1
|
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.
Collapse
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.
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Zhu H, Li Y, Zhou D, Xu Q, Yin J. Molecular dynamics study on microstructure of supercritical CO2 microemulsions containing ionic liquids. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125272] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
4
|
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]
|
5
|
Molecular dynamics simulation of supercritical CO2 microemulsion with ionic liquid domains: Structures and properties. Chin J Chem Eng 2019. [DOI: 10.1016/j.cjche.2019.04.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
6
|
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.
Collapse
Affiliation(s)
- Muhan Wang
- School of Materials Science and Engineering, China University of Petroleum, 266580 Qingdao, Shandong, China.
| | | | | | | | | | | |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Ingrosso F, Ruiz-López MF. Modeling Solvation in Supercritical CO 2. Chemphyschem 2017; 18:2560-2572. [PMID: 28719104 DOI: 10.1002/cphc.201700434] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Indexed: 11/10/2022]
Abstract
In recent decades, a microscopic understanding of solute-solvent intermolecular interactions has been key to advances in technologies based on supercritical carbon dioxide. In many cases, computational work has provided the impetus for new discoveries, shedding new light on important concepts such as the local structure around the solute in the supercritical medium, the influence of the peculiar properties of the latter on the molecular behavior of dissolved substances and, importantly, CO2 -philicity. In this Review, the theoretical work that has been relevant to these developments is surveyed and, by presenting some crucial open questions, the possible routes to achieving further progress based on the interplay between theory and experiments is discussed.
Collapse
Affiliation(s)
- Francesca Ingrosso
- SRSMC UMR 7565, Université de Lorraine, BP 70239, 54506, Vandoeuvre-lès-Nancy, France.,SRSMC UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-lès-Nancy, France
| | - Manuel F Ruiz-López
- SRSMC UMR 7565, Université de Lorraine, BP 70239, 54506, Vandoeuvre-lès-Nancy, France.,SRSMC UMR 7565, CNRS, BP 70239, 54506, Vandoeuvre-lès-Nancy, France
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Prediction of the Reverse Micellar Extraction of Papain Using Dissipative Particle Dynamics Simulation. Appl Biochem Biotechnol 2016; 181:1338-1346. [PMID: 27873058 DOI: 10.1007/s12010-016-2287-1] [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: 07/26/2016] [Accepted: 10/10/2016] [Indexed: 10/20/2022]
Abstract
Reverse micellar extraction is a promising technology for large-scale protein purification, but its molecular interaction mechanisms have not been thoroughly characterized. In this study, a dissipative particle dynamics (DPD) molecular simulation method was employed to study the interactions among the surfactant, organic phase, water, and proteins on the mesoscopic scale. This study simulated the self-assembly process of the reverse micelle extraction of papain. The results showed that the papain could be extracted by a CTAB/isooctane/n-hexanol system, which was validated by extraction experiments. The optimized extraction recovery was 76.9 %. This study elucidates the molecular process of the reverse micellar extraction of proteins and provides a method to predict its efficacy.
Collapse
|
11
|
Liu B, Tang X, Fang W, Li X, Zhang J, Zhang Z, Shen Y, Yan Y, Sun X, He J. Molecular dynamics study of di-CF4 based reverse micelles in supercritical CO 2. Phys Chem Chem Phys 2016; 18:29156-29163. [PMID: 27730238 DOI: 10.1039/c6cp04253h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Reverse micelles (RMs) in supercritical CO2 (scCO2) are promising alternatives for organic solvents, especially when both polar and non-polar components are involved. Fluorinated surfactants, particularly double-chain fluorocarbon surfactants, are able to form well-structured RMs in scCO2. The inherent self-assembly mechanisms of surfactants in scCO2 are still subject to discussion. In this study, molecular dynamics simulations are performed to investigate the self-aggregation behavior of di-CF4 based RMs in scCO2, and stable and spherical RMs are formed. The dynamics process and the self-assembly structure in the RMs reveal a three-step mechanism to form the RMs, that is, small RMs, rod-like RMs and fusion of the rod-like RMs. Hydrogen-bonds between headgroups and water molecules, and salt bridges linking Na+ ions, headgroups and water molecules enhance the interfacial packing efficiency of the surfactant. The results show that di-CF4 molecules have a high surfactant coverage at the RM interface, implying a high CO2-philicity. This mainly results from bending of the short chain (C-COO-CH2-(CF2)3-CF3) due to the flexible carboxyl group. The microscopic insight provided in this study is helpful in understanding surfactant self-assembly phenomena and designing new CO2-philic surfactants.
