Behavior of block-polyampholytes near a charged surface

TL;DR

This study uses Monte Carlo simulations to explore how block-polyampholytes behave near charged surfaces, revealing how block length and surface charge influence adsorption and chain conformation.

Contribution

It provides detailed structural insights into polyampholyte adsorption near charged surfaces, highlighting the effects of block length and surface charge density.

Findings

Adsorption is favored for longer blocks and higher surface charges.

Charged interfaces can cause swelling or shrinking of the polymer chain.

Structural properties depend non-trivially on block length and Coulomb coupling.

Abstract

The behavior of polyampholytes near a charged planar surface is studied by means of Monte Carlo simulations. The investigated polyampholytes are overall electrically neutral and made up of oppositely charged units (called blocks) that are highly charged and of the the same length. The influence of block length and substrate's surface-charge-density on the adsorption behavior is addressed. A detailed structural study, including local monomer concentration, monomer mean height, transversal chain size, interface-bond orientation correlation, is provided. It is demonstrated that adsorption is favored for long enough blocks and/or high enough Coulomb interface-ion couplings. By explicitly measuring the chain size in the bulk, it is shown that the charged interface induces either a swelling or a shrinkage of the transversal dimension of the chain depending, in a non trivial manner, on the block length.