Abstract: The micelle aggregation numbers of C12-3-C12·2Br and C12-3（OH）-C12·2Br were measured by the technique of fluorescence probe. It was found that the concentration of the Gemini surfactants had great influences on their micelle aggregation number, owing to the presence of hydroxyl group in spacer. When the concentrations were set as 5.5cmc, the aggregation number of C12-3(OH)-C12·2Br was 44.7 and was much greater than that of C12-3-C12·Br(33.2). The two surfactants followed the Newtonian flow with their shear rates γ in the range of 0~1.875 s-1 for the concentrations of C12-3-C12·2Br and C12-3(OH)-C12·2Br up to 64 mmol/L and 54 mmol/L, respectively. Beyond these, the shear rates are higher than their critical values(γ*) and then the flow transformed from Newtonian to nonNewtonian modes. In addition, the viscosity η increased with the increase of concentration accompanied with a sharp increase. It was found that the introduction of —OH into the spaces has barely effect on their flow behaviors but cause a slight increase of η.

Key words: micelle aggregation number, rheological characterization, Gemini surfactant, spacer effect