Interactions between polymers and single-walled boron nitride nanotubes: a molecular dynamics simulation approach.

Department of Physical Chemistry, School of Chemistry, College of Science, University of Tehran, Tehran, Iran.
The Journal of Physical Chemistry B (Impact Factor: 3.61). 11/2010; 114(47):15429-36. DOI: 10.1021/jp106330c
Source: PubMed

ABSTRACT In this work, we used a molecular dynamics (MD) simulation approach to investigate the interfacial binding of boron nitride nanotubes (BNNTs) with poly[m-phenylenevinylene-co-(2,5-dioctyloxy-p-phenylenevinylene)] (PmPV), polystyrene (PS), and polythiophene (PT). Quantum partial charges of BNNT-polymer composites were determined by density functional theory (DFT) calculations and then included in MD simulations. The interaction energy between nanotubes and polymer molecules was computed, and the morphology of polymers stacked onto the surface of the nanotubes was investigated based on the dihedral angle (θ). Our results confirm that the interaction energy is strongly influenced by the specific monomer structure of polymer and nanotube radius, but the influence of temperature is likely negligible. Among the investigated polymers, PT possesses the strongest adhesion to the BNNTs, followed by PmPV and PS. Moreover, the comparison of our results for BNNT-polymer composities with those of the similar carbon nanotube (CNT)-polymer composites reveals that the BNNT-polymer interactions are much stronger, which is the most important result of this work. This finding is also in good agreement with recent experimental observations. The higher values of interaction energy of BNNT-polymer composites suggest that the BNNTs could be more efficient nanofillers than the CNTs for nanocomposite reinforcement applications.

1 Bookmark
  • [Show abstract] [Hide abstract]
    ABSTRACT: 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.
    The Journal of Physical Chemistry B 04/2010; 114(16):5320-6. · 3.61 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We have measured the temperature-dependent thermal conductivity kappa(T) of individual multiwall boron nitride nanotubes using a microfabricated test fixture that allows direct transmission electron microscopy characterization of the tube being measured. kappa(T) is exceptionally sensitive to isotopic substitution, with a 50% enhancement in kappa(T) resulting for boron nitride nanotubes with 99.5% 11B. For isotopically pure boron nitride nanotubes, kappa rivals that of carbon nanotubes of similar diameter.
    Physical Review Letters 09/2006; 97(8):085901. · 7.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this work, using quantum partial charges, computed from 6-31G(**)B3LYP density functional theory, in molecular dynamics simulations, we found that water inside (6,6) and (10,0) single-walled carbon nanotubes with similar diameters but with different chiralities has remarkably different structural and dynamical properties. Density functional calculations indicate that tubes with different chiralities have significantly different partial charges at the ends of tubes. The partial charges at the ends of a (10,0) tube are around 4.5 times higher than those of a (6,6) tube. Molecular dynamics simulations with the partial charges show different water dipole orientations. In the (10,0) tube, dipole vectors of water molecules at the end of the tube point towards the water reservoir resulting in the formation of an L defect in the center region. This is not observed in the (6,6) tube where dipole vectors of all the water molecules inside the tube point towards either the top or the bottom water reservoir. The water diffusion coefficient is found to increase in the presence of the partial charges. Water in the partially charged (10,0) tube has a lower diffusion coefficient compared to that of in the partially charged (6,6) tube.
    The Journal of Chemical Physics 10/2006; 125(11):114701. · 3.12 Impact Factor


Available from