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Ren HR, Xu QQ, Yin JZ. Microscopic properties and stabilization mechanism of a supercritical carbon dioxide microemulsion with extremely high water content. J Colloid Interface Sci 2021; 607:1953-1962. [PMID: 34695744 DOI: 10.1016/j.jcis.2021.09.188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/28/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022]
Abstract
HYPOTHESIS Developing the supercritical carbon dioxide microemulsion with a broad water content (W0) window can provide more possibility for designing highly efficient chemical processes, which is challenging due to the lack of comprehension about its formation mechanism. Molecular dynamics simulation method is expected to reveal the microscopic stabilization mechanism of high-W0 microemulsions. SIMULATIONS All-atom molecular dynamics simulations of the ternary systems with varied W0 stabilized by 4FG(EO)2 surfactant were designed according to phase behavior experiments. A systematic investigation was performed concerning the self-assembling, equilibrium morphology and detailed microstructure of the microemulsion droplet. An in-depth comparative study about the distribution of both H2O and CO2, the interfacial behaviors of 4FG(EO)2, as well as the microscopic interactions was conducted. FINDINGS For the first time, direct evidence was provided for the formation of water-in-carbon dioxide microemulsion with extremely high W0 (80) under the effect of 4FG(EO)2. Furthermore, a unique interfacial phenomenon, i. e. CO2 accumulating at the interface, was revealed to be responsible for the formation and enhanced stability of the nanosized droplet with high W0. This should set a new guiding star for synthesizing and selecting effective interfacial modifiers to create high-W0 microemulsions.
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Affiliation(s)
- Hong-Rui Ren
- State Key Laboratory of Fine Chemical, School of Chemical Machinery, Dalian University of Technology, Dalian 116024, China
| | - Qin-Qin Xu
- State Key Laboratory of Fine Chemical, School of Chemical Machinery, Dalian University of Technology, Dalian 116024, China
| | - Jian-Zhong Yin
- State Key Laboratory of Fine Chemical, School of Chemical Machinery, Dalian University of Technology, Dalian 116024, China.
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Zhang Y, Li J, Yin Z, Zhang J, Guo W, Wang M. Quantum Chemical Study of the Carbon Dioxide-Philicity of Surfactants: Effects of Tail Functionalization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15352-15361. [PMID: 33300802 DOI: 10.1021/acs.langmuir.0c02789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Carbon dioxide (CO2)-philic surfactants have broad application prospects in organic synthesis, fracture-enhanced oil recovery, polymerization, extraction, and other fields and can be used to enhance the viscosity of supercritical CO2 (scCO2). In this work, the relationship between the functional group of the surfactant tail and CO2-philicity is studied from a new perspective using density functional theory. Three common functional group types (fluorinated, oxidative, and methyl groups) were investigated. The analysis of binding energy demonstrates that all three types of functional groups can improve the CO2-philicity of the surfactant. Among these three kinds of functional groups, the strongest interaction with CO2 molecules is observed for oxidative functional groups followed by semifluorinated, fluorinated, and methyl groups. However, the CO2 molecules tend to be adsorbed onto the middle segment of the oxidative group, and the intrusion of the CO2 molecules results in the low solubility of oxidative surfactants. In contrast, fluorinated and methyl groups interact with CO2 at the end of the surfactant tail. As a result, the fluorinated surfactants show the best solubility in CO2. Therefore, the solubility of a surfactant in CO2 is not only related to the interaction strength between the surfactant and CO2, it also depends on the interaction structure. The results of this study provide a new strategy for evaluating surfactant CO2-philicity and provide guidance for the design of surfactants with high solubility in scCO2.
