van der Waals interaction of parallel polymers and nanotubes

TL;DR

This paper develops a method to incorporate van der Waals interactions into density functional theory for parallel polymers and nanotubes, enabling more accurate modeling of their mutual interactions at various separations.

Contribution

It introduces a scheme to include van der Waals forces in DFT calculations specifically for polymers and nanotubes, based on first-principles electron density and response data.

Findings

Derived explicit expressions for van der Waals energy

Applied method to polyethylene, polypropylene, PVC

Applicable to all simple polymers and nanotubes

Abstract

We study the mutual interactions of simple, parallel polymers and nanotubes, and develop a scheme to include the van der Waals interactions in the framework of density functional theory (DFT) for these molecules at intermediate to long-range separations. We primarily focus on the polymers polyethylene, isotactic polypropylene, and isotactic polyvinylchloride, but our approach applies more generally to all simple polymers and nanotubes. From first-principle DFT calculations we extract the electron density of the polymers and their static electric response. We derive explicit expressions for the van der Waals interaction energy under simple symmetry assumptions.