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Rajbanshi A, Hilton E, Dreiss CA, Murnane D, Cook MT. Stimuli-Responsive Polymers for Engineered Emulsions. Macromol Rapid Commun 2024; 45:e2300723. [PMID: 38395416 DOI: 10.1002/marc.202300723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/14/2024] [Indexed: 02/25/2024]
Abstract
Emulsions are complex. Dispersing two immiscible phases, thus expanding an interface, requires effort to achieve and the resultant dispersion is thermodynamically unstable, driving the system toward coalescence. Furthermore, physical instabilities, including creaming, arise due to presence of dispersed droplets of different densities to a continuous phase. Emulsions allow the formulation of oils, can act as vehicles to solubilize both hydrophilic and lipophilic molecules, and can be tailored to desirable rheological profiles, including "gel-like" behavior and shear thinning. The usefulness of emulsions can be further expanded by imparting stimuli-responsive or "smart" behaviors by inclusion of a stimuli-responsive emulsifier, polymer or surfactant. This enables manipulation like gelation, breaking, or aggregation, by external triggers such as pH, temperature, or salt concentration changes. This platform generates functional materials for pharmaceuticals, cosmetics, oil recovery, and colloid engineering, combining both smart behaviors and intrinsic benefit of emulsions. However, with increased functionality comes greater complexity. This review focuses on the use of stimuli-responsive polymers for the generation of smart emulsions, motivated by the great adaptability of polymers for this application and their efficacy as steric stabilizers. Stimuli-responsive emulsions are described according to the trigger used to provide the reader with an overview of progress in this field.
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Affiliation(s)
- Abhishek Rajbanshi
- UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, UK
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, AL10 9AB, UK
| | - Eleanor Hilton
- UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, UK
| | - Cécile A Dreiss
- Institute of Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London, SE1 9NH, UK
| | - Darragh Murnane
- School of Life and Medical Sciences, University of Hertfordshire, Hatfield, AL10 9AB, UK
| | - Michael T Cook
- UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, UK
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Glikman D, Wyszynski L, Lindfeld V, Hochstädt S, Hansen MR, Neugebauer J, Schönhoff M, Braunschweig B. Charge Regulation at the Nanoscale as Evidenced from Light-Responsive Nanoemulsions. J Am Chem Soc 2024; 146:8362-8371. [PMID: 38483326 DOI: 10.1021/jacs.3c14112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Emulsions are indispensable in everyday life, and the demand for emulsions' diversity and control of properties is therefore substantial. As emulsions possess a high internal surface area, an understanding of the oil/water (o/w) interfaces at the molecular level is fundamental but often impaired by experimental limitations to probe emulsion interfaces in situ. Here, we have used light-responsive surfactants (butyl-AAP) that can photoisomerize between E and Z isomers by visible and UV light irradiation to tune the emulsion interfaces. This causes massive changes in the interface tension at the extended o/w interfaces in macroemulsions and a drastic shift in the surfactants' critical micelle concentration, which we show can be used to control both the stability and phase separation. Strikingly different from macroemulsions are nanoemulsions (RH ∼90 nm) as these are not susceptible to E/Z photoisomerization of the surfactants in terms of changes in their droplet size or ζ-potential. However, in situ second-harmonic scattering and pulsed-field gradient nuclear magnetic resonance (NMR) experiments show dramatic and reversible changes in the surface excess of surfactants at the nanoscopic interfaces. The apparent differences in ζ-potentials and surface excess provide evidence for a fixed charge to particle size ratio and the need for counterion condensation to renormalize the particle charge to a critical charge, which is markedly different compared to the behavior of very large particles in macroemulsions. Thus, our findings may have broader implications as the electrostatic stabilization of nanoparticles requires much lower surfactant concentrations, allowing for a more sustainable use of surfactants.
