Spontaneously organized molecular assemblies. 4.Structural characterization of n-alkyl thiol monolayers on gold by optical ellipsometry, infrared spectroscopy and electrochemistry.

Monolayer assemblies at solid surfaces provide a rational approach to obtain interfaces with well-defined composition, structure and thickness. In this paper, monolayer assemblies of n-alkyl thiols, CH sub 3(CH sub 2) sub n SH( n=1 to 21), adsorbed on gold are characterized by optical ellipsometry, infrared spectroscopy and electrochemistry. The IR spectroscopic and the ellipsometric data indicate that the long chain thiols (n >= 9) form densely packed, crystalline- like assemblies with fully extended alkyl chains tilted from the surface normal by 20-30D.