On the Existence of Prewetting in Supracritical Fluid Mixtures

TL;DR

This paper demonstrates the existence of a prewetting transition in a supracritical polymer solution model near an attractive surface, revealing new surface phenomena in complex fluids.

Contribution

It introduces a model showing prewetting transitions in supracritical conditions, extending understanding of surface behavior in polymer solutions.

Findings

Prewetting transition occurs below the lower critical solution temperature.

Surface films exhibit non-local thermodynamic behavior.

Phenomenon observed in a model mimicking aqueous polyethylene oxide solutions.

Abstract

In this communication we demonstrate the existence of a first-order prewetting transition of a supracritical model polymer solution adjacent to an attractive surface. The model fluid we use mimics (qualitatively) an aqueous polyethylene oxide solution and, like the actual solution, displays a closed loop 2-phase region with an upper and lower critical solution temperature. The model fluid is shown to undergo a prewetting transition at an adjacent attractive surface even at temperatures below the lower critical solution temperature (supracriticality). This phenomenon follows from non-local thermodynamics when the lengthscale of the relevant fluid structures of surface films are commensurate or smaller than the range of intermolecular interactions.