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Daware SV, Mondal R, Kothari M, Chowdhury A, Liu ACY, Prabhakar R, Kumaraswamy G. Synthesis and Characterization of Monolayer Colloidal Sheets. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024. [PMID: 39288076 DOI: 10.1021/acs.langmuir.4c02262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
Sheet-like colloidal assemblies represent model systems to investigate the structure and properties of two-dimensional materials. Here, we report a simple yet versatile method for the preparation of colloidal monolayer sheet-like assemblies that affords control over the size, crystalline order, flexibility, and defect density. The protocol that we report relies on self-assembly of colloids as a sessile drop of dispersion is evaporated on an oil-covered substrate. In this case, the contact line continually moves as the drop shrinks. Polyethyleneimine polymer-covered micrometer-sized colloidal particles are transported to the air-water interface and assemble to form a monolayer sheet as the drop dries. Cross-linking the polymer renders the colloidal assembly permanent. Interestingly, monodisperse colloidal particles form disordered assemblies when dried from low concentration dispersions, while polycrystalline ordered assemblies form at higher concentrations. We demonstrate that increasing the cross-linker to polymer ratio decreases the flexibility of the assembly. Introduction of different-sized colloidal particles in a sheet leads to increased disorder. Removal of sacrificial particles from the sheet allowed the introduction of "holes" in the sheets. Thus, these colloidal sheets are models for probing the effects of disorder, doping, and vacancies in two-dimensional systems.
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Affiliation(s)
- Santosh Vasant Daware
- Department of Chemical Engineering, Indian Institute of Bombay, Mumbai 400076, India
- IITB Monash Research Academy, IIT Bombay, Powai 400076, India
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton 3800, Australia
| | - Ranajit Mondal
- Department of Chemical Engineering, IIT Hyderabad, Kandi, Telangana 502284, India
| | - Mansi Kothari
- Department of Chemistry, Indian Institute of Bombay, Mumbai 400076, India
| | - Arindam Chowdhury
- Department of Chemistry, Indian Institute of Bombay, Mumbai 400076, India
| | - Amelia C Y Liu
- School of Physics and Astronomy, Monash University, Clayton 3800, Australia
| | - Ranganathan Prabhakar
- Department of Mechanical and Aerospace Engineering, Monash University, Clayton 3800, Australia
| | - Guruswamy Kumaraswamy
- Department of Chemical Engineering, Indian Institute of Bombay, Mumbai 400076, India
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2
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Bayles AV, Vermant J. Divide, Conquer, and Stabilize: Engineering Strong Fluid-Fluid Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:6499-6505. [PMID: 35584356 DOI: 10.1021/acs.langmuir.2c00948] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In multiphase materials, structured fluid-fluid interfaces can provide mechanical resistance against destabilization. Coarsening, coalescence, and significant deformation can be stalled with appropriate interfacial rheology and thus preserve interface integrity. Often, interfacial "strength" is generated by dense, packed surface populations, which are challenging to achieve through gradual, equilibrium-limited adsorption. Recent efforts have focused on developing new methods to produce kinetically trapped interfacial structures that possess desirable viscoelasticity or viscoplasticity, sometimes even with sparse populations. In creating these interfaces, we should recognize that the processing history is deterministic and offers alternative handles to engineer useful rheology. In this Perspective, we consider what can be achieved by designing not only the intrinsic qualities of surface-active species but also the process that brings them to the interface. We contrast different classes of processing history through a somewhat historical lens: after creating an interface ("divide"), what ("conquering") strategies exist for populating it with agents that ensure stabilization? Navigating the delicate interplay among property, structure, and processing history is required to improve material and energy use and to realize unique multiphase materials.
