Organized polyvinyl alcohol assemblies: Eligible luminescent centers for species dependent metal sensing

- Polyvinyl alcohol (PVA) solution shows fluorescence activity.
- Micellization in PVA solution forms the basis of fluorescence activity.
- Species dependent metal sensing for transition metal ions is possible using this solution.

Solutions of polyvinyl alcohol have been found to show fluorescence emission upon excitation (λex = 300 nm, λem = 420 nm). The site of luminescence generation has been attributed to its tendency to form organized micelles in solution which result in an electron dense region in the hydrophilic zone. The expected micellar size was evaluated using dynamic light scattering and the cmc was predicted from the conductance measurements. The spectral changes of the PVA solution were spectacular in the presence of different oxidation states of the metal ions Cr(III)/(VI), Mn(II)/(VII) and Fe(II)/(III). The spectral studies indicated a weak ground state complexation of PVA micelles with the lower oxidation state metal ions. However for the higher oxidation state species both ground and excited state fluorescence quenching were observed. The present system offers a simple and cost effective method of species dependent metal ion sensing.