Surface potentials of water, methanol and water + methanol mixtures

Barraclough, C. G.; McTigue, Peter T.; Ng, Yee-Fui

doi:10.1016/0022-0728(92)80205-i

Cited by 37 publications

(37 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In terms of the surface potential, our values for SPC and SPC/E of −0.5887 V and −0.6006 V, respectively, are more negative than the often quoted literature data of −0.53 V [74] and −0.546 V [37], respectively, reported in the 1990s. However, our result for SPC/E is in excellent agreement with the value of −0.6003 V published recently by Horváth et al [40].…”

Section: Atomistic Models: Comparison Between Datamentioning

confidence: 53%

“…Before commenting on this behaviour, we shall analyse the electrical profiles of the atomistic models. It should be noted that while these properties have been previously published for SPC [74], SPC/E [37,40], and TIP4P-Ew [75], no previous calculation has been reported for the TIP3P- −0.4080 (7) entire length of the systems can be found in the supplementary material). It can be seen from Figure 4 that the potential changes very rapidly going from the vapour to the liquid phase; over a distance of only ≈5 Å , φ drops by ≈0.4 − 0.6 V. In general, the spatial derivative of the potential gives (the negative of) the electric field; therefore, such a steep variation in φ is expected to correspond to very large field strengths.…”

Section: Surface Potential and Electric Fieldmentioning

confidence: 83%

“…While this result, and the previously noted electrical profiles which are constant and zero through the interface, are certainly unrealistic, it is not straightforward to make a clear assessment. In fact, both the magnitude and sign of the true surface potential are disputed; while, as we have seen, standard atomistic models yield values around ≈−0.5 V, the most recent experimental measurements range from + 0.025 to + 0.24 V [74,76], and density functional theory predicts + 3 to + 4 V [58,[77][78][79].…”

Section: Surface Potential and Electric Fieldmentioning

confidence: 99%

See 2 more Smart Citations

Comparative assessment of the ELBA coarse-grained model for water

Orsi

2013

Molecular Physics

View full text Add to dashboard Cite

The ELBA force field for water consists of a single spherical site embedded with a point dipole. This coarse-grained model is assessed here through the calculation of fundamental properties of bulk liquid water and the water-vapour interface. Accuracy and efficiency are evaluated and compared against simulations of standard three-and four-site atomistic models. For bulk liquid systems, ELBA reproduces accurately most of the investigated properties. However, the radial distribution function deviates from atomistic and experimental data, indicating a loss of local structure. The water-vapour interface, simulated over a range of temperatures from 300 to 600 K, is captured realistically in terms of its density distribution, and the accuracy in reproducing the experimental surface tension is as high as that of the best atomistic model. The critical temperature of ELBA is also found to be in excellent agreement with experiment. However, the interfacial electric field and surface potential are missing. The computational speed-up of ELBA compared to traditional atomistic models is estimated to be between one and two orders of magnitude.

show abstract

Section: Atomistic Models: Comparison Between Datamentioning

confidence: 53%

Section: Surface Potential and Electric Fieldmentioning

confidence: 83%

Section: Surface Potential and Electric Fieldmentioning

confidence: 99%

See 1 more Smart Citation

Comparative assessment of the ELBA coarse-grained model for water

Orsi

2013

Molecular Physics

View full text Add to dashboard Cite

show abstract

“…A similar model by Croxton in which a different quadrupole moment for water was used yielded Φ < 0 [36]. In molecular dynamics studies of a water/vapor interface by Matsumoto and Kataoka [37] and Barraclough et al [38], Φ was determined from the polarization density normal to the interface, yielding Φ < 0. Wilson et al showed that it Fig.…”

Section: Electrostatic Potential In Oil Phase Is Positivementioning

confidence: 99%

Electrophoretic mobility does not always reflect the charge on an oil droplet

Knecht

Risselada

Mark

et al. 2008

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

Electrophoresis is widely used to determine the electrostatic potential of colloidal particles. Oil droplets in pure water show negative or positive electrophoretic mobilities depending on the pH. This is commonly attributed to the adsorption of hydroxyl or hydronium ions, resulting in a negative or positive surface charge, respectively. This explanation, however, is not in agreement with the difference in isoelectric point and point of zero charge observed in experiment. Here we present molecular dynamics simulations of oil droplets in water in the presence of an external electric field but in the absence of any ions. The simulations reproduce the negative sign and the order of magnitude of the oil droplet mobilities at the point of zero charge in experiment. The electrostatic potential in the oil with respect to the water phase, induced by anisotropic dipole orientation in the interface, is positive. Our results suggest that electrophoretic mobility does not always reflect the net charge or electrostatic potential of a suspended liquid droplet and, thus, the interpretation of electrophoresis in terms of purely continuum effects may need to be reevaluated.

show abstract

“…However, we note that there is still disagreement between experiments and simulations in the sign and absolute magnitude of the electrostatic potential of water. 11,12,[71][72][73] The electrostatic potential computed in most AI-DFT studies provides information that is relevant for electron probes (see Refs. 73 and 74), hence this electrostatic potential is different from the ones computed in classical simulations of point charges (see Ref.…”

Section: Intrinsic Electrostatic Potentialmentioning

confidence: 99%

The structure of ionic aqueous solutions at interfaces: An intrinsic structure analysis

Bresme

Chacón

Tarazona

et al. 2012

The Journal of Chemical Physics

View full text Add to dashboard Cite

We investigate the interfacial structure of ionic solutions consisting of alkali halide ions in water at concentrations in the range 0.2-1.0 molal and at 300 K. Combining molecular dynamics simulations of point charge ion models and a recently introduced computational approach that removes the averaging effect of interfacial capillary waves, we compute the intrinsic structure of the aqueous interface. The interfacial structure is more complex than previously inferred from the analysis of mean profiles. We find a strong alternating double layer structure near the interface, which depends on the cation and anion size. Relatively small changes in the ion diameter disrupt the double layer structure, promoting the adsorption of anions or inducing the density enhancement of small cations with diameters used in simulation studies of lithium solutions. The density enhancement of the small cations is mediated by their strong water solvation shell, with one or more water molecules "anchoring" the ion to the outermost water layer. We find that the intrinsic interfacial electrostatic potential features very strong oscillations with a minimum at the liquid surface that is ∼4 times stronger than the electrostatic potential in the bulk. For the water model employed in this work, SPC/E, the electrostatic potential at the water surface is ∼−2 V, equivalent to ∼80 k B T (for T = 300 K), much stronger than previously considered. Furthermore, we show that the utilization of the intrinsic surface technique provides a route to extract ionic potentials of mean force that are not affected by the thermal fluctuations, which limits the accuracy of most past approaches including the popular umbrella sampling technique.

show abstract

Surface potentials of water, methanol and water + methanol mixtures

Cited by 37 publications

References 28 publications

Comparative assessment of the ELBA coarse-grained model for water

Comparative assessment of the ELBA coarse-grained model for water

Electrophoretic mobility does not always reflect the charge on an oil droplet

The structure of ionic aqueous solutions at interfaces: An intrinsic structure analysis

Contact Info

Product

Resources

About