A series of cationic surfactants of gemini nonylphenol polyoxyethylene quaternary ammonium chloride (GNPQA) were synthesized and structurally confirmed by 1H NNR, FT-IR and elemental analysis. The influences of reaction conditions on conversion ratio have been investigated, and the optimal conditions were obtained as follows: the reaction time was 12 h, the reaction temperature was 70 ℃, n(GNP)∶n(TEA)∶n(EPI)＝1∶1∶1 (molar ratio). Surface activity properties and micelle aggregation numbers (N) of the GNPQA were determined by a surface tension method and a steady-state fluorescence probe method. The experimental results showed that critical micelle concentration (CMC) of the GNPQA was 1～2 orders of magnitude smaller than that of cationic surfactant of nonylphenol polyoxyethylene quaternary ammonium chloride (NPQA), which has exhibited predominant surface activity of the GNPQA. The N value increased linearly with the increase of the GNPQA concentration in the range of 5～9 times of CMC; CMC and N of the GNPQA decreased with increasing the oxyethylene (EO) unit amount. The micropolarities of surface activities and micelle aggregates of the GNPQA were inferred by the change of surface properties and N values.

Key words: cationic surfactant of gemini nonylphenol polyoxyethylene quaternary ammonium chloride, critical micelle concentration, fluorescence probe, aggregation number of micelle