Optical spectroscopy of molecular-rotor molecules adsorbed on cellulose.

ABSTRACT

Steady-state and time-resolved emission techniques were used to study the fluorescence properties of two molecular rotors, thioflavin-T and auramine-O adsorbed on cellulose powder. Molecular rotors are known for their weak fluorescence intensity and short fluorescence lifetime when dissolved in liquids of low viscosity. We found that these molecular-rotor molecules when adsorbed on cellulose exhibit a rather strong steady-state fluorescence spectrum as well as long emission lifetime. We explain these results by the inhibition of segmental intramolecular rotation when these molecules are adsorbed on cellulose.