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Affiliation(s)
- Alexandra V Bayles
- Department of Materials, ETH Zürich, Zürich, Switzerland 8093
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Jan Vermant
- Department of Materials, ETH Zürich, Zürich, Switzerland 8093
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3
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Koroleva MY, Yurtov EV. Pickering emulsions: properties, structure, using as colloidosomes and stimuli-responsive emulsions. RUSSIAN CHEMICAL REVIEWS 2022. [DOI: 10.1070/rcr5024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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4
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Kumar H, Dugyala VR, Basavaraj MG. Phase Inversion of Ellipsoid-Stabilized Emulsions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7295-7304. [PMID: 34100620 DOI: 10.1021/acs.langmuir.1c00456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The efficacy of anisotropic particles in Pickering emulsion stabilization, attributed to shape-induced capillary interactions, is well-documented in the literature. In this contribution, we show that the surface of hematite ellipsoids can be modified in situ by the addition of oleic acid to effect transitional phase inversion of Pickering emulsions. Interestingly, incorporation of oleic acid results in the formation of nonspherical emulsion drops. The phase inversion of oil-in-water to water-in-oil and the transition in shape of emulsion drops from spherical to nonspherical is observed in two different particle systems, namely, nanoellipsoids and microellipsoids. The surface of spherical emulsion drops stabilized by particles or particles along with high concentration of oleic acid is found to consist of ellipsoids arranged in a close-packed configuration with their major axis parallel to the interface. In contrast, at intermediate oleic acid concentration, the surface of nonspherical emulsion drops is observed to be covered with loosely packed particle monolayer, with the ellipsoids at the oil/water interface taking up many different orientations. Using contact angle goniometry, the change in the wettability of hematite particles due to adsorption of oleic acid is established to be the mechanism responsible for the phase inversion of Pickering emulsions.
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Affiliation(s)
- Hemant Kumar
- Polymer Engineering and Colloid Science(PECS) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai - 600036, Tamil Nadu, India
| | - Venkateshwar Rao Dugyala
- Department of Chemical Engineering, Indian Institute of Science Education and Research Bhopal, Bhopal 462 066 Madhya Pradesh, India
| | - Madivala G Basavaraj
- Polymer Engineering and Colloid Science(PECS) Laboratory, Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai - 600036, Tamil Nadu, India
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Macmillan KA, Clegg PS. Are Langmuir Trough Studies Useful? Unexpected Emulsification Behavior Using Colloidal Rods. J Phys Chem Lett 2021; 12:5241-5247. [PMID: 34048240 DOI: 10.1021/acs.jpclett.1c00818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
While studies carried out in a Langmuir trough have rigorously demonstrated that, at high surface pressure, ellipsoidal particles do flip and spherocylinders (rods) can flip, much less is known about the practical situation on the surface of a droplet or bubble. We present emulsification studies using colloidal rods and find that the droplets are bridged by the rods independent of shear rate and particle concentration and are only weakly dependent on the pH of the continuous phase. In a trough, it is the low aspect ratio rods which flip and the high aspect ratio rods which form bilayers; on the surface of a droplet we found that the high aspect ratio rods always bridge whereas the shorter rods show random bridging behavior. Hence, the behavior of anisotropic particles "in action" is essentially opposite to expectations from trough studies.
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Affiliation(s)
- Katherine A Macmillan
- School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, U.K
| | - Paul S Clegg
- School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh EH9 3FD, U.K
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6
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Kumar S, Foroozesh J. Chitin nanocrystals based complex fluids: A green nanotechnology. Carbohydr Polym 2021; 257:117619. [PMID: 33541647 DOI: 10.1016/j.carbpol.2021.117619] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 12/31/2020] [Accepted: 01/02/2021] [Indexed: 12/31/2022]
Abstract
Chitin biopolymer has received significant attention recently by many industries as a green technology. Nanotechnology has been used to make chitin nanocrystals (ChiNCs) that are rod-shaped natural nanomaterials with nanoscale size. Owing to the unique features such as biodegradability, biocompatibility, renewability, rod-shape, and excellent surface and interfacial, physiochemical, and thermo-mechanical properties; ChiNCs have been green and attractive products with wide applications specifically in medical and pharmaceutical, food and packaging, cosmetic, electrical, and electronic, and also in the oil and gas industry. This review aims to give a comprehensive and applied insight into ChiNCs technology. It starts with reviewing different sources of chitin and their extraction methods followed by the characterization of ChiNCs. Furthermore, a detailed investigation into various complex fluids (dispersions, emulsions, foams, and gels) stabilized by ChiNCs and their characterisation have been thoroughly deliberated. Finally, the current status including ground-breaking applications, untapped investigations, and future prospective have been presented.
