The critical micelle concentration (CMC) and thermodynamic function ( , and ) of dioctyl sulfosuccinate sodium salt (AOT) in the N,N-dimethylformamide (DMF)/long-chain alcohol (n-pentanol, n-hexanol, n-heptanol, n-octanol) systems were studied using microcalorimetric method. And the relationships between alcohols concentrations, carbon number, temperature and CMC, thermodynamic properties were discussed. It can be concluded as follows: under the condition of the identical alcohols carbon number and identical concentration of alcohols, the values of CMC, and increase, while the values of decrease with the increment of the temperature. And under the identical condition of temperature and alcohol s carbon number, all the values of CMC, , and decrease with the increment of the alcohols concentrations. And when the temperature and alcohols concentrations are the same, respectively, all the values of CMC, , and decrease with the increment of the alcohols carbon number.

Key words: dioctyl sulfosuccinate sodium salt, N,N-dimethylformamide, long-chain alcohol, microcalorimetric method, critical micelle concentration, thermodynamic function