Dynamic Performance of Duolayers at the Air/Water Interface. 2. Mechanistic Insights from All-Atom Simulations

Christofferson, Andrew J.; Yiapanis, George; Leung, Andy; Prime, Emma L.; Tran, Diana; Qiao, Greg G.; Yarovsky, Irene

doi:10.1021/jp506098d

“…53,151 However, when used outside the commercial software they were parameterized for, Class II force fields should be used with caution, and may be better for comparison purposes between systems rather than for attempting to find absolute values. 16,35,152 In the past decade, many studies have examined the feasibility of using some of the more recently developed water models with existing force fields. 153,154 When done properly this can represent a significant advancement in the modeling of solvated systems, but it must be done with care.…”

Section: Discussionmentioning

confidence: 99%

A systematic comparison of the structural and dynamic properties of commonly used water models for molecular dynamics simulations

Pathirannahalage

¹

,

Meftahi

²

,

Elbourne

³

et al. 2021

Preprint

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Water is a unique solvent that is ubiquitous in biology and present in a variety of solutions, mixtures, and materials settings. It therefore forms the basis for all molecular dynamics simulations of biological phenomena, as well as for many chemical, industrial, and materials investigations. Over the years, many water models have been developed, and it remains a challenge to find a single water model that accurately reproduces all experimental properties of water simultaneously. Here, we report a comprehensive comparison of structural and dynamic properties of 30 commonly used 3-point, 4-point, 5-point, and polarizable water models simulated using consistent settings and analysis methods. For the properties of density, coordination number, surface tension, dielectric constant, self-diffusion coefficient, and solvation free energy of methane, models published within the past two decades consistently show better agreement with experimental values compared to models published earlier, albeit with some notable exceptions. However, no single model reproduced all experimental values exactly, highlighting the need to carefully choose a water model for a particular study, depending on the phenomena of interest. Finally, machine learning algorithms quantified the relationship between the water model force field parameters and the resulting bulk properties, providing insight into the parameter-property relationship and illustrating the challenges of developing a water model that can accurately reproduce all properties of water simultaneously.

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“…The previously reported nonionic duolayer system comprising C18E1 and poly(vinylpyrrolidone) (PVP) was shown to lose the increased viscosity effect after 3 h, indicating that the polymer was gradually diffusing away from the interface . In this previous system the interactions between polymer and monolayer were proposed to be through hydrogen bonding, a weak bonding force . Also, the presence of water provided competition for hydrogen bonding leading to the polymer gradually diffusing from the interface.…”

Section: Resultsmentioning

confidence: 88%

“…However, the previously reported system of ethylene glycol monooctadecyl ether (C18E1) and poly(vinylpyrrolidone) (PVP) was shown to be dynamic, with the polymer diffusing away from the interface over time and therefore having only a short-lived impact on surface film characteristics . This short lifetime has been ascribed to relatively weak hydrogen bonding being the main mechanism anchoring the water-soluble polymer to the monolayer . The use of a stronger interaction between the two components could therefore increase the lifetime of the resultant duolayer system.…”

Section: Introductionmentioning

confidence: 99%

“…23 This short lifetime has been ascribed to relatively weak hydrogen bonding being the main mechanism anchoring the water-soluble polymer to the monolayer. 24 The use of a stronger interaction between the two components could therefore increase the lifetime of the resultant duolayer system. Combination of the duolayer system with the use of ionic interactions to glue the surface film is proposed to overcome the limitations with both methods.…”

Section: ■ Introductionmentioning

confidence: 99%

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Duolayers at the Air/Water Interface: Improved Lifetime through Ionic Interactions

Prime

¹

,

Dagley

²

,

Qiao

³

2016

J. Phys. Chem. B

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Ionic interactions to stabilize Langmuir films at the air/water interface have been used to develop improved duolayer films. Two-component mixtures of octadecanoic (stearic) acid and poly(diallyldimethylammonium chloride) (polyDADMAC) with different ratios were prepared and applied to the water surface. Surface pressure isotherm cycles demonstrated a significant improvement in film stability with the inclusion of the polymer. Viscoelastic properties were measured using canal viscometry and oscillating barriers, with both methods showing that the optimum ratio for improved properties was four octadecanoic acid molecules to one DADMAC unit (1:0.25). At this ratio it is expected multiple strong ionic interactions are formed along each polymer chain. Brewster angle microscopy showed decreased domain size with increased ratios of polyDADMAC, indicating that the polymer is interspersed across the surface. This new method to stabilize and increase the viscoelastic properties of charged monolayer films, using a premixed composition, will have application in areas such as water evaporation mitigation, optical devices, and foaming.