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Affiliation(s)
- Yingnan Zhang
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Jiawei Li
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Zhipeng Yin
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Jun Zhang
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Wenyue Guo
- School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao 266580, China
| | - Muhan Wang
- Department of Civil Engineering, Qingdao University of Technology, Qingdao 266000, China
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3
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Zhou R, Jin Y, Shen Y, Lai S, Zhou Y, Zhao P. Surface activity, salt and pH tolerance, and wettability of novel nonionic fluorinated surfactants with a short fluorocarbon chain. J DISPER SCI TECHNOL 2020. [DOI: 10.1080/01932691.2020.1768862] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Rong Zhou
- Key Laboratory of Leather Chemistry and Engineering, Sichuan University, Ministry of Education , Chengdu , China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University , Chengdu , China
| | - Yong Jin
- Key Laboratory of Leather Chemistry and Engineering, Sichuan University, Ministry of Education , Chengdu , China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University , Chengdu , China
| | - Yichao Shen
- Key Laboratory of Leather Chemistry and Engineering, Sichuan University, Ministry of Education , Chengdu , China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University , Chengdu , China
| | - Shuangquan Lai
- Key Laboratory of Leather Chemistry and Engineering, Sichuan University, Ministry of Education , Chengdu , China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University , Chengdu , China
| | - Yutang Zhou
- Key Laboratory of Leather Chemistry and Engineering, Sichuan University, Ministry of Education , Chengdu , China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University , Chengdu , China
| | - Peng Zhao
- Key Laboratory of Leather Chemistry and Engineering, Sichuan University, Ministry of Education , Chengdu , China
- National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University , Chengdu , China
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The self-assembly and microscopic interfacial properties of a supercritical CO2 microemulsion having hydrotropes: Atom-level observation from molecular dynamics simulation. J CO2 UTIL 2020. [DOI: 10.1016/j.jcou.2020.01.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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5
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Shim Y. Computer simulation study of fluorocarbon phosphate surfactant based aqueous reverse micelle in supercritical CO 2: roles of surfactant functional groups, ionic strength, and phase changes in CO 2. Phys Chem Chem Phys 2020; 22:3434-3445. [PMID: 31984986 DOI: 10.1039/c9cp06613f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Structural and dynamic properties of an aqueous micelle organized from fluorocarbon phosphate surfactant molecules in supercritical carbon dioxide (CO2) are investigated via molecular dynamics computer simulations. The roles of the functional groups and ionic strength of the surfactants on the formation of reverse micelles in supercritical CO2, and related water dynamics characterized as translational and reorientational dynamics, are systematically demonstrated by employing three different phosphate-based surfactants paired with sodium cations. The strong electrostatic interactions between the phosphate head groups and sodium cations result in formation of an aqueous core inside the surfactant aggregates, where water molecules are bonded together with loss of the tetrahedral hydrogen bonded network found in bulk water. It is found that all the three surfactants with CO2-philic fluorocarbon double tails build up well-stabilized reverse micelles in supercritical CO2, avoiding direct contacts between CO2 and water molecules. Despite this, the surfactant with a carboxylic ester linkage between the phosphate head and fluorocarbon tail group tends to coordinate water molecules toward sustaining the inter-water hydrogen bonds, indicating better efficiency at covering the aqueous core with hydrophobic groups compared to one without a carboxylic ester group. As for water molecules confined in the reverse micelle, their translational and reorientational motions, and fluctuating dynamics of the inter-water hydrogen bonds, significantly slow down compared to bulk water at ambient temperature. The water dynamics become more restricted with an increase in ionic strength of the anionic surfactant; this is attributed to divalent surfactant heads and sodium cations being more tightly bound together with bonding to water compared to monovalent ones. Lastly, the structural and dynamic changes of the reverse micelle caused by a phase change in CO2 are monitored with gradually decreasing temperature and pressure from the supercritical to gaseous state for CO2. The average reverse micelle structure equilibrated in supercritical CO2 is found to remain stable over a time period of 0.2 ms through a depressurization process to gaseous CO2. We note that the diverse pathways of surfactant self-aggregation in gaseous CO2 could be controlled by the preceding solvation procedure in the supercritical regime which governs the final aggregated structures in gaseous CO2.
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Affiliation(s)
- Youngseon Shim
- CAE Group, Autonomous Material Development Laboratory, Samsung Advanced Institute of Technology, Samsung Electronics, Suwon, Gyeonggi 16678, Korea.
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6
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Stabilization of 4FS(EO)2 constructed water-in-carbon dioxide microemulsions (W/C μEs) with nonfluorinated co-surfactants. J Supercrit Fluids 2019. [DOI: 10.1016/j.supflu.2019.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Wang M, Fang T, Zhong H, Li J, Yan Y, Zhang J. Optimal aggregation number of reverse micelles in supercritical carbon dioxide: a theoretical perspective. SOFT MATTER 2019; 15:3323-3329. [PMID: 30924475 DOI: 10.1039/c8sm02299b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The aggregation number is one of the most fundamental and important structural parameters for the micelle or reverse micelle (RM) system. In this work, a simple, reliable method for the determination of the aggregation number of RMs in supercritical CO2 (scCO2) was presented through a molecular dynamics simulation. The process of pulling surfactants out of the RMs one by one was performed to calculate the aggregation number. The free energies of RMs with different numbers of surfactants were calculated through this process. We found an RM with the lowest free energy, which was considered to have the optimal number of surfactants. Therefore, the optimal aggregation number of RMs was acquired. In order to explain the existence of an optimal aggregation number, detailed analyses of surfactant accumulation were conducted by combining molecular dynamics with quantum chemistry methods. The results indicated that in the RMs with the lowest free energy, the head-group and tail-terminal of the surfactants accumulated on an equipotential surface. In this case, the surfactant film could effectively separate water and CO2; thus, the lowest free energy was expected. This method determined the aggregation number of RMs by theoretical calculations that did not depend on experimental measurements. This presented approach facilitates the evaluation of the characteristics of RMs in scCO2 and can be further applied in the RM system of organic solvents or even in the micellar system.
