M. C. Gordillo

Hydrogen bond structure of liquid water confined in nanotubes

Abstract The effects of confinement in nanotubes on the hydrogen bond structure of liquid water are studied by molecular dynamics simulation. Water has been described by means of a flexible version of the SPC potential of Berendsen et al. The carbon nanotube is modeled by a soft potential wall of the Lennard-Jones type. Our results indicate that the averaged number of hydrogen bonds decreases when we compare with bulk water and it is roughly independent of the tube radius excepting for very narrow tubes, which suffer a dramatic destruction of the H-bond network. The comparison with rigid cylinders indicates that this is a pure confinement effect.

Molecular dynamics description of a layer of water molecules on a hydrophobic surface

Static and dynamic properties of a layer of water molecules on top of a graphite surface are studied by means of molecular dynamics simulations. The water molecules are described by a simple point charge flexible model, and the graphite is taken to be a set of featureless parallel sheets separated 3.4 A in the z direction. Our results indicate that, even at the lower temperatures considered, the water layer is not flat, with some hydrogen atoms pointing perpendicularly to the surface plane. The O–H stretching frequencies are also different than those of bulk water, appearing a new peak in the simulated spectra at a frequency approximately 200 wave numbers higher than the main peak. This peak is associated with the presence of non-H-bonded molecules.

Molecular simulation of liquid water confined inside graphite channels: Thermodynamics and structural properties

We carried out molecular dynamics simulations to describe the properties of water inside a narrow graphite channel. Two stable phases were found: a low-density one made of water clusters adsorbed on the graphite sheets and a liquid one that fills the entire channel, forming several layers around a bulk-like region. We analyzed the interfacial structure, orientational order, water residence times in several regions, and hydrogen bonding of this last water phase, calculating also a quantity of electrochemical interest, the probability of electron tunneling through interfacial water. The results are in good qualitative agreement with the available experimental data.

Water on graphene surfaces.

In this paper, we summarize the main results obtained in our group about the behavior of water confined inside or close to different graphene surfaces by means of molecular dynamics simulations. These include the inside and outside of carbon nanotubes, and the confinement inside a slit pore or a single graphene sheet. We paid special attention to some thermodynamical (binding energies), structural (hydrogen-bond distributions) and dynamic (infrared spectra) properties, and their comparison to their bulk counterparts.

Quasi-one-dimensional 4 He inside carbon nanotubes

We report results of diffusion Monte Carlo calculations for both

Structure of water nanoconfined between hydrophobic surfaces

{}^{4}\mathrm{He}

Time-dependent properties of liquid water isotopes adsorbed in carbon nanotubes

absorbed in a narrow single walled carbon nanotube

Hydrogen bonding in supercritical water confined in carbon nanotubes

(R=3.42\AA{})

Structure and dynamics of liquid water adsorbed on the external walls of carbon nanotubes

and strictly one-dimensional

Zero-temperature equation of state of quasi-one-dimensional H2

{}^{4}\mathrm{He}.