A precision semimicro-titration calorimeter was designed and established on the basis of LKB-8700 precision calorimetry system for studying the weak interactions between amphiphilic molecules. On-line collection of the data could be done automatically by a microcomputer. The reaction heat of trihydroxymethyl-aminomethane(Tris), as a calorimetric standard substance, and hydrochloric acid was determined with an accuracy of ±0.2%. The results agree well with the literature values. The measured micellization enthalpies and critical micelle concentrations (cmcs) of sodium dodecyl sulfate (SDS), dodecyltrimethyl-ammonium bromide (DTAB) and Triton X-100 are also consistent with literature values.

Key words: MICELLE, ENTHALPY OF FORMATION, SURFACTANTS, HYDROCHLORIC ACID, LAURYL SODIUM SULFATE