Molecular Dynamics of Carbon Nanotube Bundles as Molecular Sieves

In this work we investigate a system composed by a bundle of carbon nanotube (BuCNT) confronted with fatty acid surrounded. The system consists of a rigid open nanotube and the oleic acid (OA) working as probe relaxing due the interaction with BuCNT. The OA has in his form an asymmetric shape with COOH termination provoking a close BuCNT interaction mainly by van der Waals (vdW) force field. The simulations were performed by classical molecular dynamics coupled with quantum mechanics Hartree-Fock simulations with standard parameterizations. Our results show that these BuCNT are dynamically stable and it shows a preferential interaction position with OA resulting in two features: (i) when the OA terminated with CH₂ is closer to open extremity of BuCNT, the OA is repelled; and (ii) when the OA terminated with COOH is closer to open extremity of BuCNT, the OA is encapsulated by them. These simulations can be utilized as a tool for the constructions of efficient molecular sieves.