Investigation of the interfacial binding between single-walled carbon nanotubes and heterocyclic conjugated polymers

Molecular dynamics (MD) simulations were performed to investigate the interfacial binding between the single-walled carbon nanotubes (SWCNTs) and conjugated polymers including polythiophene (PT), polypyrrole (PP), poly(2,6-pyridinylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene) (PPyPV), and poly(m-phenylenevinylene-co-2,5-dioctyloxy-p-phenylenevinylene) (PmPV). The intermolecular interaction energy between SWCNTs and polymer molecules was computed, and the morphology of polymers physisorbed to the surface of nanotubes was investigated by the radius of gyration (R(g)) and the alignment angle (theta). The influence of nanotube radius and temperature on the interfacial adhesion of nanotube-polymer and R(g) of polymers was explored more. Our simulation results showed that the strongest interaction between the SWCNTs and these conjugated polymers was observed, first for PT, then PPy and PmPV, and finally PPyPV. Furthermore, we compared our results to the work by Yang and his co-workers (J. Phys. Chem. B 2005, 109, 10009). Our results show that the intermolecular interaction in our systems is strongly influenced by the specific monomer structure of polymer and nanotube radius, but the influence of temperature could be negligible. The high values of intermolecular interaction energy of such composites suggest to us that an efficient load transfer will exist in the interface between nanotube and heterocyclic conjugated polymer, which is of a key role in the composite reinforcement practical applications.