Localization of a multiblock copolymer at a selective interface: Scaling predictions and Monte Carlo verification

TL;DR

This study combines scaling theory and Monte Carlo simulations to analyze how block length influences the localization behavior of copolymers at selective interfaces, providing validated predictions for chain conformation and dynamics.

Contribution

It introduces a scaling framework for copolymer localization at interfaces and verifies it through Monte Carlo simulations across various chain lengths.

Findings

Good agreement between scaling predictions and simulation results for chain conformations.

Derived scaling relations for gyration radii and diffusion coefficients.

Identified differences in behavior between weak and strong localization regimes.

Abstract

We investigate the localization of a hydrophobic - polar (HP) - regular copolymer at a selective solvent-solvent interface with emphasis on the impact of block length $M$ on the copolymer behavior. The considerations are based on simple scaling arguments and use the mapping of the problem onto a homopolymer adsorption problem. The resulting scaling relations treat the gyration radius of the copolymer chain perpendicular and parallel to the interface in terms of chain length N and block size M, as well as the selectivity parameter \chi . The scaling relations differ for the case of weak and strong localization. In the strong localization limit a scaling relation for the lateral diffusion coefficient D is also derived. We implement a dynamic off-lattice Monte - Carlo model to verify these scaling predictions. For chain lengths in a wide range (32 < N < 512) we find good agreement with the scaling predictions.