CALORIMETRIC ANALYSIS OF LIQUID-LIQUID PHASE-SEPARATION

It is shown that differential scanning calorimetry may be used to dete rmine miscibility gaps in micromolecular as well as in macromolecular systems. The first deviation of the signal from the base line is indic ative of the onset of liquid-liquid phase separation and allows determ ination of the cloud-point curve. The area of the endo- or exothermic signal is related to the heat of demixing and may be analysed to suppl y information about the enthalpic part of the pair-interaction paramet er. The method is tested on the systems water/nicotine and n-butanol/p oly(methyl methacrylate).