Using spinning drop method

the interfacial tensions between alkane and series of aryl alkyl sulfonate(CnNPAS

n=8

10

12

14

16)aqueous solutions were measured. The effects of the carbon number of alkane

the molecular weight of surfactant

the concentration of the surfactant and Na2CO3 on the interfacial tension were studied in detail. The results showed that the required time to reach the equilibrium interfacial tension increased with increasing molecular weight of the surfactant and content of Na2CO3. On the contrary

the higher carbon number of alkane and concentration of the surfactant

the less required time. The interfacial tension could be reduced obviously at a range of relative low surfactant concentrations

and then went through a minimum and eventually increased with increasing concentration.