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Affiliation(s)
- Sunil Kumar
- Institute of Hydrocarbon Recovery, Universiti Teknologi PETRONAS, Malaysia
| | - Jalal Foroozesh
- Institute of Hydrocarbon Recovery, Universiti Teknologi PETRONAS, Malaysia; Chemical Engineering Department, Universiti Teknologi PETRONAS, Malaysia.
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7
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Kumar S, Pandey A, Trifkovic M, Bryant SL. A facile and economical configuration for continuous generation and separation of oil in water emulsions. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2020.117849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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8
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Higashide N, Matsuda N, Naoe K, Imai M. Application of food-grade magnesium stearate microparticles as stabilizer in preparation of biocompatible Pickering emulsions. CHEMICAL PAPERS 2020. [DOI: 10.1007/s11696-020-01428-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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9
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The interface adsorption behavior in a Pickering emulsion stabilized by cylindrical polystyrene particles. J Colloid Interface Sci 2019; 552:230-235. [DOI: 10.1016/j.jcis.2019.05.058] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 05/17/2019] [Accepted: 05/19/2019] [Indexed: 01/01/2023]
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10
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Li S, Wang F, Liu H. pH/UV Responsive Polymeric Micelles Based on Coumarin to Tune Emulsification/Solidification Performance. ChemistrySelect 2019. [DOI: 10.1002/slct.201901579] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Sisi Li
- College of Chemistry and Chemical EngineeringCentral South University Changsha 410083, Hunan P. R. China
| | - Feng Wang
- College of Chemistry and Chemical EngineeringCentral South University Changsha 410083, Hunan P. R. China
| | - Hui Liu
- College of Chemistry and Chemical EngineeringCentral South University Changsha 410083, Hunan P. R. China
- Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese ResourcesCentral South University Changsha 410083, Hunan P. R. China
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11
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Hunter SJ, Thompson KL, Lovett JR, Hatton FL, Derry MJ, Lindsay C, Taylor P, Armes SP. Synthesis, Characterization, and Pickering Emulsifier Performance of Anisotropic Cross-Linked Block Copolymer Worms: Effect of Aspect Ratio on Emulsion Stability in the Presence of Surfactant. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:254-265. [PMID: 30562037 DOI: 10.1021/acs.langmuir.8b03727] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Reversible addition-fragmentation chain transfer (RAFT) aqueous dispersion polymerization is used to prepare epoxy-functional PGMA-P(HPMA- stat-GlyMA) diblock copolymer worms, where GMA, HPMA, and GlyMA denote glycerol monomethacrylate, 2-hydroxypropyl methacrylate, and glycidyl methacrylate, respectively. The epoxy groups on the GlyMA residues were ring-opened using 3-aminopropyltriethoxysilane (APTES) in order to cross-link the worm cores via a series of hydrolysis-condensation reactions. Importantly, the worm aspect ratio can be adjusted depending on the precise conditions selected for covalent stabilization. Relatively long cross-linked worms are obtained by reaction with APTES at 20 °C, whereas much shorter worms with essentially the same copolymer composition are formed by cooling the linear worms from 20 to 4 °C prior to APTES addition. Small-angle X-ray scattering (SAXS) studies confirmed that the mean aspect ratio for the long worms is approximately eight times greater than that for the short worms. Aqueous electrophoresis studies indicated that both types of cross-linked worms acquired weak cationic surface charge at low pH as a result of protonation of APTES-derived secondary amine groups within the nanoparticle cores. These cross-linked worms were evaluated as emulsifiers for the stabilization of n-dodecane-in-water emulsions via high-shear homogenization at 20 °C and pH 8. Increasing the copolymer concentration led to a reduction in mean droplet diameter, indicating that APTES cross-linking was sufficient to allow the nanoparticles to adsorb intact at the oil/water interface and hence produce genuine Pickering emulsions, rather than undergo in situ dissociation to form surface-active diblock copolymer chains. In surfactant challenge studies, the relatively long worms required a thirty-fold higher concentration of a nonionic surfactant (Tween 80) to be displaced from the n-dodecane-water interface compared to the short worms. This suggests that the former nanoparticles are much more strongly adsorbed than the latter, indicating that significantly greater Pickering emulsion stability can be achieved by using highly anisotropic worms. In contrast, colloidosomes prepared by reacting the hydroxyl-functional adsorbed worms with an oil-soluble polymeric diisocyanate remained intact when exposed to high concentrations of Tween 80.
