Brushes of flexible, semiflexible and rodlike diblock polyampholytes: Molecular dynamics simulation and scaling analysis

TL;DR

This study uses molecular dynamics simulations and scaling analysis to investigate how the average thickness of planar diblock polyampholyte brushes depends on grafting density across different chain flexibilities.

Contribution

It provides a comprehensive comparison of flexible, semiflexible, and rodlike diblock polyampholyte brushes, revealing universal linear dependence of thickness on grafting density.

Findings

Average thickness depends linearly on grafting density for all types.

Slopes for semiflexible and rodlike brushes are similar, different from flexible ones.

Scaling analysis agrees well with simulation results.

Abstract

Planar brushes of flexible, semiflexible and rodlike diblock polyampholytes are studied using molecular dynamics simulations and scaling analysis in a wide range of the grafting density. Simulations show linear dependence of the average thickness on the grafting density for all the brushes regardless of their different equilibrium conformations and different flexibility of anchored chains. Slopes of fitted lines to the average thickness of the brushes of semiflexible and rodlike polyampholytes versus the grafting density are approximately the same and differ considerably from that of the brush of flexible chains. The average thickness of the brush of diblock polyampholytes is also obtained as a function of the grafting density using a simple scaling analysis which is in good agreement with the results of our simulations.