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Xie D, Jiang Y. The mediated rheological properties of emulsions stabilized by thread-like mesoporous silica nanoparticles in combination with CTAB. SOFT MATTER 2022; 18:7782-7793. [PMID: 36178243 DOI: 10.1039/d2sm01064j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The combination of hydrophilic particles and surfactants provides a simple method to stabilize Pickering emulsions. The type and concentration of the particles and surfactants play important roles in the microstructure and rheological properties of the resulting emulsions. Herein, stable n-octane-in-water Pickering emulsions with tunable rheological properties were prepared using thread-like mesoporous silica nanoparticles (TMSNPs) and cetyltrimethylammonium bromide (CTAB) as emulsifiers. The CTAB concentration (CCTAB) highly affected the properties of emulsions, which were divided into three regions according to the results of large-amplitude oscillatory shear responses. In the low CCTAB range (0.03 mmol L-1 ≤ CCTAB ≤ 0.1 mmol L-1), the emulsions gelled with a high storage modulus . With CCTAB increasing, the value of emulsions, measured by the small-amplitude oscillatory shear, decreased from approximately 1000 Pa at 0.03 mmol L-1 to 100 Pa at 0.3 mmol L-1 and then to 40 Pa at 3 mmol L-1. A three-dimensional percolation structure formed by cross-linking of TMSNPs in the emulsion continuous phase was observed via cryo-SEM in the low CCTAB range but not in the intermediate and high CCTAB ranges. The mechanisms showing the synergistic stability and rheological properties of these emulsions were investigated. It is attributed to the unique morphology of TMSNPs and the competitive adsorption of CTAB molecules at the oil-water interface and on the nanoparticle surface in different CCTAB ranges. Moreover, owing to the porosity and hydrogen-bonding interactions between the TMSNPs and the confinement effect of the flocculated oil droplets, the viscoelasticity of the emulsions could be mediated by adding a trace amount of acid/base. This study provides a new strategy to regulate the rheological properties of emulsions. It also expands the Pickering emulsion systems with tunable rheological properties.
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Affiliation(s)
- Danhua Xie
- Fujian Provincial Key Laboratory of Featured Biochemical and Chemical Materials, College of Chemistry and Materials, Ningde Normal University, Ningde 352100, Fujian, China.
| | - Yulong Jiang
- Fujian Provincial Key Laboratory of Featured Biochemical and Chemical Materials, College of Chemistry and Materials, Ningde Normal University, Ningde 352100, Fujian, China.
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Xie D, Jiang Y, Li K, Yang X, Zhang Y. Pickering Emulsions Stabilized by Mesoporous Nanoparticles with Different Morphologies in Combination with DTAB. ACS OMEGA 2022; 7:29153-29160. [PMID: 36033667 PMCID: PMC9404459 DOI: 10.1021/acsomega.2c03215] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 07/28/2022] [Indexed: 05/14/2023]
Abstract
The morphology of nanoparticles plays a significant role in the properties and applications of Pickering emulsions. Oil-in-water (O/W) Pickering emulsions were prepared using spherical, rod-like, and thread-like mesoporous silica nanoparticles (MSNPs) in combination with the cationic surfactant dodecyltrimethylammonium bromide (DTAB) as a stabilizer. The effects of nanoparticle morphology on the stability and stimuli-responsive properties of Pickering emulsions were investigated. For spherical and rod-like MSNP systems, stable Pickering emulsions were obtained at DTAB concentrations above 0.2 mmol·L-1. Stable Pickering emulsions containing thread-like MSNPs were produced at lower DTAB concentrations of approximately 0.1 mmol·L-1. The droplets with thread-like MSNPs were extremely large with an average diameter around 700 μm at DTAB concentrations of 0.1-0.3 mmol·L-1, which were approximately 20 times larger than those of conventional droplets. Scanning electron microscopy (SEM) images showed that all three types of MSNPs were located at the O/W interfaces. Irrespective of the morphology of the MSNPs, all the stable Pickering emulsions retained their original appearance for more than 6 months. By adding NaOH and HCl alternatively, the Pickering emulsions containing spherical and rod-like MSNPs could be switched between unstable and stable states more than 60 times. The Pickering emulsions containing thread-like MSNPs, by contrast, could have their droplet size switched between large and small more than 10 times without any obvious phase separation. The high anisotropy of thread-like MSNPs contributed to the low interface curvature of the droplets. This study revealed the relationship between the morphology of MSNPs and the characteristics of Pickering emulsions. These results enrich our knowledge about the formulation of Pickering emulsions and expand their applications.