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Affiliation(s)
- Dana Glikman
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
- Center for Soft Nanoscience, University of Münster, Busso-Peus-Straße 10, 48149 Münster, Germany
| | - Leonard Wyszynski
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Valentin Lindfeld
- Organic Chemistry Institute, University of Münster, Corrensstraße 36, 48149 Münster, Germany
- Center for Multiscale Theory and Computation, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Sebastian Hochstädt
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Michael Ryan Hansen
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
| | - Johannes Neugebauer
- Organic Chemistry Institute, University of Münster, Corrensstraße 36, 48149 Münster, Germany
- Center for Multiscale Theory and Computation, University of Münster, Corrensstraße 36, 48149 Münster, Germany
| | - Monika Schönhoff
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
- Center for Soft Nanoscience, University of Münster, Busso-Peus-Straße 10, 48149 Münster, Germany
| | - Björn Braunschweig
- Institute of Physical Chemistry, University of Münster, Corrensstraße 28/30, 48149 Münster, Germany
- Center for Soft Nanoscience, University of Münster, Busso-Peus-Straße 10, 48149 Münster, Germany
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Xu F, Shi Y, Li B, Liu C, Zhang Y, Zhong J. Characterization, Stability and Antioxidant Activity of Vanilla Nano-Emulsion and Its Complex Essential Oil. Foods 2024; 13:801. [PMID: 38472915 DOI: 10.3390/foods13050801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/23/2024] [Accepted: 03/01/2024] [Indexed: 03/14/2024] Open
Abstract
As a natural flavoring agent, vanilla essential oil has a special aroma and flavor, but its volatility and instability limit its value. Therefore, in this study, vanilla essential oil was compounded with cinnamon essential oil to prepare nano-emulsions (composite nano-emulsions called C/VT and C/VM), and the stability of the composite essential oil emulsions was investigated. Transmission electron microscopy (TEM) images showed that the nano-emulsions were spherical in shape and some flocs were observed in C/VM and C/VT. The results showed that the average droplet sizes of C/VM and C/VT increased only by 14.99% and 15.01% after heating at 100 °C for 20 min, and the average droplet sizes were less than 120 nm after 24 days of storage at 25 °C. Possibly due to the presence of reticulated flocs, which have a hindering effect on the movement of individual droplets, the instability indices of C/VM and C/VT were reduced by 34.9% and 39.08%, respectively, in comparison to the instability indices of C/VM and C/VT. In addition, the results of antioxidant experimental studies showed that the presence of composite essential oil flocs had no significant effect on the antioxidant capacity. These results indicate that the improved stability of the composite essential oil nano-emulsions is conducive to broadening the application of vanilla essential oil emulsions.
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Affiliation(s)
- Fei Xu
- Spice and Beverage Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wanning 571533, China
- Key Laboratory of Processing Suitability and Quality Control of the Special Tropical Crops of Hainan Province, Wanning 571533, China
| | - Yucong Shi
- State Key Laboratory of Food Science and Resources, Nanchang University, No 235, Nanjing East Road, Nanchang 330047, China
| | - Bin Li
- State Key Laboratory of Food Science and Resources, Nanchang University, No 235, Nanjing East Road, Nanchang 330047, China
| | - Chengmei Liu
- State Key Laboratory of Food Science and Resources, Nanchang University, No 235, Nanjing East Road, Nanchang 330047, China
| | - Yanjun Zhang
- Spice and Beverage Research Institute, Chinese Academy of Tropical Agricultural Sciences, Wanning 571533, China
- Key Laboratory of Processing Suitability and Quality Control of the Special Tropical Crops of Hainan Province, Wanning 571533, China
| | - Junzhen Zhong
- State Key Laboratory of Food Science and Resources, Nanchang University, No 235, Nanjing East Road, Nanchang 330047, China
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Zhao Z, Zhang L, Zhang H, Lu G, Meng T, Hao H, Zhang Y, Li J, Yan H. Computational Insights into a CO 2-Responsive Emulsion Prepared Using the Superamphiphile Assembled by Electrostatic Interactions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:938-949. [PMID: 38134444 DOI: 10.1021/acs.langmuir.3c03140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2023]
Abstract
The superamphiphiles exhibit broad prospects for fabricating stimuli-responsive emulsions. Because the superamphiphiles are assembled via noncovalent interactions, they have the advantage of fast response and high efficiency. Recently, a series of switchable emulsions using CO2-responsive superamphiphiles have been developed, which extends the applications of CO2-responsive materials in widespread field. However, there is still a lack of fundamental understanding on the switching mechanism related to the assembled structure of superamphiphiles at the oil-water interface. We employed molecular dynamics (MD) simulations to investigate the reversible emulsification/demulsification process of a responsive emulsion system stabilized by a recently developed responsive superamphiphile (BTOA), which consists of oleic acid (OA) and cationic amine (named 1,3-bis(aminopropyl)tetramethyldisiloxane, BT). The simulation results present the morphologies in both the emulsion and demulsification states. It is found that the ionized OA- and the protonated BT+ together form an adsorption layer at the oil-water interface. The hydrophobic parts of BT+ are inserted into the adsorption layer, and the two amine groups contact the water phase. This adsorption layer reduces the interfacial tension and stabilizes the emulsion. After the bubbling of CO2, the surfactants were fully protonated to OA and BT2+. Because of the changes in the molecular polarity, OA and BT2+ entered the oil and water phases, respectively, resulting in demulsification. The structural and dynamical properties were analyzed to reveal the different intermolecular interactions that were responsible for the reversible reversibility of the emulsion. The observations are considered to be complementary to experimental studies and are expected to provide deeper insights into studies on developing responsive materials via supramolecular assemblies.
