Diameter-Selective Dispersion of Carbon Nanotubes via Polymers: A Competition between Adsorption and Bundling

TL;DR

This paper uses molecular dynamics simulations to explain how the selective dispersion of carbon nanotubes by polymers depends on a competition between bundling and adsorption, matching experimental observations.

Contribution

It introduces a theoretical framework that elucidates diameter selectivity based on binding energy minima from competition between bundling and polymer adsorption.

Findings

Diameter selectivity arises from local minima in binding energy differences.

The model's predictions align quantitatively with experimental preferred diameters.

Coverage changes abruptly at certain diameters, influencing selectivity.

Abstract

The mechanism of the selective dispersion of single-walled carbon nanotubes (CNTs) by polyfluorene polymers is studied in this paper. Using extensive molecular dynamics simulations, it is demonstrated that diameter selectivity is the result of a competition between bundling of CNTs and adsorption of polymers on CNT surfaces. The preference for certain diameters corresponds to local minima of the binding energy difference between these two processes. Such minima in the diameter dependence occur due to abrupt changes in the CNT's coverage with polymers and their calculated positions are in quantitative agreement with preferred diameters, reported experimentally. The presented approach defines a theoretical framework for the further understanding and improvement of dispersion/extraction processes.