Photo-physical behavior of thiazine dyes with or without surfactants into poly-HEMA hydrophilic gel matrix

The visible absorption spectra of methylene blue (MB) and thionine (Th) in aqueous solutions and in poly-2-hydoxyethyl methacrylate hydrogel (PHEMA) matrix were studied at room temperature. The optical spectra of the dye-loaded hydrogel in presence of surfactants (SDS and CTAB) were also investigated. The transport and the solute-solute interactions of the ionic dyes in aqueous solutions across the hydrophilic gel were investigated. The nature of the interacting pairs in these dyes was discussed using the exciton theory.