PHOTOPHYSICAL PROPERTIES OF LYCOPENE ORGANIZED IN LANGMUIR-BLODGETT-FILMS - FORMATION OF AGGREGATES

Mixed films of lycopene and stearic acid (SA) form highly stable float ing monolayers at the air-water interface which may be easily transfer red to glass or quartz substrates with a high transfer ratio. The surf ace pressure vs. area per molecule isotherms indicate that the lycopen e molecules have a preferred orientation at the air-water interface. P olarized absorption studies support such an orientation of lycopene mo lecules in Langmuir-Blodgett (LB) films. Repulsive-type interactions b etween lycopene and SA have been observed by Gibbs free energy measure ments. Spectroscopic studies of lycopene in solution, binary solvents and LB films suggest the formation of both J- and H-type aggregates. ( C) 1997 Elsevier Science S.A.