Collapse
Affiliation(s)
- Bing Liu
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China. and NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
| | - Xinpeng Tang
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Wenjing Fang
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Xiaoqi Li
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Jun Zhang
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Zhiliang Zhang
- NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
| | - Yue Shen
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Youguo Yan
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Xiaoli Sun
- School of Science, China University of Petroleum, Qingdao 266580, Shandong, China.
| | - Jianying He
- NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), Trondheim, 7491, Norway.
| |
Collapse
|
12
|
Wang M, Fang T, Wang P, Tang X, Sun B, Zhang J, Liu B. The self-assembly structure and the CO 2-philicity of a hybrid surfactant in supercritical CO 2: effects of hydrocarbon chain length. SOFT MATTER 2016; 12:8177-8185. [PMID: 27714309 DOI: 10.1039/c6sm01584k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Hybrid surfactants containing both fluorocarbon (FC) and hydrocarbon (HC) chains, as effective CO2-philic surfactants, could improve the solubility of polar substances in supercritical CO2. Varying the length of the HC of hybrid surfactants is an effective way to improve the CO2-philicity. In this paper, we have investigated the effects of the HC length on the self-assembly process and the CO2-philicity of hybrid surfactants (F7Hn, n = 1, 4, 7 and 10) in water/CO2 mixtures using molecular dynamics simulations. It is found that the self-assembly time of F7Hn exhibits a maximum when the length of the HC is equal to that of the FC (F7H7). In this case, the investigation of H-bonds between the water core and CO2 phase shows that F7H7 has the strongest CO2-philicity because it has the best ability to separate water and CO2. To explain the origin of the differences in separation ability, the analysis of the structures of the reverse micelles shows that there are two competing mechanisms with a shortening HC. Firstly, the volume of F7Hn is reduced, which thus decreases the separation ability. Moreover, this also leads to the curved conformation of the FC. As a result, the separation ability is enhanced. These two mechanisms are balanced in F7H7, which has the best ability to separate water and CO2. Our simulation results demonstrate that the increased volume and the curved conformation of the hybrid surfactant tail could enhance the CO2-philicity in F7Hn surfactants. It is expected that this work will provide valuable information for the design of CO2-philic surfactants.
Collapse
Affiliation(s)
- Muhan Wang
- College of Science, China University of Petroleum, 266580 Qingdao, Shandong, China.
| | - Timing Fang
- College of Science, China University of Petroleum, 266580 Qingdao, Shandong, China.
| | - Pan Wang
- College of Science, China University of Petroleum, 266580 Qingdao, Shandong, China.
| | - Xinpeng Tang
- College of Science, China University of Petroleum, 266580 Qingdao, Shandong, China.
| | - Baojiang Sun
- School of Petroleum Engineering, China University of Petroleum, 266580 Qingdao, Shandong, China
| | - Jun Zhang
- College of Science, China University of Petroleum, 266580 Qingdao, Shandong, China. 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, China University of Petroleum, 266580 Qingdao, Shandong, China.
| |
Collapse
|
13
|
|
14
|
Zhang J, Peng L, Han B. Amphiphile self-assemblies in supercritical CO2 and ionic liquids. SOFT MATTER 2014; 10:5861-5868. [PMID: 25000970 DOI: 10.1039/c4sm00890a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Supercritical (sc) CO2 and ionic liquids (ILs) are very attractive green solvents with tunable properties. Using scCO2 and ILs as alternatives of conventional solvents (water and oil) for forming amphiphile self-assemblies has many advantages. For example, the properties and structures of the amphiphile self-assemblies in these solvents can be easily modulated by tuning the properties of solvents; scCO2 has excellent solvation power and mass-transfer characteristics; ILs can dissolve both organic and inorganic substances and their properties are designable to satisfy the requirements of various applications. Therefore, the amphiphile self-assemblies in scCO2 and ILs have attracted considerable attention in recent years. This review describes the advances of using scCO2 or/and ILs as amphiphile self-assembly media in the last decade. The amphiphile self-assemblies in scCO2 and ILs are first reviewed, followed by the discussion on combination of scCO2 and ILs in creating microemulsions or emulsions. Some future directions on the amphiphile self-assemblies in scCO2 and ILs are highlighted.
Collapse
Affiliation(s)
- Jianling Zhang
- Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid and Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, China.
| | | | | |
Collapse
|
15
|
|
16
|
Phase-behavior of alkyl ketene dimmer (AKD) in supercritical carbon dioxide. The implications of using different solubility measurement methods. J Supercrit Fluids 2012. [DOI: 10.1016/j.supflu.2011.09.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|