Unexpected length dependence of the solubility of chain molecules

Abstract

We report numerical simulations of the chemical potential of a freely jointed chain molecule in a solvent of monomers, using a novel scheme to compute the chemical potential of arbritrary chain molecules. For short chains, the excess chemical potential increases linearly with the number of segments. However, as the chain length is increased, the slope of the chemical potential versus the number of segments suddenly increases. This change of slope is due to the solvent and appears to signal a solvent-induced collapse of the flexible molecule.