Developing and Validating a Set of All-Atom Potential Models for Sodium Dodecyl Sulfate

Farafonov, Vladimir; Lebed, Alexander V.

doi:10.1021/acs.jctc.7b00181

Cited by 28 publications

(39 citation statements)

References 41 publications

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“…For the surfactants, the OPLS-AA models developed by us were taken [18,19], while for water, the SPC model was used.…”

Section: Simulation Methodologymentioning

confidence: 99%

An MD simulation study of Reichardt’s betaines in surfactant micelles: Unlike orientation and solvation of cationic, zwitterionic, and anionic dye species within the pseudophase

2018

Chemical Series

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Solvatochromic indicators of the pyridinium N-phenolate series, also known as Reichardt’s betaines, or Reichardt’s dyes, are often used for examining not only pure or mixed solvents, but also various colloidal aggregates, such as surfactant micelles, droplets of microemulsions etc. In order to disclose the locus of these molecular probes within the micellar pseudophase, we recently utilized the molecular dynamics (MD) simulations for the standard dye, i.e. 4-(2,4,6-triphenylpyridinium-1-yl)-2,6-diphenylphenolate, and three other dyes of this family of higher and lower hydrophobicity. Both zwitterionic (colored) and protonated (cationic, colorless) species were involved into the research, as these compounds are also used as acid-base indicators for micellar systems. In the present paper, we extended this investigation further. MD modeling was applied to another three dyes incorporated in sodium n-dodecyl sulfate and cetyltrimethylammonium bromide micelles. The following compounds were examined: (i) the most hydrophobic dye, bearing five tert-butyl groups, 4-[2,4,6-tri(4-tert-butylphenyl)pyridinium-1-yl]-2,6-di(4-tert-butylphenyl)phenolate, (ii) a dye with a hydrocarbon loop around the oxygen atom, 4-(2,4,6-triphenylpyridinium-1-yl)-n-(3,5-nonamethylene)phenolate, and (iii) the dye with additional carboxylate group attached to the phenyl group opposite to the phenol, 4-(4-carboxylatophenyl-2,6-diphenylpyridinium-1-yl)-2,6-diphenylphenol. The orientation and solvation of the cations, zwitterions (both colored and colorless), and the anion of the last-mentioned dye in micelles appeared to be dissimilar, depending on the molecular structure and ionization state. The results were compared with those obtained previously for the standard betaine dye. In some cases, the most probable orientation of the dyes in their colorless form was opposite to that of the standard Reichardt’s dye, i.e., their OH group is directed towards the center of the micelle.

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“…For the surfactants, the OPLS-AA models developed by us were taken [18,19], while for water, the SPC model was used.…”

Section: Simulation Methodologymentioning

confidence: 99%

An MD simulation study of Reichardt’s betaines in surfactant micelles: Unlike orientation and solvation of cationic, zwitterionic, and anionic dye species within the pseudophase

2018

Chemical Series

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“…Three initial configurations were prepared for each The simulations were performed using the well known OPLS-AA force field [44]. The models for SDS and CTAB were taken from our previous works [45,46], while the one for CDAPS was prepared as follows. In the CTAB potential model, one methyl group was replaced with the ethyl group, represented the standard OPLS-AA parameters.…”

Section: Simulation Protocolmentioning

confidence: 99%

In search of an optimal acid-base indicator for examining surfactant micelles: Spectrophotometric studies and molecular dynamics simulations

Mchedlov‐Petrossyan

Farafonov

Cheipesh

et al. 2019

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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We report on combined experimental and theoretical investigations of the water/micelle interface of cationic, anionic, zwitterionic, and non-ionic surfactants using a new hydrophobic acid-base indicator 2,6dinitro-4-n-dodecylphenol. The indices of the so-called apparent ionization constant, app a pK , of the indicator fixed in the micellar pseudophase are determined by the spectrophotometric method. The data allows estimating the Stern layer's electrostatic potential of the ionic micelles . Molecular Dynamics modeling was used to locate the dye molecule and, in particular, its ionizing group OH  Owithin the micelles of the studied surfactants. The comparison of the  values estimated using 2,6-dinitro-4-ndodecylphenol with both our computer simulation and literature experimental results reveals obstacles in monitoring electrical interfacial potentials. In particular, the  values of the surfactant micelles with alkylammonium groups determined via 2,6-dinitro-4-n-dodecylphenol are overestimated. The reason is specific interactions of the indicator anion with the surfactant head groups. For anionic surfactants, however, this indicator is quite suitable, which is confirmed by the location of HA and Aequilibrium forms in the pseudophase.

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“…The models for surfactants were taken from our previous works [8,9]. They were developed in the framework of the widely used and well-validated OPLS-AA force field [10].…”

Section: Potential Modelsmentioning

confidence: 99%

Solvatochromic Reichardt’s Dye in Micelles of Sodium Cetyl Sulfate: Md Modeling of Location Character and Hydration

Farafonov¹,

Lebed²,

Mchedlov‐Petrossyan³

2017

Chemical

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Properties of the standard solvatochromic Reichardt's dye in micelles of sodium cetyl sulfate at 50°C were investigated by means of molecular dynamics simulations. The characteristics of the localization and orientation of the dye molecule as well as its microenvironment were obtained. The calculated characteristics were compared with those in micelles of sodium dodecyl sulfate at 50°C and 25°C as well as with those in micelles of cetyltrimethylammonium bromide at 25°C. The localization, orientation and hydration of the dye in both anionic micelles at both temperatures were found similar and moderately different from those in the cationic micelles. The impact of the hydrocarbon tail length and headgroup nature on these characteristics is discussed.

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Developing and Validating a Set of All-Atom Potential Models for Sodium Dodecyl Sulfate

Cited by 28 publications

References 41 publications

An MD simulation study of Reichardt’s betaines in surfactant micelles: Unlike orientation and solvation of cationic, zwitterionic, and anionic dye species within the pseudophase

An MD simulation study of Reichardt’s betaines in surfactant micelles: Unlike orientation and solvation of cationic, zwitterionic, and anionic dye species within the pseudophase

In search of an optimal acid-base indicator for examining surfactant micelles: Spectrophotometric studies and molecular dynamics simulations

Solvatochromic Reichardt’s Dye in Micelles of Sodium Cetyl Sulfate: Md Modeling of Location Character and Hydration

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