Chemical potentials of chain solutes in hard body fluids

Monte Carlo simulations and analytical statistical mechanical expressions a re used to predict the free energy required to dissolve hard chains contain ing up to ten beads in diatomic fluids, over a wide range of solute-solvent sphere diameter ratios and solvent densities. The results are compared wit h analytical expressions derived from the Bonded Hard Sphere (BHS) and Scal ed Particle Theory (SPT) mixed hard body fluid equations of state. Although both theoretical expressions agree very well with simulation results at lo wer densities, BHS predictions are found to better agree with simulation re sults at high densities (particularly for small solute particles). Both the simulation and theoretical results imply a strictly linear dependence of s olute cavity formation free energy on chain length, in a solvent of a given molecular size and density. The results are used to quantify the influence of both solute and solvent shape on solute cavity formation free energy. ( C) 2001 Elsevier Science B.V. All rights reserved.