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Xie D, Jiang Y, Song B, Yang X. Switchable Pickering foams stabilized by mesoporous nanosilica hydrophobized in situ with a Gemini surfactant. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ni L, Yu C, Wei Q, Liu D, Qiu J. Pickering Emulsion Catalysis: Interfacial Chemistry, Catalyst Design, Challenges, and Perspectives. Angew Chem Int Ed Engl 2022; 61:e202115885. [PMID: 35524649 DOI: 10.1002/anie.202115885] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Indexed: 12/17/2022]
Abstract
Pickering emulsions are particle-stabilized surfactant-free dispersions composed of two immiscible liquid phases, and emerge as attractive catalysis platform to surpass traditional technique barrier in some cases. In this review, we have comprehensively summarized the development and the catalysis applications of Pickering emulsions since the pioneering work in 2010. The explicit mechanism for Pickering emulsions will be initially discussed and clarified. Then, summarization is given to the design strategy of amphiphilic emulsion catalysts in two categories of intrinsic and extrinsic amphiphilicity. The progress of the unconventional catalytic reactions in Pickering emulsion is further described, especially for the polarity/solubility difference-driven phase segregation, "smart" emulsion reaction system, continuous flow catalysis, and Pickering interfacial biocatalysis. Challenges and future trends for the development of Pickering emulsion catalysis are finally outlined.
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Affiliation(s)
- Lin Ni
- State Key Lab of Fine Chemicals, School of Chemical Engineering, Liaoning Key Lab for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, P.R. China
| | - Chang Yu
- State Key Lab of Fine Chemicals, School of Chemical Engineering, Liaoning Key Lab for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, P.R. China
| | - Qianbing Wei
- State Key Lab of Fine Chemicals, School of Chemical Engineering, Liaoning Key Lab for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, P.R. China
| | - Dongming Liu
- State Key Lab of Fine Chemicals, School of Chemical Engineering, Liaoning Key Lab for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, P.R. China
| | - Jieshan Qiu
- State Key Lab of Fine Chemicals, School of Chemical Engineering, Liaoning Key Lab for Energy Materials and Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, P.R. China.,State Key Lab of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
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Zhang L, Zhang G, Ge J, Jiang P, Ding L. pH- and thermo-responsive Pickering emulsion stabilized by silica nanoparticles and conventional nonionic copolymer surfactants. J Colloid Interface Sci 2022; 616:129-140. [DOI: 10.1016/j.jcis.2022.02.067] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/11/2022] [Accepted: 02/16/2022] [Indexed: 11/30/2022]
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Ni L, Yu C, Wei Q, Liu D, Qiu J. Pickering Emulsion Catalysis: Interfacial Chemistry, Catalyst Design, Challenges, and Perspectives. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202115885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Lin Ni
- Dalian University of Technology School of Chemical Engineering CHINA
| | - Chang Yu
- Dalian University of Technology School of Chemical Engineering CHINA
| | - Qianbing Wei
- Dalian University of Technology School of Chemical Engineering CHINA
| | - Dongming Liu
- Dalian University of Technology School of Chemical Engineering CHINA
| | - Jieshan Qiu
- Dalian University of Technology School of Chemical Engineering High Technology Zone, No. 2 Ling Gong Road 116024 Dalian CHINA
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