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Affiliation(s)
- Muhan Wang
- School of Materials Science and Engineering, China University of Petroleum, 266580 Qingdao, Shandong, China.
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Wang M, Wang J, Fang T, Yan Y, Wang Z, Zhang J. Shape transition of water-in-CO2 reverse micelles controlled by the surfactant midpiece. Phys Chem Chem Phys 2018; 20:15535-15542. [DOI: 10.1039/c8cp01844h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Designing CO2-philic surfactants for generating wormlike reverse micelles (RMs) is an effective approach to enhance the viscosity of supercritical CO2 (scCO2), however this remains challenging.
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Affiliation(s)
- Muhan Wang
- College of Science, China University of Petroleum
- 266580 Qingdao
- China
| | - Junfeng Wang
- College of Science, China University of Petroleum
- 266580 Qingdao
- China
| | - Timing Fang
- College of Science, China University of Petroleum
- 266580 Qingdao
- China
| | - Youguo Yan
- College of Science, China University of Petroleum
- 266580 Qingdao
- China
| | - Zhiyuan Wang
- School of Petroleum Engineering
- China University of Petroleum
- 266580 Qingdao
- China
| | - Jun Zhang
- College of Science, China University of Petroleum
- 266580 Qingdao
- China
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Yu T, Lin M, Wan J, Cao X. Molecular interaction mechanisms in reverse micellar extraction of microbial transglutaminase. J Chromatogr A 2017; 1511:25-36. [PMID: 28697931 DOI: 10.1016/j.chroma.2017.07.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/23/2017] [Accepted: 07/03/2017] [Indexed: 11/17/2022]
Abstract
Reverse micellar extraction is an efficient and economical alternative for protein purification. In this study, microbial transglutaminase (MTGase) from crude materials was purified using reverse micellar extraction, and the molecular interaction mechanism in reverse micellar extraction of MTGase was explored. By using a molecular simulation study, the interaction mechanism of forward extraction was investigated. The molecular simulation results reveal the interaction of MTGase-water-surfactant is the major driving force for the forward extraction. Further, the effect of ionic strength on molecular interactions in backward extraction was investigated using 1H low-field nuclear magnetic resonance (LF-NMR) and circular dichroism (CD) spectra. In backward extraction, the interactions between water and the other two molecules (MTGase and surfactant molecules) are enhanced while the interactions between target molecules (MTGase) and the other two molecules (water and surfactant molecules) are weakened as the ionic strength increases. Moreover, the effect of size exclusion on backward extraction was also investigated. The results demonstrate size exclusion has limit effect at high ionic strength, and the weakened interaction of MTGase-water-surfactant is the main reason causing the release of the target molecules in backward extraction. This work might provide valuable reference to the MTGase purification and downstream processing.
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Affiliation(s)
- Tingting Yu
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Mingxiang Lin
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Junfen Wan
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
| | - Xuejun Cao
- State Key Laboratory of Bioreactor Engineering, Department of Bioengineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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Wang M, Fang T, Wang P, Yan Y, Zhang J, Liu B, Sun X. Molecular-Scale Design of Hydrocarbon Surfactant Self-Assembly in Supercritical CO 2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:5291-5297. [PMID: 28485950 DOI: 10.1021/acs.langmuir.7b01176] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Forming wormlike reverse micelles (RMs) by hydrocarbon surfactant self-assembly is an economic and environmental strategy to improve the physicochemical properties of supercritical carbon dioxide (scCO2), but it remains challenging. Introducing cosurfactant in hydrocarbon surfactant self-assembly system is a potential method to generate wormlike RMs. Here, adopting molecular dynamics simulations, we performed hydrocarbon surfactant (TC14) self-assembly with introducing cosurfactants (C8Benz). It is found that adding the C8Benz molecules will induce the spherical RMs to a short rodlike form. In this case, the microstructure of the short rodlike RMs shows a dumbbell-like form that is composed by three parts including a middle part of C8Benz and two parts of TC14 aggregation at both ends of rodlike RMs, which is regarded as the origin of RMs shape transition. Further, the analysis of free energy for RMs fusion indicates that the high fusion ability of C8Benz aggregation drives the formation of the dumbbell-like RMs. Accordingly, enhancing the affinity of the C8Benz is found to be effective strategy to further fusion of rodlike RMs in end-to-end manner, yielding a wormlike RMs with a beads-on-a-string structure. It is expected that this work will provide a valuable information for design the hydrocarbon wormlike RMs and facilitate the potential application of scCO2.
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Affiliation(s)
- Muhan Wang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Timing Fang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Pan Wang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Youguo Yan
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Jun Zhang
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Bing Liu
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
| | - Xiaoli Sun
- College of Science and ‡Key Laboratory of New Energy Physics & Materials Science in Universities of Shandong, China University of Petroleum , 266580 Qingdao, Shandong, China
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