Computational Studies of Poly(vinylidene fluoride)—Single Wall Carbon Nanotube Systems

Abstract

First principles and molecular mechanics methods have been used to study poly(vinylidene fluoride)-single wall carbon nanotube systems. First principles calculations (Møller-Plesset second order perturbation theory and density functional theory with B3LYP exchange correlation functional with and without dispersion correction) using short poly(vinylidene fluoride) segments and short hydrogen-capped single wall carbon nanotubes show that the polymer segments prefer to have the -rather than the -conformation both in the absence and presence of the single wall carbon nanotube. The lowest energy structure is obtained when the poly(vinylidene fluoride) has an -conformation and is located parallel to the single wall carbon nanotube wall. In contrast to the Dreiding and Universal force fields, the COMPASS force field predicts the structures containing the -conformation of poly(vinylidene fluoride) to be the lowest in energy in agreement with first principles results. The COMPASS force field was consequently used in preliminary studies of a longer poly(vinylidene fluoride) chain and a longer single wall carbon nanotube using molecular dynamics.

A molecular-level computational study of the diffusion and solubility of water and oxygen in carbonaceous polyethylene nanocomposites

“…The dispersion corrections can be of importance for systems like the ones studied here, and thus, the correction proposed by Grimme et al has been used. This method has been found to account for dispersion effects for a large variety of systems and has previously been used for systems similar to the PE–SWCNT systems studied here . All DFT‐D geometry optimizations were performed using the General Atomic and Molecular Electronic Structure System (GAMESS‐US) by using the quadratic approximation method with a gradient convergence tolerance of 4.98 × 10 −2 kJ mol −1 Å −1 and a RMS gradient tolerance of 1.65 × 10 −2 kJ mol −1 Å −1 .…”