Coarse-grained modeling of the oil–water–surfactant interface through the local definition of the pressure tensor and interfacial tension

Ndao, Makha; Goujon, Florent; Ghoufi, Aziz; Malfreyt, Patrice

doi:10.1007/s00214-016-2038-y

Cited by 20 publications

(15 citation statements)

References 70 publications

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“…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. 57−62 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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“…An alternative is to simplify the model by using a CG description [49,50] for which the key element called a bead represents several atoms or molecules. By using these CG models [51][52][53], we can improve the description of the systems by using larger system sizes. The modeling of the interfacial systems with surfactants can then be conducted by CG models [51][52][53].…”

Section: Modeling the Conformation Of Biosurfactants At The Water-airmentioning

confidence: 99%

“…By using these CG models [51][52][53], we can improve the description of the systems by using larger system sizes. The modeling of the interfacial systems with surfactants can then be conducted by CG models [51][52][53]. Figure 5A shows the CG representation of syringafactin A and Cloud Microorganisms, an Interesting Source of Biosurfactants DOI: http://dx.doi.org/10.5772/intechopen.85621 Figure 5B represents an equilibrated liquid-vapor water interface with 32 biosurfactants in the interfacial region.…”

Section: Modeling the Conformation Of Biosurfactants At The Water-airmentioning

confidence: 99%

“…Whereas the prediction of the surface tension, calculated from atomistic simulations, is quantitative, it is still subject to some adjustments due to the CG nature of the interactions. It means that the CG model must be calibrated on this property to predict in the future both the interfacial tension and its dependence on the concentration of surfactants [51]. Indeed, recent studies [52,53] show that the degree of coarse-graining impacts on the description of the interface.…”

Section: Modeling the Conformation Of Biosurfactants At The Water-airmentioning

confidence: 99%

“…On this aspect of modeling complex interfacial systems, we can conclude that the development of CG models will open the way to new force fields capable of quantitatively predicting the surface tension and main properties such as the CMC. The prediction of the CMC, already operational for some CG models [51], will require additional adjustments for new molecules with various intramolecular interactions. The development of CG force fields using mesoscale simulation methods [58][59][60] is an active area of research.…”

Section: Profiles Of the Normal P N (Z) (Mpa) And Tangential P T (Z) mentioning

confidence: 99%

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Cloud Microorganisms, an Interesting Source of Biosurfactants

Renard¹,

Canet²,

Sancelme³

et al. 2019

Surfactants and Detergents

Self Cite

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A new scientific hypothesis states that biosurfactants from cloud microorganism origin could change the surface tension of aerosols and thus the mode of precipitations. In order to check this hypothesis, our team has screened a collection of 480 microbial strains isolated from cloud waters for the production of biosurfactants and showed that 42% of these strains were producing such molecules. In the present work, we isolated and identified by LC-MS-MS lipopeptides produced from three strains issued from this screening. Viscosin and massetolide E (cyclic lipopeptides) were produced by Pseudomonas sp. PDD-14b-2, and syringafactins (linear lipopeptides) were produced by Xanthomonas campestris PDD-32b-52 and Pseudomonas syringae PDD-32b-74. The critical micelle concentration (CMC) of these biosurfactants was determined using the pendant drop method. Finally, two approaches of molecular dynamics were used to model the conformation of viscosin and syringafactin A at the water-air interface: one is based on all-atoms simulation (CHARMM force field), while the other one on coarse-grain (CG) simulation (MARTINI force field). To conclude, this work shows how the biodiversity of the cloud microbiota can be explored to search and produce biosurfactants of interest both for atmospheric sciences and also for biotechnological applications.

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Performance evaluation of different types of surfactants to inhibit clay swelling during chemical enhanced oil recovery

2023

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In most cases, sandstone reservoirs contain clay particles. When a fluid with low salt content is injected into the reservoir, clay particles swell, and the rock's permeability decreases. Since surfactant flooding with water that has lower salinity than formation water is used to improve oil recovery, this study examines the swelling inhibitive strength of various surfactants. The study investigates the effect of surfactants on clay swelling inhibition through linear swelling and sedimentation experiments which showed that cetyl trimethyl ammonium bromide (CTAB) inhibits clay swelling. The optimum CTAB concentration was found to be 1 wt.%. However, sodium dodecyl sulphate (SDS) and Triton X‐100 (TX‐100) did not inhibit clay swelling. Sandpack experiments confirmed that CTAB prevented clay swelling and sandpack permeability reduction, while SDS and TX‐100 did not. The injection pressure results for the different surfactants were as follows: CTAB—39 psi, SDS—203 psi, TX‐100—223 psi, deionized water (DW)—324 psi, and KCl—78 psi. The mechanism of surfactant performance in affecting clay swelling was investigated based on thermal gravimetric analysis (TGA), zeta potential, and scanning electron microscope (SEM) images. The results showed that CTAB compensates for the surface charge of clays through a cation exchange mechanism. The amount of absorbed water for clays modified with CTAB was lower than that for other surfactants. The SEM images confirmed that the CTAB‐modified clays were larger and did not disintegrate during dispersion; however, in other cases, the particle size was smaller.

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Coarse-grained modeling of the oil–water–surfactant interface through the local definition of the pressure tensor and interfacial tension

Cited by 20 publications

References 70 publications

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

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

Cloud Microorganisms, an Interesting Source of Biosurfactants

Performance evaluation of different types of surfactants to inhibit clay swelling during chemical enhanced oil recovery

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