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Affiliation(s)
- Saul J Hunter
- Department of Chemistry , University of Sheffield , Dainton Building, Brook Hill , Sheffield , Yorkshire S3 7HF , U.K
| | - Kate L Thompson
- The School of Materials, University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - Joseph R Lovett
- Department of Chemistry , University of Sheffield , Dainton Building, Brook Hill , Sheffield , Yorkshire S3 7HF , U.K
| | - Fiona L Hatton
- Department of Chemistry , University of Sheffield , Dainton Building, Brook Hill , Sheffield , Yorkshire S3 7HF , U.K
| | - Matthew J Derry
- Department of Chemistry , University of Sheffield , Dainton Building, Brook Hill , Sheffield , Yorkshire S3 7HF , U.K
| | - Christopher Lindsay
- Syngenta, Jealott's Hill International Research Centre , Bracknell , Berkshire RG42 6EY , U.K
| | - Philip Taylor
- Syngenta, Jealott's Hill International Research Centre , Bracknell , Berkshire RG42 6EY , U.K
| | - Steven P Armes
- Department of Chemistry , University of Sheffield , Dainton Building, Brook Hill , Sheffield , Yorkshire S3 7HF , U.K
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12
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Anjali TG, Basavaraj MG. Shape-Anisotropic Colloids at Interfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:3-20. [PMID: 29986588 DOI: 10.1021/acs.langmuir.8b01139] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Research in the 1980s demonstrated the formation of monolayers of particles achieved by interfacial particle trapping as a model system for investigating colloids in two dimensions. Since then, microscopy visualization of two-dimensional particle monolayers and quantification of the microstructure have led to significant fundamental understanding of a number of phenomena such as crystallization, freezing and melting transitions, dislocation dynamics, aggregation kinetics, and others. On the application front, particles at curved interfaces, as often the case in particle-stabilized emulsions and foams, have received considerable attention in the last few decades. The growing interest in the search for novel particles and new strategies to effect emulsion stabilization stems from their application in several disciplines. Moreover, particle-stabilized Pickering emulsions and foams can also be used to derive a number of advanced functional materials. Compared to several accounts of research on spherical colloids at fluid-fluid interfaces, investigations of the behavior of shape-anisotropic particles at interfaces, albeit receiving considerable attention in recent years, are still in a nascent stage. The objective of this feature article is to highlight our recent work in this area. In particular, the adsorption of shape-anisotropic particles to interfaces, wetting behavior, interfacial self-assembly, the response of nonspherical-particle-coated interfaces to compression and shear, and their ability to stabilize emulsions are discussed.