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“…53,151 However, when used outside the commercial software they were parameterized for, Class II force fields should be used with caution, and may be better for comparison purposes between systems rather than for attempting to find absolute values. 16,35,152 In the past decade, many studies have examined the feasibility of using some of the more recently developed water models with existing force fields. 153,154 When done properly this can represent a significant advancement in the modeling of solvated systems, but it must be done with care.…”

Section: Discussionmentioning

confidence: 99%

A systematic comparison of the structural and dynamic properties of commonly used water models for molecular dynamics simulations

Pathirannahalage

¹

,

Meftahi

²

,

Elbourne

³

et al. 2021

Preprint

Self Cite

4

0

View full text Add to dashboard Cite

Water is a unique solvent that is ubiquitous in biology and present in a variety of solutions, mixtures, and materials settings. It therefore forms the basis for all molecular dynamics simulations of biological phenomena, as well as for many chemical, industrial, and materials investigations. Over the years, many water models have been developed, and it remains a challenge to find a single water model that accurately reproduces all experimental properties of water simultaneously. Here, we report a comprehensive comparison of structural and dynamic properties of 30 commonly used 3-point, 4-point, 5-point, and polarizable water models simulated using consistent settings and analysis methods. For the properties of density, coordination number, surface tension, dielectric constant, self-diffusion coefficient, and solvation free energy of methane, models published within the past two decades consistently show better agreement with experimental values compared to models published earlier, albeit with some notable exceptions. However, no single model reproduced all experimental values exactly, highlighting the need to carefully choose a water model for a particular study, depending on the phenomena of interest. Finally, machine learning algorithms quantified the relationship between the water model force field parameters and the resulting bulk properties, providing insight into the parameter-property relationship and illustrating the challenges of developing a water model that can accurately reproduce all properties of water simultaneously. referred to as TIPS3P hereafter in this work) which is used with the Chemistry at HARvard Macromolecular Mechanics (CHARMM) force field. 46 In the same 1983 paper as the original TIP3P model, Jorgensen et al. also described a 4-point model, TIP4P, where the negative charge of the oxygen was offset from the Lennard-Jones potential, resulting in improved structural properties. 41 The TIP4P water model is also commonly used with the OPLS force field. For the Consistent-Valence Force Field (CVFF), the CVFF water model has a geometry similar to TIP3P and non-bond parameters similar to SPC. It was developed concurrently with the rest of the force field, and is notable for having a flexible geometry, the use of a Morse potential for the O-H bond, and cross-terms to reproduce vibrational frequencies. 47 These models remain a popular choice due to their simple geometry, low computational cost, and relative accuracy. With the exception of CVFF, these models have a rigid geometry, which enables the use of a larger (e.g. 2 fs) timestep in MD simulations. While these models reproduced some experimental properties of water reasonably well, limited computational resources available at the time necessitated small system sizes of 125 to 216 water molecules, short simulation times of less than 20 ps, and short cut-offs of non-bond interactions typically between 7.5 and 8.5 Å. Moreover, many structural properties, such as densities and dielectric constants, were calculated using Monte Carlo, rather tha...

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Dynamic Performance of Duolayers at the Air/Water Interface. 2. Mechanistic Insights from All-Atom Simulations

Cited by 6 publications

References 45 publications

A systematic comparison of the structural and dynamic properties of commonly used water models for molecular dynamics simulations

A systematic comparison of the structural and dynamic properties of commonly used water models for molecular dynamics simulations

Duolayers at the Air/Water Interface: Improved Lifetime through Ionic Interactions

A systematic comparison of the structural and dynamic properties of commonly used water models for molecular dynamics simulations

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