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Chan DHH, Hunter SJ, Neal TJ, Lindsay C, Taylor P, Armes SP. Adsorption of sterically-stabilized diblock copolymer nanoparticles at the oil-water interface: effect of charged end-groups on interfacial rheology. SOFT MATTER 2022; 18:6757-6770. [PMID: 36040127 DOI: 10.1039/d2sm00835a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The RAFT aqueous emulsion polymerization of either methyl methacrylate (MMA) or benzyl methacrylate (BzMA) is conducted at 70 °C using poly(glycerol monomethacrylate) (PGMA) as a water-soluble precursor to produce sterically-stabilized diblock copolymer nanoparticles of approximately 30 nm diameter. Carboxylic acid- or morpholine-functional RAFT agents are employed to confer anionic or cationic functionality at the ends of the PGMA stabilizer chains, with a neutral RAFT agent being used as a control. Thus the electrophoretic footprint of such minimally-charged model nanoparticles can be adjusted simply by varying the solution pH. Giant (mm-sized) aqueous droplets containing such nanoparticles are then grown within a continuous phase of n-dodecane and a series of interfacial rheology measurements are conducted. The interfacial tension between the aqueous phase and n-dodecane is strongly dependent on the charge of the terminal group on the stabilizer chains. More specifically, neutral nanoparticles produce a significantly lower interfacial tension than either cationic or anionic nanoparticles. Moreover, adsorption of neutral nanoparticles at the n-dodecane-water interface produces higher interfacial elastic moduli than that observed for charged nanoparticles. This is because neutral nanoparticles can adsorb at much higher surface packing densities owing to the absence of electrostatic repulsive forces in this case.
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Affiliation(s)
- Derek H H Chan
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK.
| | - Saul J Hunter
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK.
| | - Thomas J Neal
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK.
| | - Christopher Lindsay
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK.
| | - Philip Taylor
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK.
| | - Steven P Armes
- Dainton Building, Department of Chemistry, University of Sheffield, Brook Hill, Sheffield, South Yorkshire, S3 7HF, UK.
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Kim H, Park D, Jiang Z, Wei Y, Woong Kim J. Microfluidic macroemulsion stabilization through in situ interfacial coacervation of associative nanoplatelets and polyelectrolytes. J Colloid Interface Sci 2022; 614:574-582. [PMID: 35121516 DOI: 10.1016/j.jcis.2022.01.082] [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: 11/09/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 11/24/2022]
Abstract
HYPOTHESIS Since macroemulsions tend to break down to lower free energy, they hardly retain their initial drop state. Therefore, studies are being conducted to overcome this based on advanced interface engineering techniques, but it is still challenging. Herein we hypothesize that the stability of giant droplets can be secured without chemical bonding through the interfacial coacervation of polyelectrolyte and associative nanoplatelets. EXPERIMENTS We synthesized associative silica nanoplates (ASNPs) via polypeptide-templated silicification and consecutive wettability adjustment. To produce monodisperse macrodroplets, the inner fluid containing partially positively charged ASNPs and the outer fluid dissolving negatively charged polyacrylic acid (PAA) were coflowed through a capillary-based microfluidic channel. FINDINGS Dynamic interfacial tension and interfacial rheology measurements revealed that the migration of ASNPs and PAA from each phase to the interface led to the formation of a complex bilayered thin membrane with an enhanced interfacial modulus. In addition, we demonstrated that adjusting the surface properties of ASNPs by coupling a fluorochemical enabled the production of monodisperse fluorocarbon-in-oil-in-water double macroemulsions. These results highlighted the applicability of our microfluidics-based interfacial coacervation technology in the development of complex fluid products with visual differentiation and drug encapsulation.