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Affiliation(s)
- Thriveni G Anjali
- Polymer Engineering and Colloid Science (PECS) Laboratory, Department of Chemical Engineering , Indian Institute of Technology Madras , Chennai 600 036 , India
| | - Madivala G Basavaraj
- Polymer Engineering and Colloid Science (PECS) Laboratory, Department of Chemical Engineering , Indian Institute of Technology Madras , Chennai 600 036 , India
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Allahyarov E, Löwen H. Length segregation in mixtures of spherocylinders induced by imposed topological defects. SOFT MATTER 2018; 14:8962-8973. [PMID: 30375629 DOI: 10.1039/c8sm01790e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We explore length segregation in binary mixtures of spherocylinders of lengths L1 and L2 which are tangentially confined on a spherical surface of radius R. The orientation of the spherocylinders is constrained along an externally imposed direction field on the sphere which is either along the longitude or the latitude lines of the sphere. In both situations, integer orientational defects at the poles are imposed. Using computer simulations we show that these topological defects induce a complex segregation picture also depending on the length ratio factor γ = L2/L1 and the total packing fraction η of the spherocylinders. When the binary mixture is aligned along the longitude lines of the sphere, shorter rods tend to accumulate at the topological defects of the polar caps whereas longer rods occupy the central equatorial area of the spherical surface. In the reverse case of latitude ordering, a new state can emerge where longer rods are predominantly both in the cap and in the equatorial areas and shorter rods are localized in between. As a reference situation, we consider a defect-free situation in the flat plane and do not find any length segregation there at similar γ and η; hence, the segregation is purely induced by the imposed topological defects. We also develop an Onsager-like density functional theory which is capable of predicting length segregation in ordered mixtures. At low density, the results of this theory are in good agreement with the simulation data.
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Affiliation(s)
- Elshad Allahyarov
- Theoretische Chemie, Universität Duisburg-Essen, D-45141 Essen, Germany
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Anjali TG, Basavaraj MG. Influence of pH and Salt Concentration on Pickering Emulsions Stabilized by Colloidal Peanuts. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13312-13321. [PMID: 30303393 DOI: 10.1021/acs.langmuir.8b02913] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Solid-stabilized emulsions commonly known as Pickering emulsions offer unique benefits such as superior stability and controlled permeability compared to conventional surfactant stabilized emulsions. In this article, the effect of pH, the electrolyte and particle concentration, homogenization speed, and volume fraction of oil on the formation, stability, and the microstructure of emulsion droplets stabilized by micron-size peanut-shaped hematite particles are investigated. The influence of surface charge of particles on emulsification is studied by varying the pH of the dispersing medium, the addition of an electrolyte or a combination of both. Stable O/W emulsions are formed only when the aqueous dispersions at intermediate pH between 4 and 11, and decane (2:1 volume ratio) are vigorously mixed. However, emulsions are not formed when the particles are highly charged that is, at pH 2 and 12. The presence of monovalent salt or high-speed homogenization assists the emulsion formation at pH 3, whereas their combination helps in emulsification at pH 2. However, neither the addition of an electrolyte nor the high-speed homogenization or their combination facilitates the formation of emulsions at pH 12. We show that the image-charge repulsion and the surface charge induced wettability change can explain the influence of both pH and salt concentrations on the formation of Pickering emulsions. Although oil-in-water emulsions typically cream because of the density difference, microscopy observations revealed the presence of a large number of small particle-covered oil droplets in the sediments of the emulsified samples. These drops are observed to be entrapped in dense-particle networks. This leads to a considerable reduction in the number of particles available for the stabilization of floating emulsion droplets and thus influences their size and surface coverage. The possibility of tailoring the stability, droplet size and, the surface coverage discussed in this article can play a crucial role in situations that demand controlled release of active components.
