This communication reports the formation and characterization of selfassembled films of a low molecular weight anionic dye amaranth and polycationPoly (allylamine hydrochloride) (PAH) by electrostatic alternatingLayer-by-Layer (LBL) adsorption. It was observed that there was almost nomaterial loss occurred during adsorption process. The UV-Vis absorption andfluorescence spectra of amaranth solution reveal that with the increase inamaranth concentration in solution, the aggregated species starts to dominateover the monomeric species. New aggregated band at 600 nm was observed inamaranth-PAH mixture solution absorption spectrum. A new broad low intense bandat the longer wavelength region, in the amaranth-PAH mixture solutionfluorescence spectrum was observed due to the closer association of amaranthmolecule while tagged into the polymer backbone of PAH and consequent formationof aggregates. The broad band system in the 650-750 nm region in thefluorescence spectra of different layered LBL films changes in intensitydistribution among various bands within itself, with changing layer number andat 10 bilayer LBL films the longer wavelength band at 710 nm becomes prominent.Existence of dimeric or higher order n-meric species in the LBL films wasconfirmed by excitation spectroscopic studies. Almost 45 minute was required tocomplete the interaction between amaranth and PAH molecules in the 1-bilayerLBL film.
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