Wednesday, March 20, 2013

1303.4000 (John J. Williamson et al.)

On using the Carnahan-Starling free energy to model fluids with
short-range attraction
   [PDF]

John J. Williamson, R. Mike L. Evans, Wilson C. K. Poon, Siobhan M. Liddle
Within the Mean-Field Asakura-Oosawa-Vrij (MFAO) 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 due in significant part to the use of the Carnahan-Starling (CS) hard sphere free energy. Replacement of the CS expression with an alternative dramatically affects predicted phase behaviour and, for polydisperse colloid, the resultant fractionation predictions. We refer to other models exhibiting similar inaccuracies at short attraction range, and suggest that the CS free energy's status as the default choice for the hard sphere contribution in such theories must be carefully considered, since it is arguably ill-founded in the case of short-ranged attractions.
View original: http://arxiv.org/abs/1303.4000

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