Research of the dyeing thermodynamics and supramolecular structure of luteolin on wool fabric

Natural dyestuff of luteolin was used to dye wool fabric in this paper, and the interaction between dyestuff and fiber was preliminarily discussed through thermodynamic study and supramolecular structure simulation to explain the inherent reasons why the color fastness was low when natural dyestuff was applied to dyeing wool fabric. The results of dyeing thermodynamics showed that the adsorption model of luteolin on wool fabric was accordance with Nernst model and it was similar to the disperse dyestuff. With molecular simulation, luteolin and glycin composed 8 stable complexes whose Laplacian values all were greater than 0, which suggested typical hydrogen bonds existing. The interaction energy of 8 complexes ranged from -61.85 to -11.71 kJ/mol and the complex with three hydrogen bonds was proved the most stable. Both studies on thermodynamics and supramolecular simulation indicated that the interaction of luteolin on wool fabric depended mainly on the weak hydrogen bonds, which decided the low color fastness between them.