Equal G Analysis of Unusual Binary Phase Diagrams

Abstract

Abstract The equal G analysis recently introduced to the field of liquid crystals is used to fit some extraordinary phase diagrams. In binary systems of highly polar components non-linear phase transitions are observed, which give rise to reentrant behaviour. We show, that in spite of the complex phase behavior, it is possible to describe such systems in terms of the ideal mixture. To this end we take into account the heat capacity, as was already done by Oonk7 and van Hecke8 to explain binary phase diagrams. We generalize their approach and get an expression for the chemical potential up to the fifth order in the temperature. That means, the chemical potential difference of the pure component possesses up to five zeros, i.e. transition points between the two phases under discussion. Unfortunately, up to now there is a lack of experimental data to verify such a behaviour of the heat capacity.