Electrostatic contribution from solvent in modulating single-walled carbon nanotube association

Shu Ching Ou, Sandeep Patel

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We perform all-atom molecular dynamics simulations to compute the potential of mean force (PMF) between two (10,10) single-walled carbon nanotubes solvated in pure nonpolarizable SPC/E and polarizable TIP4P-FQ water, at various temperatures. In general, the reversible work required to bring two nanotubes from a dissociated state (free energy reference) to contact state (free energy minimum) is more favorable and less temperature-dependent in TIP4P-FQ than in SPC/E water models. In contrast, molecular properties and behavior of water such as the spatially-resolved water number density (intertube, intratube, or outer regions), for TIP4P-FQ are more sensitive to temperature than SPC/E. Decomposition of the solvent-induced PMF into different spatial regions suggests that TIP4P-FQ has stronger temperature dependence; the opposing destabilizing/stabilizing contributions from intertube water and more distal water balance each other and suppress the temperature dependence of total association free energy. Further investigation of hydrogen bonding network in intertube water reveals that TIP4P-FQ retains fewer hydrogen bonds than SPC/E, which correlates with the lower water number density in this region. This reduction of hydrogen bonds affects the intertube water dipoles. As the intertube volume decreases, TIP4P-FQ dipole moment approaches the gas phase value; the distribution of dipole magnitude also becomes narrower due to less average polarization/perturbation from other water molecules. Our results imply that the reduction of water under confinement may seem trivial, but underlying effects to structure and free energetics are non-negligible.

Original languageEnglish (US)
Pages (from-to)114906
Number of pages1
JournalThe Journal of Chemical Physics
Volume141
Issue number11
DOIs
StatePublished - Sep 21 2014
Externally publishedYes

Fingerprint

Single-walled carbon nanotubes (SWCN)
Electrostatics
carbon nanotubes
Association reactions
electrostatics
Water
water
Free energy
Hydrogen bonds
free energy
Temperature
water balance
hydrogen bonds
dipoles
temperature dependence
molecular properties
Dipole moment
temperature
Nanotubes
nanotubes

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Electrostatic contribution from solvent in modulating single-walled carbon nanotube association. / Ou, Shu Ching; Patel, Sandeep.

In: The Journal of Chemical Physics, Vol. 141, No. 11, 21.09.2014, p. 114906.

Research output: Contribution to journalArticle

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