In the present paper

the LB films of dansyl chloride (DNS) and 8-anilino-l-naph-thalene sulfonic acid CANS) derivatized octadecyl-amine(AM) were deposited on solid substrates and their photophysical behavior was studied by the steady-state and time-resolved fluorescence measurements.The surface pressure/molecular area curves for DNS-AM and ANS-AM in presence or absence of atearic acid (SA) show that solid-condensed films have formed. The collapse pressure for DNS-AM and (DNS-AM)/SA(1:9) is 30 and 58mN/m respectively; while that for ANS-AM and (ANS-AM)/SA(1:5) is 35 and 58 mN/m respectively. The A isotherms for DNS-AM and (DNS-AM)/SA are unusual with a platean. The isothermn of ANS-AM and (ANS-AM)/SA have a classical shape.No significant difference was found between solution spectra in the absence or presence of stearic acid for either DNS or ANS labeled octadecylamine. It means that the diluent stearic acid has no substantial perturbation to the spectral properties of the fluorescent derivatives. The emission bands of films have a small blue shift (25 and 13 nm for DNS and ANS systems respectively) with respect to corresponding solution bands. This blue shift likely implies that the fluorescent octadecylamine experiences more hy-drophobic microenvironment in ordered LB films than in the random state in solution.The fluorescence lifetimes for DNS-AM and (DNS-AM)/SA in deposited films and in spreading solutions are identical within the experimental error range

being 13.5±1.Ons. ANS-AM and (ANS-AM)/SA also have similar lifetime values in film and in solution (ca. 8 ns). This implies that the molecules deposited on the substrate did not change their microstructure(conformation

aggregation state and etc.). A small tendency of lengthening of fluorescence lifetimes of molecules in film as compared to that in solution

is consistent with the small blue shift of emission bands

indicating the more hydrophobic microenvironment of film molecules.The results show that the derivatization with fluorescent probes may render the long-chain amine

not possessing chromophores suitable for conventional spectral study

to be detected with sensitive fluorometry in deposited LB films.