Formation mechanism of solvent-induced dye supramolecular aggregates

Dye Rhodamine B(RB) was dispersed in the binary solvents of ethanol and tetrahydrofuran by solvent-induction method,and the aggregation form and micro-morphology of the dye under different conditions were investigated by varying the proportion of the two solvents.The arrangement of dye aggregate varied with the proportion of solvents was observed by means of visible absorption spectra.In the case of excessive ethanol,a J-like aggregate was observed,and in the case of excessive tetrahydrofuran,an H-like aggregate was formed.TEM observation showed that the dye molecules could form regular nano-beads or nano-spheres through self-assembly as volume ratio of binary solvents changed.The formation mechanism of supramolecular RB aggregates was discussed from the interaction of solvent with solute,and the influence of morphology of the formed dye aggregates on its fluorescent property was investigated using fluorescence spectrophotometer.