The preparation and photophysical behaviors of temperature/pH-sensitive polymer materials bearing fluorescein

A novel method for attaching fluorescein (via its epoxy derivate) to water soluble polymer and its temperature/pH-sensitive qualities of fluorescence were investigated. 3-Epoxypropoxy fluorescein (EPF) was firstly synthesized through the reaction between fluorescein and epichlorohydrin and poly (vinyl alcohol) bearing fluorescein was prepared via ring-opening reaction with EPF. Both of them were characterized by the methods of HNMR, MS, IR, UV-Vis, DSC and fluorescence spectra, respectively. The chemiluminescent and photophysical behaviors of the dye fluorescein derivative and the polymer-containing fluorescein had been studied, and the ability of film forming of PVA-EPF and the effect of different solvents on its fluorescence behavior were reported in this article. In addition, the pH and temperature dependences of fluorescence of PVA-EPF were investigated in detail. All those observations suggested that the PVA-EPF was an excellent luminescent macromolecular material with a convenience method for the preparation and an excellent water-soluble ability. Moreover its pH and temperature sensitivities of the fluorescence can be advantageous for it to become a multifunctional material to probe pH and temperature.