Statistical associating Fluid Dimer Theory

Abstract

Three modified versions of statistical associating fluid theory known as SAFT-D1, SAFT-D2 and SAFT-T for hard sphere chain molecules are used to test the approximation made in the derivation of the statistical associating fluid dimer theory (SAFT-D). The SAFT-D1 model accounts for the chain length independent site–site correlation function at contact, while SAFT-D2 and SAFT-T models account for chain length dependent site–site correlation function at contact. The residual chemical potentials are calculated for hard chain fluids containing chains of length m = 3, 4, 6, 8, 12, 16 and 32 mers and compared with the results obtained by configurational bias Monte Carlo (MC) method at various densities. We find that the approximation used in SAFT-D1 theory leads to an over prediction of residual chemical potential and its magnitude increases with increasing chain length.

Keywords:

• SAFT-D
• Chain length
• Monte Carlo