Electrostatic contribution from solvent in modulating single-walled carbon nanotube association
1Department of Chemistry and Biochemistry, University of Delaware, Newark, Delaware 19716, USA.
The Journal of Chemical Physics
|September 22, 2014
Summary
Comparing water models for carbon nanotube interactions, simulations show polarizable TIP4P-FQ water offers more favorable and stable nanotube association than SPC/E, despite greater temperature sensitivity in TIP4P-FQ
Area of Science:
- Computational chemistry
- Materials science
- Physical chemistry
Background:
- Understanding interactions between carbon nanotubes (CNTs) and water is crucial for nanotechnology applications.
- The choice of water model significantly impacts simulation accuracy for confined systems.
Purpose of the Study:
- To compute the potential of mean force (PMF) between two single-walled carbon nanotubes (SWCNTs) using different water models.
- To investigate the influence of temperature and water model (SPC/E vs. TIP4P-FQ) on SWCNT interactions and water behavior under confinement.
Main Methods:
- All-atom molecular dynamics simulations were performed.
- Potential of Mean Force (PMF) calculations were conducted for SWCNT pairs.
- Simulations utilized nonpolarizable SPC/E and polarizable TIP4P-FQ water models at various temperatures.
Main Results:
- The association free energy between SWCNTs was more favorable and less temperature-dependent with the TIP4P-FQ model compared to SPC/E.
- Water properties, including number density and hydrogen bonding, showed greater temperature sensitivity in TIP4P-FQ, especially in confined intertube regions.
- Reduced hydrogen bonding in TIP4P-FQ correlated with lower intertube water density and altered dipole moment distributions under confinement.
Conclusions:
- Polarizable water models like TIP4P-FQ provide a more accurate representation of SWCNT interactions and water behavior under confinement.
- The temperature dependence of SWCNT association is modulated by the balance of contributions from water in different spatial regions.
- Even seemingly minor effects of water confinement on structure and energetics are significant and warrant careful consideration.
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