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Affiliation(s)
- Thriveni G Anjali
- Polymer Engineering and Colloid Science (PECS) Laboratory, Department of Chemical Engineering , Indian Institute of Technology Madras , Chennai 600 036 , India
| | - Madivala G Basavaraj
- Polymer Engineering and Colloid Science (PECS) Laboratory, Department of Chemical Engineering , Indian Institute of Technology Madras , Chennai 600 036 , India
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Cho YJ, Kim DM, Song IH, Choi JY, Jin SW, Kim BJ, Jeong JW, Jang CE, Chu K, Chung CM. An Oligoimide Particle as a Pickering Emulsion Stabilizer. Polymers (Basel) 2018; 10:E1071. [PMID: 30960996 PMCID: PMC6403722 DOI: 10.3390/polym10101071] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/17/2018] [Accepted: 09/25/2018] [Indexed: 12/05/2022] Open
Abstract
A pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA)-based oligoimide (PMDA-ODA) was synthesized by a one-step procedure using water as a solvent. The PMDA-ODA particles showed excellent partial wetting properties and were stably dispersed in both water and oil phases. A stable dispersion was not obtained with comparison PMDA-ODA particles that were synthesized by a conventional two-step method using an organic solvent. Both oil-in-water and water-in-oil Pickering emulsions were prepared using the oligoimide particles synthesized in water, and the size of the emulsion droplet was controlled based on the oligoimide particle concentration. The oligoimide particles were tested to prepare Pickering emulsions using various kinds of oils. The oil-in-water Pickering emulsions were successfully applied to prepare microcapsules of the emulsion droplets. Our new Pickering emulsion stabilizer has the advantages of easy synthesis, no need for surface modification, and the capability of stabilizing both oil-in-water and water-in-oil emulsions.
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Affiliation(s)
- Yu-Jin Cho
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - Dong-Min Kim
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - In-Ho Song
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - Ju-Young Choi
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - Seung-Won Jin
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - Beom-Jun Kim
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - Jin-Won Jeong
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - Chae-Eun Jang
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
| | - Kunmo Chu
- Samsung Advanced Institute of Technology, Suwon 16678, Korea.
| | - Chan-Moon Chung
- Department of Chemistry, Yonsei University, Wonju 26493, Korea.
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Luo Q, Wang Y, Yoo E, Wei P, Pentzer E. Ionic Liquid-Containing Pickering Emulsions Stabilized by Graphene Oxide-Based Surfactants. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:10114-10122. [PMID: 30060669 DOI: 10.1021/acs.langmuir.8b02011] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Emulsions stabilized by particles (i.e., Pickering emulsions) are complementary to those stabilized by small molecules or polymers and most commonly consist of oil droplets dispersed in a continuous water phase, with particles assembled at the fluid-fluid interface. New particle surfactants and different fluid-fluid interfaces are critical for developing next-generation systems for a number of advanced applications. Herein we report the preparation of IL-containing emulsions stabilized by graphene oxide (GO)-based nanoparticles using the IL [Bmim][PF6]: GO nanosheets stabilize IL-in-water emulsions, and alkylated GO nanosheets (C18-GO) stabilize IL-in-oil emulsions. The impact of particle concentration, fluid-fluid ratio, and addition of acid or base on emulsion formation and stability is studied, with distinct effects for the water and oil systems observed. We then illustrate the broad applicability of GO-based particle surfactants by preparing emulsions with different ILs and preparing inverted emulsions (water-in-IL and oil-in-IL emulsions). The latter systems were accessed by tuning the polarity of GO nanosheets by functionalization with a perfluorinated alkyl chain such that they were dispersible in IL. This work provides insight into the preparation of different IL-containing emulsions and lays a foundation for the architecture of dissimilar materials into composite systems.
