Polymer micro-environmental effects on the fluorescence characteristics of 5-aminoquinoline and 3-aminoquinoline

In this paper we report the spectral and decay behavior of two probes viz. 5-aminoquinoline (5AQ) and 3-aminoquinoline (3AQ) in three different polymeric systems viz. poly methyl methacrylate (PMMA), polyvinyl alcohol (PVA) and cellulose acetate (CA). Absorption spectra are nearly identical for all the polymers but the emission shows larger shift in case of CA as compared to PMMA and PVA. The behavior is explained on the basis of higher hydrogen bond donating ability in case of CA because of the presence of cellulosic hydrogens. Observed multiexponential decays are explained on the basis of free as well as hydrogen-bonded species and also trapping in various excited state geometries of the matrix.