A model for phase transitions in a bidimensional monolayer of rectangular molecules with a polar head

Abstract

A model for aliphatic molecules monolayers phase transitions at air–water interfaces is proposed: the molecules are treated as rectangles lying on a square lattice, as in a previous paper. But in this work one extremity of the rectangle is discriminated as the polar head of a molecule by means of an interaction energy different from that between aliphatic chains— (Π−A) isotherms and coexistence curves are calculated in the framework of this model and we point out some improvements brought to the results obtained with our previous model, in particular, a third phase tranisition is given by a polar head orientation.