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

Abstract 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.