Photophysical studies of N-phenylanthranilic acid in polymer films

Abstract

Photophysical properties of bifunctional N-phenylanthranilic acid (NPAA) have been studied as a dopant in polystyrene (PS) films. The PS films containing fluorescent NPAA were prepared from the solutions in non-polar and polar solvents. The fluorescence spectra of PS films prepared by using non-polar solvents depend on the concentration of NPAA in the film. The films containing lower concentration have exhibited sharp emission band at 412 nm corresponding to normal emission while the films containing higher concentration of NPAA have shown broad emission band peaking at 466 nm. The broad emission band is attributed to as arising due to formation of dimeric species by hydrogen bonding between two neighbouring NPAA molecules in the films. The modification observed in the fluorescence excitation and absorption spectra of the films with dopant concentration allows to

consider the interaction between dopant molecules. In case of NPAA doped poly(vinyl acetate) films, there is an evidence for the destabilization of dimeric species as the fluorescence corresponds to the normal emission only.