The fluorescent diaminodicyanoquinodimethane, D-π-A system; DADQ, 2-{4-[(2,6-Dimethyl-morpholin-4-yl)-N-methylocatdecylamino-methylene]-cyclohexa
-2,5-dienylidene}-malonitrile, has been used to produce Langmuir monolayers at the air/water interface for the first time. The subsequent production of surface pressure – area isotherms has enabled characterisation of the film’s surface pressure-dependent phases. Langmuir-Blodgett deposition of onto hydrophilic glass substrates was shown to produce homogeneously coated Z-type films of well-characterised thicknesses. X-Type structures were also obtained. Time correlated single photon counting was employed to measure the fluorescent lifetimes of each film, and again when surface perturbations (a non-fluorescent viscous oil, and bovine serum albumin) were applied. Bi-exponential fluorescence decays were observed in all cases. Perturbation was shown to increase the total fluorescent intensity in both Z- and X-type films, with changes in decay lifetime specific to both the molecule in the films, and the perturbation. The environmentally sensitive nature of the emission and the analytical possibilities arising from the extra information resulting from the fluorescence decay curves may make such systems attractive as bio or chemical sensors.
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