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Li N, Sun Z, Pang Y, Qi Z, Liu W, Li W, Sun M, Li B, Wang Z. Microscopic mechanism for electrocoalescence of water droplets in water-in-oil emulsions containing surfactant: A molecular dynamics study. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2022.120756] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Zhang W, Zhang MY, Wang K, Sun R, Zhao S, Zhang Z, He YP, Yu F. Geometry transformation of ionic surfactants and adsorption behavior on water/ n-decane-interface: calculation by molecular dynamics simulation and DFT study. RSC Adv 2021; 11:28286-28294. [PMID: 35480765 PMCID: PMC9038023 DOI: 10.1039/d1ra04669a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/15/2021] [Indexed: 01/20/2023] Open
Abstract
Understanding the effect of surfactant structure on their ability to modify interfacial properties is of great scientific and industrial interest. In this work, we have synthesized four amide based ionic surfactants under acidic or basic conditions, including CTHA·HCl, CTEA·HCl, CTHA−Na+ and CTEA−Na+. Experiments have proved that the anionic surfactant with polyethylene oxide groups (CTEA−Na+) had the lowest surface tension on the water/n-decane interface. Molecular dynamics simulations have been applied to investigate the structural effect on the adsorption behavior of four different surfactants. The surface tension, interface thickness, interface formation energy, density profiles, order parameters, radial distribution function on the water/n-decane interfaces were calculated and compared. During the equilibrium states, we found that the interface configuration of two cationic surfactants are almost linear while the two anionic surfactants are changed to bending shapes due to the different positions of the hydrophilic head groups. Further DFT study and wavefunction analysis of surfactants have shown that CTEA−Na+ can form stronger vdW interactions with n-decane molecules due to a more neutral electrostatic potential distribution. Meanwhile, the introduction of polyethylene oxide groups has offered more H-bonding sites and resulted in more concentrated H-bonding interactions with water molecules. The difference of weak interactions may contribute to the conformational change and finally affect the interface properties of these ionic surfactants. The difference of weak interactions may contribute to the conformational change and finally affect the interface properties of these ionic surfactants.![]()
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Affiliation(s)
- Wannian Zhang
- Key Laboratory for Functional Material, Educational Department of Liaoning Province, School of Chemical Engineering, University of Science and Technology Liaoning Anshan 114051 P. R. China .,State Key Laboratory of Fine Chemicals, Ningbo Institute of Dalian University of Technology No. 26 Yucai Road, Jiangbei District Ningbo 315016 P. R. China .,Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Petrochemical University Dandong Lu West 1 Fushun 113001 Liaoning P. R. China +86-2456860548
| | - Ming-Yuan Zhang
- Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Petrochemical University Dandong Lu West 1 Fushun 113001 Liaoning P. R. China +86-2456860548
| | - Kai Wang
- State Key Laboratory of Fine Chemicals, Ningbo Institute of Dalian University of Technology No. 26 Yucai Road, Jiangbei District Ningbo 315016 P. R. China .,Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Petrochemical University Dandong Lu West 1 Fushun 113001 Liaoning P. R. China +86-2456860548
| | - Ruixia Sun
- Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Petrochemical University Dandong Lu West 1 Fushun 113001 Liaoning P. R. China +86-2456860548
| | - Shanlin Zhao
- Key Laboratory for Functional Material, Educational Department of Liaoning Province, School of Chemical Engineering, University of Science and Technology Liaoning Anshan 114051 P. R. China .,Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Petrochemical University Dandong Lu West 1 Fushun 113001 Liaoning P. R. China +86-2456860548
| | - Zhiqiang Zhang
- Key Laboratory for Functional Material, Educational Department of Liaoning Province, School of Chemical Engineering, University of Science and Technology Liaoning Anshan 114051 P. R. China
| | - Yu-Peng He
- Key Laboratory for Functional Material, Educational Department of Liaoning Province, School of Chemical Engineering, University of Science and Technology Liaoning Anshan 114051 P. R. China .,State Key Laboratory of Fine Chemicals, Ningbo Institute of Dalian University of Technology No. 26 Yucai Road, Jiangbei District Ningbo 315016 P. R. China .,Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Petrochemical University Dandong Lu West 1 Fushun 113001 Liaoning P. R. China +86-2456860548
| | - Fang Yu
- State Key Laboratory of Fine Chemicals, Ningbo Institute of Dalian University of Technology No. 26 Yucai Road, Jiangbei District Ningbo 315016 P. R. China .,Key Laboratory of Petrochemical Catalytic Science and Technology, Liaoning Petrochemical University Dandong Lu West 1 Fushun 113001 Liaoning P. R. China +86-2456860548
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Ciszewski RK, Gordon BP, Muller BN, Richmond GL. Takes Two to Tango: Choreography of the Coadsorption of CTAB and Hexanol at the Oil-Water Interface. J Phys Chem B 2019; 123:8519-8531. [PMID: 31513405 DOI: 10.1021/acs.jpcb.9b05775] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mixed surfactant systems at the oil-water interface play a vital role in applications ranging widely from drug delivery to oil-spill remediation. Synergistic mixtures are superior emulsifiers and more effective at modifying surface tension than either component alone. Mixtures of surfactants with dissimilar polar head groups are of particular interest because of the additional degree of control they offer. The interplay of hydrophobic and electrostatic effects in these systems is not well understood, in part because of the difficulty in examining their behavior at the buried oil-water interface where they reside. Here, surface-specific vibrational sum frequency spectroscopy is utilized in combination with surface tensiometry and computational methods to probe the cooperative molecular interactions between a cationic surfactant cetyltrimethylammonium bromide (CTAB) and a nonionic alcohol (1-hexanol) that induce the two initially reluctant surfactants to coadsorb synergistically at the interface. A careful deuteration study of CTAB reveals that hexanol cooperates with CTAB such that both molecules preferentially orient at the interface for sufficiently large enough concentrations of hexanol. This work's methodology is unique and serves as a guide for future explorations of macroscopic properties in these complex systems. Results from this work also provide valuable insights into how interfacial ordering impacts surface tensiometry measurements for nonionic surfactants.
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Affiliation(s)
- Regina K Ciszewski
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Brittany P Gordon
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Benjamin N Muller
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
| | - Geraldine L Richmond
- Department of Chemistry and Biochemistry , University of Oregon , 1253 University of Oregon , Eugene , Oregon 97403 , United States
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