Polymer adsorption on heterogeneous surfaces

TL;DR

This paper investigates how ideal polymers adsorb onto heterogeneous and rough surfaces, revealing that energetic heterogeneity significantly enhances adsorption and affects polymer localization.

Contribution

It introduces a variational approach to analyze polymer adsorption on complex surfaces, highlighting the impact of energetic heterogeneity over surface roughness.

Findings

Disorder enhances polymer adsorption more than surface roughness.

Polymer size becomes independent of chain length at localization transition.

Localization criterion depends on effective interaction strength and chain length.

Abstract

The adsorption of a single ideal polymer chain on energetically heterogeneous and rough surfaces is investigated using a variational procedure introduced by Garel and Orland (Phys. Rev. B 55 (1997), 226). The mean polymer size is calculated perpendicular and parallel to the surface and is compared to the Gaussian conformation and to the results for polymers at flat and energetically homogeneous surfaces. The disorder-induced enhancement of adsorption is confirmed and is shown to be much more significant for a heterogeneous interaction strength than for spatial roughness. This difference also applies to the localization transition, where the polymer size becomes independent of the chain length. The localization criterion can be quantified, depending on an effective interaction strength and the length of the polymer chain.