Does a surface attached globule phase exist ?

TL;DR

This paper investigates whether a surface attached globule phase exists for a long flexible polymer near an attractive surface, analyzing phase diagrams and monomer distributions in 2D and 3D.

Contribution

It provides evidence for the existence of a surface attached globule phase and characterizes its properties and phase transition behavior.

Findings

The SAG phase has the same free energy per monomer as the globular phase.

The transition between SAG and globular phases is a surface transition.

Phase diagrams in 2D and 3D are mapped and analyzed.

Abstract

A long flexible neutral polymer chain immersed in a poor solvent and interacting with an impenetrable attractive surface exhibits a phase known as surface attached globule ({\bf SAG}) in addition to other adsorbed and desorbed phases. In the thermodynamic limit, the {\bf SAG} phase has the same free energy per monomer as the globular phase, and the transition between them is a surface transition. We have investigated the phase diagrams of such a chain in both two- and three- dimensions and calculated the distribution of monomers in different domains of the phase diagram.