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Wang H, Wang W, Zhu G, Cao Y, Zhang L. A perspective of microemulsions in critical metal separation and recovery: Implications for potential application of CO 2-responsive microemulsions. CHEMOSPHERE 2023; 338:139494. [PMID: 37451640 DOI: 10.1016/j.chemosphere.2023.139494] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/01/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
Since the discovery of microemulsions, they have attracted great attention due to its unique properties, such as ultra-low interfacial tension and nanoscale droplets. During the past several decades, microemulsions have shown unparalleled advantages in critical metal separation and recovery, e.g., high separation rate, high recovery efficiency, and good selectivity. Therefore, fundamental understandings of such metal recovery behavior are of great significance for the continuous development of microemulsion-based separation technology in this field. Herein, we first systematically reviewed the application of regular microemulsion in the separation and recovery process of critical metals focusing on their separation mechanisms. Then, we summarized the recent progress of CO2-responsive microemulsions and highlighted their potential application in critical metal separation and recovery, aiming to provide some insights into alleviating the difficulties in demulsification during the stripping stage using regular microemulsions. In this section, the latest development of CO2-responsive microemulsions is introduced, and the relationship between their composition, microstructure and macroscopic properties is discussed. Discussion and future perspectives are provided highlighting the design of new microemulsions and potential application of CO2-responsive microemulsions for metal separation and recovery in the future.
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Affiliation(s)
- Haoxuan Wang
- School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Wei Wang
- Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou, 450001, Henan, China; School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Guangli Zhu
- Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Yijun Cao
- Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou, 450001, Henan, China; School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, Henan, China.
| | - Ling Zhang
- Zhongyuan Critical Metals Laboratory, Zhengzhou University, Zhengzhou, 450001, Henan, China; School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, Henan, China.
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2
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Zhang Y, Mu M, Zhou Y, Xie H, Zhao S. Redox-responsive microemulsion: Fabrication and application to curcumin encapsulation. J Colloid Interface Sci 2023; 647:384-394. [PMID: 37269735 DOI: 10.1016/j.jcis.2023.05.129] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 04/20/2023] [Accepted: 05/18/2023] [Indexed: 06/05/2023]
Abstract
HYPOTHESIS Stimulus-responsive microemulsions have aroused significant attention because of their versatile and reversible switchability between stable and unstable states. However, most stimuli-responsive microemulsions are based on stimuli-responsive surfactants. We posit that the change in the hydrophilicity of a selenium-containing alcohol triggered by a mild redox reaction could also influence the stability of microemulsions and provide a new nanoplatform for the delivery of bioactive substances. EXPERIMENTS A selenium-containing diol (3,3'-selenobis(propan-1-ol), PSeP) was designed and used as a co-surfactant in a microemulsion with ethoxylated hydrogenated castor oil (HCO40), diethylene glycol monohexyl ether (DGME), 2-n-octyl-1-dodecanol (ODD) and water. The redox-induced transition in PSeP was characterized by 1H NMR, 77Se NMR, and MS. The redox-responsiveness of the ODD/HCO40/DGME/PSeP/water microemulsion was investigated through determination of a pseudo-ternary phase diagram, analysis by dynamic light scattering, and electrical conductivity, and its encapsulation performance was evaluated by determination of the solubility, stability, antioxidant activity, and skin penetrability of encapsulated curcumin. FINDINGS The redox conversion of PSeP enabled efficient switching of ODD/HCO40/DGME/PSeP/water microemulsions. Addition of oxidant (H2O2), oxidized PSeP into more hydrophilic PSeP-Ox (selenoxide), disrupting the emulsifying capacity of the combination of HCO40/DGME/PSeP, markedly reducing the monophasic microemulsion region in the phase diagram, and inducing phase separation in some formulations. Addition of reductant (N2H4·H2O), reduced PSeP-Ox and restored the emulsifying capacity of the combination of HCO40/DGME/PSeP. In addition, PSeP-based microemulsions can significantly enhance the solubility in oil (by 23 times), stability, antioxidant capacity (DPPH∙ radical scavenging by 91.74 %), and skin penetrability of curcumin, showing clear potential for encapsulation and delivery of curcumin and other bioactive substances.