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Affiliation(s)
- Zhen Zhao
- School of Pharmaceutical Sciences, Liaocheng University, Liaocheng, Shandong 252059, P. R. China
| | - Lu Zhang
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong 252059, P. R. China
| | - Hao Zhang
- School of Pharmaceutical Sciences, Liaocheng University, Liaocheng, Shandong 252059, P. R. China
| | - Guoqiang Lu
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, No. 1800 Lihu Avenue, Wuxi 214122, P. R. China
| | - Tong Meng
- School of Pharmaceutical Sciences, Liaocheng University, Liaocheng, Shandong 252059, P. R. China
| | - Hongguo Hao
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng, Shandong 252059, P. R. China
| | - Yongmin Zhang
- Key Laboratory of Synthetic and Biological Colloids, Ministry of Education, School of Chemical & Materials Engineering, Jiangnan University, No. 1800 Lihu Avenue, Wuxi 214122, P. R. China
| | - Jun Li
- School of Pharmaceutical Sciences, Liaocheng University, Liaocheng, Shandong 252059, P. R. China
| | - Hui Yan
- School of Pharmaceutical Sciences, Liaocheng University, Liaocheng, Shandong 252059, P. R. China
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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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Tirgarian B, Farmani J, Farahmandfar R, Milani JM, Van Bockstaele F. Switchable pH-responsive Biopolymeric Stabilizers Made by Sonothermal Glycation of Sodium Caseinate with κappa-carrageenan. FOOD BIOPHYS 2023. [DOI: 10.1007/s11483-023-09778-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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Deng CF, Su YY, Yang SH, Jiang QR, Xie R, Ju XJ, Liu Z, Pan DW, Wang W, Chu LY. Designable microfluidic ladder networks from backstepping microflow analysis for mass production of monodisperse microdroplets. LAB ON A CHIP 2022; 22:4962-4973. [PMID: 36420612 DOI: 10.1039/d2lc00771a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Controllable mass production of monodisperse droplets plays a key role in numerous fields ranging from scientific research to industrial application. Microfluidic ladder networks show great potential in mass production of monodisperse droplets, but their design with uniform microflow distribution remains challenging due to the lack of a rational design strategy. Here an effective design strategy based on backstepping microflow analysis (BMA) is proposed for the rational development of microfluidic ladder networks for mass production of controllable monodisperse microdroplets. The performance of our BMA rule for rational microfluidic ladder network design is demonstrated by using an existing analogism-derived rule that is widely used for the design of microfluidic ladder networks as the control group. The microfluidic ladder network designed by the BMA rule shows a more uniform flow distribution in each branch microchannel than that designed by the existing rule, as confirmed by single-phase flow simulation. Meanwhile, the microfluidic ladder network designed by the BMA rule allows mass production of droplets with higher size monodispersity in a wider window of flow rates and mass production of polymeric microspheres from such highly monodisperse droplet templates. The proposed BMA rule provides new insights into the microflow distribution behaviors in microfluidic ladder networks based on backstepping microflow analysis and provides a rational guideline for the efficient development of microfluidic ladder networks with uniform flow distribution for mass production of highly monodisperse droplets. Moreover, the BMA method provides a general analysis strategy for microfluidic networks with parallel multiple microchannels for rational scale-up.
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Affiliation(s)
- Chuan-Fu Deng
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yao-Yao Su
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Shi-Hao Yang
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Qing-Rong Jiang
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Rui Xie
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Xiao-Jie Ju
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Zhuang Liu
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Da-Wei Pan
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Wei Wang
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Liang-Yin Chu
- School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, China
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Wu Y, Zeng M, Cheng Q, Huang C. Recent Progress toward Physical Stimuli-Responsive Emulsions. Macromol Rapid Commun 2022; 43:e2200193. [PMID: 35622941 DOI: 10.1002/marc.202200193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/30/2022] [Indexed: 11/11/2022]
Abstract
Emulsion as a fine dispersion of immiscible liquids has involved widespread applications in industry, pharmaceuticals, agriculture and personal care. Stimuli-responsive emulsions capable of on-demand demulsification or changing their properties are required in many cases such as controllable release cargo, oil recovery, emulsifiers recycle and product separation, great progress has been achieved in these areas. Among these various triggers, much effort has been made to develop physical stimuli, due to the noninvasive and environmentally friendly characteristics. Physical stimuli-responsive emulsions provide a plenty of valuable practical applications in the fields of sustainable industry, biomedical reaction, drug delivery. Here, we summarize the recent development in the field of emulsions in response to physical stimuli consisting of temperature, light, magnetic field, electrical field, etc. The preparation methods and mechanisms of physical stimuli-responsive emulsions and their applications of catalysis reaction, drug delivery, and oil recovery are highlighted in this review. The future directions and outstanding problems of the physical stimuli-responsive emulsions are also discussed. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Yutian Wu
- School of chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430070, China
| | - Min Zeng
- School of chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430070, China
| | - Quanyong Cheng
- School of chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430070, China
| | - Caili Huang
- School of chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430070, China
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