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Affiliation(s)
- Qinmo Luo
- Department of Chemistry , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Yifei Wang
- Department of Chemistry , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Esther Yoo
- Department of Chemistry , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Peiran Wei
- Department of Chemistry , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
| | - Emily Pentzer
- Department of Chemistry , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States
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Mallikarjunachari G, Nallamilli T, Ravindran P, Basavaraj MG. Nanoindentation of clay colloidosomes. Colloids Surf A Physicochem Eng Asp 2018. [DOI: 10.1016/j.colsurfa.2018.04.041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Shahid S, Gurram SR, Basavaraj MG. Doubly pH Responsive Emulsions by Exploiting Aggregation of Oppositely Charged Nanoparticles and Polyelectrolytes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:5060-5071. [PMID: 29649875 DOI: 10.1021/acs.langmuir.8b00795] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
We present a simple and modular approach to realize highly stable pH responsive Pickering emulsion from mixtures of commercially available oppositely charged nanoparticle and polyelectrolyte. While highly charged nanoparticles and polyelectrolytes when used solely do not stabilize emulsions, we show that the electrostatic attraction between oppositely charged nanoparticles and polyelectrolytes can be exploited to formulate emulsions with long-term stability of up to 8 months. The Ludox CL nanoparticles and poly(4-styrenesulfonate) sodium salt (PSS) when dispersed in aqueous solution at pH 2-11 form particle polyelectrolyte complexes (PPCs) due to heteroaggregation. These complexes are effective in stabilizing oil-in-water Pickering emulsions. We demonstrate that this is due to the formation of weakly charged complexes that are surface active and hence readily adsorbed to the oil-water interface created during emulsification. We show that the composition of nanoparticles and polyelectrolytes in the mixture as well as the pH can be tuned to control the average diameter of the emulsions droplets. Immediate destabilization and doubled responsiveness of the emulsions stabilized by particle polyelectrolyte complexes are illustrated by changing the pH of the stable emulsions formed at intermediate pH to either 1 or 13. The aggregation behavior of nanoparticle-polyelectrolyte mixtures and the effect of various parameters such as mixing fraction, pH, and energy input on the formation of Pickering emulsions is discussed. Furthermore, we show that the formation of near charge neutral aggregates that exhibit optimal wetting conditions is a requirement to accomplish emulsion formation. The visualization of particle polyelectrolyte complexes around the emulsion droplets, their morphology prior to emulsification, and their wetting properties are also investigated to elucidate the mechanism of emulsification.
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Affiliation(s)
- Shumaila Shahid
- Polymer Engineering and Colloid Science Laboratory, Department of Chemical Engineering , Indian Institute of Technology , Madras, Chennai 600036 , India
| | - Swaroop Rajesh Gurram
- Polymer Engineering and Colloid Science Laboratory, Department of Chemical Engineering , Indian Institute of Technology , Madras, Chennai 600036 , India
| | - Madivala G Basavaraj
- Polymer Engineering and Colloid Science Laboratory, Department of Chemical Engineering , Indian Institute of Technology , Madras, Chennai 600036 , India
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Wang Z, Wang Y. Tuning Amphiphilicity of Particles for Controllable Pickering Emulsion. MATERIALS (BASEL, SWITZERLAND) 2016; 9:E903. [PMID: 28774029 PMCID: PMC5457260 DOI: 10.3390/ma9110903] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/03/2016] [Accepted: 11/04/2016] [Indexed: 01/14/2023]
Abstract
Pickering emulsions with the use of particles as emulsifiers have been extensively used in scientific research and industrial production due to their edge in biocompatibility and stability compared with traditional emulsions. The control over Pickering emulsion stability and type plays a significant role in these applications. Among the present methods to build controllable Pickering emulsions, tuning the amphiphilicity of particles is comparatively effective and has attracted enormous attention. In this review, we highlight some recent advances in tuning the amphiphilicity of particles for controlling the stability and type of Pickering emulsions. The amphiphilicity of three types of particles including rigid particles, soft particles, and Janus particles are tailored by means of different mechanisms and discussed here in detail. The stabilization-destabilization interconversion and phase inversion of Pickering emulsions have been successfully achieved by changing the surface properties of these particles. This article provides a comprehensive review of controllable Pickering emulsions, which is expected to stimulate inspiration for designing and preparing novel Pickering emulsions, and ultimately directing the preparation of functional materials.
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Affiliation(s)
- Zhen Wang
- Department of Chemistry, Renmin University of China, Beijing 100872, China.
| | - Yapei Wang
- Department of Chemistry, Renmin University of China, Beijing 100872, China.
