1, 45.
5. Folkers, J. P.; German, C. B.; Laibinis, P. E.; Buchholz, S.; Whitesides, G. M.; Nuzzo, R. G. Langmuir 1995, 11, 813.
6. Xia, Y.; Mrksich, M.; Kim, E.; Whitesides, G. M. J. Am. Chem. Soc. 1995, 117, 9576.
7. Miller, J. B.; Schwartz, J., Bernasek, S. L. J. Am. Chem. Soc. 1993, 115, 8239.
8. Miller, J. B.; Bernasek, S. L.; Schwartz, J. J. Am. Chem. Soc. 1995, 117, 4037.
9. Miller, J. B.; Schwartz, J. Inorg. Chem. 1990, 29, 4579.
10. Miller, J. B.; Bernasek, S. L.; Schwartz, J. Langmuir 1994, 10, 2629.
11. Initial exposure could yield a multilayer of alkanecarboxylic acid on the surface adsorbed carboxylate. Apparently, both the multilayer and the alkanecarboxylate overlayer (film 1) are unstable, even at room temperature, with regard to desorption in vacuo.
12. 2, when the treated QCM surface is exposed to that vapor; this multilayer desorbs on subsequent evacuation.
13. 1 species are present, formed by protolytic loss of one or three alkoxides, respectively.
14. In a typical experiment, the frequency change initially measured on exposure to the acid was 644 Hz, which was reduced to 462 Hz after isolation of the acid source and exposure to vacuum. Re-exposure of the QCM to vapors of the acid gave an additional frequency change of 838 Hz. When the acid source was closed off and the QCM was exposed to vacuum, the net total frequency change (based on the clean oxide surface) returned to ca. 400 Hz and was stable for at least 10 h (Figure 5). Apparently, acid can physisorb onto the surface of film 2 (Figure 2b), likely through weak Van der Waals interactions.
15. 2.
16. In other runs, ratios of 76, 62, 61, 49% were noted (five run average 62%). In one case a very high change in frequency was noted on initial deposition (1513 Hz), and a low ratio (29%) for acid/Zr deposition was recorded. We believe this last result could derive from residual water on the QCM electrode surface.
17. The octanoate chains are apparently not in an all-trans, crystalline arrangement (Sondag, A. H. M.; Raas, M. C. Chem. Phys. 1989, 91, 4926), but this is not unexpected for a rough surface.
18. -1. See: Tackett, J. E. Appl. Spectrosc. 1989, 43, 483.
19. Determination of Zr is less sensitive than C by either AES or XPS. However, it is the most useful, since it is the central atom of the complex and is present in both the intact complex and the deposited fragment.
20. -1.
21. 4Zr onto Al(110) were consistent with these assignments (Bernasek, S. L.; Lu, G.; Schwartz, J. Unpublished results).
22. 2; thus, multilayer coverage of the physisorbed species is not expected for the QCM surfaces at room temperature at the pressure indicated.