Surface-enhanced Raman study of the solid/liquid interface: Conformational changes in adsorbed molecules

✍ Scribed by C.J. Sandroff; S. Garoff; K.P. Leung

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 441 KB
• Volume: 96
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(83)80445-x

✦ Synopsis

Surfaceenhanced Raman scattering was seen from I-hehadecane thiol adsorbed on silver-island f&ns. The adsorbeul amphiphile in contact with air and water exhibited similar trans. or solid-like stiuctures. In contact with chloroform which wets the thiolcoated fihn, there was a decrease in the number of trans conformations. The wettability of a solid is just one exanlple of a macroscopic property that can be greatly affected by molecular adsorbates. Amphiphilic molecules, possessing a polar head group attached to a long, non-polar tail, are probably the most common surface-active agents used to alter wettability and surface tensions at the liquid/solid interface. To what extent is adsorbate structure and conformation affected by this fluid contact and how might such microscopic information provide insight into the large-scale processes occurring at the liquid/solid interface? We explore such questions in the ing (SERS) P resent surface-enhanced

RAman scatterstudy. The amphiphile used here was I-hexadecane thiol (C~GH~~SH, hereafter HXDSH), which was found to strongly chemisorb to silver surfaces_ Obtained from Aldrich Chemical Co., HXDSH was purified by highpressure liquid chromatography using a Silica Prep Pak column (Waters Associates) and pentane as the mobile phase. Subsequent chromatographic analysis showed the purified sample to be =97% (by weight) HXDSH with the major impurity most likely the C,, thiol.

SERS spectra were recorded with HXDSH ad-