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Li Q, Jin S, Tan B. Template-mediated Synthesis of Hollow Microporous Organic Nanorods with Tunable Aspect Ratio. Sci Rep 2016; 6:31359. [PMID: 27506370 PMCID: PMC4979212 DOI: 10.1038/srep31359] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 07/18/2016] [Indexed: 12/02/2022] Open
Abstract
Hollow microporous organic nanorods (HMORs) with hypercrosslinked polymer (HCPs) shells were synthesized through emulsion polymerization followed by hypercrosslinking. The HMORs have tunable aspect ratios, high BET surface areas and monodispersed morphologies, showing good performance in gas adsorpion.
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Affiliation(s)
- Qingyin Li
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Shangbin Jin
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Bien Tan
- School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, 430074, China
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21
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Controlling Pickering Emulsion Destabilisation: A Route to Fabricating New Materials by Phase Inversion. MATERIALS 2016; 9:ma9080626. [PMID: 28773747 PMCID: PMC5509044 DOI: 10.3390/ma9080626] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 07/22/2016] [Accepted: 07/22/2016] [Indexed: 11/30/2022]
Abstract
The aim of this paper is to review the key findings about how particle-stabilised (or Pickering) emulsions respond to stress and break down. Over the last ten years, new insights have been gained into how particles attached to droplet (and bubble) surfaces alter the destabilisation mechanisms in emulsions. The conditions under which chemical demulsifiers displace, or detach, particles from the interface were established. Mass transfer between drops and the continuous phase was shown to disrupt the layers of particles attached to drop surfaces. The criteria for causing coalescence by applying physical stress (shear or compression) to Pickering emulsions were characterised. These findings are being used to design the structures of materials formed by breaking Pickering emulsions.
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Lou F, Ye L, Kong M, Yang Q, Li G, Huang Y. Pickering emulsions stabilized by shape-controlled silica microrods. RSC Adv 2016. [DOI: 10.1039/c6ra00360e] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Silica microrods with varying aspect ratios but similar surface characteristics are synthesized and their potential in preparing stable oil-in-water Pickering emulsions are explored.
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Affiliation(s)
- Fangli Lou
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering of China
- Sichuan University
- Chengdu 610065
- China
| | - Lishaya Ye
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering of China
- Sichuan University
- Chengdu 610065
- China
| | - Miqiu Kong
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering of China
- Sichuan University
- Chengdu 610065
- China
| | - Qi Yang
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering of China
- Sichuan University
- Chengdu 610065
- China
| | - Guangxian Li
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering of China
- Sichuan University
- Chengdu 610065
- China
| | - Yajiang Huang
- College of Polymer Science and Engineering
- State Key Laboratory of Polymer Materials Engineering of China
- Sichuan University
- Chengdu 610065
- China
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Davies GB, Botto L. Dipolar capillary interactions between tilted ellipsoidal particles adsorbed at fluid-fluid interfaces. SOFT MATTER 2015; 11:7969-76. [PMID: 26323324 DOI: 10.1039/c5sm01815c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Capillary interactions have emerged as a tool for the directed assembly of particles adsorbed at fluid-fluid interfaces, and play a role in controlling the mechanical properties of emulsions and foams. In this paper, following Davies et al. [Adv. Mater., 2014, 26, 6715] investigation into the assembly of ellipsoidal particles at interfaces interacting via dipolar capillary interactions, we numerically investigate the interaction between tilted ellipsoidal particles adsorbed at a fluid-fluid interface as their aspect ratio, tilt angle, bond angle, and separation vary. High-resolution Surface Evolver simulations of ellipsoidal particle pairs in contact reveal an energy barrier between a metastable tip-tip configuration and a stable side-side configuration. The side-side configuration is the global energy minimum for all parameters we investigated. Lattice Boltzmann simulations of clusters of up to 12 ellipsoidal particles show novel highly symmetric flower-like and ring-like arrangements.
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Affiliation(s)
- Gary B Davies
- Institute for Computational Physics, Allmandring 3, 70569 Stuttgart, Germany.
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