Random copolymers at a selective interface: many chains with excluded volume interactions

TL;DR

This study uses numerical simulations to explore how multiple random copolymers with excluded volume interactions behave at a solvent interface, revealing two distinct regimes of polymer extension and density distribution.

Contribution

It identifies and characterizes two regimes of copolymer adsorption at interfaces, depending on the total number of polymers, using the bond-fluctuation model.

Findings

In the dilute regime, copolymers extend parallel to the interface.

In the concentrated regime, copolymers extend perpendicular to the interface.

Density at the interface increases more rapidly than in the bulk in the dilute regime.

Abstract

We investigate numerically, using the bond-fluctuation model, the adsorption of many random AB--copolymers with excluded volume interactions at the interface between two solvents. We find two regimes, controlled by the total number of polymers. In the first (dilute) regime, the copolymers near the interface extend parallel to it, while in the second regime they extend perpendicular to it. The density at the interface and the density in the bulk depend differently on the total number of copolymers: In the first regime the density at the interface increases more rapidly then in the bulk, whereas the opposite is true in the second regime.