Morphology and molecular orientation and structure of Langmuir–Blodgett films of chlorophyll a studied by atomic force microscopy and UV–VIS and IR spectroscopies

摘要: Atomic force microscopy (AFM), scanning electron (SEM) and UV–VIS absorption IR spectroscopies have been used to investigate the morphological molecular structure of Langmuir–Blodgett (LB) films title compound (Chl-a). The AFM SEM measurements reveal that surface LB are very smooth consist rigid condensed monolayers. tilt angle chlorin plane in a six-monolayer film Chl-a has calculated be 35° between normal substrate 44° dipping direction projection plane, from its polarized spectra. Band frequencies 1750–1400 cm −1 region spectra one-, six- ten-monolayer (ML) suggest exists five-coordinated monomer films, irrespective number Comparison transmission reflection–absorption 6 ML indicates ester keto CO groups tilted considerably with respect normal. pheophytine (Phe-a) also studied for comparison. Phe-a show pheophytinization occurs little Chl-a. High-performance liquid chromatography (HPLC) examination supported this conclusion. All experiments carried out present study molecules oriented an orderly manner face-to-face packing rings.