MOLECULAR-LEVEL INTERFACE DESIGNS USING SELF-ASSEMBLING TECHNIQUE FORSTABILIZING LANGMUIR-BLODGETT-FILMS

Self-assembled monolayers (SAMs) of HS-(CH2)(2)-X with X being -COOH, -OH, -NH2, and -CH2SO3Na were fabricated on Au surfaces for deposition of C8H17-C6H4-N = N-C6H4-O-(CH2)(3)-COOH (ABD) LB films. Thus-created SAM/LB interfaces were studied by the grazing-angle incident reflecti on absorption FTIR technique. For -NH2 group, the interface was proved to be dominated by -NH3+-OOC- ionic bonding structure. When X was -CO OH, an eight-membered face-to-face hydrogen bond was observed at the S AM/LB interface. With the -OH terminated interface, two types of hydro gen bond were created: one is the face-to-face hydrogen bond and the o ther one is the side-by-side hydrogen bond. In the case of Au/-CH2SO3N a/HOOC- interface, two terminal groups seem to exchange their cations, forming a -CH2SO3H/NaOOC-structure. The stability of these monolayer assemblies was investigated using Atomic Force Microscopy (AFM). II is found that all these films showed a greatly improved structural stabi lity and the destructive three-dimensional rearrangement of ABD molecu les has been effectively prohibited. The sequence of film stability wa s -NH2>-COOH>-OH>-CH2SO3Na, with the first two interfaces exhibiting e ven nice stability in aqueous solution, strong enough for tolerating t he interfacial electron transfer studies.