Coarse-Grain Molecular Dynamics Simulations To Investigate the Bulk Viscosity and Critical Micelle Concentration of the Ionic Surfactant Sodium Dodecyl Sulfate (SDS) in Aqueous Solution

Ruiz‐Morales, Yosadara; Romero‐Martínez, Ascención

doi:10.1021/acs.jpcb.7b10770

Cited by 58 publications

(35 citation statements)

References 54 publications

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“…Atomic-scale simulations of macromolecular systems are limited to take into account the difference in length and time scales for the macromolecules and the individual solvent molecules. − Coarse-grain simulation schemes are used here to span molecular simulations to longer time and length scales. We use the MARTINI force-field, which consistently maps to some atomistic details and has been used to simulate systems of large molecules like biomolecules, surfactants, and polymers. − In the remainder of the paper we discuss the experimental and simulation results followed by discussion and conclusions, with experimental and simulation details provided at the end of the paper.…”

Section: Introductionmentioning

confidence: 99%

Self-Assembly of Charge-Containing Copolymers at the Liquid–Liquid Interface

et al. 2019

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Quantitatively understanding the self-assembly of amphiphilic macromolecules at liquid–liquid interfaces is a fundamental scientific concern due to its relevance to a broad range of applications including bottom-up nanopatterning, protein encapsulation, oil recovery, drug delivery, and other technologies. Elucidating the mechanisms that drive assembly of amphiphilic macromolecules at liquid–liquid interfaces is challenging due to the combination of hydrophobic, hydrophilic, and Coulomb interactions, which require consideration of the dielectric mismatch, solvation effects, ionic correlations, and entropic factors. Here we investigate the self-assembly of a model block copolymer with various charge fractions at the chloroform–water interface. We analyze the adsorption and conformation of poly(styrene)- block -poly(2-vinylpyridine) (PS- b -P2VP) and of the homopolymer poly(2-vinylpyridine) (P2VP) with varying charge fraction, which is controlled via a quaternization reaction and distributed randomly along the backbone. Interfacial tension measurements show that the polymer adsorption increases only marginally at low charge fractions (<5%) but increases more significantly at higher charge fractions for the copolymer, while the corresponding randomly charged P2VP homopolymer analogues display much more sensitivity to the presence of charged groups. Molecular dynamics (MD) simulations of the experimental systems reveal that the diblock copolymer (PS- b -P2VP) interfacial activity could be mediated by the formation of a rich set of complex interfacial copolymer aggregates. Circular domains to elongated stripes are observed in the simulations at the water–chloroform interface as the charge fraction increases. These structures are shown to resemble the spherical and cylindrical helicoid structures observed in bulk chloroform as the charge fraction increases. The self-assembly of charge-containing copolymers is found to be driven by the association of the charged component in the hydrophilic block, with the hydrophobic segments extending away from the hydrophilic cores into the chloroform phase.

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Section: Introductionmentioning

confidence: 99%

Self-Assembly of Charge-Containing Copolymers at the Liquid–Liquid Interface

et al. 2019

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“… 3 − 14 The use of surfactants in the hydrate research fields is of broad interest in flow-assurance and gas storage. 15 − 23 …”

Section: Introductionmentioning

confidence: 99%

Hydrophobic Hydration and the Effect of NaCl Salt in the Adsorption of Hydrocarbons and Surfactants on Clathrate Hydrates

2018

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Adsorption of functional molecules on the surface of hydrates is key in the understanding of hydrate inhibitors. We investigate the adsorption of a hydrocarbon chain, nonionic and ionic surfactants, and ions at the hydrate–aqueous interface. Our results suggest a strong connection between the water ordering around solutes in bulk and the affinity for the hydrates surface. We distinguish two types of water ordering around solutes: (i) hydrophobic hydration where water molecules form a hydrogen bond network similar to clathrate hydrates, and (ii) ionic hydration where water molecules align according to the polarity of an ionic group. The nonionic surfactant and the hydrocarbon chain induce hydrophobic hydration and are favorably adsorbed on the hydrate surface. Adsorption of ions and the ionic headgroups on the hydrate surface is not favorable because ionic hydration and the hydrogen bond structure of hydrates are incompatible. The nonionic surfactant is adsorbed by the headgroup and tail while adsorption of the ionic surfactants is not favorable through the head. Water ordering is analyzed using the hydrogen bond and tetrahedral density profiles as a function of the distance to the chemical groups. The adsorption of solutes is studied through the free energy profiles as a function of the distance to the hydrate surface. Salt lowers the melting temperature of hydrates, disrupts hydrophobic hydration, reduces the solubility of solutes in the aqueous solution, and increases the propensity of solutes to be adsorbed on hydrate surfaces. Our studies are performed by the unbiased and steered molecular dynamics simulations. The results are in line with experiments on the effect of salt and alkanes in hydrate antiagglomeration.

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“…Therefore, the effect of SDS on the solubility of RIV cocrystals was also studied here. The critical micelle concentration (CMC) of SDS is 0.24% (w/v) at 298 K ( Ruiz-Morales and Romero-Martinez, 2018 ). In pure RIV, a good linear relationship was obtained between the SDS levels (w/v) and the RIV solubility when the concentration of SDS is abo v e the CMC (data not shown).…”

Section: Resultsmentioning

confidence: 99%