MOLECULAR-ORIENTATION AND AGGREGATION IN THE LANGMUIR-BLODGETT-FILMS OF 4-[4'-(4''-DECYLOXY PHENYLAZO)NAPHTHLOXY]BUTYL TRIMETHYLAMMONIUM DEXTRAN SULFATE STUDIED BY ULTRA-VIOLET AND INFRARED-SPECTROSCOPY

Infrared transmission, Reflectance-Absorption (RA) and Ultra-Violet (U V) spectra were measured for mono-and multi-layers Langmuir-Blodgett ( LB) films of 4-[4'-(4 ''-decyloxy phenylazo)naphthloxy] butyl trimethy lammonium bromide formed with SDS to study the molecular orientation a nd aggregation. The results indicate that the compound do not aggregat e in the LB films, and the alkyl tail is nearly perpendicular to the s ubstrate surface and the chromorphore part adopts trans-zigzag conform ation. These results also suggest that the molecular orientation and a ggregation are not depend upon the number of monolayers. The compariso n of infrared transmission and RA spectra indicates that the hydrocarb on chain is nearly perpendicular to the substrate surface, but the two rings in the chromophore part are tilted considerably from the surfac e normal.