Effect of structure and concentration of polymer, metal ion and pH of the medium on the fluorescence characteristics of hyperbranched polyamines

A series of hyperbranched polyamines have been prepared by the reported method. All these polyamines exhibit fluorescence at about 350-650 nm with maximum intensity at about 450 nm. The study shows that the fluorescence intensity and the range of wavelength of fluorescence are strongly influenced by the structure of the hyperbranched polyamines. The effect of concentration of the polymer, pH of the medium and metal ion has also been investigated on the fluorescence characteristics of sulfone containing hyperbranched polyamine (Ps), as it shows the best result among the studied polymers. The results show that the intensity of fluorescence increases with the decrease of concentration (5-0.1 g/L in N,N′-dimethyl sulfoxide) of polymer and with the increase of pH (3.1-11.6) of the medium. The quenching of fluorescence increases with the increase of concentration of Cu²⁺ ions (0.01-0.04%). The hyperbranched polyamine (Ps) has also been end capped with benzoyl chloride and 4-hydroxybenzaldehyde to study the influence of end groups. The results showed that the structure of end capped compounds has prominent role to influence fluorescence characteristics of this hyperbranched polyamine.