STRUCTURAL INVESTIGATION OF LANGMUIR-BLODGETT-FILMS ON SELF-ASSEMBLY MODIFIED AU SUBSTRATES

To improve the homogeneity and stability of single-layer azobenzene LB films on gold, self-assembled monolayers (SAMs) of terminally substit uted alkyl thiol, HS(CH2)(2)-X(X=NH2, OH, COOH and CH2SO3Na, respectiv ely), were used to modify the substrates before LB film deposition. It was found that single-layer C8C3 LB films on these modified substrate s were more uniform and stable. Reflecion-Absorption (RA) FTIR measure ments on these films indicated that at the LB/SAMs interface, ionic bo nds, have formed for the modification with -NH2 while hydrogen bonding occurred for modifications with -OH, -COOH and -SO3Na, respectively. It can be concluded that the ionic or hydrogen bonding at the LB/SAM i nterface is responsible for the improvement in homogeneity and stabili ty. It was believed that the less defected films after the time aging were most probably due to the ionic bond and hydrogen bonding mentione d above.