Resonance energy transfer in the systems of smectite modified with a fluorescent cationic polymer and a photosensitizer

Abstract

The hybrid materials studied in this work consisted of synthetic saponite (Sap) particles, dextran polymer with positively charged alkylammonium and fluorescein luminophore groups (FITC), and photosensitizer - phloxine B (PhB). Solid films of these materials were prepared by vacuum filtration from colloidal precursors. The film composition has been designed in such a way that the amount of fluorescently active components was constant and only the ratio between chromophores and the amount of Sap was changed. Based on this, it was possible to evaluate the optical properties of the materials as a result of the interactions and equilibria taking place between the components. In addition to the basic characterization of materials, the emphasis was on evaluating the spectral properties of the films and their colloidal precursors. The composition of the systems and the interactions between the components significantly affected the equilibria between the anionic forms of both FITC and PhB. Such changes were also significantly reflected in the photoactivity and fluorescence properties of the samples. The aim was to prepare films that exhibit efficient absorption of visible light and excitation energy transfer from FITC groups to PhB molecules. The potential importance of materials of this type is briefly discussed.