Molecular and fluorescence spectroscopic studies of polyacrylic acid blended with rhodamine B mixed gold nanoparticles

Abstract

This work studies the improvement of the emission spectra of polyacrylic acid (PAA) by adding different ratios of rhodamine dye (RhB) to different sizes and shapes of gold nanoparticles (AuNPs). AuNPs were prepared by chemical reduction method at heating temperature 80°C and a different time. The experimental results of both UV–Visible spectroscopy and TEM technique showed that the AuNPs were formed at different times (1–15 min) with different plasmonic band positions and has particle sizes 11 and 13 nm, for AuNPs were formed at 1 and 10 min respectively. FTIR, UV–Vis, X-ray diffraction, and SEM techniques used in the characterization of PAA blended by an equivalent amount of RhB and AuNPs with size 11 and 13 nm. The band appeared at 1683 cm−1 in PAA spectra which is assigned to C=O became doubling in the PAA blended samples due to the AuNPs may be coordinating with the oxygen atom in the C=O group. Fluorescence measurements indicated an emission band appeared at 585 and 590 nm for PAA doped by RhB and AuNPs with size 11 and 13 nm, respectively. The intensity of these emission bands was enhanced for the PAA blended by increasing both AuNPs and RhB ratios due to the interactions between dipole moments of the SPR of the AuNPs and RhB molecules. Therefore, it could be enhancing the fluorescence intensity of these samples, and it can be used as an laser active medium. Highlights Synthesis of AuNPs with different sizes. Prepare PAA blended by RhB and AuNPs. Study the coordination of AuNPs with PAA using FTIR. Explain the effect of RhB and AuNPs on fluorescence spectra.