Flory-Huggins interaction parameter small molecule solutions

The usefulness of inverse gas chromatography for determining polymer-small molecule interactions is well established (1,2). This method provides a fast and convenient way of obtaining thermodynamic data for concentrated polymer systems. However, this technique can also be used to measure polymer-polymer interaction parameters via a ternary solution approach Q). Measurements of specific retention volumes of two binary (volatile probe-polymer) and one ternary (volatile probe-polymer blend) system are sufficient to calculate xp3 > the Flory-Huggins interaction parameter, which is a measure of the thermodynamic... 

The thermodynamic data of polymer solutions were first derived from the approach of regular solutions of small molecules by Flory [29] and by Huggins [30]. In the original quasi-lattice model of Flory, the interaction parameter, x, was representative of the enthalpic difference of polymer/polymer, sol-vent/solvent and polymer/solvent contacts. Progressively % lost this simple signification and represented the shift with an ideal behavior (including entropic effects) but nevertheless the model was established for... 

Phase Diagrams. The phase diagrams reported so far in Figures 2, 3, and 5 refer to UCS behavior. These types of phase equilibria are those predicted on the basis of the Flory-Huggins theory and are observed experimentally for solutions of small molecules as well as polymer solutions. This situation implies that mixing is favored by heating and that it is accompanied by a decrease of the interaction parameter, while cooling may lead to a two-phase system. 

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