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Affiliation(s)
- Hajeong Kim
- School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Daehwan Park
- School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Zhiting Jiang
- BASF Advanced Chemicals CO., Ltd., Shanghai 200137, China
| | - Ying Wei
- BASF Advanced Chemicals CO., Ltd., Shanghai 200137, China
| | - Jin Woong Kim
- School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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Gao Y, Xiang Z, Zhao X, Wang G, Qi C. Pickering Emulsions Stabilized by Diblock Copolymer Worms Prepared via Reversible Addition-Fragmentation Chain Transfer Aqueous Dispersion Polymerization: How Does the Stimulus Sensitivity Affect the Rate of Demulsification? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11695-11706. [PMID: 34579524 DOI: 10.1021/acs.langmuir.1c01609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Responsive Pickering emulsions exhibit promising application in industry owing to the integration of the high storage stability with on-demand demulsification. In this study, stimuli-responsive Pickering emulsions stabilized by poly[oligo(ethylene glycol) methyl ether methacrylate]15-b-poly(diacetone acrylamide)120 (E15D120) worms were indicated, in which E15D120 worms were prepared via reversible addition-fragmentation chain transfer-based aqueous dispersion polymerization using thermo-sensitive POEGMA15 as both the stabilizer block and macro-chain transfer agent. The factors influencing the morphologies of copolymers during polymerization-induced self assembly have been investigated. A series of different morphological polymer nanoparticles including spheres, worms, and vesicles could be produced through rational synthesis. E15D120 worms demonstrated excellent emulsifying performances and could be used as emulsifiers to form n-dodecane-in-water Pickering emulsions at a low content. The formed n-dodecane-in-water Pickering emulsions revealed a slow demulsification at pH 10 or 70 °C or pH 10/70 °C combinations, and several hours were needed for the demulsification of Pickering emulsions. However, n-dodecane-in-water Pickering emulsions displayed a rapid demulsification (∼10 min) at an elevated temperature, such as 90 °C. The different demulsification rates were attributed to different sensitivities of E15D120 worms to external stimuli. Pickering emulsions integrating a rapid responsive demulsification with a slow one would be well satisfactory on different occasions.
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Affiliation(s)
- Yong Gao
- Key Laboratory of Alternative Technologies for Fine Chemicals Process of Zhejiang Province, College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, Zhejiang 312000, China
- College of Chemistry and Key Lab of Environment-Friendly Chemistry and Application in Ministry of Education; Key Laboratory of Polymeric Materials & Application Technology of Hunan Province, Key Laboratory of Advanced Functional Polymeric Materials of College of Hunan Province, Xiangtan University, Xiangtan, Hunan Province 411105, China
| | - Zhe Xiang
- College of Chemistry and Key Lab of Environment-Friendly Chemistry and Application in Ministry of Education; Key Laboratory of Polymeric Materials & Application Technology of Hunan Province, Key Laboratory of Advanced Functional Polymeric Materials of College of Hunan Province, Xiangtan University, Xiangtan, Hunan Province 411105, China
| | - Xi Zhao
- Key Laboratory of Alternative Technologies for Fine Chemicals Process of Zhejiang Province, College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, Zhejiang 312000, China
- College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang, Hunan Province 414006, China
| | - Guoxiang Wang
- College of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang, Hunan Province 414006, China
| | - Chenze Qi
- Key Laboratory of Alternative Technologies for Fine Chemicals Process of Zhejiang Province, College of Chemistry and Chemical Engineering, Shaoxing University, Shaoxing, Zhejiang 312000, China
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Hunter SJ, Armes SP. Pickering Emulsifiers Based on Block Copolymer Nanoparticles Prepared by Polymerization-Induced Self-Assembly. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:15463-15484. [PMID: 33325720 PMCID: PMC7884006 DOI: 10.1021/acs.langmuir.0c02595] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/27/2020] [Indexed: 05/28/2023]
Abstract
Block copolymer nanoparticles prepared via polymerization-induced self-assembly (PISA) represent an emerging class of organic Pickering emulsifiers. Such nanoparticles are readily prepared by chain-extending a soluble homopolymer precursor using a carefully selected second monomer that forms an insoluble block in the chosen solvent. As the second block grows, it undergoes phase separation that drives in situ self-assembly to form sterically stabilized nanoparticles. Conducting such PISA syntheses in aqueous solution leads to hydrophilic nanoparticles that enable the formation of oil-in-water emulsions. Alternatively, hydrophobic nanoparticles can be prepared in non-polar media (e.g., n-alkanes), which enables water-in-oil emulsions to be produced. In this review, the specific advantages of using PISA to prepare such bespoke Pickering emulsifiers are highlighted, which include fine control over particle size, copolymer morphology, and surface wettability. This has enabled various fundamental scientific questions regarding Pickering emulsions to be addressed. Moreover, block copolymer nanoparticles can be used to prepare Pickering emulsions over various length scales, with mean droplet diameters ranging from millimeters to less than 200 nm.
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Affiliation(s)
- Saul J. Hunter
- Department of Chemistry,
Dainton Building, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
| | - Steven P. Armes
- Department of Chemistry,
Dainton Building, University of Sheffield, Brook Hill, Sheffield, South Yorkshire S3 7HF, U.K.
