SPECTROSCOPIC CHARACTERIZATION OF NIAGARA BLUE DYE IN THE RESTRICTED GEOMETRY OF LAYER-BY-LAYER SELF-ASSEMBLED FILMS

Abstract

Multilayer films can be precisely engineered on solid substrate via layer-by-layer (LbL) self-assemble technique using negatively charged organic dye and positively charged polyelectrolytes or surfactants. This communication first time reports the successful incorporation of an anionic dye Niagara blue (NB) in Polyallylamine hydrochloride (PAH) by electrostatic sequential alternative LbL adsorption. The photo-physical characteristics of LbL films are investigated by varying different parameters such as number of deposited layer, dipping time in dye solution, pH of PAH solution, concentration of the dye, etc. In addition, the interaction of NB with double tail surfactant Didodecyl dimethyl ammonium bromide (DDAB) at different concentrations is also studied in the light of UV–Vis absorption spectroscopy. Spectroscopic analysis reveals that NB has been successfully anchored to PAH or DDAB through electrostatic self-assembled technique and forms molecular aggregates. The formation of aggregates is further confirmed by atomic force microscopic (AFM) study.