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Affiliation(s)
- Yongmin Zhang
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, PR China; Key Laboratory of Green Cleaning Technology and Detergents of Zhejiang Province, Hangzhou 310056, PR China.
| | - Meng Mu
- Petroleum Engineering Technology Research Institute of Shengli Oilfield, SINOPEC, Dongying, Shandong 257067, China
| | - Yue Zhou
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, PR China
| | - Huan Xie
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, PR China
| | - Shanjuan Zhao
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, PR China
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3
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Dowlati S, Mokhtari R, Hohl L, Miller R, Kraume M. Advances in CO 2-switchable surfactants towards the fabrication and application of responsive colloids. Adv Colloid Interface Sci 2023; 315:102907. [PMID: 37086624 DOI: 10.1016/j.cis.2023.102907] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/13/2023] [Accepted: 04/13/2023] [Indexed: 04/24/2023]
Abstract
CO2-switchable surfactants have selective surface-activity, which can be activated or deactivated either by adding or removing CO2 from the solution. This feature enables us to use them in the fabrication of responsive colloids, a group of dispersed systems that can be controlled by changing the environmental conditions. In chemical processes, including extraction, reaction, or heterogeneous catalysis, colloids are required in some specific steps of the processes, in which maximum contact area between immiscible phases or reactants is desired. Afterward, the colloids must be broken for the postprocessing of products, solvents, and agents, which can be facilitated by using CO2-switchable surfactants in surfactant-stabilized colloids. These surfactants are mainly cationic and can be activated by the protonation of a nitrogen-containing group upon sparging CO2 gas. Also, CO2-switchable superamphiphiles can be formed by non-covalent bonding between components at least one of which is CO2-switchable. So far, CO2-switchable surfactants have been used in CO2-switchable spherical and wormlike micelles, vesicles, emulsions, foams, and Pickering emulsions. Here, we review the fabrication procedure, chemical structure, switching scheme, stability, environmental conditions, and design philosophy of such responsive colloids. Their fields of application are wide, including emulsion polymerization, catalysis, soil washing, drug delivery, extraction, viscosity control, and oil transportation. We also emphasize their application for the CO2-assisted enhanced oil recovery (EOR) process as a promising approach for carbon capture, utilization, and storage to combat climate change.
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Affiliation(s)
- Saeid Dowlati
- Chair of Chemical and Process Engineering, Technical University of Berlin, Ackerstraße 76, D-13355 Berlin, Germany.
| | - Rasoul Mokhtari
- Danish Offshore Technology Centre, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Lena Hohl
- Chair of Chemical and Process Engineering, Technical University of Berlin, Ackerstraße 76, D-13355 Berlin, Germany
| | - Reinhard Miller
- Institute for Condensed Matter Physics, Technical University of Darmstadt, Hochschulstraße 8, D-64289 Darmstadt, Germany
| | - Matthias Kraume
- Chair of Chemical and Process Engineering, Technical University of Berlin, Ackerstraße 76, D-13355 Berlin, Germany
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4
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Chen J, Huang Z, Liu D, Zhang Y, Li H, Lu H. Wettability reversal of reservoir rock surface through surfactant stabilized microemulsion. J SURFACTANTS DETERG 2022. [DOI: 10.1002/jsde.12586] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jun Chen
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu P. R. China
| | - Zhiyu Huang
- School of New Energy and Materials Southwest Petroleum University Chengdu P. R. China
| | - Dongfang Liu
- Department of Chemistry, School of Science Xihua University Chengdu P. R. China
| | - Ying Zhang
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu P. R. China
| | - Hanmin Li
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu P. R. China
| | - Hongsheng Lu
- College of Chemistry and Chemical Engineering Southwest Petroleum University Chengdu P. R. China
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Huang Z, Sun X, Liu Y, Cui J, Song A, Hao J. Metal ion-triggered Pickering emulsions and foams for efficient metal ion extraction. J Colloid Interface Sci 2021; 602:187-196. [PMID: 34119757 DOI: 10.1016/j.jcis.2021.05.182] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/19/2021] [Accepted: 05/31/2021] [Indexed: 11/28/2022]
Abstract
Emulsions and foams were constructed by using surfactant particles as stabilizers. Bis(2-ethylhexyl) phosphate, abbreviated as HDEHP, was used as both an oil in neutral form and an anionic surfactant in deprotonated form, DEHP-. In the system of HDEHP/H2O, upon adding NaOH, a portion of HDEHP was deprotonated to form DEHP- as stabilizers of O/W emulsions. After introducing some certain metal ions, the O/W emulsions were transformed to W/O Pickering emulsions due to the generation of insoluble particles by DEHP- and metal ions. In addition, DEHP- could also combine with some metal ions to produce particles absorbed at air/water interface, forming ultrastable foams. Accompanied with the formation of Pickering emulsions and foams, the extraction of metal ions from water could be realized with high removal efficiency. The extractant, HDEHP, could be effectively recycled through convenient demulsification of Pickering emulsions or destruction of foams. This work provides new ideas for the construction of particle-stabilized dispersion systems and proposes methods with potential applications in industrial wastewater treatments.
