Adsorption and Structure of Octadecanethiol on Zinc Surfaces As Probed by SumFrequency Generation Spectroscopy, Imaging, and Electrochemical Techniques
2007 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 111, no 47, 17587-17596 p.Article in journal (Refereed) Published
Octadecanethiol (ODT) adsorbed onto zinc has been studied with sum frequency generation (SFG), sum frequency generation imaging microscopy (SFG-IM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrical impedance spectroscopy (EIS) in order to investigate its corrosion protective ability and conformational ordering. SFG shows that ODT forms an ordered adsorbate on both reduced and oxidized zinc within short times after immersion in 1 mM ODT/ethanol solution. The corrosion protection, deduced by EIS, is also improved after immersion in the ODT solution. After longer immersion times, the corrosion protection decreases as well as the conformational order of the adsorbed ODT. Increasing the ODT concentration avoids this degradation with prolonged immersion time. The ODT is seen in the XPS spectra to adsorb to the reduced as well as the oxidized zinc by forming a Zn-S bond for both short and long immersion times. The SFG-IM completes the picture, showing a heterogeneous surface with areas corresponding to ordered ODT as well as disordered or uncovered regions. The density of adsorbed ODT after 24 h immersion time for both reduced and oxidized zinc was deduced from CV and was found to be approximately 6.7 x 10(-9) mol/cm(2).
Place, publisher, year, edition, pages
2007. Vol. 111, no 47, 17587-17596 p.
self-assembled monolayers; ray photoelectron-spectroscopy; vibrational spectroscopy; alkanethiol monolayers; impedance spectroscopy; molecular-orientation; zno nanoparticles; stretching modes; single-crystal; spectrum
Other Basic Medicine
IdentifiersURN: urn:nbn:se:kth:diva-11723DOI: 10.1021/jp075286+ISI: 000251141100021ScopusID: 2-s2.0-37049013707OAI: oai:DiVA.org:kth-11723DiVA: diva2:280059
QC 201007192009-12-082009-12-082010-12-06Bibliographically approved