The characteristics of the LB films of Schiff base aluminium(Ⅲ), tris(2-hydroxy-5-nitro-N-dodecyl-benzylideneaminato) aluminium(Ⅲ)[Al(TA12)_3], were studied. The surface pressure-area(π-A) isotherm of Al(TA12)_3 in the pure water subphase was investigated. The molecular area, 0.48 nm^2, is one-third of the expected value that indicates the formation of an aggregate. The Langmuir-Blodgett(LB) films of Al(TA12)_3 were transferred and characterized. The UV-Vis spectra and the AFM image both confirmed that the J-aggregates formed. The polarized UV-Vis spectra indicated that the complex plane had to be oriented with an angle of about 30° to the substrate surface. The IR spectra suggested that the complexation took place between aluminium ions and the oxygen atoms of the ligand rather than the nitrogen atom.
LIAN WeiCAO WeiWANG GangWEI LiHONG XiaSHEN Dong-fangLIU Chun-yanSHAO Hui-boBAI Yu-bai
In this paper, the membrane capacitance (Cm), which was obtained from the electro- chemical impedance spectroscopy (EIS) method, was used to characterize the effect of pH value on the self-assembled monolayers (SAMs) of octadecanethiol(18SH) for the first time. The results not only strongly proved that inorganic ions could penetrate the SAMs of 18SH, but also ascertained that SAMs of 18SH were not an absolute of free of ion-penetration. Verifying the existence of pin-holes in the octadecanethiol SAMs was the main contribution of this paper, which coincided with the former conjecture very well.
The effect of polarization time on the schiff base self assembled monolayer containing hydrosulfo group has been investigated by CV and ac impedance measurements. The results showed that, when the potential of -0 87 V( vs .SCE) was applied on the monolayer, the electrochemical charge transfer resistance R ct originated from the reduction of CN increased with the polarization time within 4 min and then decreased. This phenomenon may be related to the relationship between the CN group and the structure of the Schiff base self assembled monolayer.
