Dye adsorption on self-assembled silane monolayers: optical absorption and modeling

A comparative study has been carried out on the adsorption of the Rhodamine 6G dye on glass slides covered with self assembled monolayers of phenyltrichlorosilane and uncoated plain glass. Optical absorption measurements indicate enhancement of the amount of dye adsorbed on silane coated glass as compared to uncoated glass, possibly due to the interaction of the phenyl group in the silane molecule with the dye. Experiments also indicate the formation of dimers of Rhodamine 6G and that the coverage of the dye on the silane modified surface is preferentially as monomers when compared to uncoated glass. Molecular modeling studies on this system support these results.