Effects of the Carnahan-Starling free energy within theories of fluids with short-range attraction
| Autor: | Williamson, John J., Evans, R. Mike L., Poon, Wilson C. K., Liddle, Siobhan M. |
|---|---|
| Rok vydání: | 2013 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | Within the Free-Volume Asakura-Oosawa-Vrij (FVAO) theory of colloid-polymer mixtures, we show that unphysical gas-liquid binodals predicted in the regime of small attraction range (i.e. polymer size) are caused in part by the use of the Carnahan-Starling (CS) hard sphere (HS) reference free energy. Replacement of the CS expression with an alternative dramatically affects predicted phase behaviour and, for polydisperse colloid, the resultant fractionation predictions. Although short-range attractions render FVAO, as a perturbative HS-based theory, less accurate anyway, we argue that the particular effects of CS in this regime are an important consideration -- usually ignored -- in the evaluation of such theories. We refer to a variety of literature exhibiting similarly inaccurate gas-liquid binodals, and suggest CS's status as the de facto choice of hard sphere reference should be carefully considered where short-range attractions are present. Comment: This paper has been withdrawn following a collaborative investigation of other theories which showed that the conclusions drawn here are important, for practical purposes, only in a small regime of volume fractions |
| Databáze: | arXiv |
| Externí odkaz: |
|