AVS 52nd International Symposium
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP4
Comparison of Thiol and Disulfide Based Self-Assembled Monolayers (SAMs) by Reactive Ion Scattering Spectrometry (RISS)

Tuesday, November 1, 2005, 4:00 pm, Room Exhibit Hall C&D

Session: Surface Science Poster Session
Presenter: K.E. Joyce, University of Arizona
Authors: K.E. Joyce, University of Arizona
S. Ravindran, University of Texas
V.H. Wysocki, University of Arizona
Correspondent: Click to Email
Reactive Ion Scattering Spectrometry (RISS) was used to investigate self-assembled monolayers (SAMs) formed from symmetric disulfides and thiol solutions of corresponding chain lengths. A series of odd and even alkanethiol (CH@sub 3@(CH@sub 2@)@sub n@SH; n= 15, 16, 17) and disulfide ((CH@sub 3@(CH@sub 2@)@sub n@S)@sub 2@; n= 15, 16, 17) SAMs were probed with benzene and pyrazine projectile ions to investigate both neutralization and reaction differences. RISS utilizes a tandem quadrupole mass spectrometer to select ions of a given mass-to-charge value and collides them with a given collision energy into the surface. Reactions of the ion beam with the surface are sensitive to factors such as the nature of the orientation of the terminal functional group. RISS revealed differences between disulfide and thiol based SAMs in both neutralization characteristics of the films, as evidenced by differences in total scattered ion currents, as well as differences in reactions via hydrogen and methyl abstractions from the surfaces. Systematic studies were conducted where fully formed disulfide based SAMs were introduced to thiol solutions to show incorporation of thiol species. FT-IR and contact angle experiments were also performed to examine SAM film chain-to-chain interactions.