Molecular dynamics simulation study on interfacial behaviors of betaines and extended surfactants

Ren, Jia; Xiao, Hongyan; Cao, Xun; Yuan, Fuqing; Pan, Binlin; Ma, Bin; Zhang, Lei; Zhang, Lu

doi:10.1016/j.colsurfa.2023.131323

Cited by 9 publications

(12 citation statements)

References 42 publications

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“…The tilt angle of polar and nonpolar groups of the single betaine system had been reported in our previous work. 23 The results showed that the polar part of betaine was almost flat at the oil/water interface to form a sizable interfacial vacancy, and the hydrophobic chain of betaine was closer to the z-direction relative to the polar part.…”

Section: ■ Results and Discussionmentioning

confidence: 96%

“…The definition of the tilt angle of the polar part (S− N tilt angle) and the nonpolar part (N−C tilt angle) are shown in Figure 6A, and the specific definition refers to our previous work. 23 A larger tilt angle corresponds to a stronger tendency of the molecular groups to parallel the oil/water interface. Otherwise, the group tends to be parallel to the z-axis and away from the oil/water interface.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The GROMACS 2018.1 software package − was applied to perform all molecular dynamics simulations. See our previous work for more details.…”

Section: Methodsmentioning

confidence: 99%

“…In both single and mixed systems, the amount of AOT and betaine was set to 30 and a ratio of 1:1 was uniformly stacked to form the monolayer. The other conditions and molecular number settings mentioned in our previous work 23 are listed in Table S1.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Synergistic Effect of Betaines and Dialkyl Chain Anionic Surfactants on Interfacial Arrangement: A Molecular Dynamics Simulation Study

Liu,

Xiao,

Pan

et al. 2024

Langmuir

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Mixed systems of betaines and anionic surfactants can have a significant synergistic effect and greatly reduce the interfacial tension (IFT), which has attracted an extensive amount of attention. However, this synergistic effect requires an anionic surfactant and betaine molecular size matching, which limits the scope of its application. In this work, we studied three mixed systems of sodium dialkyl sulfosuccinate (AOT) and betaines with different sizes by molecular dynamics simulation and an IFT experiment and explored the interfacial behavior and synergistic mechanism of AOT in single and mixed systems. The hydrophobic tail chain center angle, average rising height of carbon atoms, stretch degree and distance between the terminal carbon atoms of AOT, and tilt angles of betaine were calculated and analyzed in detail. Simulation results showed that the hydrophobic tail chain center angle of AOT in the single system was smaller, and it tended to extend into the oil phase. After being mixed with different betaines, AOT can adjust its size according to the interfacial vacancies of different betaine systems by changing the alkyl chain orientation and forming tighter interfacial films. The IFT experiment showed that betaine/AOT mixed systems achieved a lower IFT value compared with that of the single system, indicating that AOT showed a synergistic effect with betaines with different structures. This study will be importantly instructively significant for the design and research of betaine mixed systems in crude oil exploitation.

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Section: ■ Results and Discussionmentioning

confidence: 96%

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The GROMACS 2018.1 software package − was applied to perform all molecular dynamics simulations. See our previous work for more details.…”

Section: Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Synergistic Effect of Betaines and Dialkyl Chain Anionic Surfactants on Interfacial Arrangement: A Molecular Dynamics Simulation Study

Liu,

Xiao,

Pan

et al. 2024

Langmuir

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“…With the development of chemical flooding enhanced oil recovery technology, more extended surfactants 14 are being studied and expected to be used in oil displacement. 15 It is necessary to design reasonable hydrophilic and hydrophobic groups to improve the emulsification performance of the surfactant. The current research results mainly include carboxylate, sulfate, and sulfonate.…”

Section: Introductionmentioning

confidence: 99%

Study on the Behavior of Saturated Cardanol-Based Surfactants at the Crude Oil/Water Interface through Molecular Dynamics Simulations