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Llamas S, Ponce Torres A, Liggieri L, Santini E, Ravera F. Surface properties of binary TiO2 - SiO2 nanoparticle dispersions relevant for foams stabilization. Colloids Surf A Physicochem Eng Asp 2019. [DOI: 10.1016/j.colsurfa.2019.05.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhang L, Lei Q, Luo J, Zeng M, Wang L, Huang D, Wang X, Mannan S, Peng B, Cheng Z. Natural Halloysites-Based Janus Platelet Surfactants for the Formation of Pickering Emulsion and Enhanced Oil Recovery. Sci Rep 2019; 9:163. [PMID: 30655562 PMCID: PMC6336865 DOI: 10.1038/s41598-018-36352-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 11/05/2018] [Indexed: 11/23/2022] Open
Abstract
Janus colloidal surfactants with opposing wettabilities are receiving attention for their practical application in industry. Combining the advantages of molecular surfactants and particle-stabilized Pickering emulsions, Janus colloidal surfactants generate remarkably stable emulsions. Here we report a straightforward and cost-efficient strategy to develop Janus nanoplate surfactants (JNPS) from an aluminosilicate nanoclay, halloysite, by stepwise surface modification, including an innovative selective surface modification step. Such colloidal surfactants are found to be able to stabilize Pickering emulsions of different oil/water systems. The microstructural characterization of solidified polystyrene emulsions indicates that the emulsion interface is evenly covered by JNPS. The phase behaviors of water/oil emulsion generated by these novel platelet surfactants were also investigated. Furthermore, we demonstrate the application of JNPS for enhanced oil recovery with a microfluidic flooding test, showing a dramatic increase of oil recovery ratio. This research provides important insights for the design and synthesis of two-dimensional Janus colloidal surfactants, which could be utilized in biomedical, food and mining industries, especially for circumstances where high salinity and high temperature are involved.
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Affiliation(s)
- Lecheng Zhang
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA.,Mary Kay O'Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA
| | - Qun Lei
- Research Institute of Petroleum Exploration & Development (RIPED), PetroChina, Beijing, 100083, China
| | - Jianhui Luo
- Research Institute of Petroleum Exploration & Development (RIPED), PetroChina, Beijing, 100083, China.,Key Laboratory of Nano Chemistry (KLNC), CNPC, Beijing, 100083, China
| | - Minxiang Zeng
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA
| | - Ling Wang
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA
| | - Dali Huang
- Department of Materials Science & Engineering, Texas A&M University, College Station, TX, 77843-3003, USA
| | - Xuezhen Wang
- Mary Kay O'Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA
| | - Sam Mannan
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA.,Mary Kay O'Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA
| | - Baoliang Peng
- Research Institute of Petroleum Exploration & Development (RIPED), PetroChina, Beijing, 100083, China. .,Key Laboratory of Nano Chemistry (KLNC), CNPC, Beijing, 100083, China.
| | - Zhengdong Cheng
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA. .,Mary Kay O'Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, TX, 77843-3122, USA. .,Department of Materials Science & Engineering, Texas A&M University, College Station, TX, 77843-3003, USA.
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Kaptay G. On the Negative Surface Tension of Solutions and on Spontaneous Emulsification. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:10550-10560. [PMID: 28918625 DOI: 10.1021/acs.langmuir.7b01968] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The condition of negative surface tension of a binary regular solution is discussed in this paper using the recently reconfirmed Butler equation (Langmuir 2015, 31, 5796-5804). It is shown that the surface tension becomes negative only for solutions with strong repulsion between the components. This repulsion for negative surface tension should be so strong that this phenomenon appears only within a miscibility gap, that is, in a two-phase region of macroscopic liquid solutions. Thus, for a macroscopic solution, the negative surface tension is possible only in a nonequilibrium state. However, for a nano-solution, negative surface tension is also possible in equilibrium state. It is also shown that nano- and microemulsions can be thermodynamically stable against both coalescence and phase separation. Further, the thermodynamic theory of emulsion stability is developed for a three-component (A-B-C) system with A-rich droplets dispersed in a C-rich matrix, separated by the segregated B-rich layer (the solubility of B is limited in both A and C while the mutual solubility of A and C is neglected). It is shown that when a critical droplet size is achieved by forced emulsification, it is replaced by spontaneous emulsification and the droplet size is reduced further to its equilibrium value. The existence of maximum temperature of emulsion stability is shown. Using low-energy emulsification below this maximum temperature, spontaneous emulsification can appear, which is enhanced with further decrease of temperature. This finding can be applied to interpret the experimental observations on spontaneous emulsification or for the design of stable micro- and nanoemulsions.
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Affiliation(s)
- George Kaptay
- Department of Nanotechnology, University of Miskolc , Egyetemvaros, Miskolc 3515, Hungary
- MTA-ME Materials Science Research Group , Egyetemvaros, Miskolc 3515, Hungary
- Bay Zoltan Ltd on Applied Research, BAY-ENG , 2 Igloi, Miskolc 3519, Hungary
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