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Affiliation(s)
- Zhaohui Huang
- Key Laboratory of Colloids and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China
| | - Xiuping Sun
- Key Laboratory of Colloids and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China
| | - Yihan Liu
- Key Laboratory of Colloids and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China
| | - Jiwei Cui
- Key Laboratory of Colloids and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China
| | - Aixin Song
- Key Laboratory of Colloids and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China.
| | - Jingcheng Hao
- Key Laboratory of Colloids and Interface Chemistry (Ministry of Education), Shandong University, Jinan 250100, China
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Lu Y, Zhu Y, Yang F, Xu Z, Liu Q. Advanced Switchable Molecules and Materials for Oil Recovery and Oily Waste Cleanup. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2004082. [PMID: 34047073 PMCID: PMC8336505 DOI: 10.1002/advs.202004082] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 01/19/2021] [Indexed: 05/07/2023]
Abstract
Advanced switchable molecules and materials have shown great potential in numerous applications. These novel materials can express different states of physicochemical properties as controlled by a designated stimulus, such that the processing condition can always be maintained in an optimized manner for improved efficiency and sustainability throughout the whole process. Herein, the recent advances in switchable molecules/materials in oil recovery and oily waste cleanup are reviewed. Oil recovery and oily waste cleanup are of critical importance to the industry and environment. Switchable materials can be designed with various types of switchable properties, including i) switchable interfacial activity, ii) switchable viscosity, iii) switchable solvent, and iv) switchable wettability. The materials can then be deployed into the most suitable applications according to the process requirements. An in-depth discussion about the fundamental basis of the design considerations is provided for each type of switchable material, followed by details about their performances and challenges in the applications. Finally, an outlook for the development of next-generation switchable molecules/materials is discussed.
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Affiliation(s)
- Yi Lu
- Department of Chemical and Materials EngineeringUniversity of AlbertaEdmontonAlbertaT6G 1H9Canada
| | - Yeling Zhu
- Department of Chemical and Materials EngineeringUniversity of AlbertaEdmontonAlbertaT6G 1H9Canada
| | - Fan Yang
- College of New Materials and New EnergiesShenzhen Technology UniversityShenzhen518118P. R. China
| | - Zhenghe Xu
- Department of Chemical and Materials EngineeringUniversity of AlbertaEdmontonAlbertaT6G 1H9Canada
- Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen518055P. R. China
| | - Qingxia Liu
- Department of Chemical and Materials EngineeringUniversity of AlbertaEdmontonAlbertaT6G 1H9Canada
- College of New Materials and New EnergiesShenzhen Technology UniversityShenzhen518118P. R. China
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Zhou Y, He S, Li H, Zhang Y. CO 2 and Temperature Control over Nanoaggregates in Surfactant-Free Microemulsion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:1983-1990. [PMID: 33512168 DOI: 10.1021/acs.langmuir.0c03527] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Smart microemulsions (MEs) recently have attracted significant interests. However, MEs, especially surfactant-free MEs (SFMEs) that respond to more than one stimulus, are rarely reported to date. Here, we reported the first example of dual-responsive SFME in which a CO2-sensitive hydroxyethylamine was used as an amphisolvent. This SFME was investigated utilizing ternary phase diagram, dynamic light scattering, and UV-visible spectrum techniques. It was found that three hydroxyethylamines could stabilize the octanol-water mixture to form transparent and isotropic SFMEs including nanoaggregates-rich pre-ouzo zone, regardless of the number of the hydroxyl group. Among them, 2-(dimethyl amino) ethanol (DMEA)-based SFME possesses the largest single-phase region and most sensitive to CO2 and the changes in temperature. With bubbling of CO2/N2 or decreasing/increasing temperature, both the single-phase region and pre-ouzo zone reversibly shrink and expand, as well as with breathing. However, CO2/N2-induced change is more significant than that induced by temperature. The former is mainly ascribed to the reversible protonation and deprotonation of DMEA, while the latter is generally interpreted as the effects of temperature on hydrogen bond interaction. Note that CO2 leads to a thorough demusification from Winsor IV ME to oil-rich and water-rich two phases without nanoaggregates, while cooling only causes to a particular phase separation, producing two new MEs phases, not typical Winsor I or II MEs. Such a unique dual-responsive SFME can not only be applied in the remediation of contaminated soil, drug delivery, and nanoparticles preparation but also opens a new door to switchable emulsion.
