| Abstract
| - The molecular organization of Langmuir−Blodgett (LB) multilayers of a phospholipid (DMPA) and LBalternate multilayers consisting of mixed monolayers of a viologen (TDMV) and a phospholipid (DMPA),molar ratio of TDMV:DMPA=1:2, and pure DMPA monolayers have been studied by infrared (IR) transmissionand reflection−absorption (RA) spectroscopies. The infrared study shows that the DMPA monolayers areordered like a crystalline phase where the alkyl chains are almost normally oriented to the substrate surfaceapproaching an all-trans configuration. Also, the stretching mode of the carboxyl group lines up with a largecomponent normal to the substrate, as seems to be the transition dipole moments of phosphate and COCgroups. The presence of TDMV molecules in the mixed LB films does not significantly alter the structure ofthe DMPA films. The TDMV rings are tilted relative to the substrate surface, and located between the phosphategroups of the DMPA molecules of the mixed monolayer and of the subsequent DMPA layer. Thus, the influenceof the TDMV molecules on the dehydration of the film is extended to the phospholipid in the mixed monolayeras well as to the one in the pure DMPA layer.
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