Chains in critical fluids and nanopores

TL;DR

This paper investigates how polymer conformations in critical binary solvents are affected by confinement in nanopores, revealing that pore size significantly influences polymer size through solvent fluctuation correlations.

Contribution

It introduces a model linking pore size, solvent criticality, and polymer conformation, highlighting the impact of confinement on polymer behavior in critical fluids.

Findings

Polymer size depends on proximity to the solvent's critical point.

Pore size controls the correlation length of solvent fluctuations.

Confinement alters polymer conformational properties compared to bulk behavior.

Abstract

The conformational behavior of a polymer in a critical binary solvent confined in a porous medium is studied. The size of the polymer in bulk, which is mainly governed by the correlation length of the solvent density fluctuations, depends on the proximity to the critical point of the binary mixture. We find that in contrast to the bulk behavior, the conformational properties of the polymer in a porous medium depends strongly on the pore size. The latter controls the correlation length of the solvent density fluctuations and thus determines the polymer size.