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Affiliation(s)
- Yue Zhou
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Shuai He
- College of Chemistry and Environmental Protection Engineering, Southwest Minzu University, Chengdu 610041, P. R. China
| | - Huanhuan Li
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Yongmin Zhang
- The Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
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9
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Zhang Y, Liu D, Wang B, Lu H, Huang Z. Reversible temperature regulation of CO2-responsive ionic liquid microemulsion. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125000] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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10
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Zhang Y, Chen X, Zhu B, Zhou Y, Liu X, Yang C. Temperature-Switchable Surfactant-Free Microemulsion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:7356-7364. [PMID: 32527085 DOI: 10.1021/acs.langmuir.0c00828] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Stimuli-responsive microemulsions have recently attracted significant interest due to their unique properties. Here, we developed a novel surfactant-free microemulsion (SFME) in a nontoxic ternary mixture, in which dimethyl sulfoxide (DMSO) was used as an amphisolvent, n-butanol was used as a nonpolar phase, and water was used as a polar phase. The DLS results confirmed the presence of the preouzo zone, and the polarity experiment revealed that the single-phase region can be further divided into oil-in-water, bicontinuous, and water-in-oil subregions. The size of droplets increased upon increasing the water or n-butanol content but decreased with increasing DMSO content. With increasing temperature, the area of the single-phase region increased, accompanied by a decrease in the size of the droplets, and the critical point moved to the corner of n-butanol. No matter in what subregion the formulation was found, decreasing temperature to below the phase-transition temperature (PTT) will induce a transition from monophasic MEs to complete phase separation and vice versa. This is mainly attributed to the effect of temperature on the hydrogen-bond interaction. Ag nanoparticles (Ag NPs) can be prepared above the PTT and facilely separated below PTT. The Ag NPs obtained from the current SFME showed higher catalytic activity than that obtained from a common surfactant-based ME.
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Affiliation(s)
- Yongmin Zhang
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Xuelian Chen
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Bo Zhu
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Yue Zhou
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Xuefeng Liu
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
| | - Cheng Yang
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, Wuxi 214122, P. R. China
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Li X, Wang B, Dai S, Lu H, Huang Z. Ionic Liquid-Based Microemulsions with Reversible Microstructures Regulated by CO 2. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:264-272. [PMID: 31845812 DOI: 10.1021/acs.langmuir.9b03327] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
CO2-responsive microemulsions based on ionic liquid 1,1,3,3-tetramethylguanidine-oleic acid (TMG-OA) have been designed to provide an approach for reducing the volatilization of amine in amine-containing microemulsions effectively and exhibit reversible transitions of microstructures. The ionic liquid TMG-OA was prepared by the direct neutralization of oleic acid (HOA) and 1,1,3,3-tetramethylguanidine (TMG, one of volatile and toxic amines). From the investigations of nuclear magnetic resonance hydrogen spectrum, pH, thermogravimetry, and automatic interface tension meter, the excellent properties of switchability, stability, and surface activity of TMG-OA were demonstrated, and then the ionic liquid-based microemulsions with CO2 response were prepared with TMG-OA (surfactant), HOA (oil phase), isopropyl alcohol (IPA, cosurfactant), and water. Interestingly, for microemulsions with a higher IPA content (47.42, 44.48 wt %), sizes of microemulsions are increased upon introducing CO2 and decreased upon addition of N2/65 °C. In addition, for microemulsions with a lower IPA content (26.22 wt %), the new microemulsions with different sizes are regenerated after the phase separation of emulsions generated by introducing CO2, and incomplete recovery of microemulsions can be observed upon addition of N2/65 °C. The reversible microstructures are induced by the swelling behavior and the reduced single phase area, which are caused by the reversible conversion between TMG-OA and HOA components.
