Molecular modeling study of the structure and stability of polymer/carbon nanotube interfaces

A molecular modeling strategy is proposed to characterize the morphological and energetic properties polymer chains and carbon nanotubes interfaces and is applied to polyethylene/carbon nanotubes (PE/CNT) interfaces. The influence on the polymer chain adsorption and stability of a number of parameters (polymer molecular weight, nanotube structure and diameter, nanotube functionalization) is examined. The polymer chains are found to form regular lamellar-type structures on the CNT surface, which may act as template for the organization of the polymer around the nanotubes. Also, the nanotube diameter and the presence of hydroxyl groups clearly affect the PE chain adsorption: the interface stability decreases with the curvature of the carbon surface, while the chemical groups present on the tube wall sterically hinder the formation of the lamellar structures. Finally, the behavior of a cluster of PE chains (representing a polymer melt) interacting with the nanotube is compared to that of a single chain.