Lu,

Liu,

Yuan

et al. 2023

J. Phys. Chem. B

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Cardanol is a green biosurfactant with broad application prospects, which is expected to be used to enhance oil recovery (EOR). This paper designed two types of surfactants (extended and nonextended), including six kinds of nonionic and anion–nonionic surfactants. The position changes of PO and EO chains and the effects of different hydrophilic groups on the interface properties were studied with molecular dynamics simulations by constructing a model of crude oil (containing four components) and water molecules. The results of interfacial tension and solvent-accessible surface area showed that the interfacial properties of sulfate were better than those of sulfonates and nonionic surfactants. Meanwhile, the interface properties of nonextended surfactants were better than those of extended surfactants. The gyration radius (R g) and tilt angle data demonstrated that when EO chains were located between hydrophobic groups and PO chains (nonextended surfactants), the adsorption capacity of surfactants at crude oil and water interfaces could be effectively improved. The radial distribution function of the hydrophilic group and hydrophobic group of surfactants with water molecules and four components of the crude oil molecule, respectively, explained that surfactants (8EO8POSO4) had better emulsification performance when the intermolecular interactions between crude oil and water two phases were relatively balanced. This study provides a theoretical reference for the design of oil-displacement surfactants and the mechanism analysis of emulsification properties.

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Effects of block and random copolymerization on the properties of fatty alcohol polyoxypropylene‐polyoxyethylene ether sulfates for enhanced oil recovery

Chen,

Lin,

Chen

et al. 2024

J Surfact & Detergents

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Enhanced oil recovery (EOR) by surfactant flooding has been attractive. Among the surfactants developed alcohol polyoxypropylene (PO)‐polyoxyethylene (EO) ether sulfates (APES), also named extended surfactants, have been proved efficient. However, the arrangement of the PO and EO chains as well as the hydrocarbon structure in the molecules may significantly affect their performances. In this paper three APES, C18−16PO25EO10SO4Na (I), C18−16(PO/EO)25+10SO4Na (II), and C16GA(PO/EO)25+10SO4Na (III) were prepared and investigated, in which APES (I) and APES (II) were designed to have same PO and EO numbers but block and randomly copolymerized respectively with linear C18−16 fatty alcohols as starting agent, whereas the APES (III) was derived from double chain C16 Guerbet alcohol (C16GA) with PO and EO randomly copolymerized. The results show that the block copolymerized APES (I) gives much better brine solubility and counterion tolerance than the randomly copolymerized APES (II) and (III). Although all APES synthesized are highly surface‐active and can reduce Daqing crude oil/simulated brine interfacial tension (IFT) to ultralow by mixing with more hydrophobic surfactants in presence or absence of alkali, the APES (III) gives the lowest IFT due to with double hydrocarbon chains. In addition, it is found that for APES (I) gelation occurs in neutralization process and the corresponding nonionic intermediate is highly viscous, whereas the randomly copolymerized two intermediates are liquid‐like with low viscosity, which may be feasible to apply SO3/air falling film sulfation. This study provided useful information for arrangement of embedded nonionic moiety and hydrocarbon structure in designing extended surfactants for EOR.

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Molecular dynamics simulation study on interfacial behaviors of betaines and extended surfactants

Cited by 9 publications

References 42 publications

Synergistic Effect of Betaines and Dialkyl Chain Anionic Surfactants on Interfacial Arrangement: A Molecular Dynamics Simulation Study

Synergistic Effect of Betaines and Dialkyl Chain Anionic Surfactants on Interfacial Arrangement: A Molecular Dynamics Simulation Study

Study on the Behavior of Saturated Cardanol-Based Surfactants at the Crude Oil/Water Interface through Molecular Dynamics Simulations

Effects of block and random copolymerization on the properties of fatty alcohol polyoxypropylene‐polyoxyethylene ether sulfates for enhanced oil recovery

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