DIFFERENTIAL SCANNING MICROCALORIMETRIC STUDY OF SODIUM DI-N-DODECYLPHOSPHATE VESICLES IN AQUEOUS-SOLUTION

The scans recorded by differential scanning calorimetry are reported for aqueous solutions containing vesicles formed by sodium di-n-dodecylphosphate (DDP). The gel-to-liquid-crystal transition occurs near 35-degrees-C, the melting temperature T(m). The dependences of heat capacity on temperature near T(m) are analysed to yield related enthalpies of transition and patch numbers which record the number of DDP monomers which melt co-operatively. The dependences of the enthalpy of transition and patch number offer indications of vesicle size and the tightness of packing of monomers within the vesicles.