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Affiliation(s)
- Xiaojiang Li
- College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu 610500 , P. R. China
| | - Baogang Wang
- College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu 610500 , P. R. China
- Engineering Research Center of Oilfield Chemistry , Ministry of Education , Chengdu 610500 , P. R. China
| | - Shanshan Dai
- College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu 610500 , P. R. China
- Engineering Research Center of Oilfield Chemistry , Ministry of Education , Chengdu 610500 , P. R. China
| | - Hongsheng Lu
- College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu 610500 , P. R. China
- Engineering Research Center of Oilfield Chemistry , Ministry of Education , Chengdu 610500 , P. R. China
| | - Zhiyu Huang
- College of Chemistry and Chemical Engineering , Southwest Petroleum University , Chengdu 610500 , P. R. China
- Engineering Research Center of Oilfield Chemistry , Ministry of Education , Chengdu 610500 , P. R. China
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12
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Dai S, Tao M, Lu H. CO2-switchable wormlike micelles based on a switchable ionic liquid and tetradecyl trimethyl ammonium bromide. J DISPER SCI TECHNOL 2019. [DOI: 10.1080/01932691.2019.1699430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Shanshan Dai
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, P. R. China
- Engineering Research Center of Oilfield Chemistry, Ministry of Education, Chengdu, P. R. China
| | - Minmin Tao
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, P. R. China
| | - Hongsheng Lu
- College of Chemistry and Chemical Engineering, Southwest Petroleum University, Chengdu, P. R. China
- Engineering Research Center of Oilfield Chemistry, Ministry of Education, Chengdu, P. R. China
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Zhang Y, Chen X, Liu X. Temperature-Induced Reversible-Phase Transition in a Surfactant-Free Microemulsion. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14358-14363. [PMID: 31600447 DOI: 10.1021/acs.langmuir.9b02842] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Microemulsion represents an important class of the colloidal system, though the development of stimuli-responsive microemulsion is still in its infancy. Here, we demonstrated the temperature responsiveness of a conventional surfactant-free microemulsion composed of n-octanol as nonpolar phase, ethanol as amphi-solvent, and water as polar phase for the first time. In the single-phase region of the phase diagram, the pre-ouzo zone was confirmed by dynamic light scattering (DLS), and the type of microemulsion was confirmed via the conductivity and polarity probe methods. The effects of temperature on the phase behavior and droplet size of the n-octanol-water-ethanol microemulsion system were systemically evaluated by the ternary phase diagram and DLS techniques. The results showed that the area of single-phase increases upon increasing temperature, but the area of pre-ouzo zone decreases accompanied by a decrease in the droplet size. Moreover, the critical point gradually draws close to the n-octanol corner with increasing temperature. When one formulation is far away from the demixing border, the droplet size can be reversibly and precisely regulated by changing temperature. When one formulation is located on the vicinity of the boundary, a minor variation in temperature can lead to a prominent phase transition between Winsor IV (high temperature) and Winsor II (low temperature). Such a temperature-responsive microemulsion can be used as a microreactor for Knoevenagel condensation. The reaction was carried out at 35 °C, and the product was collected from the water phase by simple filtration at 25 °C.
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Affiliation(s)
- Yongmin Zhang
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering , Jiangnan University , Wuxi , Jiangsu 214122 , P. R. China
| | - Xuelian Chen
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering , Jiangnan University , Wuxi , Jiangsu 214122 , P. R. China
| | - Xuefeng Liu
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering , Jiangnan University , Wuxi , Jiangsu 214122 , P. R. China
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