Influence of Nanotube Chirality, Temperature, and Chemical Modification on the Interfacial Bonding between Carbon Nanotubes and Polyphenylacetylene

Molecular dynamics (MD) simulations were used to study the interaction energy between single-walled carbon nanotubes (SWNTs) and polyphenylacetylene (PPA). The "wrapping" of nanotubes by PPA chains was computed. The influence of nanotube chirality, temperature, and chemical modification on the interfacial adhesion of nanotube-PPA was investigated. The results showed that the interaction energy between the SWNTs and PPA is strongly influenced by chirality but the influence by temperature could be negligible. For SWNTs with similar molecular weights, diameters, and lengths, the armchair-type nanotube may be the best nanotube for reinforcement. Besides, our simulations indicated that some specific chemical modifications of SWNTs play a very important role in determining the strength of interaction between the SWNTs and PPA. The SWNTs modified by methyl or phenyl groups can be well-wrapped by PPA, while the SWNTs modified by other types of groups cannot. The results also indicated that the interaction energy between the SWNTs and PPA increases with the increase of the concentration of functionalized groups. People have demonstrated that the increase of the concentration of functionalized groups can weaken the mechanics of SWNT. Therefore, the attachment of methyl or phenyl groups with reasonable concentration to the outer SWNTs should significantly improve the load transfer between the SWNTs and polymer when the SWNTs are used to produce nanocomposites.