Determine whether the contact-rarification mechanism is effectively equivalent to other LCST mechanisms

Determine whether the contact-rarification mechanism producing LCST and closed-loop phase behavior in fully symmetric, non-associating coarse-grained multicomponent liquids has an effective equivalence to previously described mechanisms based on association or asymmetry between species.

Background

The paper identifies a mechanism in which low monomer density produces strong temperature-dependent monomer–monomer positional correlations, causing a nonmonotonic effective Flory–Huggins parameter and consequently LCST or closed-loop phase behavior. This mechanism differs from earlier explanations based on specific association, temperature-dependent interactions, or asymmetry in equation-of-state properties.

The authors state that the possible existence of an effective equivalence between their mechanism and those earlier mechanisms has not been resolved and should be investigated. The issue is relevant to determining whether apparently different microscopic explanations can produce the same effective thermodynamic behavior.