The phase diagrams of CTAB/n-butanol/water/styrene system were constructed with variable amounts of styrene, and the effect of the styrene contents on the microemulsion stability was also studied. The solubilization of styrene in the O/W microemulsion systems was investigated by ¹H NMR method. The results showed that the solubilization site was mainly in the palisade layer of the microemulsions and less of styrene was located in the inner core. Meanwhile, due to the steric hindrance effect styrene molecules can be hardly distributed near the N-CH₃ group of CTAB. By means of ¹³C NMR, it was found that the solubilization of styrene in the palisade layer was not uniform, the location of the highest styrene content was around the β-carbon of CTAB, and its content was gradually decreased from the outer to inner along the hydrocarbon chain of CTAB. The tendency of ¹³C NMR value of n butanol with molar fraction of styrene was like the type of “V”, and it was due to the addition of styrene that may change the partitioning of n-butanol between the microemulsion phases.

Key words: styrene, microemulsion, CTAB, solubilization, HR-NMR